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Question 1
Correct
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A 26-year-old woman comes to her GP complaining of low back pain. She is in good health otherwise. She reports several finger and wrist fractures during her childhood. Her father and sister have also experienced multiple fractures throughout their lives. On examination, she displays paralumbar tenderness and scoliosis. Her sclera is blue-grey. What type of collagen mutation is likely responsible for her condition?
Your Answer: Type 1
Explanation:Osteogenesis imperfecta is caused by an abnormality in type 1 collagen, which is the primary component of bone, skin, and tendons. The diagnosis is based on a combination of factors, including a history of fractures, scoliosis, family history, and physical examination findings. In contrast, mutations in type 2 collagen can lead to chondrodysplasias, while mutations in type 3 collagen may cause a type of Ehlers-Danlos syndrome. Additionally, mutations in type 4 collagen can result in Alport’s syndrome and Goodpasture’s syndrome, as this type of collagen forms the basal lamina.
Understanding Osteogenesis Imperfecta
Osteogenesis imperfecta, also known as brittle bone disease, is a group of disorders that affect collagen metabolism, leading to bone fragility and fractures. The most common type of osteogenesis imperfecta is type 1, which is inherited in an autosomal dominant manner and is caused by decreased synthesis of pro-alpha 1 or pro-alpha 2 collagen polypeptides.
This condition typically presents in childhood, with individuals experiencing fractures following minor trauma. Other common features include blue sclera, deafness secondary to otosclerosis, and dental imperfections. Despite these symptoms, adjusted calcium, phosphate, parathyroid hormone, and ALP results are usually normal in individuals with osteogenesis imperfecta.
Overall, understanding the symptoms and underlying causes of osteogenesis imperfecta is crucial for proper diagnosis and management of this condition.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 2
Incorrect
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A 70-year-old man presents to his GP complaining of a severe throbbing headache on one side of his head. He reports that it started two weeks ago and has now progressed to affect his vision. Additionally, he experiences discomfort in his jaw while chewing, which has made it difficult for him to eat. The patient has a medical history of hypertension and is currently taking ramipril.
During the examination, the GP notes a tender temporal artery that is palpable. Fundoscopy reveals a swollen pale optic disc with blurred margins.
Which artery is responsible for the patient's visual symptoms?Your Answer: Temporal artery
Correct Answer: Posterior ciliary artery
Explanation:The correct answer is posterior ciliary artery. When a patient presents with temporal arteritis, they may experience a headache, jaw claudication, and visual symptoms that can progress to anterior ischemic optic neuropathy. This occurs due to occlusion of the posterior ciliary artery, which is a branch of the ophthalmic artery. When this artery is blocked, it can result in retinal ischemia and necrosis, leading to visual loss.
The answer of anterior ciliary artery is incorrect because it does not have a direct supply to the retina. Instead, it supplies the conjunctiva, sclera, and rectus muscles. Therefore, it would not show a pale swollen optic disc on fundoscopy, which suggests retinal ischemia.
Central retinal artery is also an incorrect answer because it is not typically affected in temporal arteritis. When this artery is occluded, it results in a cherry red spot on fundoscopy without associated mastication symptoms.
Finally, the lacrimal artery is an incorrect answer because it supplies the lacrimal gland, conjunctiva, and eyelids, but not the retina. Therefore, it would not show a pale optic disc on fundoscopy.
Temporal arteritis is a type of large vessel vasculitis that often occurs in patients over the age of 60 and is commonly associated with polymyalgia rheumatica. This condition is characterized by changes in the affected artery that skip certain sections while damaging others. Symptoms of temporal arteritis include headache, jaw claudication, and visual disturbances, with anterior ischemic optic neuropathy being the most common ocular complication. A tender, palpable temporal artery is also often present, and around 50% of patients may experience symptoms of PMR, such as muscle aches and morning stiffness.
To diagnose temporal arteritis, doctors will typically look for elevated inflammatory markers, such as an ESR greater than 50 mm/hr or elevated CRP levels. A temporal artery biopsy may also be performed to confirm the diagnosis, with skip lesions often being present. Treatment for temporal arteritis involves urgent high-dose glucocorticoids, which should be given as soon as the diagnosis is suspected and before the temporal artery biopsy. If there is no visual loss, high-dose prednisolone is typically used, while IV methylprednisolone is usually given if there is evolving visual loss. Patients with visual symptoms should be seen by an ophthalmologist on the same day, as visual damage is often irreversible. Other treatments may include bone protection with bisphosphonates and low-dose aspirin, although the evidence supporting the latter is weak.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 3
Correct
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A 67-year-old woman with breast cancer is prescribed a chemotherapy treatment that involves methotrexate.
