-
Question 1
Correct
-
An 80-year-old white woman visits her GP with complaints of stiffness, pain, and swelling in her hands. The symptoms are more severe in the morning and gradually improve throughout the day. She has a medical history of hypertension and gout. She admits to taking her husband's prednisolone tablets occasionally to manage her symptoms.
What risk factors does this patient have for the probable diagnosis?Your Answer: Female sex
Explanation:Rheumatoid arthritis is more prevalent in female patients, with a 3-fold higher incidence compared to males. It is characterized by symmetrical pain and stiffness, particularly in the morning. Rheumatoid arthritis can affect individuals of any age and is treated with medications such as prednisolone. Contrary to popular belief, gout does not increase the likelihood of developing rheumatoid arthritis. Additionally, ethnicity, specifically being of white descent, is not considered a risk factor for this condition.
Understanding the Epidemiology of Rheumatoid Arthritis
Rheumatoid arthritis is a chronic autoimmune disease that affects people of all ages, but it typically peaks between the ages of 30 and 50. The condition is more common in women, with a female-to-male ratio of 3:1. The prevalence of rheumatoid arthritis is estimated to be around 1% of the population. However, there are some ethnic differences in the incidence of the disease, with Native Americans having a higher prevalence than other groups.
Researchers have identified a genetic link to rheumatoid arthritis, with the HLA-DR4 gene being associated with the development of the condition. This gene is particularly linked to a subtype of rheumatoid arthritis known as Felty’s syndrome. Understanding the epidemiology of rheumatoid arthritis is important for healthcare professionals to provide appropriate care and support to those affected by the disease. By identifying risk factors and understanding the prevalence of the condition, healthcare providers can better tailor their treatment plans to meet the needs of their patients.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 2
Incorrect
-
An 82-year-old man arrives at the emergency department with sepsis of unknown origin. During a thorough examination, it is discovered that his big toe is swollen, black, and tender. A fluid collection is also present at the nail bed. The patient has a history of uncontrolled type 1 diabetes mellitus. An MRI confirms the diagnosis of osteomyelitis. What is the probable causative organism?
Your Answer: Staphylococcus epidermidis
Correct Answer: Staphylococcus aureus
Explanation:The most common cause of osteomyelitis is Staphylococcus aureus, a bacteria that is normally found on the skin and mucus membranes but can become pathogenic in individuals who are immunocompromised or have risk factors for infections. Clostridium perfringens, Pseudomonas aeruginosa, and Staphylococcus epidermidis are not common causes of osteomyelitis, although they may cause other types of infections.
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.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 3
Incorrect
-
A 30-year-old man falls and suffers a fracture to the medial third of his clavicle. What is the vessel that is most vulnerable to injury?
Your Answer: Subclavian artery
Correct Answer: Subclavian vein
Explanation:The subclavian vein is situated at the back of the subclavius muscle and the medial portion of the clavicle. It is positioned below and in front of the third segment of the subclavian artery, resting on the first rib, and then on scalenus anterior, which separates it from the second segment of the artery at the back.
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.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 4
Incorrect
-
Which one of the following is not closely related to the capitate bone?
Your Answer: Trapezoid bone
Correct Answer: Ulnar nerve
Explanation:The pisiform bone is in close proximity to both the ulnar nerve and artery. Additionally, the capitate bone is in articulation with the lunate, scaphoid, hamate, and trapezoid bones, indicating a close relationship between them.
The Capitate Bone: Largest of the Carpal Bones
The capitate bone is the largest of the carpal bones and is located centrally in the wrist. It has a rounded head that fits into the cavities of the lunate and scaphoid bones. The bone also has flatter articular surfaces for the hamate medially and the trapezoid laterally. At the distal end, the capitate bone primarily articulates with the middle metacarpal. Overall, the capitate bone plays an important role in the structure and function of the wrist joint.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 5
Incorrect
-
The etiology of osteopetrosis is most effectively described by a malfunction in which of the following?
Your Answer: PTH receptors
Correct Answer: Osteoclast function
Explanation:Understanding Osteopetrosis: A Rare Disorder of Bone Resorption
Osteopetrosis, also known as marble bone disease, is a rare disorder that affects the normal function of osteoclasts, leading to a failure of bone resorption. This results in the formation of dense, thick bones that are more prone to fractures. Individuals with osteopetrosis often experience bone pains and neuropathies. Despite the abnormal bone growth, levels of calcium, phosphate, and ALP remain normal.
