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Question 1
Correct
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A 35-year-old woman arrives at the emergency department complaining of worsening bone pain in her left hip over the past few days. She mentions feeling ill and feverish, but attributes it to a recent cold. The patient is a known IV drug user and has not traveled recently.
During the examination, the left hip appears red and tender, and multiple track marks are visible.
Which organism is most likely responsible for her symptoms?Your Answer: Staphylococcus aureus
Explanation:Osteomyelitis is most commonly caused by Staphylococcus aureus in both adults and children. IV drug use is a known risk factor for this condition as it can introduce microorganisms directly into the bloodstream. While Escherichia coli can also cause osteomyelitis, it is more prevalent in children than adults. Mycobacterium tuberculosis can also lead to osteomyelitis, but it is less common than Staphylococcus aureus. Bone introduction typically occurs via the circulatory system from pulmonary tuberculosis. However, antitubercular therapy has reduced the incidence of tuberculosis, making bone introduction less likely than with Staphylococcus aureus, which is part of the normal skin flora. Salmonella enterica is the most common cause of osteomyelitis in individuals with sickle cell disease. As the patient is not known to have sickle cell, Staphylococcus aureus remains the most probable cause.
Understanding Osteomyelitis: Types, Causes, and Treatment
Osteomyelitis is a bone infection that can be classified into two types: haematogenous and non-haematogenous. Haematogenous osteomyelitis is caused by bacteria in the bloodstream and is usually monomicrobial. It is more common in children and can be caused by risk factors such as sickle cell anaemia, intravenous drug use, immunosuppression, and infective endocarditis. On the other hand, non-haematogenous osteomyelitis is caused by the spread of infection from adjacent soft tissues or direct injury to the bone. It is often polymicrobial and more common in adults, with risk factors such as diabetic foot ulcers, pressure sores, diabetes mellitus, and peripheral arterial disease.
Staphylococcus aureus is the most common cause of osteomyelitis, except in patients with sickle-cell anaemia where Salmonella species are more prevalent. To diagnose osteomyelitis, MRI is the imaging modality of choice, with a sensitivity of 90-100%.
The treatment for osteomyelitis involves a course of antibiotics for six weeks. Flucloxacillin is the preferred antibiotic, but clindamycin can be used for patients who are allergic to penicillin. Understanding the types, causes, and treatment of osteomyelitis is crucial in managing this bone infection.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 2
Correct
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A 28-year-old male presents to the emergency department with a complaint of right arm pain. He reports that the pain started abruptly while lifting weights at the gym and that his arm feels weaker than usual.
Upon performing an ultrasound of the upper arm, a distal biceps tendon tear is identified.
Which specific movement is expected to be impacted by this injury?Your Answer: Supination and elbow flexion
Explanation:The biceps brachii is mainly responsible for supination and elbow flexion. If the tendon associated with this muscle is torn, it can affect these movements.
External rotation is primarily performed by the infraspinatus and teres minor muscles, not the biceps brachii.
The teres major muscle, not the biceps brachii, is responsible for internal rotation.
Pronation is performed by the pronator quadratus and pronator teres muscles, while elbow flexion is performed by the triceps muscle. Therefore, these actions are not associated with the biceps brachii.
Shoulder abduction involves muscles such as the supraspinatus and deltoid, but it does not involve the biceps brachii.
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 3
Incorrect
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A 65-year-old man with critical limb ischaemia is having a femoro-distal bypass graft. When mobilizing the proximal part of the posterior tibial artery, what is the most vulnerable structure to injury?
Your Answer: Common peroneal nerve
Correct Answer: Tibial nerve
Explanation:The posterior tibial artery and tibial nerve are in close proximity to each other. The nerve passes behind the vessel about 2.5cm below where it begins. Initially, the nerve is positioned on the medial side of the artery, but it shifts to the lateral side after crossing it.
Anatomy of the Posterior Tibial Artery
The posterior tibial artery is a major branch of the popliteal artery that terminates by dividing into the medial and lateral plantar arteries. It is accompanied by two veins throughout its length and its position corresponds to a line drawn from the lower angle of the popliteal fossa to a point midway between the medial malleolus and the most prominent part of the heel.
The artery is located anteriorly to the tibialis posterior and flexor digitorum longus muscles, and posteriorly to the surface of the tibia and ankle joint. The posterior tibial nerve is located 2.5 cm distal to its origin. The proximal part of the artery is covered by the gastrocnemius and soleus muscles, while the distal part is covered by skin and fascia. The artery is also covered by the fascia overlying the deep muscular layer.
Understanding the anatomy of the posterior tibial artery is important for medical professionals, as it plays a crucial role in the blood supply to the foot and ankle. Any damage or blockage to this artery can lead to serious complications, such as peripheral artery disease or even amputation.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 4
Correct
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A 36-year-old woman has a thyroidectomy for Graves disease and subsequently develops a tense hematoma in her neck. Which fascial plane will contain the hematoma?