What specific enzyme does methotrexate inhibit?Your Answer: Dihydrofolate reductase
Explanation:Methotrexate hinders the activity of dihydrofolate reductase, which is a crucial enzyme in folate metabolism. This drug is effective in treating various conditions, such as Crohn’s disease, psoriasis, rheumatoid arthritis, and certain types of cancer, by disrupting DNA synthesis and repair. Although other enzymes are also involved in folate metabolism and homeostasis, methotrexate does not inhibit them. Notably, 5-Fluorouracil inhibits thymidylate synthase, while methionine synthase, methylenetetrahydrofolate reductase, and folylpolyglutamate synthase play different roles in folate metabolism.
Methotrexate is an antimetabolite that hinders the activity of dihydrofolate reductase, an enzyme that is crucial for the synthesis of purines and pyrimidines. It is a significant drug that can effectively control diseases, but its side-effects can be life-threatening. Therefore, careful prescribing and close monitoring are essential. Methotrexate is commonly used to treat inflammatory arthritis, especially rheumatoid arthritis, psoriasis, and acute lymphoblastic leukaemia. However, it can cause adverse effects such as mucositis, myelosuppression, pneumonitis, pulmonary fibrosis, and liver fibrosis.
Women should avoid pregnancy for at least six months after stopping methotrexate treatment, and men using methotrexate should use effective contraception for at least six months after treatment. Prescribing methotrexate requires familiarity with guidelines relating to its use. It is taken weekly, and FBC, U&E, and LFTs need to be regularly monitored. Folic acid 5 mg once weekly should be co-prescribed, taken more than 24 hours after methotrexate dose. The starting dose of methotrexate is 7.5 mg weekly, and only one strength of methotrexate tablet should be prescribed.
It is important to avoid prescribing trimethoprim or co-trimoxazole concurrently as it increases the risk of marrow aplasia. High-dose aspirin also increases the risk of methotrexate toxicity due to reduced excretion. In case of methotrexate toxicity, the treatment of choice is folinic acid. Overall, methotrexate is a potent drug that requires careful prescribing and monitoring to ensure its effectiveness and safety.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 4
Incorrect
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A 32-year-old male is requested to hold a pen between his thumb and index finger. He finds it difficult to accomplish this task.
What other activity is the patient likely to have difficulty with?Your Answer: Abduction of the thumb
Correct Answer: Adduction of his fingers
Explanation:If a patient exhibits a positive Froment’s sign, it suggests that they may have ulnar nerve palsy. The ulnar nerve is responsible for controlling finger adduction and abduction. Meanwhile, the median nerve is responsible for thumb abduction and wrist pronation, while the radial nerve controls wrist extension.
Nerve signs are used to assess the function of specific nerves in the body. One such sign is Froment’s sign, which is used to assess for ulnar nerve palsy. During this test, the adductor pollicis muscle function is tested by having the patient hold a piece of paper between their thumb and index finger. The object is then pulled away, and if the patient is unable to hold the paper and flexes the flexor pollicis longus to compensate, it may indicate ulnar nerve palsy.
Another nerve sign used to assess for carpal tunnel syndrome is Phalen’s test. This test is more sensitive than Tinel’s sign and involves holding the wrist in maximum flexion. If there is numbness in the median nerve distribution, the test is considered positive.
Tinel’s sign is also used to assess for carpal tunnel syndrome. During this test, the median nerve at the wrist is tapped, and if the patient experiences tingling or electric-like sensations over the distribution of the median nerve, the test is considered positive. These nerve signs are important tools in diagnosing and assessing nerve function in patients.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 5
Correct
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What is a true statement about slipped capital femoral epiphysis?
Your Answer: A chronic slip, with symptoms over weeks to months is the most common presentation
Explanation:Common Causes of Hip Problems in Children
Hip problems in children can be caused by various conditions. Development dysplasia of the hip is often detected during newborn examination and can be identified through positive Barlow and Ortolani tests, as well as unequal skin folds or leg length. Transient synovitis, also known as irritable hip, is the most common cause of hip pain in children aged 2-10 years and is associated with acute hip pain following a viral infection.
