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  • Question 1 - A 25-year-old individual visits a maxillofacial clinic complaining of facial pain that has...

    Correct

    • A 25-year-old individual visits a maxillofacial clinic complaining of facial pain that has persisted for 3 months after sustaining a basal skull fracture in a car accident. According to neuroimaging reports, where is the lesion most likely located, indicating damage to the maxillary nerve as it traverses the sphenoid bone?

      Your Answer: Foramen rotundum

      Explanation:

      The correct location for the passage of the maxillary nerve is the foramen rotundum. In the case of a basal skull fracture involving the sphenoid bone, the lesion is most likely located in the foramen rotundum. The foramen ovale is not the correct location as it is where the mandibular nerve passes through. The foramen spinosum is also not the correct location as it transmits the middle meningeal artery and vein, not the maxillary nerve. The hypoglossal canal is also not the correct location as it transmits the twelfth cranial nerve, not the maxillary nerve.

      Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.

      In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.

    • This question is part of the following fields:

      • Neurological System
      59.2
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  • Question 2 - A 28-year-old woman has been brought to the emergency department via ambulance after...

    Incorrect

    • A 28-year-old woman has been brought to the emergency department via ambulance after being discovered unconscious in a nearby park, with a heroin-filled needle found nearby.

      During the examination, the patient's heart rate is recorded at 44/min, BP at 110/60 mmHg, and respiratory rate at 10. Upon checking her pupils, they are observed to be pinpoint.

      Which three G protein-coupled receptors are affected by the drug responsible for this?

      Your Answer: GABA-A, delta and mu

      Correct Answer: Delta, mu and kappa

      Explanation:

      The three clinically relevant opioid receptors in the body are delta, mu, and kappa. These receptors are all G protein-coupled receptors and are responsible for the pharmacological actions of opioids. Based on the examination findings of bradycardia, bradypnoea, and pinpoint pupils, it is likely that the woman has experienced an opioid overdose. The answer GABA-A, delta and mu is not appropriate as the GABA-A receptor is a ligand-gated ion channel receptor for the inhibitory neurotransmitter GABA. Similarly, GABA-A, kappa and mu is not appropriate for the same reason. GABA-B, D-2 and kappa is also not appropriate as the GABA-B receptor is a G-protein-coupled receptor for the inhibitory neurotransmitter GABA, and the D-2 receptor is a G protein-coupled receptor for dopamine.

      Understanding Opioids: Types, Receptors, and Clinical Uses

      Opioids are a class of chemical compounds that act upon opioid receptors located within the central nervous system (CNS). These receptors are G-protein coupled receptors that have numerous actions throughout the body. There are three clinically relevant groups of opioid receptors: mu (µ), kappa (κ), and delta (δ) receptors. Endogenous opioids, such as endorphins, dynorphins, and enkephalins, are produced by specific cells within the CNS and their actions depend on whether µ-receptors or δ-receptors and κ-receptors are their main target.

      Drugs targeted at opioid receptors are the largest group of analgesic drugs and form the second and third steps of the WHO pain ladder of managing analgesia. The choice of which opioid drug to use depends on the patient’s needs and the clinical scenario. The first step of the pain ladder involves non-opioids such as paracetamol and non-steroidal anti-inflammatory drugs. The second step involves weak opioids such as codeine and tramadol, while the third step involves strong opioids such as morphine, oxycodone, methadone, and fentanyl.

      The strength, routes of administration, common uses, and significant side effects of these opioid drugs vary. Weak opioids have moderate analgesic effects without exposing the patient to as many serious adverse effects associated with strong opioids. Strong opioids have powerful analgesic effects but are also more liable to cause opioid-related side effects such as sedation, respiratory depression, constipation, urinary retention, and addiction. The sedative effects of opioids are also useful in anesthesia with potent drugs used as part of induction of a general anesthetic.

    • This question is part of the following fields:

      • Neurological System
      1131.6
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  • Question 3 - A 23-year-old man is in a physical altercation resulting in a skull fracture...

    Correct

    • A 23-year-old man is in a physical altercation resulting in a skull fracture and damage to the middle meningeal artery. After undergoing a craniotomy, the bleeding from the artery is successfully stopped through ligation near its origin. What sensory impairment is the patient most likely to experience after the operation?

      Your Answer: Parasthesia of the ipsilateral external ear

      Explanation:

      The middle meningeal artery is in close proximity to the auriculotemporal nerve, which could potentially be harmed in this situation. This nerve is responsible for providing sensation to the outer ear and the outer layer of the tympanic membrane. The C2,3 roots innervate the jaw angle and would not be impacted. The glossopharyngeal nerve is responsible for supplying the tongue.

      The Middle Meningeal Artery: Anatomy and Clinical Significance

      The middle meningeal artery is a branch of the maxillary artery, which is one of the two terminal branches of the external carotid artery. It is the largest of the three arteries that supply the meninges, the outermost layer of the brain. The artery runs through the foramen spinosum and supplies the dura mater. It is located beneath the pterion, where the skull is thin, making it vulnerable to injury. Rupture of the artery can lead to an Extradural hematoma.

      In the dry cranium, the middle meningeal artery creates a deep indentation in the calvarium. It is intimately associated with the auriculotemporal nerve, which wraps around the artery. This makes the two structures easily identifiable in the dissection of human cadavers and also easily damaged in surgery.

      Overall, understanding the anatomy and clinical significance of the middle meningeal artery is important for medical professionals, particularly those involved in neurosurgery.

    • This question is part of the following fields:

      • Neurological System
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  • Question 4 - As a doctor on a 4-month placement in intensive care, you admit a...

    Correct

    • As a doctor on a 4-month placement in intensive care, you admit a 32-year-old man following a closed head injury sustained in a road traffic accident. The patient has no past medical history and initially presents with a Glasgow coma score of 14/15 and no focal neurological deficit. Invasive monitoring is undertaken, and his heart rate, blood pressure, and intracranial pressure are normal. He is started on maintenance intravenous fluids.

      However, a few hours later, the patient becomes agitated and confused, and his Glasgow coma score drops to 11/15. His observations reveal a regular heart rate of 101 beats per minute, a blood pressure of 161/89 mmHg, and an intracranial pressure of 18 mmHg. Which pathophysiological changes could explain his clinical deterioration and hypertension?

      Your Answer: Rise in intracranial pressure causing fall in cerebral perfusion pressure

      Explanation:

      When intracranial pressure (ICP) rises rapidly, it can lead to a decrease in cerebral perfusion pressure (CPP). This can occur in individuals with head injuries, as seen in the scenario where a patient’s Glasgow coma score dropped from 14/15 to 11/15 and they became agitated. The patient’s ICP also increased to 18 mmHg, likely due to brain swelling or a hematoma. The decrease in CPP can cause hypoperfusion and hypoxia in normal brain tissue, leading to neurological deterioration. CPP is calculated by subtracting ICP from mean arterial pressure. As a result of the decrease in CPP, the body may respond by increasing mean arterial pressure, resulting in hypertension in the patient.

      Understanding Cerebral Perfusion Pressure

      Cerebral perfusion pressure (CPP) refers to the pressure gradient that drives blood flow to the brain. It is a crucial factor in maintaining optimal cerebral perfusion, which is tightly regulated by the body. Any sudden increase in CPP can lead to a rise in intracranial pressure (ICP), while a decrease in CPP can result in cerebral ischemia. To calculate CPP, one can subtract the ICP from the mean arterial pressure.

      In cases of trauma, it is essential to carefully monitor and control CPP. This may require invasive methods to measure both ICP and mean arterial pressure (MAP). By doing so, healthcare professionals can ensure that the brain receives adequate blood flow and oxygenation, which is vital for optimal brain function. Understanding CPP is crucial in managing traumatic brain injuries and other conditions that affect cerebral perfusion.

    • This question is part of the following fields:

      • Neurological System
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  • Question 5 - A 49-year-old man is admitted to the neurology ward following a subarachnoid haemorrhage....

    Correct

    • A 49-year-old man is admitted to the neurology ward following a subarachnoid haemorrhage. The neurologist inserts an intraventricular catheter to monitor the patient's intracranial pressure (ICP) as part of their ongoing monitoring.