Your Answer: Pretracheal fascia
Explanation:Tense haematomas can develop due to the unyielding nature of the pretracheal fascia that encloses the thyroid.
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 5
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: Type 2
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 6
Incorrect
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A 25-year-old male patient arrives with a belated diagnosis of appendicitis. The appendix is located retrocaecally and has resulted in a psoas abscess due to perforation. What is the structure that the psoas major muscle inserts into?
Your Answer: None of the above
Correct Answer: Lesser trochanter of the femur
Explanation:The lesser trochanter is the insertion point of the psoas major.
The Psoas Muscle: Origin, Insertion, Innervation, and Action
The psoas muscle is a deep-seated muscle that originates from the transverse processes of the five lumbar vertebrae and the superficial part originates from T12 and the first four lumbar vertebrae. It inserts into the lesser trochanter of the femur and is innervated by the anterior rami of L1 to L3.
The main action of the psoas muscle is flexion and external rotation of the hip. When both sides of the muscle contract, it can raise the trunk from the supine position. The psoas muscle is an important muscle for maintaining proper posture and movement, and it is often targeted in exercises such as lunges and leg lifts.
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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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You are a doctor in the emergency department. A 33-year-old man comes in with weakness in his hand. He was playing basketball with his friends and fell on his hand an hour ago. During the examination, it is observed that the patient cannot extend his forearm, wrist, and fingers, and there is unopposed flexion of the wrist.
Which nerve is most likely affected?Your Answer: Musculocutaneous
Correct Answer: Radial
Explanation:A patient with a humeral midshaft fracture is experiencing wrist drop, which is indicative of radial nerve injury. This is characterized by the inability to extend the forearm, wrist, and fingers, and unopposed flexion of the wrist. It is important to note that injury to the axillary nerve results in flattened deltoid, while median nerve injury can cause paralysis of the thenar muscles or loss of pronation of the forearm and weak wrist flexion. Musculocutaneous nerve injury primarily affects elbow flexion and supination and is unlikely to affect the movements of the forearm, wrist, and fingers. Ulnar nerve injury, on the other hand, leads to a claw hand rather than wrist drop.
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 8
Incorrect
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A 2nd-year medical student is tasked with placing a cannula in the cubital fossa of the patient.
What anatomical structure can be found in the cubital fossa?Your Answer: Ulnar nerve
Correct Answer: Median nerve
Explanation:The only content of the cubital fossa is the median nerve, while the ulnar nerve passes posterior to the medial epicondyle to enter the forearm. The femoral nerve and artery are located in the femoral canal, and the tricep tendon is situated on the posterior aspect of the arm.
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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Question 9
Incorrect
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A 42-year-old female with uncontrolled rheumatoid arthritis and a history of extensive large bowel surgery is prescribed sulfasalazine, a prodrug. However, the consultant is concerned that her shortened colon may hinder the conversion of the prodrug into its active form.
What is the name of the therapeutically active compound that sulfasalazine is converted to in the colon?Your Answer: Sulfamethoxazole
Correct Answer: 5-ASA (5-aminosalicylates)
Explanation:Sulfasalazine: A DMARD for Inflammatory Arthritis and Bowel Disease
Sulfasalazine is a type of disease modifying anti-rheumatic drug (DMARD) that is commonly used to manage inflammatory arthritis, particularly rheumatoid arthritis, as well as inflammatory bowel disease. This medication is a prodrug for 5-ASA, which works by reducing neutrophil chemotaxis and suppressing the proliferation of lymphocytes and pro-inflammatory cytokines.
However, caution should be taken when using sulfasalazine in patients with G6PD deficiency or those who are allergic to aspirin or sulphonamides due to the risk of cross-sensitivity. Adverse effects of sulfasalazine may include oligospermia, Stevens-Johnson syndrome, pneumonitis/lung fibrosis, myelosuppression, Heinz body anaemia, megaloblastic anaemia, and the potential to color tears and stain contact lenses.
Despite these potential side effects, sulfasalazine is considered safe to use during pregnancy and breastfeeding, making it a viable option for women who require treatment for inflammatory arthritis or bowel disease.
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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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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: 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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Question 11
Incorrect
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A 25-year-old male arrives at the emergency department with a deep cut on his left forearm following a knife assault. Upon examination, a deep laceration is observed on his anterior forearm, exposing muscle and subcutaneous tissue. He is unable to flex his left metacarpophalangeal and proximal interphalangeal joints, but his distal interphalangeal joint flexion remains intact. Which structure is the most likely to have been affected?