Perthes disease is a degenerative condition that affects the hip joints of children between the ages of 4-8 years. It is more common in boys and can be identified through symptoms such as hip pain, limp, stiffness, and reduced range of hip movement. X-rays may show early changes such as widening of joint space, followed by decreased femoral head size or flattening.
Slipped upper femoral epiphysis is more common in obese children and boys aged 10-15 years. It is characterized by the displacement of the femoral head epiphysis postero-inferiorly and may present acutely following trauma or with chronic, persistent symptoms such as knee or distal thigh pain and loss of internal rotation of the leg in flexion.
Juvenile idiopathic arthritis (JIA) is a type of arthritis that occurs in children under 16 years old and lasts for more than three months. Pauciarticular JIA, which accounts for around 60% of JIA cases, affects four or fewer joints and is characterized by joint pain and swelling, usually in medium-sized joints such as knees, ankles, and elbows. ANA may be positive in JIA and is associated with anterior uveitis.
The image gallery shows examples of Perthes disease and slipped upper femoral epiphysis. It is important to identify and treat hip problems in children early to prevent long-term complications.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 6
Incorrect
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A 38-year-old woman has made the decision to have a thyroidectomy for her Graves' disease. During the procedure, one of the blood vessels supplying the thyroid gland, the superior thyroid artery, will be ligated.
What is the correct description of the superior thyroid artery?Your Answer: A branch of the thyrocervical trunk that supplies the anterior portions of the thyroid gland
Correct Answer: A branch of the external carotid artery that supplies the superior portion of the thyroid gland
Explanation:The superior thyroid artery is the initial branch of the external carotid artery and is responsible for supplying the upper pole of the thyroid gland. It descends towards the gland after arising and generally provides blood to the superior and anterior regions. On the other hand, the inferior thyroid artery originates from the thyrocervical trunk, which is a branch of the subclavian artery. It travels in a superomedial direction to reach the inferior pole of the thyroid and typically supplies the postero-inferior aspect.
Anatomy of the Thyroid Gland
The thyroid gland is a butterfly-shaped gland located in the neck, consisting of two lobes connected by an isthmus. It is surrounded by a sheath from the pretracheal layer of deep fascia and is situated between the base of the tongue and the fourth and fifth tracheal rings. The apex of the thyroid gland is located at the lamina of the thyroid cartilage, while the base is situated at the fourth and fifth tracheal rings. In some individuals, a pyramidal lobe may extend from the isthmus and attach to the foramen caecum at the base of the tongue.
The thyroid gland is surrounded by various structures, including the sternothyroid, superior belly of omohyoid, sternohyoid, and anterior aspect of sternocleidomastoid muscles. It is also related to the carotid sheath, larynx, trachea, pharynx, oesophagus, cricothyroid muscle, and parathyroid glands. The superior and inferior thyroid arteries supply the thyroid gland with blood, while the superior and middle thyroid veins drain into the internal jugular vein, and the inferior thyroid vein drains into the brachiocephalic veins.
In summary, the thyroid gland is a vital gland located in the neck, responsible for producing hormones that regulate metabolism. Its anatomy is complex, and it is surrounded by various structures that are essential for its function. Understanding the anatomy of the thyroid gland is crucial for the diagnosis and treatment of thyroid disorders.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 7
Correct
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A 25-year-old male is scheduled for hernia repair surgery where the mesh will be sutured to the inguinal ligament. What is the origin of the inguinal ligament?
Your Answer: External oblique aponeurosis
Explanation:The external oblique aponeurosis forms the inguinal ligament, which extends from the pubic tubercle to the anterior superior iliac spine.
Muscles and Layers of the Abdominal Wall
The abdominal wall is composed of various muscles and layers that provide support and protection to the organs within the abdominal cavity. The two main muscles of the abdominal wall are the rectus abdominis and the quadratus lumborum. The rectus abdominis is located anteriorly, while the quadratus lumborum is located posteriorly.
