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Question 1
Correct
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A 25-year-old man presents with elbow pain after falling onto his outstretched hand at work. The fall occurred with his elbow fully extended. An x-ray confirms a fracture of his medial epicondyle.
During the examination, the patient reports reduced sensation on the medial side of his palm and some weakness in his wrist. Based on the nerve likely affected, what muscle may also exhibit weakness?Your Answer: Flexor carpi ulnaris
Explanation:The correct answer is flexor carpi ulnaris, which is supplied by the ulnar nerve. If there is an injury to the medial epicondyle, it may result in damage to the ulnar nerve, which runs posterior to the medial epicondyle. This nerve injury would cause sensory loss in the medial portion of the hand. The ulnar nerve supplies intrinsic muscles of the hand, hypothenar muscles, and the flexor carpi ulnaris, which aids in wrist flexion and adduction.
Coracobrachialis is an incorrect answer. It is innervated by the musculocutaneous nerve and aids in arm flexion at the shoulder. The musculocutaneous nerve is rarely injured in isolation.
Extensor carpi ulnaris is also an incorrect answer. It is innervated by the radial nerve and controls wrist extension and adduction. Mid-shift fractures of the humerus may damage the radial nerve.
Flexor carpi radialis is another incorrect answer. It is innervated by the median nerve and controls wrist flexion and abduction.
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 2
Incorrect
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During a soccer match, a young player is tackled and suffers a twisting injury to their knee. They are diagnosed with a soft tissue knee injury. What is the name of the structure that originates from the medial surface of the lateral femoral condyle and inserts onto the anterior intercondylar area of the tibial plateau?
Your Answer: Popliteus
Correct Answer: Anterior cruciate ligament
Explanation:To recall the attachments of the ACL, one can imagine placing their hand in their pocket and moving from the superolateral to inferomedial direction. Conversely, for the PCL, the movement would be from inferolateral to superomedial.
The ACL originates from the medial surface of the lateral condyle, while the PCL originates from the lateral surface of the medial condyle.
Located in the medial compartment of the knee, beneath the medial condyle of the femur, is the medial meniscus.
The knee joint is the largest and most complex synovial joint in the body, consisting of two condylar joints between the femur and tibia and a sellar joint between the patella and femur. The degree of congruence between the tibiofemoral articular surfaces is improved by the presence of the menisci, which compensate for the incongruence of the femoral and tibial condyles. The knee joint is divided into two compartments: the tibiofemoral and patellofemoral compartments. The fibrous capsule of the knee joint is a composite structure with contributions from adjacent tendons, and it contains several bursae and ligaments that provide stability to the joint. The knee joint is supplied by the femoral, tibial, and common peroneal divisions of the sciatic nerve and by a branch from the obturator nerve, while its blood supply comes from the genicular branches of the femoral artery, popliteal, and anterior tibial arteries.
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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 26-year-old motorcyclist is in a road traffic accident and undergoes treatment for a tibial fracture with an intra medullary nail. However, he develops compartment syndrome post-operatively. Which of the following muscles will not have pressure relieved by surgical decompression of the anterior compartment?
Your Answer: Peroneus tertius
Correct Answer: Peroneus brevis
Explanation:The deep peroneal nerve innervates all the muscles in the anterior compartment, including the Tibialis anterior, Extensor digitorum longus, Peroneus tertius, and Extensor hallucis longus. Additionally, the Anterior tibial artery is also located in this compartment.
Muscular Compartments of the Lower Limb
The lower limb is composed of different muscular compartments that perform various actions. The anterior compartment includes the tibialis anterior, extensor digitorum longus, peroneus tertius, and extensor hallucis longus muscles. These muscles are innervated by the deep peroneal nerve and are responsible for dorsiflexing the ankle joint, inverting and evert the foot, and extending the toes.
The peroneal compartment, on the other hand, consists of the peroneus longus and peroneus brevis muscles, which are innervated by the superficial peroneal nerve. These muscles are responsible for eversion of the foot and plantar flexion of the ankle joint.