Your Answer: Flexor carpi radialis
Correct Answer: Flexor digitorum superficialis
Explanation: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 12
Correct
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A 9-year-old boy came to the clinic with a smooth, painless swelling on the superotemporal aspect of his orbit. There were no visual disturbances observed during examination. Upon excision, the lesion was found to be lined by squamous epithelium and hair follicles. Which of the following conditions is most similar to these findings?
Your Answer: Dermoid cyst
Explanation:Dermoid cysts are remnants from embryonic development and can be lined with hair and squamous epithelium, similar to teratomas. They are typically found in the midline and may be connected to deeper structures, resulting in a dumbbell-shaped lesion. Complete removal is necessary as they have a tendency to recur locally if not completely excised.
On the other hand, desmoid tumors are distinct from dermoid cysts. They usually develop in ligaments and tendons and are also known as aggressive fibromatosis. These tumors consist of dense fibroblasts, resembling scar tissue. Treatment for desmoid tumors should be similar to that of soft tissue sarcomas.
Skin Diseases
Skin diseases can be classified into malignant and non-malignant conditions. Malignant skin diseases include basal cell carcinoma, squamous cell carcinoma, malignant melanoma, and Kaposi sarcoma. Basal cell carcinoma is the most common form of skin cancer and typically occurs on sun-exposed areas. Squamous cell carcinoma may arise from pre-existing solar keratoses and can metastasize if left untreated. Malignant melanoma is characterized by changes in size, shape, and color and requires excision biopsy for diagnosis. Kaposi sarcoma is a tumor of vascular and lymphatic endothelium and is associated with immunosuppression.
Non-malignant skin diseases include dermatitis herpetiformis, dermatofibroma, pyogenic granuloma, and acanthosis nigricans. Dermatitis herpetiformis is a chronic itchy condition linked to underlying gluten enteropathy. Dermatofibroma is a benign lesion usually caused by trauma and consists of histiocytes, blood vessels, and fibrotic changes. Pyogenic granuloma is an overgrowth of blood vessels that may mimic amelanotic melanoma. Acanthosis nigricans is characterized by brown to black hyperpigmentation of the skin and is commonly caused by insulin resistance. In the context of a malignant disease, it is referred to as acanthosis nigricans maligna.
In summary, skin diseases can range from benign to malignant conditions. It is important to seek medical attention for any suspicious skin lesions or changes in the skin’s appearance. Early diagnosis and treatment can improve outcomes and prevent complications.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 13
Correct
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Liam is a 5-year-old boy playing outside in the park on his scooter. He accidentally falls off his scooter and scrapes his elbow, causing a small amount of bleeding. After a few days, a scab forms and eventually falls off, leaving the skin healed. What is the outermost layer of the epidermis?
Your Answer: Stratum corneum
Explanation:The epidermis comprises five distinct layers that consist of various cell types and perform different functions. These layers, listed from outermost to innermost, are the stratum corneum, stratum lucidum*, and stratum granulosum.
The Layers of the Epidermis
The epidermis is the outermost layer of the skin and is made up of a stratified squamous epithelium with a basal lamina underneath. It can be divided into five layers, each with its own unique characteristics. The first layer is the stratum corneum, which is made up of flat, dead, scale-like cells filled with keratin. These cells are continually shed and replaced with new ones. The second layer, the stratum lucidum, is only present in thick skin and is a clear layer. The third layer, the stratum granulosum, is where cells form links with their neighbors. The fourth layer, the stratum spinosum, is the thickest layer of the epidermis and is where squamous cells begin keratin synthesis. Finally, the fifth layer is the stratum germinativum, which is the basement membrane and is made up of a single layer of columnar epithelial cells. This layer gives rise to keratinocytes and contains melanocytes. Understanding the layers of the epidermis is important for understanding the structure and function of the skin.
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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 32-year-old cyclist has fallen off his bicycle and landed on an outstretched arm. He complains of pain and swelling in his left shoulder. Upon examination, the shoulder is tender and swollen to the touch. The patient experiences pain when attempting active and passive movement of the shoulder joint. A radiograph is ordered, which reveals an undisplaced fracture of the surgical neck of the humerus. What muscle, in addition to the deltoid muscle, is supplied by the axillary nerve, which is commonly injured in cases of surgical neck humerus fractures? Choose from the following options: subscapularis, teres major, supraspinatus, teres minor, or infraspinatus.
Your Answer: Teres major
Correct Answer: Teres minor
Explanation:The teres minor is the correct answer, as it is a rotator cuff muscle. The supraspinatus and infraspinatus are also rotator cuff muscles that are innervated by the suprascapular nerve, while the subscapularis is innervated by the superior and inferior subscapular nerves. The teres major, however, is not a rotator cuff muscle and is innervated by the inferior subscapular nerve. Fractures of the surgical neck of the humerus can result in injury to the axillary nerve and posterior circumflex artery, making it important to test for axillary nerve function by checking sensation in the ‘regimental badge’ area of the arm and observing shoulder movements.