Treatment options for osteopetrosis include stem cell transplant and interferon-gamma therapy. However, these treatments are not always effective and may have significant side effects. As such, early diagnosis and management of osteopetrosis is crucial in preventing complications and improving quality of life for affected individuals.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 6
Incorrect
-
A 56-year-old man presents to his GP complaining of numbness and tingling in his thumb, middle, and index fingers for the past 8 months. This is beginning to interfere with his work as a financial analyst. He has a history of hypothyroidism for which he takes 100 micrograms of thyroxine daily.
Which nerves are involved in this condition?Your Answer: Axillary nerve
Correct Answer: Median nerve
Explanation:To identify the affected nerve, it is crucial to accurately diagnose the underlying condition. The patient’s symptoms, such as numbness and tingling in the thumb and middle finger (and possibly the radial half of the ring finger), suggest carpal tunnel syndrome. Additionally, the patient’s occupation involving computer use and hypothyroidism are risk factors for this condition.
Carpal tunnel syndrome occurs when the median nerve is compressed at the carpal tunnel as it passes through the wrist.
Carpal tunnel syndrome is a condition that occurs when the median nerve in the carpal tunnel is compressed. This can cause pain and pins and needles sensations in the thumb, index, and middle fingers. In some cases, the symptoms may even travel up the arm. Patients may shake their hand to alleviate the discomfort, especially at night. During an examination, weakness in thumb abduction and wasting of the thenar eminence may be observed. Tapping on the affected area may also cause paraesthesia, and flexing the wrist can trigger symptoms.
There are several potential causes of carpal tunnel syndrome, including idiopathic factors, pregnancy, oedema, lunate fractures, and rheumatoid arthritis. Electrophysiology tests may reveal prolongation of the action potential in both motor and sensory nerves. Treatment options may include a six-week trial of conservative measures such as wrist splints at night or corticosteroid injections. If symptoms persist or are severe, surgical decompression may be necessary, which involves dividing the flexor retinaculum.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 7
Incorrect
-
A 9-year-old child has been brought to the emergency department after falling onto their shoulder during a soccer game. They are experiencing pain across their shoulder and upper chest, which is most severe when the clavicular area is palpated. A visible bony deformity is present in the clavicular area. The physician suspects a fracture and orders an x-ray.
What is the most probable location of the fracture?Your Answer: Distal third of the clavicle
Correct Answer: Middle third of the clavicle
Explanation:The most frequent location for clavicle fractures is the middle third, which is the weakest part of the bone and lacks any ligaments or muscles. This is especially common in young children. Fractures in the proximal and distal thirds are less frequent and therefore incorrect answers. While sternum fractures can occur in high-force trauma, the mechanism of injury and visible bony deformity in this case suggest a clavicular fracture. Acromion fractures are rare and would not result in the observed bony injury.
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.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 8
Incorrect
-
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: Brachioradialis muscle
Correct Answer: Radial nerve
Explanation:Upper limb anatomy is a common topic in examinations, and it is important to know certain facts about the nerves and muscles involved. The musculocutaneous nerve is responsible for elbow flexion and supination, and typically only injured as part of a brachial plexus injury. The axillary nerve controls shoulder abduction and can be damaged in cases of humeral neck fracture or dislocation, resulting in a flattened deltoid. The radial nerve is responsible for extension in the forearm, wrist, fingers, and thumb, and can be damaged in cases of humeral midshaft fracture, resulting in wrist drop. The median nerve controls the LOAF muscles and can be damaged in cases of carpal tunnel syndrome or elbow injury. The ulnar nerve controls wrist flexion and can be damaged in cases of medial epicondyle fracture, resulting in a claw hand. The long thoracic nerve controls the serratus anterior and can be damaged during sports or as a complication of mastectomy, resulting in a winged scapula. The brachial plexus can also be damaged, resulting in Erb-Duchenne palsy or Klumpke injury, which can cause the arm to hang by the side and be internally rotated or associated with Horner’s syndrome, respectively.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 9
Incorrect
-
A 79-year-old woman arrived at the hospital complaining of pain in her right hip and thigh after falling from her bed. According to her, she fell while attempting to get up and go to the bathroom during the night. During the physical examination, the physician observed that her right leg was externally rotated and shorter than her left leg. What is the most probable pathological alteration present in this woman?
Your Answer: Impaired mineralization of osteoid and hyperactive osteoblasts
Correct Answer: Decreased cortical and trabecular bone mass with normal bone mineralization
Explanation:The patient’s shortened and externally rotated right leg indicated a fracture of the neck of the femur, which was determined to be a fragility fracture due to osteoporosis. This condition is a common cause of fragility fractures in postmenopausal women, as decreased estrogen levels lead to increased bone resorption and decreased bone mass. Other bone-related conditions, such as osteopetrosis, osteomalacia, Paget disease of the bone, and osteosarcoma, have different underlying causes and presentations.