The remaining abdominal wall is made up of three muscular layers, each passing from the lateral aspect of the quadratus lumborum to the lateral margin of the rectus sheath. These layers are muscular posterolaterally and aponeurotic anteriorly. The external oblique muscle lies most superficially and originates from the 5th to 12th ribs, inserting into the anterior half of the outer aspect of the iliac crest, linea alba, and pubic tubercle. The internal oblique arises from the thoracolumbar fascia, the anterior 2/3 of the iliac crest, and the lateral 2/3 of the inguinal ligament, while the transversus abdominis is the innermost muscle, arising from the inner aspect of the costal cartilages of the lower 6 ribs, the anterior 2/3 of the iliac crest, and the lateral 1/3 of the inguinal ligament.
During abdominal surgery, it is often necessary to divide either the muscles or their aponeuroses. It is desirable to divide the aponeurosis during a midline laparotomy, leaving the rectus sheath intact above the arcuate line and the muscles intact below it. Straying off the midline can lead to damage to the rectus muscles, particularly below the arcuate line where they may be in close proximity to each other. The nerve supply for these muscles is the anterior primary rami of T7-12.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 8
Incorrect
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During a block dissection of the thigh, the sartorius muscle is identified. What is the nerve supply to this muscle?
Your Answer: Posterior division of the femoral nerve
Correct Answer: Anterior division of the femoral nerve
Explanation:The superficial femoral nerve primarily provides cutaneous branches, but it also innervates the sartorius muscle.
The Sartorius Muscle: Anatomy and Function
The sartorius muscle is the longest strap muscle in the human body and is located in the anterior compartment of the thigh. It is the most superficial muscle in this region and has a unique origin and insertion. The muscle originates from the anterior superior iliac spine and inserts on the medial surface of the body of the tibia, anterior to the gracilis and semitendinosus muscles. The sartorius muscle is innervated by the femoral nerve (L2,3).
The primary action of the sartorius muscle is to flex the hip and knee, while also slightly abducting the thigh and rotating it laterally. It also assists with medial rotation of the tibia on the femur, which is important for movements such as crossing one leg over the other. The middle third of the muscle, along with its strong underlying fascia, forms the roof of the adductor canal. This canal contains important structures such as the femoral vessels, the saphenous nerve, and the nerve to vastus medialis.
In summary, the sartorius muscle is a unique muscle in the anterior compartment of the thigh that plays an important role in hip and knee flexion, thigh abduction, and lateral rotation. Its location and relationship to the adductor canal make it an important landmark for surgical procedures in the thigh region.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 9
Incorrect
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A 25-year-old patient arrives at the emergency department half an hour after experiencing severe burns in a house fire. According to a Lund and Browder chart, approximately 42% of the patient's body is affected, with significant areas of full-thickness burns and oedema. During examination, the patient's heart rate is recorded at 124/min and blood pressure at 92/48 mmHg. What is the probable reason for the patient's vital signs?
Your Answer: Secondary infection
Correct Answer: Third space fluid loss
Explanation:Third space fluid loss is a common occurrence in patients with severe burns. This happens when fluid leaks into the area surrounding cells, leading to symptoms such as edema, tachycardia, and hypotension.
It is unlikely that neurogenic shock is the cause of these symptoms. Neurogenic shock is typically caused by damage to the autonomic pathways in the central nervous system, which is usually the result of spinal cord or central nervous system trauma.
While secondary bacterial infections and sepsis are important considerations in patients with major burns, it is unlikely that this patient has an infection since the burns occurred only 30 minutes ago.
Severe pain may explain the tachycardia, but it does not account for the hypotension.
Smoke inhalation can cause coughing, shortness of breath, and burns around the airway, but it is unlikely to be the cause of the hypotension and tachycardia in this patient.
First Aid and Management of Burns
Burns can be caused by heat, electricity, or chemicals. Immediate first aid involves removing the person from the source of the burn and irrigating the affected area with cool water. The extent of the burn can be assessed using Wallace’s Rule of Nines or the Lund and Browder chart. The depth of the burn can be determined by its appearance, with full-thickness burns being the most severe. Referral to secondary care is necessary for deep dermal and full-thickness burns, as well as burns involving certain areas of the body or suspicion of non-accidental injury.