Understanding the Rotator Cuff Muscles
The rotator cuff muscles are a group of four muscles that are responsible for the movement and stability of the shoulder joint. These muscles are known as the SItS muscles, which stands for Supraspinatus, Infraspinatus, teres minor, and Subscapularis. Each of these muscles has a specific function in the movement of the shoulder joint.
The Supraspinatus muscle is responsible for abducting the arm before the deltoid muscle. It is the most commonly injured muscle in the rotator cuff. The Infraspinatus muscle rotates the arm laterally, while the teres minor muscle adducts and rotates the arm laterally. Lastly, the Subscapularis muscle adducts and rotates the arm medially.
Understanding the functions of each of these muscles is important in diagnosing and treating rotator cuff injuries. By identifying which muscle is injured, healthcare professionals can develop a treatment plan that targets the specific muscle and promotes healing. Overall, the rotator cuff muscles play a crucial role in the movement and stability of the shoulder joint.
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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 35-year-old female tennis player visits her GP with a complaint of pain on the lateral side of her wrist and at the base of her left thumb. The pain has been gradually worsening over the past few weeks and is aggravated by thumb movement. Upon examination, the GP observes tenderness in the area above the first dorsal compartment and a positive Finkelstein test. The GP diagnoses her with De Quervain's tenosynovitis, which is an inflammation of a tendon sheath. What tendons are impacted by this condition?
Your Answer: Flexor pollicis brevis and flexor pollicis longus
Correct Answer: Extensor pollicis brevis and abductor pollicis longus
Explanation:De Quervain’s tenosynovitis is a condition characterized by inflammation of the synovium surrounding a tendon. Specifically, it affects the tendon sheath that encloses two adjacent tendons – the extensor pollicis brevis and abductor pollicis longus – responsible for extending and abducting the thumb. It is important to note that De Quervain’s syndrome only affects these two tendons and not the extensor pollicis longus or any flexors. Additionally, the adductor pollicis muscle is not involved in this condition. Tenderness over the first dorsal compartment is a common sign of De Quervain’s tenosynovitis, as the affected tendons do not travel underneath it.
De Quervain’s Tenosynovitis: Symptoms, Diagnosis, and Treatment
De Quervain’s tenosynovitis is a condition that commonly affects women between the ages of 30 and 50. It occurs when the sheath containing the tendons of the extensor pollicis brevis and abductor pollicis longus becomes inflamed. The condition is characterized by pain on the radial side of the wrist, tenderness over the radial styloid process, and pain when the thumb is abducted against resistance. A positive Finkelstein’s test, in which pain is elicited by ulnar deviation and longitudinal traction of the thumb, is also indicative of the condition.
Treatment for De Quervain’s tenosynovitis typically involves analgesia, steroid injections, and immobilization with a thumb splint (spica). In some cases, surgical intervention may be necessary. With proper diagnosis and treatment, patients can experience relief from the pain and discomfort associated with this condition.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 16
Incorrect
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A 23-year-old man presents to the emergency department after a car accident with complaints of shortness of breath and right shoulder pain. Upon examination, his vital signs are as follows: temperature of 36.5ºC, heart rate of 96 bpm, respiratory rate of 36 breaths per minute, and blood pressure of 125/95 mmHg. The right clavicle is tender and deformed, and there is hyper resonance over the right thorax. A chest x-ray is ordered, which reveals a right-sided apical pneumothorax. Which part of the clavicle is most likely fractured?
Your Answer: Medial third of the clavicle
Correct Answer: Middle third of the clavicle
Explanation:The correct answer is the middle third of the clavicle. The apex of the pleural cavity is located behind this area, with its tip situated in the supraclavicular fossa.
The acromioclavicular junction, lateral third of the clavicle, medial third of the clavicle, and sternoclavicular junction are all incorrect answers. These areas have different anatomical structures and functions.
Anatomy of the Clavicle
The clavicle is a bone that runs from the sternum to the acromion and plays a crucial role in preventing the shoulder from falling forwards and downwards. Its inferior surface is marked by ligaments at each end, including the trapezoid line and conoid tubercle, which provide attachment to the coracoclavicular ligament. The costoclavicular ligament attaches to the irregular surface on the medial part of the inferior surface, while the subclavius muscle attaches to the intermediate portion’s groove.
The superior part of the clavicle’s medial end has a raised surface that gives attachment to the clavicular head of sternocleidomastoid, while the posterior surface attaches to the sternohyoid. On the lateral end, there is an oval articular facet for the acromion, and a disk lies between the clavicle and acromion. The joint’s capsule attaches to the ridge on the margin of the facet.
