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Question 1
Correct
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A 54-year-old lady comes in for a right-sided elective bunionectomy with a realignment osteotomy under local anaesthetic on her first (large) toe. For the operation, which of the following nerve blocks will be most effective?
Your Answer: Superficial peroneal, deep peroneal and posterior tibial nerves
Explanation:An ankle block is commonly used for anaesthesia and postoperative analgesia when operating on bunions. It results in the selective block of the superficial peroneal, deep peroneal, and posterior tibial nerves.
The deep peroneal nerve supplies sensory input to the web space between the first and second toes (L4-5).
The L2-S1 nerve, often known as the superficial peroneal nerve, is a mixed motor and sensory neuron. It gives sensory supply to the anterolateral region of the leg, the anterior aspect of the 1st, 2nd, 3rd, and 4th toes, and innervates the peroneus longus and brevis muscles (with the exception of the web space between 1st and 2nd toes).
The sensory area of the saphenous nerve (L3-4) in the foot stretches from the proximal portion of the midfoot on the medial side to the proximal part of the midfoot on the lateral side.
The lateral side of the little (fifth) toe is innervated by the sural nerve’s sensory supply (S1-2). The heel, medial (medial plantar nerve), and lateral (lateral plantar nerve) soles of the foot are all served by the posterior tibial nerve.
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This question is part of the following fields:
- Pathophysiology
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Question 2
Correct
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With regards to the internal carotid artery, which of these statements is correct.
Your Answer: Enters the skull and divides into the anterior and middle cerebral arteries
Explanation:The internal carotid artery passes through the carotid canal in the petrous part of the temporal bone into the cranial cavity. It does NOT groove the sphenoid bone.
The internal carotid artery gives off no branches in the neck and is a terminal branch of the common carotid artery.
These structures pass between the external and internal carotid arteries: the styloglossus and stylopharyngeus muscles, the glossopharyngeal nerve (CN IX), and the pharyngeal branch of the vagus.
Accompanied by its sympathetic plexus, the internal carotid artery, passes through the cavernous sinus and is crossed by the abducent nerve.
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This question is part of the following fields:
- Anatomy
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Question 3
Correct
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Which of these statements is false relating to the posterior cerebral artery?
Your Answer: It is connected to the circle of Willis via the superior cerebellar artery
Explanation:The posterior cerebral arteries are the terminal branches of the basilar artery and are connected to the circle of Willis via the posterior communicating artery. The posterior cerebral artery supplies the visual areas of the cerebral cortex and other structures in the visual pathway.
The posterior cerebral artery is separated from the superior cerebellar artery near its origin by the oculomotor nerve (3rd cranial nerve) and, lateral to the midbrain, by the trochlear nerve.
PCA strokes will primarily cause a visual field loss or homonymous hemianopia to the opposite side. This large occipital or PCA stroke causes people to be €œblind€� on one side of the visual field. This is the most common symptom of a large occipital lesion or PCA stroke.
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This question is part of the following fields:
- Anatomy
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Question 4
Correct
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While on the ward, you notice a patient that is lying down supine and attached to a monitor is hypotensive with a blood pressure of 90/70mmHg and he is also tachycardic with a pulse of 120 beats/minute. After adjusting the bed with the patient's legs raised by 45 degrees, you reassess the blood pressure after 1 minute and his blood pressure has increased to 100/75mmHg. You then prescribe IV fluids and ask for 500ml of normal saline to be given intravenously over 15 minutes. The increase in the blood pressure can be explained by which physiological association?
Your Answer: Venous return is proportional to stroke volume
Explanation:Cardiac muscle contraction strength is dependent on the action of adrenaline and noradrenaline, but these hormones contribute to cardiac contractility, not to Starling’s law.
Stroke volume (via a cardiac monitor) and/or pulse pressure (via an arterial line) should be measured to assess the effects of a passive leg raise. An increase in stroke volume by 9% or in pulse pressure by 10% are considered indicative of fluid responsiveness.
A passive leg raise can lead to transient increases in blood pressure and stroke volume as it increased the amount of venous return to the heart. Venous return increases in this situation as it transfers a larger volume of blood from the lower limbs to the right heart. It therefore mimics a fluid challenge. However its effects are short lasting and often lead to minimal increases in blood pressure. It therefore should not be used to treat shock in isolation. The passive leg raise is useful in determining the likelihood that a patient with shock will respond to fluid resuscitation.