The superficial posterior compartment includes the gastrocnemius and soleus muscles, which are innervated by the tibial nerve. These muscles are responsible for plantar flexion of the foot and may also flex the knee.
Lastly, the deep posterior compartment includes the flexor digitorum longus, flexor hallucis longus, and tibialis posterior muscles, which are innervated by the tibial nerve. These muscles are responsible for flexing the toes, flexing the great toe, and plantar flexion and inversion of the foot, respectively.
Understanding the muscular compartments of the lower limb is important in diagnosing and treating injuries and conditions that affect these muscles. Proper identification and management of these conditions can help improve mobility and function of the lower limb.
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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 ligament contains the artery supplying the head of femur in infants?
Your Answer: Ischiofemoral 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 5
Correct
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A 70-year-old man is recuperating from a fall that resulted in a fracture of his left fibular neck. He has observed that his left foot drags on the ground when he attempts to walk. Which nerve is the most probable to have been affected?
Your Answer: Common peroneal nerve
Explanation:The patient is likely to have suffered damage to their common peroneal nerve, resulting in foot drop, following a fibular neck fracture. This is a common occurrence in such cases.
It is important to note that damage to the lateral cutaneous nerve of the thigh, obturator nerve, or pudendal nerve is unlikely to cause foot drop. These nerves are associated with different symptoms and conditions.
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 6
Incorrect
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A 33-year-old man presents to the emergency department with complaints of pain in his left hand following a fall that occurred 4 days ago. The pain is located on the dorsum of his hand, near the base of his index finger. He reports that he tripped and fell while running and used his left hand to break his fall.
Upon examination, there is significant tenderness upon palpation of the base of the first metacarpal on the dorsum of his hand. There is also noticeable swelling in the affected area.
What type of fracture is the patient most likely to have sustained?Your Answer: Boxer's fracture
Correct Answer: Scaphoid fracture
Explanation:The most likely cause of the patient’s pain in the anatomical snuffbox is a scaphoid fracture, which is often the result of falling onto an outstretched hand (FOOSH). Scaphoid fractures are the most common type of carpal fracture. In contrast, a boxer’s fracture involves the 5th metacarpal bone and is typically caused by punching something with a closed fist, while a Colles’ fracture affects the distal radius and causes a dorsal displacement of the fragments. A Galeazzi fracture involves the radial bone and dislocation of the distal radioulnar joint, and is typically caused by a fall on the hand with rotational force.
A scaphoid fracture is a type of wrist fracture that usually occurs when a person falls onto an outstretched hand or during contact sports. It is important to identify scaphoid fractures as they can lead to avascular necrosis due to the unusual blood supply of the scaphoid bone. Patients with scaphoid fractures typically experience pain along the radial aspect of the wrist and loss of grip or pinch strength. Clinical examination involves checking for tenderness over the anatomical snuffbox, wrist joint effusion, pain on telescoping of the thumb, tenderness of the scaphoid tubercle, and pain on ulnar deviation of the wrist. Plain film radiographs and scaphoid views are used to diagnose scaphoid fractures, but MRI is considered the definitive investigation. Initial management involves immobilization with a splint or backslab and referral to orthopaedics. Orthopaedic management depends on the type of fracture, with undisplaced fractures typically treated with a cast and displaced fractures requiring surgical fixation. Complications of scaphoid fractures include non-union and avascular necrosis.
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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 50-year-old woman comes to the emergency department complaining of crushing chest pain. Her ECG shows no abnormalities. She has a medical history of rheumatoid arthritis managed with methotrexate, hypertension, and type II diabetes. Her BMI is 34 kg/m². As a healthcare provider, you initiate aspirin therapy.