In summary, the clavicle is a vital bone that helps stabilize the shoulder joint and provides attachment points for various ligaments and muscles. Its anatomy is marked by distinct features that allow for proper function and movement.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 17
Correct
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A 65-year-old man is scheduled for a revisional total hip replacement via a posterior approach. During the procedure, upon dividing the gluteus maximus along its fiber line, there is sudden arterial bleeding. Which vessel is most likely the source of the bleeding?
Your Answer: Inferior gluteal artery
Explanation:The internal iliac artery gives rise to the inferior gluteal artery, which travels along the deep side of the gluteus maximus muscle. This artery is often separated when using the posterior approach to the hip joint.
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 18
Incorrect
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What is a true statement about slipped capital femoral epiphysis?
Your Answer: More common in girls
Correct 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 19
Incorrect
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A 40-year-old male is admitted to a neurology ward with a diagnosis of Guillain-Barre syndrome. During examination, it is observed that there is paralysis of big toe extension.
Which myotome is affected by this paralysis?Your Answer:
Correct Answer: L5
Explanation:The L5 myotome is responsible for extending the big toe, while S1 is responsible for ankle plantar-flexion, ankle eversion, and knee flexion. L4 is responsible for ankle dorsiflexion, and T12 is responsible for abdominal muscle contraction.
The foot has two arches: the longitudinal arch and the transverse arch. The longitudinal arch is higher on the medial side and is supported by the posterior pillar of the calcaneum and the anterior pillar composed of the navicular bone, three cuneiforms, and the medial three metatarsal bones. The transverse arch is located on the anterior part of the tarsus and the posterior part of the metatarsus. The foot has several intertarsal joints, including the sub talar joint, talocalcaneonavicular joint, calcaneocuboid joint, transverse tarsal joint, cuneonavicular joint, intercuneiform joints, and cuneocuboid joint. The foot also has various ligaments, including those of the ankle joint and foot. The foot is innervated by the lateral plantar nerve and medial plantar nerve, and it receives blood supply from the plantar arteries and dorsalis pedis artery. The foot has several muscles, including the abductor hallucis, flexor digitorum brevis, abductor digit minimi, flexor hallucis brevis, adductor hallucis, and extensor digitorum brevis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 20
Incorrect
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During a hip examination, Sarah, a 65-year-old female, is found to have a positive trendelenburg's sign. When she stands on only her left leg, her right pelvis drops.
If the cause of her positive trendelenburg's sign is neurological, which nerve is affected in Sarah?Your Answer:
Correct Answer: Right superior gluteal
Explanation:If the superior gluteal nerve is damaged, it can result in a positive Trendelenburg sign. This nerve is responsible for providing innervation to the gluteus minimus and gluteus medius muscles, which are important for abducting and medially rotating the lower limb, as well as preventing pelvic drop of the opposing limb. For example, when standing on only the right leg, the right gluteus minimus and gluteus medius muscles stabilize the pelvis. However, if the right superior gluteal nerve is damaged, the right gluteus minimus and gluteus medius muscles will not receive proper innervation, leading to instability and a drop in the left pelvis when standing on the right leg. On the other hand, the inferior gluteal nerve innervates the gluteus maximus muscles, which are responsible for extending the thigh and performing lateral rotation.
The Trendelenburg Test: Assessing Gluteal Nerve Function
The Trendelenburg test is a diagnostic tool used to assess the function of the superior gluteal nerve. This nerve is responsible for the contraction of the gluteus medius muscle, which is essential for maintaining balance and stability while standing on one leg.
When the superior gluteal nerve is injured or damaged, the gluteus medius muscle is weakened, resulting in a compensatory shift of the body towards the unaffected side. This shift is characterized by a gravitational shift, which causes the body to be supported on the unaffected limb.
To perform the Trendelenburg test, the patient is asked to stand on one leg while the physician observes the position of the pelvis. In a healthy individual, the gluteus medius muscle contracts as soon as the contralateral leg leaves the floor, preventing the pelvis from dipping towards the unsupported side. However, in a person with paralysis of the superior gluteal nerve, the pelvis on the unsupported side descends, indicating that the gluteus medius on the affected side is weak or non-functional. This is known as a positive Trendelenburg test.
It is important to note that the Trendelenburg test is also used in vascular investigations to determine the presence of saphenofemoral incompetence. In this case, tourniquets are placed around the upper thigh to assess blood flow. However, in the context of assessing gluteal nerve function, the Trendelenburg test is a valuable tool for diagnosing and treating motor deficits and gait abnormalities.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 21
Incorrect
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A 35-year-old male patient arrives at the emergency department following a bicycle accident. He reports experiencing pain and swelling in his right hand and has difficulty moving his thumb. Upon examination, there is reduced range of motion of the thumb and palpable tenderness over the anatomical snuffbox. However, his hand is neurovascularly intact. Can you identify the structures that form the lateral border of this anatomical landmark?