Osteoporosis is a condition that is more prevalent in women and increases with age. However, there are many other risk factors and secondary causes of osteoporosis. Some of the most significant risk factors include a history of glucocorticoid use, rheumatoid arthritis, alcohol excess, parental hip fracture history, low body mass index, and current smoking. Other risk factors include a sedentary lifestyle, premature menopause, certain ethnicities, endocrine disorders, gastrointestinal disorders, chronic kidney disease, and certain genetic disorders. Additionally, certain medications such as SSRIs, antiepileptics, and proton pump inhibitors may worsen osteoporosis.
If a patient is diagnosed with osteoporosis or has a fragility fracture, further investigations may be necessary to identify the cause of osteoporosis and assess the risk of subsequent fractures. Recommended investigations include a history and physical examination, blood tests such as a full blood count, urea and electrolytes, liver function tests, bone profile, CRP, and thyroid function tests. Other procedures may include bone densitometry, lateral radiographs, protein immunoelectrophoresis, and urinary Bence-Jones proteins. Additionally, markers of bone turnover and urinary calcium excretion may be assessed. By identifying the cause of osteoporosis and contributory factors, healthcare providers can select the most appropriate form of treatment.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 10
Incorrect
-
At what level does the inferior thyroid artery penetrate the thyroid gland?
Your Answer: C4
Correct Answer: C6
Explanation:Surface Anatomy of the Neck: Identifying Structures and Corresponding Levels
The neck is a complex region of the body that contains numerous structures and landmarks. By understanding the surface anatomy of the neck, healthcare professionals can accurately identify and locate important structures during physical examinations and medical procedures.
In the midline of the neck, several structures can be felt from top to bottom. These include the hyoid at the level of C3, the notch of the thyroid cartilage at C4, and the cricoid cartilage at C6. The lower border of the cricoid cartilage is particularly significant as it corresponds to several important structures, including the junction of the larynx and trachea, the junction of the pharynx and esophagus, and the level at which the inferior thyroid artery enters the thyroid gland. Additionally, the vertebral artery enters the transverse foramen in the 6th cervical vertebrae at this level, and the superior belly of the omohyoid muscle crosses the carotid sheath. The middle cervical sympathetic ganglion is also located at this level, as well as the carotid tubercle, which can be used to compress the carotid artery.
Overall, understanding the surface anatomy of the neck is crucial for healthcare professionals to accurately identify and locate important structures during physical examinations and medical procedures.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 11
Incorrect
-
A 67-year-old postmenopausal woman visits the clinic to discuss her bone densitometry results. She has a history of hypertension and does not use tobacco, alcohol, or illicit drugs. Her BMI is 22.1 kg/m² and physical examination is unremarkable. Serum calcium, phosphorus concentrations, and serum alkaline phosphatase activity are within the reference ranges. The bone densitometry shows low bone density consistent with osteoporosis. What medication was most likely prescribed to inhibit osteoclast-mediated bone resorption, and resulted in no further loss of bone mineral density on repeat bone densitometry 1 year later?
Your Answer: Denosumab
Correct Answer: Risedronate
Explanation:Bisphosphonates, such as alendronate and risedronate, are used to treat osteoporosis by preventing bone resorption through the inhibition of osteoclasts. These drugs are taken up by the osteoclasts, preventing them from adhering to the bone surface and continuing the resorption process.
Denosumab is a monoclonal antibody that works by binding to the receptor activator of nuclear factor kappa-B ligand (RANK-L), which blocks the interaction between RANK-L and RANK, ultimately reducing bone resorption.
Raloxifene is a selective estrogen receptor modulator that has estrogen-like effects on bone, leading to decreased bone resorption and improved bone density.
Romosozumab is a monoclonal antibody that inhibits the action of sclerostin, a regulatory factor in bone metabolism, ultimately leading to increased bone formation.
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.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 12
Incorrect
-
Which nerve provides innervation to the interossei of the fifth finger?
Your Answer: Radial
Correct Answer: Deep ulnar
Explanation:PAD and DAB can be remembered as a mnemonic for the actions of the palmar and dorsal interossei muscles. The palmar interossei muscles ADduct the fingers towards the midline of the hand, while the dorsal interossei muscles ABduct the fingers away from the midline.