      Which of the following values would be considered pathological in this setting?

      Your Answer: 21 mmHg

      Explanation:

      Subarachnoid haemorrhage often leads to increased intracranial pressure, which requires careful monitoring in a hospital setting. The normal range for intracranial pressure is between 7 and 15 mmHg, and any readings above 20 mmHg require immediate intervention.

      Since the brain is enclosed in a fixed space within the skull, there is little room for additional substances such as blood, tissue, or cerebrospinal fluid before intracranial pressure rises rapidly. In subarachnoid haemorrhage, the haematoma’s mass effect can cause increased intracranial pressure.

      Other causes of increased intracranial pressure include meningitis, trauma, and idiopathic presentations. Symptoms of increased intracranial pressure include headache, vomiting, altered consciousness, and Cushing’s triad (widening pulse pressure, bradycardia, irregular breathing).

      Management of increased intracranial pressure should be tailored to the underlying cause. The first-line treatment involves elevating the head to 30º, and more severe cases may require intravenous mannitol to lower intracranial pressure.

      Understanding Raised Intracranial Pressure

      As the brain and ventricles are enclosed by a rigid skull, any additional volume such as haematoma, tumour, or excessive cerebrospinal fluid (CSF) can lead to a rise in intracranial pressure (ICP). The normal ICP in adults in the supine position is 7-15 mmHg. Cerebral perfusion pressure (CPP) is the net pressure gradient causing cerebral blood flow to the brain, and it is calculated by subtracting ICP from mean arterial pressure.

      Raised intracranial pressure can be caused by various factors such as idiopathic intracranial hypertension, traumatic head injuries, infection, meningitis, tumours, and hydrocephalus. Its features include headache, vomiting, reduced levels of consciousness, papilloedema, and Cushing’s triad, which is characterized by widening pulse pressure, bradycardia, and irregular breathing.

      To investigate raised intracranial pressure, neuroimaging such as CT or MRI is key to determine the underlying cause. Invasive ICP monitoring can also be done by placing a catheter into the lateral ventricles of the brain to monitor the pressure, collect CSF samples, and drain small amounts of CSF to reduce the pressure. A cut-off of > 20 mmHg is often used to determine if further treatment is needed to reduce the ICP.

      Management of raised intracranial pressure involves investigating and treating the underlying cause, head elevation to 30º, IV mannitol as an osmotic diuretic, controlled hyperventilation to reduce pCO2 and vasoconstriction of the cerebral arteries, and removal of CSF through techniques such as drain from intraventricular monitor, repeated lumbar puncture, or ventriculoperitoneal shunt for hydrocephalus.

    • This question is part of the following fields:

      • Neurological System
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  • Question 6 - A 31-year-old woman is seeking advice at the family planning clinic as she...

    Correct

    • A 31-year-old woman is seeking advice at the family planning clinic as she plans to start a family soon. She has been researching medications that may harm her baby's growth during pregnancy, especially those that can cause cleft palate and heart defects. Her concerns stem from her friend's experience with her baby being born with these conditions. Can you identify the drug that is linked to cleft palate and congenital heart disease?

      Your Answer: Phenytoin

      Explanation:

      Phenytoin is linked to the development of cleft palate and congenital heart disease, making it a known teratogenic substance.

      Insulin and acetaminophen are considered safe for use during pregnancy and are not known to have any harmful effects on the developing fetus.

      Warfarin, on the other hand, is known to be teratogenic and may cause defects in the hands, nose, and eyes, as well as growth retardation. However, it is not associated with cleft palate or congenital heart disease.

      Tetracyclines can cause discoloration of the teeth and bone defects due to their deposition in these tissues.

      Understanding the Adverse Effects of Phenytoin

      Phenytoin is a medication commonly used to manage seizures. Its mechanism of action involves binding to sodium channels, which increases their refractory period. However, the drug is associated with a large number of adverse effects that can be categorized as acute, chronic, idiosyncratic, and teratogenic.

      Acute adverse effects of phenytoin include dizziness, diplopia, nystagmus, slurred speech, ataxia, confusion, and seizures. Chronic adverse effects may include gingival hyperplasia, hirsutism, coarsening of facial features, drowsiness, megaloblastic anemia, peripheral neuropathy, enhanced vitamin D metabolism causing osteomalacia, lymphadenopathy, and dyskinesia.

      Idiosyncratic adverse effects of phenytoin may include fever, rashes, including severe reactions such as toxic epidermal necrolysis, hepatitis, Dupuytren’s contracture, aplastic anemia, and drug-induced lupus. Finally, teratogenic adverse effects of phenytoin are associated with cleft palate and congenital heart disease.

      It is important to note that phenytoin is also an inducer of the P450 system. While routine monitoring of phenytoin levels is not necessary, trough levels should be checked immediately before a dose if there is a need for adjustment of the phenytoin dose, suspected toxicity, or detection of non-adherence to the prescribed medication.

    • This question is part of the following fields:

      • Neurological System
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  • Question 7 - A 20-year-old man visits the clinic with a complaint of ear pain that...

    Incorrect

    • A 20-year-old man visits the clinic with a complaint of ear pain that started two days ago. He mentions that the pain has reduced considerably, but there is a lot of discharge and he cannot hear from the affected ear. During the examination, you observe a perforated tympanic membrane and yellow discharge in the external auditory canal. Based on the symptoms, you suspect a middle ear infection that led to fluid buildup and subsequent perforation of the tympanic membrane. In this context, which nerve branch innervates the stapedius muscle located in the middle ear?

      Note: The changes made are minimal and do not affect the meaning or context of the original text.

      Your Answer: Vestibulocochlear nerve

      Correct Answer: Facial nerve

      Explanation:

      The correct answer is the facial nerve, the seventh cranial nerve. Other nerves mentioned include the vestibulocochlear nerve, maxillary nerve, glossopharyngeal nerve, and mandibular nerve. The stapedius muscle, innervated by the facial nerve, is also discussed. The patient’s ear pain could be due to a perforated eardrum caused by infection.

      The facial nerve is responsible for supplying the muscles of facial expression, the digastric muscle, and various glandular structures. It also contains a few afferent fibers that originate in the genicular ganglion and are involved in taste. Bilateral facial nerve palsy can be caused by conditions such as sarcoidosis, Guillain-Barre syndrome, Lyme disease, and bilateral acoustic neuromas. Unilateral facial nerve palsy can be caused by these conditions as well as lower motor neuron issues like Bell’s palsy and upper motor neuron issues like stroke.

      The upper motor neuron lesion typically spares the upper face, specifically the forehead, while a lower motor neuron lesion affects all facial muscles. The facial nerve’s path includes the subarachnoid path, where it originates in the pons and passes through the petrous temporal bone into the internal auditory meatus with the vestibulocochlear nerve. The facial canal path passes superior to the vestibule of the inner ear and contains the geniculate ganglion at the medial aspect of the middle ear. The stylomastoid foramen is where the nerve passes through the tympanic cavity anteriorly and the mastoid antrum posteriorly, and it also includes the posterior auricular nerve and branch to the posterior belly of the digastric and stylohyoid muscle.

    • This question is part of the following fields:

      • Neurological System
      89.2
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  • Question 8 - A 5-year-old child is brought to the pediatric clinic by their mother. The...

    Incorrect

    • A 5-year-old child is brought to the pediatric clinic by their mother. The child was born to a mother with gestational diabetes and had a difficult delivery due to shoulder dystocia. During the physical examination, the doctor observes paralysis of the intrinsic hand muscles. The doctor suspects the child has Klumpke's paralysis. What is commonly associated with this presentation?

      Your Answer: Anterior cord syndrome

      Correct Answer: Horner's syndrome

      Explanation:

      Klumpke’s paralysis is not associated with Horner’s syndrome. It is caused by injury to the brachial plexus, specifically nerve roots C8-T1, and results in paralysis of the intrinsic hand muscles, weakness of wrist flexion, and movement of the fingers. When the T1 nerve root is affected, there may be an associated injury to the sympathetic chain, which can lead to symptoms of Horner’s syndrome such as partial ptosis, miosis, enophthalmos, and anhidrosis.