Your Answer:
Correct Answer: Extensor pollicis brevis and abductor pollicis longus tendon
Explanation:The tendons of the extensor pollicis brevis and abductor pollicis longus form the lateral border of the anatomical snuffbox, not the muscles themselves. This patient’s pain and tenderness over the anatomical snuffbox suggest a likely scaphoid fracture, which is a common injury resulting from a fall on an outstretched hand. It is important to keep in mind the boundaries of the anatomical snuffbox, which include the tendons of the extensor pollicis longus, brevis, and abductor pollicis muscles. The proximal border is the styloid process of the radius, the distal border is the apex of the snuffbox triangle, and the floor is made up of the trapezium and scaphoid bones.
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 22
Incorrect
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A 29-year-old Jewish woman comes to a doctor complaining of mouth ulcers and skin blistering. During the examination, the doctor observes Nikolsky's sign. The doctor informs her that she has an autoimmune disease where her body's own cells are being attacked by antibodies. What is the specific target for these antibodies in her condition?
Your Answer:
Correct Answer: Desmoglein 3
Explanation:Pemphigus vulgaris is characterized by the presence of antibodies against desmoglein 3, while Grave’s disease is associated with antibodies against TSH receptors. Cardiac myopathy is linked to antibodies against desmoglein 2, while pemphigus foliaceus is associated with antibodies against desmoglein 1. Hashimoto’s hypothyroidism is characterized by the presence of antibodies against thyroid peroxidase.
Pemphigus vulgaris is an autoimmune condition that occurs when the body’s immune system attacks desmoglein 3, a type of cell adhesion molecule found in epithelial cells. This disease is more prevalent in the Ashkenazi Jewish population. The most common symptom is mucosal ulceration, which can be the first sign of the disease. Oral involvement is seen in 50-70% of patients. Skin blistering is also a common symptom, with easily ruptured vesicles and bullae. These lesions are typically painful but not itchy and may appear months after the initial mucosal symptoms. Nikolsky’s sign is a characteristic feature of pemphigus vulgaris, where bullae spread following the application of horizontal, tangential pressure to the skin. Biopsy results often show acantholysis.
The first-line treatment for pemphigus vulgaris is steroids, which help to reduce inflammation and suppress the immune system. Immunosuppressants may also be used to manage the disease.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 23
Incorrect
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A 48-year-old woman comes to the clinic complaining of chronic back pain. She has no known medical conditions and was recently hospitalized for a wrist fracture sustained while playing frisbee. The hospital discharged her with conservative management. Her blood test results are as follows:
Calcium 1.9 mmol/L (2.1-2.6)
Phosphate 0.8 mmol/L (0.8-1.4)
ALP 172 IU/L (44-147)
Parathyroid Hormone 65 pg/mL (15-65)
What is the probable diagnosis?Your Answer:
Correct Answer: Osteomalacia
Explanation:The patient’s lab results suggest that they have osteomalacia, a condition caused by vitamin D deficiency that results in weak and soft bones. This deficiency leads to poor absorption of calcium in the gastrointestinal tract, which causes low serum calcium levels. In response, the body produces more parathyroid hormone (PTH) to compensate, which lowers serum phosphate levels and increases alkaline phosphatase (ALP) due to increased osteoclast activity.
Osteoporosis also causes weak bones, but it is not a metabolic disease and does not affect electrolyte and hormone levels. Paget’s disease, on the other hand, is characterized by bone pain and abnormal bone growth, but typically has normal calcium, phosphate, and PTH levels. Primary hyperparathyroidism causes high PTH levels, leading to high serum calcium and low serum phosphate levels, and can cause bone pain and fractures. Secondary hyperparathyroidism occurs in chronic kidney disease and is characterized by low serum calcium and high serum phosphate levels, with elevated PTH and ALP levels.
Lab Values for Bone Disorders
When it comes to bone disorders, certain lab values can provide important information about the condition. In cases of osteoporosis, calcium, phosphate, alkaline phosphatase (ALP), and parathyroid hormone (PTH) levels are typically normal. However, in osteomalacia, calcium and phosphate levels are decreased while ALP and PTH levels are increased. Primary hyperparathyroidism, which can lead to osteitis fibrosa cystica, is characterized by increased calcium and PTH levels but decreased phosphate levels. Chronic kidney disease can result in secondary hyperparathyroidism, which is marked by decreased calcium levels and increased phosphate and PTH levels. Paget’s disease, on the other hand, typically shows normal calcium and phosphate levels but increased ALP levels. Finally, osteopetrosis is associated with normal levels of calcium, phosphate, ALP, and PTH. By analyzing these lab values, healthcare professionals can better diagnose and treat bone disorders.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 24
Incorrect
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A 70-year-old retired delivery man visits his family physician with a complaint of knee pain. He reports that the pain is present in both knees and worsens towards the end of the day. The pain usually subsides after resting and in the morning. He has been experiencing knee pain for the past few years and used to take paracetamol, which provided relief. However, the pain has recently intensified, limiting his ability to work. The patient occasionally experiences right hip pain, but it does not bother him much. The patient has a medical history of well-controlled diabetes mellitus, hypertension, and lower back pain. He has a body mass index of 32 kg per m2 and takes metformin, insulin, and candesartan regularly. On examination, there is no redness, swelling, or tenderness over the knees. The physician recommends an X-ray of both knees. What is the most probable X-ray finding?