Interossei: Muscles of the Hand
Interossei are a group of muscles located in the hand that occupy the spaces between the metacarpal bones. There are three palmar and four dorsal interossei, each with a specific origin and insertion point. Palmar interossei originate from the metacarpal of the digit on which it acts, while dorsal interossei come from the surface of the adjacent metacarpal on which it acts. The interosseous tendons, except the first palmar, pass to one or other side of the metacarpophalangeal joint posterior to the deep transverse metacarpal ligament. They become inserted into the base of the proximal phalanx and partly into the extensor hood.
All interossei are innervated by the ulnar nerve and have specific actions. Dorsal interossei abduct the fingers, while palmar interossei adduct the fingers. Along with the lumbricals, the interossei flex the metacarpophalangeal joints and extend the proximal and distal interphalangeal joints. They are responsible for fine-tuning these movements.
In cases where the interossei and lumbricals are paralyzed, the digits are pulled into hyperextension by extensor digitorum, resulting in a claw hand. Understanding the function and innervation of the interossei is important in diagnosing and treating hand injuries and conditions.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 13
Incorrect
-
A 75-year-old woman experiences a fracture at the surgical neck of her humerus and requires surgery. During the operation, there are challenges in realigning the fracture, and a blood vessel located behind the surgical neck is damaged. What is the most probable vessel that was injured?
Your Answer: Axillary artery
Correct Answer: Posterior circumflex humeral artery
Explanation:The surgical neck is where the circumflex humeral arteries are located, with the posterior circumflex humeral artery being the most susceptible to injury in this situation. The thoracoacromial and transverse scapular arteries are situated in a more superomedial position. It is worth noting that the axillary artery gives rise to the posterior circumflex humeral artery.
The shoulder joint is a shallow synovial ball and socket joint that is inherently unstable but capable of a wide range of movement. Stability is provided by the muscles of the rotator cuff. The glenoid labrum is a fibrocartilaginous rim attached to the free edge of the glenoid cavity. The fibrous capsule attaches to the scapula, humerus, and tendons of various muscles. Movements of the shoulder joint are controlled by different muscles. The joint is closely related to important anatomical structures such as the brachial plexus, axillary artery and vein, and various nerves and vessels.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 14
Incorrect
-
Which of the following structures separates the ulnar artery from the median nerve?
Your Answer: Brachioradialis
Correct Answer: Pronator teres
Explanation:It is located deeply to the pronator teres muscle, which creates a separation from the median nerve.
Anatomy of the Ulnar Artery
The ulnar artery is a blood vessel that begins in the middle of the antecubital fossa and runs obliquely downward towards the ulnar side of the forearm. It then follows the ulnar border to the wrist, where it crosses over the flexor retinaculum and divides into the superficial and deep volar arches. The artery is deep to the pronator teres, flexor carpi radialis, and palmaris longus muscles, and lies on the brachialis and flexor digitorum profundus muscles. At the wrist, it is superficial to the flexor retinaculum.
The ulnar nerve runs medially to the lower two-thirds of the artery, while the median nerve is in relation with the medial side of the artery for about 2.5 cm before crossing over it. The artery also gives off a branch called the anterior interosseous artery.
Understanding the anatomy of the ulnar artery is important for medical professionals, as it plays a crucial role in the blood supply to the forearm and hand.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 15
Incorrect
-
A 68-year-old woman presents to her GP for a routine health check-up. She has a medical history of hypertension, which is managed with a daily dose of ACE inhibitor. During a screening DEXA scan, her pelvis and femur show T-scores of -2.6 and -2.9, respectively.
What results would you anticipate from her laboratory tests?Your Answer: Increased ALP, PTH and serum phosphate; decreased serum calcium
Correct Answer: Normal serum calcium, serum phosphate, ALP and PTH
Explanation:Osteoporosis is the diagnosis for this patient, as indicated by a T-score of less than -2.5 on their DEXA scan. Their lab results for serum calcium, serum phosphate, ALP, and PTH are all within normal ranges for osteoporosis.
Patients with osteomalacia typically have decreased serum calcium and serum phosphate levels, along with increased ALP and PTH levels.
Paget’s disease is characterized by an isolated increase in ALP, while the rest of the lab values are normal.
Hyperparathyroidism is indicated by increased PTH levels, with the specific lab values depending on whether the patient has primary or secondary hyperparathyroidism.
Primary hyperparathyroidism is characterized by raised PTH, calcium, and ALP levels, as increased bone resorption leads to high serum calcium and ALP levels. PTH also causes increased phosphate excretion by the kidneys, resulting in low serum phosphate levels.