      Anterior cord syndrome, Brown-Séquard syndrome, and central cord syndrome are all incorrect as they are not associated with Klumpke’s paralysis. Anterior cord syndrome causes motor paralysis and loss of pain and temperature sensation below the lesion, and is caused by ischaemia of the anterior spinal artery. Brown-Séquard syndrome is caused by a hemisection of the spinal cord due to traumatic injury, and central cord syndrome is the most common cervical cord injury that causes motor impairment of the upper limbs, usually due to trauma or osteoarthritis.

      Horner’s syndrome is a condition characterized by several features, including a small pupil (miosis), drooping of the upper eyelid (ptosis), a sunken eye (enophthalmos), and loss of sweating on one side of the face (anhidrosis). The cause of Horner’s syndrome can be determined by examining additional symptoms. For example, congenital Horner’s syndrome may be identified by a difference in iris color (heterochromia), while anhidrosis may be present in central or preganglionic lesions. Pharmacologic tests, such as the use of apraclonidine drops, can also be helpful in confirming the diagnosis and identifying the location of the lesion. Central lesions may be caused by conditions such as stroke or multiple sclerosis, while postganglionic lesions may be due to factors like carotid artery dissection or cluster headaches. It is important to note that the appearance of enophthalmos in Horner’s syndrome is actually due to a narrow palpebral aperture rather than true enophthalmos.

    • This question is part of the following fields:

      • Neurological System
      64.5
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  • Question 9 - A 65-year-old man presents to the hospital with a 3-day history of headaches....

    Incorrect

    • A 65-year-old man presents to the hospital with a 3-day history of headaches. He has a medical history of type 2 diabetes mellitus and hypertension.

      During the examination, it is observed that his left pupil is constricted with enophthalmos and ptosis of the left eyelid. However, the right side of his face appears to be unaffected.

      What could be the probable reason for this patient's symptoms?

      Your Answer: Uncal herniation

      Correct Answer: Carotid artery dissection

      Explanation:

      Carotid artery dissection is the likely cause of the patient’s Horner’s syndrome, which presents with ptosis, enophthalmos, and miosis. This syndrome occurs when there is damage to the cervical sympathetic chain, resulting in the loss of sympathetic innervation to the head and neck. The patient’s history of hypertension and headache further support this diagnosis.

      Facial nerve schwannoma is an incorrect diagnosis, as it would present with facial nerve palsy rather than Horner’s syndrome.

      Microvascular oculomotor nerve palsy is also an incorrect diagnosis, as it typically presents with complete ptosis and an eye that is turned outwards and downwards, without pupil dilatation.

      Uncal herniation is another incorrect diagnosis, as it can cause an oculomotor nerve palsy with pupillary involvement, but typically presents with a ‘down and out’ facing eye, rather than Horner’s syndrome.

      Horner’s syndrome is a condition characterized by several features, including a small pupil (miosis), drooping of the upper eyelid (ptosis), a sunken eye (enophthalmos), and loss of sweating on one side of the face (anhidrosis). The cause of Horner’s syndrome can be determined by examining additional symptoms. For example, congenital Horner’s syndrome may be identified by a difference in iris color (heterochromia), while anhidrosis may be present in central or preganglionic lesions. Pharmacologic tests, such as the use of apraclonidine drops, can also be helpful in confirming the diagnosis and identifying the location of the lesion. Central lesions may be caused by conditions such as stroke or multiple sclerosis, while postganglionic lesions may be due to factors like carotid artery dissection or cluster headaches. It is important to note that the appearance of enophthalmos in Horner’s syndrome is actually due to a narrow palpebral aperture rather than true enophthalmos.

    • This question is part of the following fields:

      • Neurological System
      166.2
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  • Question 10 - A 42-year-old female arrives at the emergency department with sudden onset of drooping...

    Incorrect

    • A 42-year-old female arrives at the emergency department with sudden onset of drooping on the right side of her mouth. She is unable to smile on the right-hand side but can frown and lift her eyebrows. The patient has a medical history of asthma and has experienced four miscarriages in the past. She does not smoke and drinks alcohol moderately on weekends. Based on this information, what is the probable diagnosis?

      Your Answer: Bell's palsy

      Correct Answer: Stroke

      Explanation:

      If a facial palsy only affects the lower face and spares the forehead, it is likely caused by an upper motor neuron (UMN) lesion. In this case, stroke is the most probable cause of the UMN lesion. However, the patient’s young age and social history make stroke less likely. The patient’s history of multiple miscarriages suggests antiphospholipid syndrome, which is a significant risk factor for stroke. Bell’s palsy, HIV, diabetes mellitus, and acoustic neuroma would all cause lower motor neuron (LMN) lesions, resulting in LMN signs that involve the forehead.

      The facial nerve is responsible for supplying the muscles of facial expression, the digastric muscle, and various glandular structures. It also contains a few afferent fibers that originate in the genicular ganglion and are involved in taste. Bilateral facial nerve palsy can be caused by conditions such as sarcoidosis, Guillain-Barre syndrome, Lyme disease, and bilateral acoustic neuromas. Unilateral facial nerve palsy can be caused by these conditions as well as lower motor neuron disease like Bell’s palsy and upper motor neuron disease like stroke.

      The upper motor neuron lesion typically spares the upper face, specifically the forehead, while a lower motor neuron lesion affects all facial muscles. The facial nerve path includes the subarachnoid path, where it originates in the pons and passes through the petrous temporal bone into the internal auditory meatus with the vestibulocochlear nerve. The facial canal path passes superior to the vestibule of the inner ear and contains the geniculate ganglion at the medial aspect of the middle ear. The stylomastoid foramen is where the nerve passes through the tympanic cavity anteriorly and the mastoid antrum posteriorly, and it also includes the posterior auricular nerve and branch to the posterior belly of the digastric and stylohyoid muscle.

    • This question is part of the following fields:

      • Neurological System
      24.7
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  • Question 11 - A 75-year-old man comes to the GP complaining of double vision that has...

    Correct

    • A 75-year-old man comes to the GP complaining of double vision that has been present for 3 days. He has a medical history of diabetes mellitus. During the examination, it was observed that his right eye was completely drooping and in a 'down and out' position. Additionally, his right pupil was slightly larger than his left pupil.

      Based on these findings, which cranial nerve is most likely to be affected in this patient?

      Your Answer: Oculomotor nerve

      Explanation:

      When the third cranial nerve is affected, it can result in ptosis (drooping of the upper eyelid) and an down and out eye appearance. This is because the oculomotor nerve controls several muscles that are responsible for eye movements. The levator palpebrae superioris muscle, which lifts the upper eyelid, becomes paralyzed, causing ptosis. The pupillary sphincter muscle, which constricts the pupil, also becomes paralyzed, resulting in dilation of the affected pupil. The paralysis of the medial rectus, superior rectus, inferior rectus, and inferior oblique muscles causes the eye to move downward and outward due to the unopposed action of the other muscles controlling eye movements (the lateral rectus and superior oblique muscles, controlled by the sixth and fourth cranial nerves, respectively).

      If the optic nerve is damaged, it can lead to vision problems as it is responsible for transmitting visual information from the retina to the brain. A trochlear nerve palsy can cause double vision that is worse when looking downward. Damage to the ophthalmic nerve, which is the first branch of the trigeminal nerve, can cause neuralgia (nerve pain) and an absent corneal reflex. An abducens nerve palsy can cause a horizontal gaze palsy that is more pronounced when looking at objects in the distance.

      Understanding Third Nerve Palsy: Causes and Features

      Third nerve palsy is a neurological condition that affects the third cranial nerve, which controls the movement of the eye and eyelid. The condition is characterized by the eye being deviated ‘down and out’, ptosis, and a dilated pupil. In some cases, it may be referred to as a ‘surgical’ third nerve palsy due to the dilation of the pupil.