Your Answer:
Correct Answer: Narrowed joint space, subchondral sclerosis, osteophytes
Explanation:The patient’s symptoms are most consistent with osteoarthritis, with no signs of inflammation. Radiographic findings of narrowed joint space and osteophytes support this diagnosis. Other differential diagnoses include rheumatoid arthritis, gout, and pseudogout. The patient’s occupation as a delivery man may have contributed to the development of osteoarthritis. The presence of symptoms and limitations in daily activities should be considered in developing a management plan.
Comparison of Osteoarthritis and Rheumatoid Arthritis
Osteoarthritis and rheumatoid arthritis are two types of arthritis that affect the joints. Osteoarthritis is caused by mechanical wear and tear, resulting in the localized loss of cartilage, remodelling of adjacent bone, and associated inflammation. On the other hand, rheumatoid arthritis is an autoimmune disease that affects women more commonly than men and can occur in adults of all ages. It typically affects the MCP and PIP joints, causing bilateral symptoms and systemic upset, while osteoarthritis affects large weight-bearing joints such as the hip and knee, as well as the carpometacarpal joint and DIP and PIP joints, causing unilateral symptoms and no systemic upset.
The typical history of osteoarthritis involves pain following use, which improves with rest, while rheumatoid arthritis involves morning stiffness that improves with use. X-ray findings for osteoarthritis include loss of joint space, subchondral sclerosis, subchondral cysts, and osteophytes forming at joint margins. For rheumatoid arthritis, X-ray findings include loss of joint space, juxta-articular osteoporosis, periarticular erosions, and subluxation.
In summary, while both osteoarthritis and rheumatoid arthritis affect the joints, they have different causes, affected joints, symptoms, and X-ray findings. Understanding these differences can help with accurate diagnosis and appropriate treatment.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 25
Incorrect
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A 23-year-old man acquires an infection in the pulp of his pinky finger. What is the closest location to which this infection can spread?
Your Answer:
Correct Answer: Proximal to the flexor retinaculum
Explanation:The tendon sheath that runs from the little finger to the proximal part of the carpal tunnel poses a considerable risk of facilitating the spread of infections towards the proximal direction.
Anatomy of the Hand: Fascia, Compartments, and Tendons
The hand is composed of bones, muscles, and tendons that work together to perform various functions. The bones of the hand include eight carpal bones, five metacarpals, and 14 phalanges. The intrinsic muscles of the hand include the interossei, which are supplied by the ulnar nerve, and the lumbricals, which flex the metacarpophalangeal joints and extend the interphalangeal joint. The thenar eminence contains the abductor pollicis brevis, opponens pollicis, and flexor pollicis brevis, while the hypothenar eminence contains the opponens digiti minimi, flexor digiti minimi brevis, and abductor digiti minimi.
The fascia of the palm is thin over the thenar and hypothenar eminences but relatively thick elsewhere. The palmar aponeurosis covers the soft tissues and overlies the flexor tendons. The palmar fascia is continuous with the antebrachial fascia and the fascia of the dorsum of the hand. The hand is divided into compartments by fibrous septa, with the thenar compartment lying lateral to the lateral septum, the hypothenar compartment lying medial to the medial septum, and the central compartment containing the flexor tendons and their sheaths, the lumbricals, the superficial palmar arterial arch, and the digital vessels and nerves. The deepest muscular plane is the adductor compartment, which contains adductor pollicis.
The tendons of the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) enter the common flexor sheath deep to the flexor retinaculum. The tendons enter the central compartment of the hand and fan out to their respective digital synovial sheaths. The fibrous digital sheaths contain the flexor tendons and their synovial sheaths, extending from the heads of the metacarpals to the base of the distal phalanges.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 26
Incorrect
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A 23-year-old individual presents to the emergency department with a gym-related injury. While lifting a heavy barbell off the floor, they experienced a hamstring pull. Upon examination, the doctor notes weak knee flexion facilitated by the biceps femoris muscle. The doctor suspects nerve damage to the nerves innervating the short and long head of biceps femoris. Which nerve specifically provides innervation to the short head of biceps femoris?
Your Answer:
Correct Answer: Common peroneal branch of sciatic nerve
Explanation:The short head of biceps femoris receives innervation from the common peroneal division of the sciatic nerve. The superior gluteal nerve supplies the gluteus medius and minimus, while the inferior gluteal nerve supplies the gluteus maximus. The perineum is primarily supplied by the pudendal nerve.