Severe burns can lead to tissue loss, fluid loss, and a catabolic response. Intravenous fluids and analgesia are necessary for resuscitation and pain relief. Smoke inhalation can result in airway edema, and early intubation may be necessary. Circumferential burns may require escharotomy to relieve compartment syndrome and improve ventilation. Conservative management is appropriate for superficial burns, while more complex burns may require excision and skin grafting. There is no evidence to support the use of antimicrobial prophylaxis or topical antibiotics in burn patients.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 10
Incorrect
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Sophie, a 35-year-old female, is brought to the Emergency Department by ambulance after being involved in a car accident.
Upon conducting several tests, an X-ray reveals that she has sustained a mid shaft humeral fracture.
What is the structure that is typically most vulnerable to injury in cases of mid shaft humeral fractures?Your Answer: Axillary nerve
Correct Answer: Radial nerve
Explanation:The humerus is a long bone that runs from the shoulder blade to the elbow joint. It is mostly covered by muscle but can be felt throughout its length. The head of the humerus is a smooth, rounded surface that connects to the body of the bone through the anatomical neck. The surgical neck, located below the head and tubercles, is the most common site of fracture. The greater and lesser tubercles are prominences on the upper end of the bone, with the supraspinatus and infraspinatus tendons inserted into the greater tubercle. The intertubercular groove runs between the two tubercles and holds the biceps tendon. The posterior surface of the body has a spiral groove for the radial nerve and brachial vessels. The lower end of the humerus is wide and flattened, with the trochlea, coronoid fossa, and olecranon fossa located on the distal edge. The medial epicondyle is prominent and has a sulcus for the ulnar nerve and collateral vessels.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 11
Incorrect
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A 25-year-old male is stabbed in the groin, resulting in injury to multiple structures and a laceration of the adductor longus muscle. Which nerve is responsible for the innervation of the adductor longus?
Your Answer: Common peroneal nerve
Correct Answer: Obturator nerve
Explanation:Adductor Longus Muscle
The adductor longus muscle originates from the anterior body of the pubis and inserts into the middle third of the linea aspera. Its main function is to adduct and flex the thigh, as well as medially rotate the hip. This muscle is innervated by the anterior division of the obturator nerve, which originates from the spinal nerves L2, L3, and L4. The adductor longus is one of the adductor muscles, which are a group of muscles located in the thigh that work together to bring the legs towards the midline of the body. The schematic image below illustrates the relationship of the adductor muscles.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 12
Incorrect
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A 65-year-old woman presented with pain, weakness, and numbness in her right arm one day after undergoing surgery on her right shoulder. Upon neurological examination, it was found that the patient had full power in all upper limb movements except for a 4/5 power in right elbow flexion. Sensation was normal throughout the upper limbs except for a specific area on the lateral part of the forearm. The surgeon suspects that the nerve supplying the biceps brachii in the right arm was damaged during the surgical procedure. Which nerve is most likely to have been affected?
Your Answer: Median nerve
Correct Answer: Musculocutaneous nerve
Explanation:If a person experiences weakness in elbow flexion, it may be due to an injury to the musculocutaneous nerve. This nerve is responsible for supplying the biceps brachii, coracobrachialis, and brachialis muscles, as well as the skin on the lateral aspect of the forearm.
Other nerves in the arm include the axillary nerve, which supplies the teres minor and deltoid muscles, as well as skin over the lower half of the deltoid and adjacent areas of the arm. The median nerve supplies most of the muscles in the anterior part of the forearm, as well as skin over the lateral portion of the palm, the palmar surface of the thumb, and the lateral two and a half fingers. The radial nerve supplies the supinator and extensor muscles in the forearm, as well as skin on the posterior side of the lateral aspect of the hand, the dorsum of the thumb, and the proximal part of the lateral two and a half fingers. Finally, the ulnar nerve supplies one and a half muscles in the anterior part of the forearm, as well as skin over the medial portion of the palm and the posterior surface of the medial part of the hand.
The shoulder joint is a shallow synovial ball and socket joint that is inherently unstable but capable of a wide range of movement. Stability is provided by the muscles of the rotator cuff. The glenoid labrum is a fibrocartilaginous rim attached to the free edge of the glenoid cavity. The fibrous capsule attaches to the scapula, humerus, and tendons of various muscles. Movements of the shoulder joint are controlled by different muscles. The joint is closely related to important anatomical structures such as the brachial plexus, axillary artery and vein, and various nerves and vessels.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 13
Incorrect
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Which ligament contains the artery supplying the head of femur in infants?