Sarcomeres, which can be in cardiac, smooth or skeletal muscle, function optimally when stretched to a specific point.
Blood that enters the ventricles during diastole causing stretching of sarcomeres within cardiac muscle. The extent to which they stretch is proportional to the strength of ventricular muscle contraction. Therefore, the venous return (amount of blood returned to the heart) is proportional to stroke volume. The end diastolic volume is determined by venous return and is also proportional to stroke volume. -
This question is part of the following fields:
- Physiology And Biochemistry
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Question 5
Incorrect
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Which of the following statement is false regarding dopamine?
Your Answer: Pulmonary vascular resistance is increased
Correct Answer: Urine output decreases due to inhibition of proximal tubule Na+ reabsorption
Explanation:Dopamine (DA) is a dopaminergic (D1 and D2) as well as adrenergic α and β1 (but not β2 ) agonist.
The D1 receptors in renal and mesenteric blood vessels are the most sensitive: i.v. infusion of a low dose of Dopamine dilates these vessels (by raising intracellular cAMP). This increases g.f.r. In addition, DA exerts a natriuretic effect by D1 receptors on proximal tubular cells.
Moderately high doses produce a positive inotropic (direct β1 and D1 action + that due to NA release), but the little chronotropic effect on the heart.
Vasoconstriction (α1 action) occurs only when large doses are infused.
At doses normally employed, it raises cardiac output and systolic BP with little effect on diastolic BP. It has practically no effect on nonvascular α and β receptors; does not penetrate the blood-brain barrier€”no CNS effects.
Dopamine is less arrhythmogenic than adrenaline
Regarding dopamine part of the dose is converted to Noradrenaline in sympathetic nerve terminals.
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This question is part of the following fields:
- Pharmacology
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Question 6
Correct
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A patient is evaluated for persistent dysphonia six months after undergoing a subtotal thyroidectomy. Which of the following is the most likely reason for the change in this patient's voice?
Your Answer: Damage to recurrent laryngeal nerve
Explanation:After thyroid surgery, about 10-15% of patients experience a temporary subjective voice change of varying degrees. A frog in the throat or cracking of the voice, or a weak voice, are common descriptions. These modifications are only temporary, lasting a few days to a few weeks.
Swelling of the muscles in the area of the dissection, as well as inflammation and oedema of the larynx due to the dissection, or minor trauma from the tracheal tube, are all suspected causes.
On both sides of the thyroid gland, the superior laryngeal nerve (EBSLN) runs along the upper part. The muscles that fine-tune the vocal cords are innervated by these nerves. The quality of their voice is usually normal if they are injured, but making high-pitched sounds may be difficult. Injury to the EBSLN occurs in about 2% of the population.
Injuries to the recurrent laryngeal nerve (RLN) have been reported to occur in 1 percent to 14 percent of people. Except for the cricothyroid muscle, the RLN supplies all of the laryngeal intrinsic muscles.
This complication is usually unilateral and temporary, but it can also be bilateral and permanent, and it can be intentional or unintentional. The most common complication following thyroid surgery is a permanent lesion of damaged RLN, which manifests as an irreversible phonation dysfunction.
The crico-arytenoid joint dislocation is a relatively uncommon complication of tracheal intubation and blunt neck trauma. The probability is less than one in a thousand.
Vocal cord polyps affect 0.8 percent of people.
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This question is part of the following fields:
- Pathophysiology
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Question 7
Incorrect
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A 76-year-old man, presents to his general practitioner with a lump in his left groin. Upon examination, his doctor is able to diagnose a direct inguinal hernia. There are many structures present in the inguinal canal. Where is the ilioinguinal nerve located in relation to the spermatic cord?
Your Answer: Medial to the spermatic cord
Correct Answer: Anterior to the spermatic cord
Explanation:The answer is anterior to the spermatic cord.
The inguinal canal in men contains the ilioinguinal nerve, the genitofemoral nerve and the spermatic cord.
The ilioinguinal nerve arises of the L1 nerve root with the Iliohypogastric nerve, before entering the inguinal canal from the side, through the muscles of the abdomen, travelling superficial to the spermatic cord.