      There are several possible causes of third nerve palsy, including diabetes mellitus, vasculitis (such as temporal arteritis or SLE), uncal herniation through tentorium if raised ICP, posterior communicating artery aneurysm, and cavernous sinus thrombosis. In some cases, it may also be a false localizing sign. Weber’s syndrome, which is characterized by an ipsilateral third nerve palsy with contralateral hemiplegia, is caused by midbrain strokes. Other possible causes include amyloid and multiple sclerosis.

    • This question is part of the following fields:

      • Neurological System
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  • Question 12 - The initial root of the brachial plexus typically emerges at what level? ...

    Incorrect

    • The initial root of the brachial plexus typically emerges at what level?

      Your Answer: C6

      Correct Answer: C5

      Explanation:

      The nerve plexus originates from the level of C5 and consists of 5 primary nerve roots. It ultimately gives rise to a total of 15 nerves, including the major nerves that innervate the upper limb such as the axillary, radial, ulnar, musculocutaneous, and median nerves.

      Understanding the Brachial Plexus and Cutaneous Sensation of the Upper Limb

      The brachial plexus is a network of nerves that originates from the anterior rami of C5 to T1. It is divided into five sections: roots, trunks, divisions, cords, and branches. To remember these sections, a common mnemonic used is Real Teenagers Drink Cold Beer.

      The roots of the brachial plexus are located in the posterior triangle and pass between the scalenus anterior and medius muscles. The trunks are located posterior to the middle third of the clavicle, with the upper and middle trunks related superiorly to the subclavian artery. The lower trunk passes over the first rib posterior to the subclavian artery. The divisions of the brachial plexus are located at the apex of the axilla, while the cords are related to the axillary artery.

      The branches of the brachial plexus provide cutaneous sensation to the upper limb. This includes the radial nerve, which provides sensation to the posterior arm, forearm, and hand; the median nerve, which provides sensation to the palmar aspect of the thumb, index, middle, and half of the ring finger; and the ulnar nerve, which provides sensation to the palmar and dorsal aspects of the fifth finger and half of the ring finger.

      Understanding the brachial plexus and its branches is important in diagnosing and treating conditions that affect the upper limb, such as nerve injuries and neuropathies. It also helps in understanding the cutaneous sensation of the upper limb and how it relates to the different nerves of the brachial plexus.

    • This question is part of the following fields:

      • Neurological System
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  • Question 13 - A 57-year-old man with a long-standing history of type 2 diabetes and hypertension...

    Incorrect

    • A 57-year-old man with a long-standing history of type 2 diabetes and hypertension visited his physician for a routine check-up. Due to his prolonged diabetes history, the physician referred the man for an eye examination to detect any diabetes-related conditions. The ophthalmology clinic report revealed a slight increase in the intraocular pressure. Although the man reported no vision problems, the physician recommended starting treatment with a medication to reduce the risk of future vision damage, warning the patient that the drug may darken his eye color. What is the drug's mechanism of action prescribed by the doctor?

      Your Answer: Decrease formation of aqueous humor by inhibiting the enzyme carbonic anhydrase

      Correct Answer: Improves uveoscleral outflow

      Explanation:

      Latanoprost is a medication used to treat glaucoma by increasing the outflow of aqueous humor. Diabetic patients are at risk of various eye-related complications, including glaucoma. Chronic closed-angle glaucoma is common in diabetic patients due to the proliferation of blood vessels in the iris, which blocks the drainage pathway of aqueous humor. Treatment is necessary to reduce intraocular pressure and prevent damage to the optic nerve. Acetazolamide works by reducing intraocular pressure, while carbachol and pilocarpine activate muscarinic cholinergic receptors to open the trabecular meshwork pathway. Epinephrine administration produces alpha-1-agonist effects. Prostaglandin analogs such as latanoprost, bimatoprost, and travoprost are the only medications used to reduce intraocular pressure that cause darkening of the iris, but they do not affect the formation of aqueous humor.

      Primary open-angle glaucoma is a type of optic neuropathy that is associated with increased intraocular pressure (IOP). It is classified based on whether the peripheral iris is covering the trabecular meshwork, which is important in the drainage of aqueous humour from the anterior chamber of the eye. In open-angle glaucoma, the iris is clear of the meshwork, but the trabecular network offers increased resistance to aqueous outflow, causing increased IOP. This condition affects 0.5% of people over the age of 40 and its prevalence increases with age up to 10% over the age of 80 years. Both males and females are equally affected. The main causes of primary open-angle glaucoma are increasing age and genetics, with first-degree relatives of an open-angle glaucoma patient having a 16% chance of developing the disease.

      Primary open-angle glaucoma is characterised by a slow rise in intraocular pressure, which is symptomless for a long period. It is typically detected following an ocular pressure measurement during a routine examination by an optometrist. Signs of the condition include increased intraocular pressure, visual field defect, and pathological cupping of the optic disc. Case finding and provisional diagnosis are done by an optometrist, and referral to an ophthalmologist is done via the GP. Final diagnosis is made through investigations such as automated perimetry to assess visual field, slit lamp examination with pupil dilatation to assess optic nerve and fundus for a baseline, applanation tonometry to measure IOP, central corneal thickness measurement, and gonioscopy to assess peripheral anterior chamber configuration and depth. The risk of future visual impairment is assessed using risk factors such as IOP, central corneal thickness (CCT), family history, and life expectancy.

      The majority of patients with primary open-angle glaucoma are managed with eye drops that aim to lower intraocular pressure and prevent progressive loss of visual field. According to NICE guidelines, the first line of treatment is a prostaglandin analogue (PGA) eyedrop, followed by a beta-blocker, carbonic anhydrase inhibitor, or sympathomimetic eyedrop as a second line of treatment. Surgery or laser treatment can be tried in more advanced cases. Reassessment is important to exclude progression and visual field loss and needs to be done more frequently if IOP is uncontrolled, the patient is high risk, or there

    • This question is part of the following fields:

      • Neurological System
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  • Question 14 - A 25-year-old male is at the doctor's office with his girlfriend, reporting that...

    Incorrect

    • A 25-year-old male is at the doctor's office with his girlfriend, reporting that she sleepwalks at night. During which stage of the sleep cycle is this most likely to happen?

      Your Answer: REM sleep

      Correct Answer: Non-REM stage 3 (N3)

      Explanation:

      Understanding Sleep Stages: The Sleep Doctor’s Brain

      Sleep is a complex process that involves different stages, each with its own unique characteristics. The Sleep Doctor’s Brain provides a simplified explanation of the four main sleep stages: N1, N2, N3, and REM.

      N1 is the lightest stage of sleep, characterized by theta waves and often associated with hypnic jerks. N2 is a deeper stage of sleep, marked by sleep spindles and K-complexes. This stage represents around 50% of total sleep. N3 is the deepest stage of sleep, characterized by delta waves. Parasomnias such as night terrors, nocturnal enuresis, and sleepwalking can occur during this stage.

      REM, or rapid eye movement, is the stage where dreaming occurs. It is characterized by beta-waves and a loss of muscle tone, including erections. The sleep cycle typically follows a pattern of N1 → N2 → N3 → REM, with each stage lasting for different durations throughout the night.

      Understanding the different sleep stages is important for maintaining healthy sleep habits and identifying potential sleep disorders. By monitoring brain activity during sleep, the Sleep Doctor’s Brain can provide valuable insights into the complex process of sleep.

    • This question is part of the following fields:

      • Neurological System
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  • Question 15 - A 35-year-old woman presents to the Emergency Department with a stab wound to...

    Correct

    • A 35-year-old woman presents to the Emergency Department with a stab wound to her forearm following a robbery. Upon examination, there is numbness observed in the thenar eminence and weakness in finger and wrist flexion. Which nerve is the most probable to have been damaged?

      Your Answer: Median nerve

      Explanation:

      The median nerve is responsible for providing sensation to the thenar eminence and controlling finger and wrist flexion. Its palmar cutaneous branch supplies sensation to the skin on the lateral side of the palm, including the thenar eminence. The median nerve directly innervates the flexor carpi radialis and palmaris longus muscles, which are responsible for wrist flexion, as well as the flexor digitorum superficialis and lateral half of the flexor digitorum profundus muscles via the anterior interosseous nerve, which control finger flexion. Damage to the median nerve can result in weakness in these movements.