Your Answer: Iliofemoral ligament
Correct Answer: Ligamentum teres
Explanation:Anatomy of the Hip Joint
The hip joint is formed by the articulation of the head of the femur with the acetabulum of the pelvis. Both of these structures are covered by articular hyaline cartilage. The acetabulum is formed at the junction of the ilium, pubis, and ischium, and is separated by the triradiate cartilage, which is a Y-shaped growth plate. The femoral head is held in place by the acetabular labrum. The normal angle between the femoral head and shaft is 130 degrees.
There are several ligaments that support the hip joint. The transverse ligament connects the anterior and posterior ends of the articular cartilage, while the head of femur ligament (ligamentum teres) connects the acetabular notch to the fovea. In children, this ligament contains the arterial supply to the head of the femur. There are also extracapsular ligaments, including the iliofemoral ligament, which runs from the anterior iliac spine to the trochanteric line, the pubofemoral ligament, which connects the acetabulum to the lesser trochanter, and the ischiofemoral ligament, which provides posterior support from the ischium to the greater trochanter.
The blood supply to the hip joint comes from the medial circumflex femoral and lateral circumflex femoral arteries, which are branches of the profunda femoris. The inferior gluteal artery also contributes to the blood supply. These arteries form an anastomosis and travel up the femoral neck to supply the head of the femur.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 14
Incorrect
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A 55-year-old man presents with a complaint of stiffness in his right shoulder for the past 8 months. Initially, he experienced severe pain, but now only stiffness persists. Upon examination, you observe that the right shoulder is stiff during both active and passive movements.
What is the probable underlying cause of this stiffness?Your Answer: Supraspinatus tear
Correct Answer: Adhesive capsulitis
Explanation:Adhesive capsulitis is identified by a decrease in shoulder mobility, both when moving the shoulder voluntarily and when it is moved by someone else. The ability to rotate the shoulder outward is more affected than the ability to rotate it inward or lift it away from the body.
On the other hand, a tear in the rotator cuff muscles will result in a reduction in active movement due to muscle weakness. Passive movement may also be restricted due to pain. However, we would not anticipate a rigid joint that opposes passive movement.
Adhesive capsulitis, also known as frozen shoulder, is a common cause of shoulder pain that is more prevalent in middle-aged women. The exact cause of this condition is not fully understood. It is associated with diabetes mellitus, with up to 20% of diabetics experiencing an episode of frozen shoulder. Symptoms typically develop over a few days and affect external rotation more than internal rotation or abduction. Both active and passive movement are affected, and patients usually experience a painful freezing phase, an adhesive phase, and a recovery phase. Bilateral frozen shoulder occurs in up to 20% of patients, and the episode typically lasts between 6 months and 2 years.
The diagnosis of frozen shoulder is usually made based on clinical presentation, although imaging may be necessary for atypical or persistent symptoms. There is no single intervention that has been proven to improve long-term outcomes. Treatment options include nonsteroidal anti-inflammatory drugs (NSAIDs), physiotherapy, oral corticosteroids, and intra-articular corticosteroids. It is important to note that the management of frozen shoulder should be tailored to the individual patient, and a multidisciplinary approach may be necessary for optimal outcomes.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 15
Incorrect
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A 75-year-old man comes to the hospital following a fall where he landed on his outstretched left hand. He reports experiencing pain in his left arm. Upon conducting an x-ray, it is revealed that he has a surgical neck fracture of the left humerus. Which nerve is commonly affected by this type of injury?
Your Answer: Radial nerve
Correct Answer: Axillary nerve
Explanation:The axillary nerve is frequently injured in cases of surgical neck fractures of the humerus, as it passes through this area. Symptoms of axillary nerve injury include loss of sensation in the regimental badge area and difficulty with arm abduction due to the affected deltoid and teres minor muscles.
Damage to the median nerve is uncommon in cases of proximal or mid-shaft humeral fractures, as it is protected by surrounding muscle. However, it may be affected in distal humeral fractures as it passes through the cubital fossa.
The musculocutaneous nerve is well-protected by muscle and is rarely injured in cases of proximal humeral fractures.
The radial nerve is most commonly injured in midshaft humeral fractures, as it runs along the radial groove of the humerus.
Similarly to the median nerve, the ulnar nerve arises from the brachial plexus and runs along the medial surface of the upper arm. It is most commonly injured in cases of distal humeral fractures.
