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Question 1
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A 19-year-old athlete presents to the orthopaedic clinic complaining of pain and swelling on the medial side of the knee joint. The pain is experienced while climbing stairs, but not while walking on level ground. On clinical examination, there is tenderness over the proximal medial tibia and the McMurray test is negative. What is the probable cause of this patient's symptoms?
Your Answer: Pes Anserinus Bursitis
Explanation:The Pes Anserinus, also known as the goose’s foot, is formed by the combination of the tendons of the sartorius, gracilis, and semitendinous muscles as they insert into the anteromedial proximal tibia.
Overuse injuries can lead to Pes Anserinus Bursitis, which is frequently seen in athletes. The primary symptom is pain in the medial proximal tibia. A negative McMurray test can rule out medial meniscal injury.
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 2
Incorrect
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The etiology of osteopetrosis is most effectively described by a malfunction in which of the following?
Your Answer: Calcium resorption in proximal tubule
Correct Answer: Osteoclast function
Explanation:Understanding Osteopetrosis: A Rare Disorder of Bone Resorption
Osteopetrosis, also known as marble bone disease, is a rare disorder that affects the normal function of osteoclasts, leading to a failure of bone resorption. This results in the formation of dense, thick bones that are more prone to fractures. Individuals with osteopetrosis often experience bone pains and neuropathies. Despite the abnormal bone growth, levels of calcium, phosphate, and ALP remain normal.
Treatment options for osteopetrosis include stem cell transplant and interferon-gamma therapy. However, these treatments are not always effective and may have significant side effects. As such, early diagnosis and management of osteopetrosis is crucial in preventing complications and improving quality of life for affected individuals.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 3
Incorrect
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A 20-year-old man visits his GP with a complaint of right arm weakness that he noticed upon waking up after a night out. He is concerned that he may be experiencing a stroke, as his uncle had died from one.
During the examination, the doctor observes that the patient's right arm is drooping to the side. There is a decrease in power for elbow and wrist extension, but elbow and wrist flexion remain intact.
Which anatomical structure is most likely damaged, resulting in this patient's symptoms?Your Answer: Extensor carpi radialis muscle
Correct Answer: Radial nerve
Explanation:Upper limb anatomy is a common topic in examinations, and it is important to know certain facts about the nerves and muscles involved. The musculocutaneous nerve is responsible for elbow flexion and supination, and typically only injured as part of a brachial plexus injury. The axillary nerve controls shoulder abduction and can be damaged in cases of humeral neck fracture or dislocation, resulting in a flattened deltoid. The radial nerve is responsible for extension in the forearm, wrist, fingers, and thumb, and can be damaged in cases of humeral midshaft fracture, resulting in wrist drop. The median nerve controls the LOAF muscles and can be damaged in cases of carpal tunnel syndrome or elbow injury. The ulnar nerve controls wrist flexion and can be damaged in cases of medial epicondyle fracture, resulting in a claw hand. The long thoracic nerve controls the serratus anterior and can be damaged during sports or as a complication of mastectomy, resulting in a winged scapula. The brachial plexus can also be damaged, resulting in Erb-Duchenne palsy or Klumpke injury, which can cause the arm to hang by the side and be internally rotated or associated with Horner’s syndrome, respectively.
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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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Which muscle is connected to the front of the fibrous capsule that surrounds the elbow joint?
Your Answer:
Correct Answer: Brachialis
Explanation:When the brachialis muscle contracts, it aids in elbow flexion by inserting some of its fibers into the fibrous joint of the elbow capsule.
Anatomy of the Elbow Joint
The elbow joint is a large synovial hinge joint that connects the bones of the forearm to the lower end of the humerus. It consists of the humeral articular surface, which comprises the grooved trochlea, the spheroidal capitulum, and the sulcus between them, and the ulnar and radial surfaces. The joint is encased within a fibrous capsule that is relatively weak anteriorly and posteriorly but strengthened at the sides to form the radial and ulnar collateral ligaments. The synovial membrane follows the attachments of the fibrous capsule, and the joint is innervated by the musculocutaneous, median, radial, and ulnar nerves.