Secondary hyperparathyroidism is indicated by raised PTH, phosphate, and ALP levels, typically seen in patients with chronic kidney disease. In this case, the kidneys cannot excrete phosphate, leading to increased serum phosphate levels, which in turn causes increased PTH secretion. PTH causes bone resorption, leading to high ALP levels. Chronic kidney disease also impairs vitamin D activation, resulting in hypocalcemia.
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.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 16
Incorrect
-
Which structure divides the cephalic vein and the brachial artery in the antecubital fossa?
Your Answer: Origin of flexor digitorum profundus muscle
Correct Answer: Biceps muscle
Explanation: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.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 17
Incorrect
-
A 25-year-old woman has fallen off her horse and landed on the side of her neck. Despite having a glasgow coma scale of 15 and being able to move all her limbs, she has been taken to the emergency department for examination. Upon examination, it was discovered that she has a medially rotated arm with an extended and pronated forearm, along with a flexion of the wrist. What type of injury has she sustained?
Your Answer: Humeral fracture
Correct Answer: Erb's Palsy
Explanation:What is the location of an erb’s palsy? This condition is a nerve disorder in the arm that results from damage to the upper group of the brachial plexus, primarily affecting the C5-C6 nerves in the upper trunk. It is often caused by trauma to the head and neck, which can stretch the nerves in the plexus and cause more damage to the upper trunk.
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.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 18
Incorrect
-
A 50-year-old obese female with twice-yearly flares of ulcerative colitis has presented to the gastroenterology department with flare. She was previously being managed well with steroids. After doing the thiopurine methyltransferase (TPMT) test she is started on a medication. A complete blood count done after a month of starting treatment shows:
Hb 112 g/L Male: (135-180)
Female: (115 - 160)
Platelets 68 * 109/L (150 - 400)
WBC 25 * 109/L (4.0 - 11.0)
What is the active compound that the drug being used in the treatment of this patient's condition is metabolized to?Your Answer: Purine
Correct Answer: Mercaptopurine
Explanation:Azathioprine is utilized for treating Crohn’s disease in this patient, and it is likely that the drug is metabolized into mercaptopurine, an active compound that acts as a purine analogue and inhibits purine synthesis.
In the purine catabolism pathway, inosine is produced when AMP is deaminated by adenylate (AMP) deaminase to form IMP. Inosine is then formed by hydrolysis of IMP with nucleotidase.
Hypoxanthine is also produced in the purine catabolism pathway through the phosphorylation of inosine. Xanthine is formed when hypoxanthine is oxidized by xanthine oxidase.
The answer purine is incorrect because azathioprine does not convert into purines, but rather it inhibits their synthesis.
Azathioprine is a medication that is converted into mercaptopurine, which is an active compound that inhibits the production of purine. To determine if someone is at risk for azathioprine toxicity, a test for thiopurine methyltransferase (TPMT) may be necessary. Adverse effects of this medication include bone marrow depression, nausea and vomiting, pancreatitis, and an increased risk of non-melanoma skin cancer. If infection or bleeding occurs, a full blood count should be considered. It is important to note that there may be a significant interaction between azathioprine and allopurinol, so lower doses of azathioprine should be used. However, azathioprine is generally considered safe to use during pregnancy.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 19
Incorrect
-
As a medical student on placement with a surgical team, you come across a patient who has developed foot drop in their right leg after surgery. You notice that the patient is dragging their right foot and experiencing weakness in dorsiflexion and eversion of their foot, as well as an inability to extend their toes. Which nerve is most likely to have been affected during the operation?
Your Answer: Sciatic nerve
Correct Answer: Common fibular nerve
Explanation:The common fibular nerve starts at the top of the popliteal fossa, passing medial to the biceps femoris and then crossing over the head of the gastrocnemius. It provides an articular branch to the knee before winding around the neck and passing under the Fibularis longus. At this point, it divides into superficial and deep branches. In the popliteal fossa, it also divides to give the lateral sural cutaneous nerve, which joins with a branch from the tibial nerve to form the sural nerve. If the nerve is damaged, it can result in foot drop, which can occur due to prolonged pressure on the nerve during an operation or other causes. Motor loss of other nerves, such as the tibial, sciatic, inferior gluteal, or femoral nerves, can result in weakness in other muscles.
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.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
-
Question 20
Incorrect
-
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: Osteoporosis
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.
-
This question is part of the following fields:
- Musculoskeletal System And Skin
-
00
Correct
00
Incorrect
00
:
00
:
00
Session Time
00
:
00
Average Question Time (
Secs)