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This question is part of the following fields:
- Anatomy
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Question 8
Incorrect
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A 20-year-old boy is undergoing surgery for indirect inguinal hernia repair. The deep inguinal ring is exposed and held with a retractor at its medial aspect during the procedure. What structure is most likely to lie under the retractor on the medial side?
Your Answer: Lateral border of rectus abdominis
Correct Answer: Inferior epigastric artery
Explanation:The deep inguinal ring is the entrance of the inguinal canal. It is an opening in the transversalis fascia around 1 cm above the inguinal ligament. Therefore, the superolateral wall is made by the transervalis fascia.
The inferior epigastric vessels run medially to the deep inguinal ring forming its inferomedial border.
The inguinal canal extends obliquely from the deep inguinal ring to the superficial inguinal ring.
An indirect inguinal hernia arises through the deep inguinal ring lateral to the inferior epigastric vessels. -
This question is part of the following fields:
- Anatomy
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Question 9
Incorrect
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A laser is a device that stimulates atoms or molecules to emit light at particular wavelengths and amplifies that light, typically producing a very narrow beam of radiation. This can be of visible, infrared, or ultraviolet wavelengths. They have been widely utilized in theatre environment. Which of the following safety measures is most likely to reduce chances of eye injury to the theatre personnel?
Your Answer:
Correct Answer: Wearing laser protective goggles
Explanation:Eye damage is the most common potential hazard associated with laser energy. Everyone in the laser treatment room has the risk of eye exposure when working with a Class 3b or Class 4 healthcare laser system, and damage to various structures in the eye depending on wavelength of the laser if they are unprotected.
Red and near-infrared light (400-1400 nm) has very high penetration power. The light causes painless burns on the retina after it is absorbed by melanin in the pigment epithelium just behind the photoreceptors.
Infrared radiation (IR), or infrared light (>1060 nm), is a type of radiant energy that’s invisible to human eyes and hence won’t elicit the protective blink.
Ultraviolet light (<400 nm) is also a form of electromagnetic radiation which is can penetrate the cornea and be absorbed by the iris or the pupil and cause burn injuries or cataract occur due to irreversible photochemical retinal damage.
Safety eyewear is the best method of providing eye protection and are designed to absorb light specific to the laser being used. Laser protective eyewear (LPE) includes glasses or goggles of proper optical density (OD). The lenses should not be glass or plastic. The LPE should withstand direct and diffuse scattered laser beams.
The laser protection supervisor (LPS) or LSO is an individual who is responsible for any clinical area in which lasers are used. They are expected to have a certain level of equipment and determine what control measures are appropriate, for each individual system, but their presence does not guarantee the chances of having an eye injury.
Class 1 lasers are generally safe under every conceivable condition and is not likely to cause any eye damage. Class 3b or Class 4 medical laser systems are utilized in healthcare which have their own safety precautions.
Polarized spectacles can make your eyes more comfortable by eliminated glare, however, they will not be able to offer any protection against wavelengths at which laser act.
Using short bursts to reduce energy is also not correct as it would still be harmful to eye. -
This question is part of the following fields:
- Anaesthesia Related Apparatus
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Question 10
Incorrect
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A 75-year-old man, visits his general practitioner. He complains of changes to his bowel habit and unexpected weight loss in the last 6 months. He is scheduled for a colonoscopy and biopsy where he is diagnosed with a transverse colon malignancy. The transverse colon is one of many organs tethered to the posterior wall of the abdominal cavity by a double fold of the peritoneum. Which of the listed organs is also tethered to the peritoneum in a similar way?
Your Answer:
Correct Answer: The stomach
Explanation:The peritoneal cavity is made up of the omentum, the ligaments and the mesentery.
The section of the peritoneum responsible for tethering organs to the posterior abdominal wall is the mesentery.
These tethered organs are classified as intraperitoneal, and these include the stomach, spleen, liver, first and fourth parts of the duodenum, jejunum, ileum, transverse, and sigmoid colon.
Retroperitoneal organs are located posterior to the peritoneum and include: the rest of the duodenum, the ascending colon, the descending colon, the middle third of the rectum, and the remainder of the pancreas.
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This question is part of the following fields:
- Anatomy
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