The humerus is a long bone that runs from the shoulder blade to the elbow joint. It is mostly covered by muscle but can be felt throughout its length. The head of the humerus is a smooth, rounded surface that connects to the body of the bone through the anatomical neck. The surgical neck, located below the head and tubercles, is the most common site of fracture. The greater and lesser tubercles are prominences on the upper end of the bone, with the supraspinatus and infraspinatus tendons inserted into the greater tubercle. The intertubercular groove runs between the two tubercles and holds the biceps tendon. The posterior surface of the body has a spiral groove for the radial nerve and brachial vessels. The lower end of the humerus is wide and flattened, with the trochlea, coronoid fossa, and olecranon fossa located on the distal edge. The medial epicondyle is prominent and has a sulcus for the ulnar nerve and collateral vessels.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 16
Correct
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A mother brings her 3-year-old son to the GP worried about his motor development. Since he started walking 9 months ago, the child has been limping and avoiding weight bearing on the left leg. He has otherwise been healthy. He was born at term via a caesarean section, due to his breech position, and weighed 4.5kg. What is the probable reason for his limp?
Your Answer: Developmental dysplasia of the hip
Explanation:The condition is developmental dysplasia of the hip, which is typically observed in individuals under the age of 4.
Lower limb anatomy is an important topic that often appears in examinations. One aspect of this topic is the nerves that control motor and sensory functions in the lower limb. The femoral nerve controls knee extension and thigh flexion, and provides sensation to the anterior and medial aspect of the thigh and lower leg. It is commonly injured in cases of hip and pelvic fractures, as well as stab or gunshot wounds. The obturator nerve controls thigh adduction and provides sensation to the medial thigh. It can be injured in cases of anterior hip dislocation. The lateral cutaneous nerve of the thigh provides sensory function to the lateral and posterior surfaces of the thigh, and can be compressed near the ASIS, resulting in a condition called meralgia paraesthetica. The tibial nerve controls foot plantarflexion and inversion, and provides sensation to the sole of the foot. It is not commonly injured as it is deep and well protected, but can be affected by popliteral lacerations or posterior knee dislocation. The common peroneal nerve controls foot dorsiflexion and eversion, and can be injured at the neck of the fibula, resulting in foot drop. The superior gluteal nerve controls hip abduction and can be injured in cases of misplaced intramuscular injection, hip surgery, pelvic fracture, or posterior hip dislocation. Injury to this nerve can result in a positive Trendelenburg sign. The inferior gluteal nerve controls hip extension and lateral rotation, and is generally injured in association with the sciatic nerve. Injury to this nerve can result in difficulty rising from a seated position, as well as difficulty jumping or climbing stairs.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 17
Incorrect
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A 32-year-old female patient visits the GP with a concern about her middle finger's inability to flex at the end. During the examination, it is observed that she cannot bend the distal interphalangeal joint of her middle finger.
Which muscle is accountable for this movement?Your Answer: Flexor pollicis longus
Correct Answer: Flexor digitorum profundus
Explanation:The correct answer is that the flexor digitorum profundus muscle is responsible for flexing the distal interphalangeal joint. The other options, such as the flexor digitorum superficialis and flexor pollicis longus, are responsible for different movements and are therefore incorrect. The palmar interossei are also not responsible for flexion at the distal interphalangeal joint. Lastly, there is no such muscle as the flexor digiti medius.
The forearm flexor muscles include the flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis, and flexor digitorum profundus. These muscles originate from the common flexor origin and surrounding fascia, and are innervated by the median and ulnar nerves. Their actions include flexion and abduction of the carpus, wrist flexion, adduction of the carpus, and flexion of the metacarpophalangeal and interphalangeal joints.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 18
Incorrect
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A 35-year-old woman presents to the emergency department after falling off her bike and landing on her outstretched hand. She experiences tenderness in the anatomical snuffbox and is treated conservatively before being discharged. However, when she returns for outpatient follow-up several weeks later, she reports ongoing wrist pain. What is the probable complication that has arisen from her initial injury?