      Anatomy and Function of the Median Nerve

      The median nerve is a nerve that originates from the lateral and medial cords of the brachial plexus. It descends lateral to the brachial artery and passes deep to the bicipital aponeurosis and the median cubital vein at the elbow. The nerve then passes between the two heads of the pronator teres muscle and runs on the deep surface of flexor digitorum superficialis. Near the wrist, it becomes superficial between the tendons of flexor digitorum superficialis and flexor carpi radialis, passing deep to the flexor retinaculum to enter the palm.

      The median nerve has several branches that supply the upper arm, forearm, and hand. These branches include the pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, flexor pollicis longus, and palmar cutaneous branch. The nerve also provides motor supply to the lateral two lumbricals, opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis muscles, as well as sensory supply to the palmar aspect of the lateral 2 ½ fingers.

      Damage to the median nerve can occur at the wrist or elbow, resulting in various symptoms such as paralysis and wasting of thenar eminence muscles, weakness of wrist flexion, and sensory loss to the palmar aspect of the fingers. Additionally, damage to the anterior interosseous nerve, a branch of the median nerve, can result in loss of pronation of the forearm and weakness of long flexors of the thumb and index finger. Understanding the anatomy and function of the median nerve is important in diagnosing and treating conditions that affect this nerve.

    • This question is part of the following fields:

      • Neurological System
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  • Question 16 - A 20-year-old man is admitted to the emergency department after being stabbed in...

    Incorrect

    • A 20-year-old man is admitted to the emergency department after being stabbed in the back. The knife has penetrated his spinal column at a perpendicular angle, causing damage to the termination of his spinal cord.

      Which spinal level has been affected by the knife's penetration?

      Your Answer: T11

      Correct Answer: L1

      Explanation:

      In adults, the level of L1 is where the spinal cord usually ends.

      Lumbar Puncture Procedure

      Lumbar puncture is a medical procedure that involves obtaining cerebrospinal fluid. In adults, the procedure is typically performed at the L3/L4 or L4/5 interspace, which is located below the spinal cord’s terminates at L1.

      During the procedure, the needle passes through several layers. First, it penetrates the supraspinous ligament, which connects the tips of spinous processes. Then, it passes through the interspinous ligaments between adjacent borders of spinous processes. Next, the needle penetrates the ligamentum flavum, which may cause a give. Finally, the needle passes through the dura mater into the subarachnoid space, which is marked by a second give. At this point, clear cerebrospinal fluid should be obtained.

      Overall, the lumbar puncture procedure is a complex process that requires careful attention to detail. By following the proper steps and guidelines, medical professionals can obtain cerebrospinal fluid safely and effectively.

    • This question is part of the following fields:

      • Neurological System
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  • Question 17 - A 36-year-old woman presents to her general practitioner with sudden-onset painful red-eye and...

    Incorrect

    • A 36-year-old woman presents to her general practitioner with sudden-onset painful red-eye and blurred vision in her left eye. She reports that the pain started suddenly while she was out for lunch with her friends. On examination, a hypopyon is present in the left eye, which is also red and has a small and irregularly shaped pupil. Ophthalmoscopy cannot be performed due to photophobia. The patient is diagnosed with anterior uveitis. What medical history might be observed in this patient's past?

      Your Answer: Sjogren's syndrome

      Correct Answer: Ankylosing spondylitis

      Explanation:

      The patient in this scenario is likely suffering from anterior uveitis, which is characterized by inflammation of the ciliary body and iris. Symptoms include a red and painful eye, irregularly shaped pupil, and the presence of a hypopyon. Anterior uveitis is commonly associated with the HLA-B27 haplotype. The correct answer to the question about conditions associated with anterior uveitis is ankylosing spondylitis, which is the only condition mentioned that has a known association with HLA-B27. Coeliac disease, Goodpasture’s syndrome, and haemochromatosis are all incorrect answers as they do not have an association with HLA-B27.

      Anterior uveitis, also known as iritis, is a type of inflammation that affects the iris and ciliary body in the front part of the uvea. This condition is often associated with HLA-B27 and may be linked to other conditions such as ankylosing spondylitis, reactive arthritis, ulcerative colitis, Crohn’s disease, Behcet’s disease, and sarcoidosis. Symptoms of anterior uveitis include sudden onset of eye discomfort and pain, small and irregular pupils, intense sensitivity to light, blurred vision, redness in the eye, tearing, and a ring of redness around the cornea. In severe cases, pus and inflammatory cells may accumulate in the front chamber of the eye, leading to a visible fluid level. Treatment for anterior uveitis involves urgent evaluation by an ophthalmologist, cycloplegic agents to relieve pain and photophobia, and steroid eye drops to reduce inflammation.

    • This question is part of the following fields:

      • Neurological System
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  • Question 18 - A 9-year-old girl has recently been diagnosed with focal seizures. She reports feeling...

    Incorrect

    • A 9-year-old girl has recently been diagnosed with focal seizures. She reports feeling tingling in her left leg before an episode, but has no other symptoms. Upon examination, her upper limbs, lower limbs, and cranial nerves appear normal. She does not experience postictal dysphasia and is fully oriented to time, place, and person.

      Which specific region of her brain is impacted by the focal seizures?

      Your Answer: Prefrontal cortex

      Correct Answer: Posterior to the central gyrus

      Explanation:

      Paraesthesia is a symptom that can help localize a seizure in the parietal lobe.

      The correct location for paraesthesia is posterior to the central gyrus, which is part of the parietal lobe. This area is responsible for integrating sensory information, including touch, and damage to this region can cause abnormal sensations like tingling.

      Anterior to the central gyrus is not the correct location for paraesthesia. This area is part of the frontal lobe and seizures here can cause motor disturbances like hand twitches that spread to the face.

      The medial temporal gyrus is also not the correct location for paraesthesia. Seizures in this area can cause symptoms like lip-smacking and tugging at clothes.

      Occipital lobe seizures can cause visual disturbances like flashes and floaters, but not paraesthesia.

      Finally, the prefrontal cortex, which is also located in the frontal lobe, is not associated with paraesthesia.

      Localising Features of Focal Seizures in Epilepsy

      Focal seizures in epilepsy can be localised based on the specific location of the brain where they occur. Temporal lobe seizures are common and may occur with or without impairment of consciousness or awareness. Most patients experience an aura, which is typically a rising epigastric sensation, along with psychic or experiential phenomena such as déjà vu or jamais vu. Less commonly, hallucinations may occur, such as auditory, gustatory, or olfactory hallucinations. These seizures typically last around one minute and are often accompanied by automatisms, such as lip smacking, grabbing, or plucking.

      On the other hand, frontal lobe seizures are characterised by motor symptoms such as head or leg movements, posturing, postictal weakness, and Jacksonian march. Parietal lobe seizures, on the other hand, are sensory in nature and may cause paraesthesia. Finally, occipital lobe seizures may cause visual symptoms such as floaters or flashes. By identifying the specific location and type of seizure, doctors can better diagnose and treat epilepsy in patients.

    • This question is part of the following fields:

      • Neurological System
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  • Question 19 - A 29 week pregnant 26-year-old has been informed that her baby has hypoplasia...

    Incorrect

    • A 29 week pregnant 26-year-old has been informed that her baby has hypoplasia of the cerebellar vermis, as shown by antenatal ultrasound and subsequent MRI. The baby has been diagnosed with Dandy-Walker syndrome. The neurologist explains to the mother that during embryonic development, the brain is formed from different swellings or vesicles of the neural tube, which eventually becomes the central nervous system.

      What specific embryological vesicle has not developed properly in the affected baby?

      Your Answer: Diencephalon

      Correct Answer: Metencephalon

      Explanation:

      During embryonic development, the metencephalon is responsible for the formation of the pons and cerebellum.

      As the prosencephalon grows, it splits into two ear-shaped structures: the telencephalon (which develops into the hemispheres) and the diencephalon (which develops into the thalamus and hypothalamus).