Movement occurs around a transverse axis, with flexion occurring when the forearm makes anteriorly a diminishing angle with the upper arm and extension when the opposite occurs. The axis of movement passes through the humeral epicondyles and is not at right angles with either the humerus or bones of the forearm. In full extension with the forearm supinated, the arm and forearm form an angle which is more than 180 degrees, the extent to which this angle is exceeded is termed the carrying angle. The carrying angle is masked when the forearm is pronated.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 5
Incorrect
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A 35-year-old woman presents to your clinic complaining of increased joint pain and fatigue. She reports no significant medical history but mentions that her sister was recently diagnosed with systemic lupus erythematosus (SLE). On examination, there are no notable findings. Laboratory tests reveal the following results:
- Hemoglobin: 118 g/L (normal range for females: 115-160 g/L)
- Platelets: 260 * 109/L (normal range: 150-400 * 109/L)
- White blood cells: 7.5 * 109/L (normal range: 4.0-11.0 * 109/L)
- ANA: Negative
- ANCA: Negative
- Anti-La antibody: Negative
- Rheumatoid factor: Positive
Which blood test result is the most reliable indicator that SLE is unlikely in this patient?Your Answer:
Correct Answer: ANA (antinuclear antibodies)
Explanation:Systemic lupus erythematosus (SLE) can be investigated through various tests, including antibody tests. ANA testing is highly sensitive and useful for ruling out SLE, but it has low specificity. About 99% of SLE patients are ANA positive. Rheumatoid factor testing is positive in 20% of SLE patients. Anti-dsDNA testing is highly specific (>99%) but less sensitive (70%). Anti-Smith testing is also highly specific (>99%) but has a lower sensitivity (30%). Other antibody tests that can be used include anti-U1 RNP, SS-A (anti-Ro), and SS-B (anti-La).
Monitoring of SLE can be done through various markers, including inflammatory markers such as ESR. During active disease, CRP levels may be normal, and a raised CRP may indicate an underlying infection. Complement levels (C3, C4) are low during active disease due to the formation of complexes that lead to the consumption of complement. Anti-dsDNA titres can also be used for disease monitoring, but it is important to note that they are not present in all SLE patients. Overall, these investigations can help diagnose and monitor SLE, allowing for appropriate management and treatment.
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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 6-year-old girl is brought to the clinic by her mother who is worried about her daughter's hearing loss. The girl has a history of frequent bone fractures. During the examination, the doctor observes that the external ear canal and tympanic membrane appear normal and there is no discharge or swelling. However, the girl's sclera has a bluish tint. What type of collagen is most likely affected in this case?
Your Answer:
Correct Answer: Type 1
Explanation:Osteogenesis imperfecta is caused by a defect in type 1 collagen, which is found in the skin, tendons, vasculature, and bones. This abnormality results in fragile bones, leading to multiple fractures, as seen in a child with deafness, blue sclera, and fractures. Type 2 collagen is present in cartilage and is not typically affected in osteogenesis imperfecta. Type 3 collagen is the primary component of reticular fibers, which are also not typically affected in this condition. Type 4 collagen makes up basement membranes, which are also not typically affected in osteogenesis imperfecta.
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 7
Incorrect
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A 65-year-old woman comes to the clinic complaining of a severe headache on both sides of her temples. Upon further inquiry, she reports a temporary loss of vision in one eye and pain in her jaw. What is the probable diagnosis?
Your Answer:
Correct Answer: Temporal/giant cell arteritis
Explanation:Temporal arteritis, space occupying lesions, migraines, and tension headaches all cause headaches, but they differ in their specific symptoms and causes. Temporal arteritis causes pain in the inflamed temporal artery, which can also lead to jaw pain and temporary vision loss. Space occupying lesions can cause severe morning headaches with vomiting. Migraines are characterized by hours-long headache attacks preceded by an aura and changes in mood, appetite, and sleepiness. Tension headaches cause a band-like pain around the head and are often associated with stress.
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 8
Incorrect
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A 35-year-old man arrives at the Emergency Department complaining of pain in his right hand following a fall during a football match earlier in the day. Upon conducting a thorough hand examination, you identify that the pain is concentrated in the anatomical snuffbox. To investigate a possible scaphoid bone fracture, you order an x-ray.
Which structure, passing through the anatomical snuffbox, is most likely to have been affected by this injury?Your Answer:
Correct Answer: The radial artery
Explanation:The radial artery is the only structure that passes through the anatomical snuffbox and is commonly injured by scaphoid bone fractures, as it runs over the bone at the snuffbox. Therefore, it is the most likely structure to be affected by such a fracture.
The median nerve does not pass through the anatomical snuffbox, but rather through the carpal tunnel, so it is less likely to be injured by a scaphoid fracture.