Your Answer: Carpal tunnel syndrome
Correct Answer: Avascular necrosis
Explanation:A scaphoid fracture can result in avascular necrosis due to the bone’s limited blood supply through the tubercle. This complication is often seen in patients who have fallen on an outstretched hand and may not be immediately visible on X-ray. Carpal tunnel syndrome, compartment syndrome, and Guyon canal syndrome are not typically associated with a scaphoid fracture and present with different symptoms and causes.
The scaphoid bone has various articular surfaces for different bones in the wrist. It has a concave surface for the head of the capitate and a crescentic surface for the lunate. The proximal end has a wide convex surface for the radius, while the distal end has a tubercle that can be felt. The remaining articular surface faces laterally and is associated with the trapezium and trapezoid bones. The narrow strip between the radial and trapezial surfaces and the tubercle gives rise to the radial collateral carpal ligament. The tubercle also receives part of the flexor retinaculum and is the only part of the scaphoid bone that allows for the entry of blood vessels. However, this area is commonly fractured and can lead to avascular necrosis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 19
Incorrect
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A 35-year-old man visits his GP complaining of a painful, erythematous, vesicular rash on the anteromedial aspect of his left arm and a small area of his left chest. The patient reports that he first experienced pain in the affected area three days ago and noticed the rash yesterday morning. He attributes his current stressful state to work-related issues, which were exacerbated by a recent COVID-19 infection that required him to take 10 days off. The patient confirms that he had chickenpox during his childhood. Based on this information, where is the virus responsible for his symptoms most likely to have been dormant in his nervous system?
Your Answer: Inferior trunk of the brachial plexus
Correct Answer: T1 dorsal root ganglion
Explanation:After the primary infection (usually chickenpox during childhood), the herpes zoster virus remains inactive in the dorsal root or cranial nerve ganglia. The patient’s rash, which appears in the left T1 dermatome, indicates that the virus has been dormant in the T1 dorsal root ganglion. Although herpes zoster can reactivate at any time, it is more commonly associated with older age, recent viral infections, periods of stress, or immunosuppression.
Shingles is a painful blistering rash caused by reactivation of the varicella-zoster virus. It is more common in older individuals and those with immunosuppressive conditions. The diagnosis is usually clinical and management includes analgesia, antivirals, and reminding patients they are potentially infectious. Complications include post-herpetic neuralgia, herpes zoster ophthalmicus, and herpes zoster oticus. Antivirals should be used within 72 hours to reduce the incidence of post-herpetic neuralgia.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 20
Correct
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A nine-year-old tumbles from the climbing equipment at the park and is taken to the emergency department. X-rays reveal a supracondylar fracture of the left distal humerus. During the examination, the child exhibits weakened finger flexion in the left hand, inability to perform opposition of the left thumb and little finger, and altered sensation over the lateral aspect of the palm and first three digits. Can you identify the location of the damaged structure in the antecubital fossa?
Your Answer: Medial to the brachial artery
Explanation:The cubital fossa contains the following structures in order from lateral to medial: radial nerve, brachial tendon, brachial artery, and median nerve. In this case, the damaged nerve is the median nerve, which is located most medially in the cubital fossa, next to the brachial artery.
In the antecubital fossa, the radial nerve is located deep and laterally, next to the biceps tendon. The biceps tendon serves as a marker for finding the brachial artery, which is located medially to it.
It is incorrect to say that there is a nerve located between the biceps tendon and the brachial artery in the antecubital fossa.
The Antecubital Fossa: Anatomy and Clinical Significance
The antecubital fossa is a depression located on the anterior aspect of the arm, between the arm and forearm. It is an important area for medical professionals as it is where venous blood samples are typically taken from. The borders of the antecubital fossa are the brachioradialis muscle laterally, the pronator teres medially, and a line between the medial and lateral epicondyles superiorly.
There are both deep and superficial structures found in the antecubital fossa. Deep structures include the radial nerve, tendon of the biceps muscle, brachial artery, and medial nerve. Superficial structures consist of a network of veins, including the cephalic vein and basilic vein, which come together as the median cubital vein.
The main clinical relevance of the antecubital fossa is its use for blood sampling and cannulation. However, it is also important to have a working knowledge of the anatomy as structures can become damaged. Excessive straining of the biceps tendon can cause it to rupture, leading to a ‘Popeye sign’. Damage to the medial nerve can also occur, resulting in muscle paralysis in the forearm and hand. Overall, understanding the anatomy and clinical significance of the antecubital fossa is crucial for medical professionals.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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