      The mesencephalon grows slowly, and its central cavity eventually becomes the cerebral aqueduct.

      The rhombencephalon divides into two parts: the metencephalon (which forms the pons and cerebellum) and the myelencephalon (which forms the medulla).

      Embryonic Development of the Nervous System

      The nervous system develops from the embryonic neural tube, which gives rise to the brain and spinal cord. The neural tube is divided into five regions, each of which gives rise to specific structures in the nervous system. The telencephalon gives rise to the cerebral cortex, lateral ventricles, and basal ganglia. The diencephalon gives rise to the thalamus, hypothalamus, optic nerves, and third ventricle. The mesencephalon gives rise to the midbrain and cerebral aqueduct. The metencephalon gives rise to the pons, cerebellum, and superior part of the fourth ventricle. The myelencephalon gives rise to the medulla and inferior part of the fourth ventricle.

      The neural tube is also divided into two plates: the alar plate and the basal plate. The alar plate gives rise to sensory neurons, while the basal plate gives rise to motor neurons. This division of the neural tube into different regions and plates is crucial for the proper development and function of the nervous system. Understanding the embryonic development of the nervous system is important for understanding the origins of neurological disorders and for developing new treatments for these disorders.

    • This question is part of the following fields:

      • Neurological System
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  • Question 20 - A 35-year-old woman presents with a 2-day history of vision difficulty. She is...

    Incorrect

    • A 35-year-old woman presents with a 2-day history of vision difficulty. She is experiencing peripheral vision loss and feels nauseous and dizzy when attempting to look towards the sides. Two months ago, she had a tingling sensation in her left foot. During physical examination, there is a limitation in adduction of both eyes and nystagmus with lateral gaze. An MRI of the brain is scheduled.

      Based on the current clinical presentation and likely diagnosis, what is the expected location of lesions on the MRI scan?

      Your Answer: Caudal pons at level of middle cerebellar peduncles

      Correct Answer: Paramedian area of midbrain & pons

      Explanation:

      The medial longitudinal fasciculus is located in the midbrain and pons and connects cranial nerves III, IV, and VI to facilitate eye movements. Multiple sclerosis can affect this area, causing episodic neurological symptoms and bilateral internuclear ophthalmoplegia, which is characterized by the inability to adduct the affected eye and results in nystagmus and double vision.

      The oculomotor nucleus, located in the midbrain, controls the movement of several eye muscles. A lesion here can cause the eye to point downward and outward, resulting in diplopia and difficulty accommodating.

      The trochlear nerve nucleus, also located in the midbrain, controls the superior oblique muscle. A lesion here can cause diplopia, especially on downward gaze, and a characteristic head tilt towards the unaffected side.

      The abducens nerve nucleus, located in the pons, controls the lateral rectus muscle. A lesion here can cause the affected eye to be unable to abduct, resulting in nystagmus and diplopia.

      The facial nerve nucleus, located in the pons, controls the muscles of the face. A lesion here can cause facial muscle palsies.

      Understanding Internuclear Ophthalmoplegia

      Internuclear ophthalmoplegia is a condition that affects the horizontal movement of the eyes. It is caused by a lesion in the medial longitudinal fasciculus (MLF), which is responsible for interconnecting the IIIrd, IVth, and VIth cranial nuclei. This area is located in the paramedian region of the midbrain and pons. The main feature of this condition is impaired adduction of the eye on the same side as the lesion, along with horizontal nystagmus of the abducting eye on the opposite side.

      The most common causes of internuclear ophthalmoplegia are multiple sclerosis and vascular disease. It is important to note that this condition can also be a sign of other underlying neurological disorders.

    • This question is part of the following fields:

      • Neurological System
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  • Question 21 - A 65-year-old patient presents with dysdiadochokinesia, gait ataxia, nystagmus, intention tremor and slurred...

    Incorrect

    • A 65-year-old patient presents with dysdiadochokinesia, gait ataxia, nystagmus, intention tremor and slurred speech. What investigation would be most appropriate for the likely diagnosis?

      Your Answer: CT Brain

      Correct Answer: MRI Brain

      Explanation:

      When it comes to cerebellar disease, MRI is the preferred diagnostic tool. CT brain scans are better suited for detecting ischemic or hemorrhagic strokes in the brain, rather than identifying cerebellar lesions. X-rays of the brain are not effective in detecting cerebellar lesions. PET-CT scans are typically used in cancer cases where there is active uptake of the radioactive isotope by cancer cells.

      Cerebellar syndrome is a condition that affects the cerebellum, a part of the brain responsible for coordinating movement and balance. When there is damage or injury to one side of the cerebellum, it can cause symptoms on the same side of the body. These symptoms can be remembered using the mnemonic DANISH, which stands for Dysdiadochokinesia, Dysmetria, Ataxia, Nystagmus, Intention tremour, Slurred staccato speech, and Hypotonia.

      There are several possible causes of cerebellar syndrome, including genetic conditions like Friedreich’s ataxia and ataxic telangiectasia, neoplastic growths like cerebellar haemangioma, strokes, alcohol use, multiple sclerosis, hypothyroidism, and certain medications or toxins like phenytoin or lead poisoning. In some cases, cerebellar syndrome may be a paraneoplastic condition, meaning it is a secondary effect of an underlying cancer like lung cancer. It is important to identify the underlying cause of cerebellar syndrome in order to provide appropriate treatment and management.

    • This question is part of the following fields:

      • Neurological System
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  • Question 22 - A 14-month-old infant is undergoing investigation by community paediatrics for developmental delay. The...

    Incorrect

    • A 14-month-old infant is undergoing investigation by community paediatrics for developmental delay. The mother has observed that the child has poor balance, cannot take steps alone, and walks on tiptoes with support. The infant was delivered via c-section at 28 weeks gestation and weighed 1400 grams at birth.

      During the assessment, the infant exhibits hyperreflexia, increased tone in the lower limbs, and sustained clonus in both ankles. The suspected diagnosis is cerebral palsy.

      What type of cerebral palsy is likely to be present in this infant based on the observed symptoms?

      Your Answer:

      Correct Answer: Spastic cerebral palsy

      Explanation:

      Understanding Cerebral Palsy

      Cerebral palsy is a condition that affects movement and posture due to damage to the motor pathways in the developing brain. It is the most common cause of major motor impairment and affects 2 in 1,000 live births. The causes of cerebral palsy can be antenatal, intrapartum, or postnatal. Antenatal causes include cerebral malformation and congenital infections such as rubella, toxoplasmosis, and CMV. Intrapartum causes include birth asphyxia or trauma, while postnatal causes include intraventricular hemorrhage, meningitis, and head trauma.

      Children with cerebral palsy may exhibit abnormal tone in early infancy, delayed motor milestones, abnormal gait, and feeding difficulties. They may also have associated non-motor problems such as learning difficulties, epilepsy, squints, and hearing impairment. Cerebral palsy can be classified into spastic, dyskinetic, ataxic, or mixed types.

      Managing cerebral palsy requires a multidisciplinary approach. Treatments for spasticity include oral diazepam, oral and intrathecal baclofen, botulinum toxin type A, orthopedic surgery, and selective dorsal rhizotomy. Anticonvulsants and analgesia may also be required. Understanding cerebral palsy and its management is crucial in providing appropriate care and support for individuals with this condition.

    • This question is part of the following fields:

      • Neurological System
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  • Question 23 - A 56-year-old patient has undergone surgery for thyroid cancer and his family has...

    Incorrect

    • A 56-year-old patient has undergone surgery for thyroid cancer and his family has noticed a change in his voice, becoming more hoarse a week after the surgery. Which nerve is likely to have been damaged during the surgery to cause this change in his voice?

      Your Answer:

      Correct Answer: Recurrent laryngeal nerve

      Explanation:

      During surgeries of the thyroid and parathyroid glands, the recurrent laryngeal nerve is at risk due to its close proximity to the inferior thyroid artery. This nerve is responsible for supplying all intrinsic muscles of the larynx (excluding the cricothyroid muscle) that control the opening and closing of the vocal folds, as well as providing sensory innervation below the vocal folds. If damaged, it can result in hoarseness of voice or, in severe cases, aphonia.