What is the most significant risk this patient is facing?Your Answer: Rhabdomyolysis
Correct Answer: Bone marrow toxicity
Explanation:Taking aspirin while on methotrexate treatment can be dangerous as it reduces the excretion of methotrexate, leading to an increased risk of toxicity and bone marrow problems. However, some studies suggest that methotrexate may be helpful in treating severe osteoarthritis and polymyositis. All other options are incorrect.
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 8
Correct
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A 26-year-old medical student visits his doctor with a complaint of experiencing dry mouth, particularly at night, which has been affecting his sleep. He has a medical history of allergic rhinitis and is currently taking chlorphenamine for it.
What is the correct explanation for the mechanism of action of chlorphenamine?Your Answer: H1 receptor antagonist
Explanation:Chlorphenamine is a medication.
Antihistamines for Allergic Rhinitis and Urticaria
Antihistamines, specifically H1 inhibitors, are effective in treating allergic rhinitis and urticaria. Sedating antihistamines like chlorpheniramine have antimuscarinic properties that can cause dry mouth and urinary retention. On the other hand, non-sedating antihistamines like loratadine and cetirizine are less likely to cause drowsiness. However, there is some evidence that cetirizine may still cause some level of drowsiness compared to other non-sedating antihistamines. Overall, antihistamines are a valuable treatment option for those suffering from allergic rhinitis and urticaria.
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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 young girl comes to the clinic complaining of severe menstrual cramps that occur every month. Her physician assures her that this is a common issue and prescribes mefenamic acid as a pain reliever. What is the mechanism of action of mefenamic acid?
Your Answer: Directly decreasing prostaglandin production
Correct Answer: Inhibiting COX, decreasing prostaglandin production
Explanation:Mefenamic acid is classified as an NSAID because it works by inhibiting COX, which ultimately leads to a decrease in prostaglandin production. Any response indicating an increase or alteration in prostaglandin levels would be inaccurate. The idea of blocking dorsal horn sodium channels is more characteristic of a neuropathic medication rather than an NSAID.
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
Correct
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An 81-year-old female is admitted to the hospital with a Colles fracture in her left wrist. Upon conducting a bone scan, it is revealed that she has osteoporosis. The medical team decides to initiate treatment. What category of medications is recommended?
Your Answer: Bisphosphonates
Explanation:Bisphosphonates, particularly alendronate, are the recommended treatment for fragility fractures in postmenopausal women. Additionally, calcium and vitamin D supplementation should be considered, along with lifestyle advice on nutrition, exercise, and fall prevention.
Bisphosphonates: Uses, Adverse Effects, and Patient Counselling
Bisphosphonates are drugs that mimic the action of pyrophosphate, a molecule that helps prevent bone demineralization. They work by inhibiting osteoclasts, the cells responsible for breaking down bone tissue. Bisphosphonates are commonly used to prevent and treat osteoporosis, hypercalcemia, Paget’s disease, and pain from bone metastases.
However, bisphosphonates can cause adverse effects such as oesophageal reactions, osteonecrosis of the jaw, and an increased risk of atypical stress fractures of the proximal femoral shaft in patients taking alendronate. Patients may also experience an acute phase response, which includes fever, myalgia, and arthralgia following administration. Hypocalcemia may also occur due to reduced calcium efflux from bone, but this is usually clinically unimportant.
To minimize the risk of adverse effects, patients taking oral bisphosphonates should swallow the tablets whole with plenty of water while sitting or standing. They should take the medication on an empty stomach at least 30 minutes before breakfast or another oral medication and remain upright for at least 30 minutes after taking the tablet. Hypocalcemia and vitamin D deficiency should be corrected before starting bisphosphonate treatment. However, calcium supplements should only be prescribed if dietary intake is inadequate when starting bisphosphonate treatment for osteoporosis. Vitamin D supplements are usually given.
The duration of bisphosphonate treatment varies depending on the level of risk. Some experts recommend stopping bisphosphonates after five years if the patient is under 75 years old, has a femoral neck T-score of more than -2.5, and is at low risk according to FRAX/NOGG.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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