While the radial nerve does pass through the snuffbox, it is the superficial branch, not the deep branch, that does so. Therefore, if a scaphoid bone fracture were to damage the radial nerve, it would likely affect the superficial branch rather than the deep branch.
The basilic vein does not pass through the anatomical snuffbox, but rather travels along the ulnar side of the arm. The cephalic vein is the vein that passes through the snuffbox.
The extensor pollicis longus tendon forms the medial border of the snuffbox, but it is not one of its contents. It runs relatively superficially and is therefore less likely to be affected by a scaphoid bone fracture than a structure that runs closer to the bone, such as the radial artery.
The Anatomical Snuffbox: A Triangle on the Wrist
The anatomical snuffbox is a triangular depression located on the lateral aspect of the wrist. It is bordered by tendons of the extensor pollicis longus, extensor pollicis brevis, and abductor pollicis longus muscles, as well as the styloid process of the radius. The floor of the snuffbox is formed by the trapezium and scaphoid bones. The apex of the triangle is located distally, while the posterior border is formed by the tendon of the extensor pollicis longus. The radial artery runs through the snuffbox, making it an important landmark for medical professionals.
In summary, the anatomical snuffbox is a small triangular area on the wrist that is bordered by tendons and bones. It is an important landmark for medical professionals due to the presence of the radial artery.
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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 49-year-old male is seeking information about his prescribed secondary prophylaxis medications following a recent myocardial infarction. He expresses concern about taking aspirin due to his history of acid reflux, despite being given gastric protection. As an alternative, he is prescribed celecoxib, another COX inhibitor. What is the mechanism of action of this drug?
Your Answer:
Correct Answer: Reversible COX-2 inhibitor
Explanation:Celecoxib inhibits COX-2 in a reversible manner, while aspirin inhibits both COX-1 and COX-2 irreversibly. Celecoxib is classified as a selective NSAID that works by reducing the production of prostaglandins.
Understanding Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and COX-2 Selective NSAIDs
Non-steroidal anti-inflammatory drugs (NSAIDs) are medications that work by inhibiting the activity of cyclooxygenase enzymes, which are responsible for producing key mediators involved in inflammation such as prostaglandins. By reducing the production of these mediators, NSAIDs can help alleviate pain and reduce inflammation. Examples of NSAIDs include ibuprofen, diclofenac, naproxen, and aspirin.
However, NSAIDs can also have important and common side-effects, such as peptic ulceration and exacerbation of asthma. To address these concerns, COX-2 selective NSAIDs were developed. These medications were designed to reduce the incidence of side-effects seen with traditional NSAIDs, particularly peptic ulceration. Examples of COX-2 selective NSAIDs include celecoxib and etoricoxib.
Despite their potential benefits, COX-2 selective NSAIDs are not widely used due to ongoing concerns about cardiovascular safety. This led to the withdrawal of rofecoxib (‘Vioxx’) in 2004. As with any medication, it is important to discuss the potential risks and benefits of NSAIDs and COX-2 selective NSAIDs with a healthcare provider before use.
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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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A 70-year-old man with non-reconstructible arterial disease is having an above knee amputation. The posterior compartment muscles are being separated. Which muscle is not located in the posterior compartment of the thigh?
Your Answer:
Correct Answer: Quadriceps femoris
Explanation:The anterior compartment contains the quadriceps femoris.
Fascial Compartments of the Leg
The leg is divided into compartments by fascial septae, which are thin layers of connective tissue. In the thigh, there are three compartments: the anterior, medial, and posterior compartments. The anterior compartment contains the femoral nerve and artery, as well as the quadriceps femoris muscle group. The medial compartment contains the obturator nerve and artery, as well as the adductor muscles and gracilis muscle. The posterior compartment contains the sciatic nerve and branches of the profunda femoris artery, as well as the hamstrings muscle group.
In the lower leg, there are four compartments: the anterior, posterior (divided into deep and superficial compartments), lateral, and deep posterior compartments. The anterior compartment contains the deep peroneal nerve and anterior tibial artery, as well as the tibialis anterior, extensor digitorum longus, extensor hallucis longus, and peroneus tertius muscles. The posterior compartment contains the tibial nerve and posterior tibial artery, as well as the deep and superficial muscles. The lateral compartment contains the superficial peroneal nerve and peroneal artery, as well as the peroneus longus and brevis muscles. The deep posterior compartment contains the tibial nerve and posterior tibial artery, as well as the flexor hallucis longus, flexor digitorum longus, tibialis posterior, and popliteus muscles.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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