      The glossopharyngeal nerve, on the other hand, does not play a role in voice production. Its primary areas of innervation include the posterior part of the tongue, the middle ear, part of the pharynx, the carotid body and carotid sinus, and the parotid gland. It also provides motor supply to the stylopharyngeus muscle. Damage to this nerve typically presents with impaired swallowing and changes in taste.

      The ansa cervicalis is located in the carotid triangle and is unlikely to be damaged during thyroid surgery. However, it may be used to re-innervate the vocal folds in the event of damage to the recurrent laryngeal nerve post-thyroidectomy. The ansa cervicalis primarily innervates the majority of infrahyoid muscles, with the exception of the stylohyoid and thyrohyoid. Damage to these muscles would primarily result in difficulty swallowing.

      Finally, the superior laryngeal nerve is responsible for innervating the cricothyroid muscle. If this nerve is paralyzed, it can cause an inability to produce high-pitched voice, which may go unnoticed in many patients for an extended period of time.

      The Recurrent Laryngeal Nerve: Anatomy and Function

      The recurrent laryngeal nerve is a branch of the vagus nerve that plays a crucial role in the innervation of the larynx. It has a complex path that differs slightly between the left and right sides of the body. On the right side, it arises anterior to the subclavian artery and ascends obliquely next to the trachea, behind the common carotid artery. It may be located either anterior or posterior to the inferior thyroid artery. On the left side, it arises left to the arch of the aorta, winds below the aorta, and ascends along the side of the trachea.

      Both branches pass in a groove between the trachea and oesophagus before entering the larynx behind the articulation between the thyroid cartilage and cricoid. Once inside the larynx, the recurrent laryngeal nerve is distributed to the intrinsic larynx muscles (excluding cricothyroid). It also branches to the cardiac plexus and the mucous membrane and muscular coat of the oesophagus and trachea.

      Damage to the recurrent laryngeal nerve, such as during thyroid surgery, can result in hoarseness. Therefore, understanding the anatomy and function of this nerve is crucial for medical professionals who perform procedures in the neck and throat area.

    • This question is part of the following fields:

      • Neurological System
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  • Question 24 - Your next patient, Emily, is a 26-year-old female who is an avid athlete....

    Incorrect

    • Your next patient, Emily, is a 26-year-old female who is an avid athlete. She arrives at the emergency department with an arm injury. After a basic x-ray, it is revealed that she has a humerus shaft fracture.

      Considering the probable nerve damage, which of the subsequent movements will Emily have difficulty with?

      Your Answer:

      Correct Answer: Wrist extension

      Explanation:

      The radial nerve is susceptible to injury in the case of a humerus shaft fracture, which can result in impaired wrist extension.

      The Radial Nerve: Anatomy, Innervation, and Patterns of Damage

      The radial nerve is a continuation of the posterior cord of the brachial plexus, with root values ranging from C5 to T1. It travels through the axilla, posterior to the axillary artery, and enters the arm between the brachial artery and the long head of triceps. From there, it spirals around the posterior surface of the humerus in the groove for the radial nerve before piercing the intermuscular septum and descending in front of the lateral epicondyle. At the lateral epicondyle, it divides into a superficial and deep terminal branch, with the deep branch crossing the supinator to become the posterior interosseous nerve.

      The radial nerve innervates several muscles, including triceps, anconeus, brachioradialis, and extensor carpi radialis. The posterior interosseous branch innervates supinator, extensor carpi ulnaris, extensor digitorum, and other muscles. Denervation of these muscles can lead to weakness or paralysis, with effects ranging from minor effects on shoulder stability to loss of elbow extension and weakening of supination of prone hand and elbow flexion in mid prone position.

      Damage to the radial nerve can result in wrist drop and sensory loss to a small area between the dorsal aspect of the 1st and 2nd metacarpals. Axillary damage can also cause paralysis of triceps. Understanding the anatomy, innervation, and patterns of damage of the radial nerve is important for diagnosing and treating conditions that affect this nerve.

    • This question is part of the following fields:

      • Neurological System
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  • Question 25 - A 47-year-old woman is being evaluated on the ward 24 hours after a...

    Incorrect

    • A 47-year-old woman is being evaluated on the ward 24 hours after a thyroidectomy. Although she has been feeling fine, she has noticed a hoarseness in her voice. Which nerve may have been affected during the operation?

      Your Answer:

      Correct Answer: Right recurrent laryngeal nerve

      Explanation:

      During neck surgery, the right recurrent laryngeal nerve is at a higher risk of injury compared to the left due to its diagonal path across the neck originating under the subclavian. Both the recurrent and superior laryngeal nerves play a crucial role in the sensory and motor function of the vocal cords. The superior laryngeal nerve is less likely to be damaged during thyroid surgery in the lower neck as it descends from above the vocal cords. The glossopharyngeal nerve is also not commonly affected by this mechanism, but if injured, it can cause difficulty swallowing, changes in taste, and altered sensation in the back of the mouth. Hypoglossal nerve injury is rare and does not align with this mechanism, but if it occurs, it can lead to atrophy of the tongue muscles on the same side.

      The Recurrent Laryngeal Nerve: Anatomy and Function

      The recurrent laryngeal nerve is a branch of the vagus nerve that plays a crucial role in the innervation of the larynx. It has a complex path that differs slightly between the left and right sides of the body. On the right side, it arises anterior to the subclavian artery and ascends obliquely next to the trachea, behind the common carotid artery. It may be located either anterior or posterior to the inferior thyroid artery. On the left side, it arises left to the arch of the aorta, winds below the aorta, and ascends along the side of the trachea.

      Both branches pass in a groove between the trachea and oesophagus before entering the larynx behind the articulation between the thyroid cartilage and cricoid. Once inside the larynx, the recurrent laryngeal nerve is distributed to the intrinsic larynx muscles (excluding cricothyroid). It also branches to the cardiac plexus and the mucous membrane and muscular coat of the oesophagus and trachea.

      Damage to the recurrent laryngeal nerve, such as during thyroid surgery, can result in hoarseness. Therefore, understanding the anatomy and function of this nerve is crucial for medical professionals who perform procedures in the neck and throat area.

    • This question is part of the following fields:

      • Neurological System
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  • Question 26 - A 31-year-old man visits an ophthalmology clinic with a complaint of experiencing double...

    Incorrect

    • A 31-year-old man visits an ophthalmology clinic with a complaint of experiencing double vision while descending stairs. He reports a recent mountain biking accident that required him to seek emergency medical attention. Although he has recuperated, he mentions that he sustained a severe frontal head injury after colliding with a tree.

      During the examination, his left eye is raised and deviated medially, and he experiences vertical diplopia when looking up and down.

      Which cranial nerve is most likely affected in this individual?

      Your Answer:

      Correct Answer: Trochlear nerve

      Explanation:

      Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.

      In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.

    • This question is part of the following fields:

      • Neurological System
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  • Question 27 - A patient in their 50s presents with acute onset of slurred speech and...

    Incorrect

    • A patient in their 50s presents with acute onset of slurred speech and weakness on the left side of their body. During examination, you observe weakness in their left arm and face. Despite the slurred speech, the patient is able to comprehend and respond to your questions. Which of the following sites is the most probable location of the lesion causing dysarthria?

      Your Answer:

      Correct Answer: Corticobulbar tract

      Explanation:

      The corticobulbar tract is responsible for motor innervation to the cranial nerves, including the hypoglossal nerve that controls the tongue. A lesion in this tract can cause dysarthria, which is the inability to articulate speech. Other cranial nerve signs, such as facial paralysis and difficulty swallowing, may also occur.

      Wernicke’s area is involved in language comprehension and understanding, and lesions in this area can result in receptive dysphasia. Patients with receptive dysphasia may speak fluently but their sentences may not make sense.

      The primary sensory cortex, located in the parietal lobe, receives sensory innervation. Lesions in this area can cause loss of sensation, proprioception, fine touch, and vibration sense on the contralateral side.