The Biceps Femoris Muscle
The biceps femoris is a muscle located in the posterior upper thigh and is part of the hamstring group of muscles. It consists of two heads: the long head and the short head. The long head originates from the ischial tuberosity and inserts into the fibular head. Its actions include knee flexion, lateral rotation of the tibia, and extension of the hip. It is innervated by the tibial division of the sciatic nerve and supplied by the profunda femoris artery, inferior gluteal artery, and the superior muscular branches of the popliteal artery.
On the other hand, the short head originates from the lateral lip of the linea aspera and the lateral supracondylar ridge of the femur. It also inserts into the fibular head and is responsible for knee flexion and lateral rotation of the tibia. It is innervated by the common peroneal division of the sciatic nerve and supplied by the same arteries as the long head.
Understanding the anatomy and function of the biceps femoris muscle is important in the diagnosis and treatment of injuries and conditions affecting the posterior thigh.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 27
Incorrect
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A basketball enthusiast in his early twenties visits his GP complaining of discomfort in his right shoulder and neck, and also reports an unusual appearance on the right side of his upper back.
To assess the condition, the GP asks the patient to stand facing a wall and extend his arms straight in front of him, with his palms flat against the wall. The GP then instructs the patient to bend his arms and push away from the wall. During the movement, the patient's right shoulder blade protrudes from his back.
Based on the symptoms, which nerve is most likely to be affected?Your Answer:
Correct Answer: Long thoracic nerve
Explanation:The correct nerve that supplies the serratus anterior muscle is the long thoracic nerve. This muscle is responsible for pulling the scapula around the thorax, and damage to this nerve can cause medial winging of the scapula.
The axillary nerve is not the correct answer as it supplies the deltoid muscle, which is responsible for shoulder abduction. Damage to this nerve results in a flattened deltoid muscle, not winging of the scapula.
The musculocutaneous nerve supplies the biceps brachii muscle, which is responsible for elbow flexion. Damage to this nerve does not affect the scapulae.
The spinal accessory nerve supplies the sternocleidomastoid and trapezius muscles, and injury to this nerve may result in difficulty turning the head from side to side or shrugging the shoulders. It does not affect the scapulae.
Trauma to the thoracodorsal nerve may cause atrophy of the latissimus dorsi muscle and difficulty moving the affected shoulder, but it does not cause winging of the scapula.
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 28
Incorrect
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Which one of the following is a branch of the fourth part of the axillary artery?
Your Answer:
Correct Answer: Posterior circumflex humeral
Explanation:Anatomy of the Axilla
The axilla, also known as the armpit, is a region of the body that contains important structures such as nerves, veins, and lymph nodes. It is bounded medially by the chest wall and serratus anterior, laterally by the humeral head, and anteriorly by the lateral border of the pectoralis major. The floor of the axilla is formed by the subscapularis muscle, while the clavipectoral fascia forms its fascial boundary.
One of the important nerves that passes through the axilla is the long thoracic nerve, which supplies the serratus anterior muscle. The thoracodorsal nerve and trunk, on the other hand, innervated and vascularize the latissimus dorsi muscle. The axillary vein, which is the continuation of the basilic vein, lies at the apex of the axilla and becomes the subclavian vein at the outer border of the first rib. The intercostobrachial nerves, which provide cutaneous sensation to the axillary skin, traverse the axillary lymph nodes and are often divided during axillary surgery.
The axilla is also an important site of lymphatic drainage for the breast. Therefore, any pathology or surgery involving the breast can affect the lymphatic drainage of the axilla and lead to lymphedema. Understanding the anatomy of the axilla is crucial for healthcare professionals who perform procedures in this region, as damage to any of the structures can lead to significant complications.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 29
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:
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 30
Incorrect
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Rachel is a 26-year-old female who arrives at the emergency department with an anteriorly dislocated shoulder and fracture of the surgical neck of the humerus.
What signs are most likely to be elicited due to the probable nerve damage?Your Answer:
Correct Answer: Loss of sensation over the deltoid muscle on the outer-upper arm
Explanation:If a patient is experiencing difficulty abducting their arm after a humeral neck fracture, it may be due to damage to the axillary nerve. This nerve is commonly affected by anterior shoulder dislocations and surgical neck fractures of the humerus. The axillary nerve provides sensation to the area over the deltoid muscle, known as the regimental area. It is important to note that the skin over the olecranon is supplied by the radial nerve, while the intercostobrachial nerve supplies the skin over the axilla. The musculocutaneous nerve is responsible for supplying sensation to the skin over the palmar surface of the lateral forearm. Damage to the axillary nerve would not specifically affect the C6 dermatome.
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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