      Broca’s area, found in the frontal lobe, is associated with expressive dysphasia. This type of dysphasia is characterized by difficulty producing language, resulting in labored and non-fluent speech.

      The occipital lobe, responsible for visual processing, can be affected by lesions that cause homonymous hemianopia, agnosias, and cortical blindness.

      Brain lesions can be localized based on the neurological disorders or features that are present. The gross anatomy of the brain can provide clues to the location of the lesion. For example, lesions in the parietal lobe can result in sensory inattention, apraxias, astereognosis, inferior homonymous quadrantanopia, and Gerstmann’s syndrome. Lesions in the occipital lobe can cause homonymous hemianopia, cortical blindness, and visual agnosia. Temporal lobe lesions can result in Wernicke’s aphasia, superior homonymous quadrantanopia, auditory agnosia, and prosopagnosia. Lesions in the frontal lobes can cause expressive aphasia, disinhibition, perseveration, anosmia, and an inability to generate a list. Lesions in the cerebellum can result in gait and truncal ataxia, intention tremor, past pointing, dysdiadokinesis, and nystagmus.

      In addition to the gross anatomy, specific areas of the brain can also provide clues to the location of a lesion. For example, lesions in the medial thalamus and mammillary bodies of the hypothalamus can result in Wernicke and Korsakoff syndrome. Lesions in the subthalamic nucleus of the basal ganglia can cause hemiballism, while lesions in the striatum (caudate nucleus) can result in Huntington chorea. Parkinson’s disease is associated with lesions in the substantia nigra of the basal ganglia, while lesions in the amygdala can cause Kluver-Bucy syndrome, which is characterized by hypersexuality, hyperorality, hyperphagia, and visual agnosia. By identifying these specific conditions, doctors can better localize brain lesions and provide appropriate treatment.

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      • Neurological System
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  • Question 28 - A 15-year-old boy comes to see his GP accompanied by his mother who...

    Incorrect

    • A 15-year-old boy comes to see his GP accompanied by his mother who is worried about his facial expressions. The boy has been experiencing difficulty using the muscles in his face for the past month. He also reports weakness in his arms, but no pain.

      During the examination, the GP observes that the boy's facial muscles are weak, he struggles to puff out his cheeks, and has difficulty raising his arms in the classroom. Additionally, the boy has abnormally large gastrocnemius muscles and his scapulae are 'winged'.

      Which nerve is responsible for innervating the muscle that prevents the scapulae from forming a 'winged' position?

      Your Answer:

      Correct Answer: Long thoracic nerve

      Explanation:

      The Serratus Anterior Muscle and its Innervation

      The serratus anterior muscle is a muscle that originates from the first to eighth ribs and inserts along the entire medial border of the scapulae. Its main function is to protract the scapula, allowing for anteversion of the upper limb. This muscle is innervated by the long thoracic nerve, which receives innervation from roots C5-C7 of the brachial plexus.

      Based on the patient’s clinical history, it is likely that they are suffering from muscular dystrophy, specifically facioscapulohumeral muscular dystrophy. The long thoracic nerve is solely responsible for innervating the serratus anterior muscle, making it a key factor in the diagnosis of this condition.

      Other nerves of the brachial plexus include the axillary nerve, which mainly innervates the deltoid muscles and provides sensory innervation to the skin covering the deltoid muscle. The upper and lower subscapular nerves are branches of the posterior cord of the brachial plexus and provide motor innervation to the subscapularis muscle. The thoracodorsal nerve is also a branch of the posterior cord of the brachial plexus and provides motor innervation to the latissimus dorsi.

      the innervation of the serratus anterior muscle and its relationship to other nerves of the brachial plexus is important in diagnosing and treating conditions that affect this muscle.

    • This question is part of the following fields:

      • Neurological System
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  • Question 29 - A motorcyclist in his mid-thirties is in a road traffic accident and sustains...

    Incorrect

    • A motorcyclist in his mid-thirties is in a road traffic accident and sustains a complex humeral shaft fracture that requires plating. After the surgery, he reports an inability to extend his fingers. What structure is most likely to have been damaged?

      Your Answer:

      Correct Answer: Radial nerve

      Explanation:

      Mnemonic for the muscles innervated by the radial nerve: BEST

      B – Brachioradialis
      E – Extensors
      S – Supinator
      T – Triceps

      Remembering this acronym can help in recalling the muscles that are supplied by the radial nerve, which is responsible for the movement of the extensor compartment of the forearm.

      The Radial Nerve: Anatomy, Innervation, and Patterns of Damage

      The radial nerve is a continuation of the posterior cord of the brachial plexus, with root values ranging from C5 to T1. It travels through the axilla, posterior to the axillary artery, and enters the arm between the brachial artery and the long head of triceps. From there, it spirals around the posterior surface of the humerus in the groove for the radial nerve before piercing the intermuscular septum and descending in front of the lateral epicondyle. At the lateral epicondyle, it divides into a superficial and deep terminal branch, with the deep branch crossing the supinator to become the posterior interosseous nerve.

      The radial nerve innervates several muscles, including triceps, anconeus, brachioradialis, and extensor carpi radialis. The posterior interosseous branch innervates supinator, extensor carpi ulnaris, extensor digitorum, and other muscles. Denervation of these muscles can lead to weakness or paralysis, with effects ranging from minor effects on shoulder stability to loss of elbow extension and weakening of supination of prone hand and elbow flexion in mid prone position.

      Damage to the radial nerve can result in wrist drop and sensory loss to a small area between the dorsal aspect of the 1st and 2nd metacarpals. Axillary damage can also cause paralysis of triceps. Understanding the anatomy, innervation, and patterns of damage of the radial nerve is important for diagnosing and treating conditions that affect this nerve.

    • This question is part of the following fields:

      • Neurological System
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  • Question 30 - A 29-year-old Caucasian female presented to her primary care physician complaining of left...

    Incorrect

    • A 29-year-old Caucasian female presented to her primary care physician complaining of left eye pain that has been bothering her for the past week. She also reported experiencing tingling sensations in her upper limbs and two episodes of weakness in her right arm that lasted for a few days before resolving. She noted that the weakness and tingling were exacerbated after taking a hot bath. What is the origin of the cells primarily impacted in this woman's condition?

      Your Answer:

      Correct Answer: Neural tube neuroepithelia

      Explanation:

      Multiple sclerosis is a neurodegenerative disorder caused by the loss of oligodendrocytes, which produce myelin in the central nervous system. These cells are derived from the neural tube neuroepithelial cells, not from mesenchymal cells, which develop into other tissue cells such as bone marrow, adipose tissue, and muscle cells. The neural crest cells give rise to the neurons of the peripheral nervous system and myelin-producing Schwann cells, while the mesoderm only gives rise to microglia during nervous system development. The notochord plays a role in inducing the overlying ectoderm to develop into the neuroectoderm and neural plate, and gives rise to the nucleus pulposus of the intervertebral disc. Ultimately, the oligodendrocytes are embryological derivatives of the neural tube neuroepithelia, which develop from the ectoderm overlying the notochord.

      Embryonic Development of the Nervous System

      The nervous system develops from the embryonic neural tube, which gives rise to the brain and spinal cord. The neural tube is divided into five regions, each of which gives rise to specific structures in the nervous system. The telencephalon gives rise to the cerebral cortex, lateral ventricles, and basal ganglia. The diencephalon gives rise to the thalamus, hypothalamus, optic nerves, and third ventricle. The mesencephalon gives rise to the midbrain and cerebral aqueduct. The metencephalon gives rise to the pons, cerebellum, and superior part of the fourth ventricle. The myelencephalon gives rise to the medulla and inferior part of the fourth ventricle.

      The neural tube is also divided into two plates: the alar plate and the basal plate. The alar plate gives rise to sensory neurons, while the basal plate gives rise to motor neurons. This division of the neural tube into different regions and plates is crucial for the proper development and function of the nervous system. Understanding the embryonic development of the nervous system is important for understanding the origins of neurological disorders and for developing new treatments for these disorders.

    • This question is part of the following fields:

      • Neurological System
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