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Question 1
Correct
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A 28 years old has a bike accident leading to a fracture in the wrist.
What is the type of joint that is fractured?Your Answer: Synovial condyloid
Explanation:The wrist is classified as a synovial condyloid joint, consisting of 8 carpal bones that enable movements such as abduction, adduction, flexion, and extension. On the other hand, synovial hinge joints only allow movement in one plane, such as the elbow and knee joints. Meanwhile, secondary cartilaginous joints, also known as midline joints, are fibrocartilaginous fusions between two bones that allow very minimal movement, such as the sternomanubrial joint and symphysis pubis. Synovial saddle joints, on the other hand, allow flexion, extension, adduction, abduction, and circumduction, but not axial rotation, with examples including the carpometacarpal joint of the thumb and the sternoclavicular joint of the chest. Lastly, synovial plane joints only permit gliding movement, such as the joint between carpal bones in the hand.
Carpal Bones: The Wrist’s Building Blocks
The wrist is composed of eight carpal bones, which are arranged in two rows of four. These bones are convex from side to side posteriorly and concave anteriorly. The trapezium is located at the base of the first metacarpal bone, which is the base of the thumb. The scaphoid, lunate, and triquetrum bones do not have any tendons attached to them, but they are stabilized by ligaments.
In summary, the carpal bones are the building blocks of the wrist, and they play a crucial role in the wrist’s movement and stability. The trapezium bone is located at the base of the thumb, while the scaphoid, lunate, and triquetrum bones are stabilized by ligaments. Understanding the anatomy of the wrist is essential for diagnosing and treating wrist injuries and conditions.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 2
Incorrect
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A 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: Internal carotid 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.
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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 46-year-old woman arrives at the emergency department after falling while walking her dog. She explains that she stumbled on the pavement and landed on her left hand, with her hands taking the brunt of the fall.
During the examination, the doctor notices tenderness over the anatomical snuffbox and telescoping of the left thumb. What other structure is in danger of being harmed, considering the probable diagnosis?Your Answer: Ulnar artery
Correct Answer: Radial artery
Explanation:The anatomical snuffbox contains the radial artery and is a common site for scaphoid fractures. The scaphoid bone forms the floor of the snuffbox and the radial artery provides its blood supply. Missing a scaphoid fracture can lead to avascular necrosis. Other structures such as the flexor pollicis longus tendon, median nerve, pisiform bone, and ulnar artery do not lie within the snuffbox.
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 4
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: S2
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 5
Incorrect
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A 25-year-old man was in a car accident where two cars collided at around 60 miles per hour. After being stabilized, the doctor conducts a secondary survey and finds that the patient's right leg is adducted, flexed, and internally rotated. The diagnosis is a hip dislocation. What type of dislocation is probable and why?
Your Answer: Anterior dislocation as the ischiofemoral ligament is strongest
Correct Answer: Posterior dislocation as the iliofemoral ligament is strongest
Explanation:The iliofemoral ligament is the strongest ligament stabilizing the hip joint, making posterior dislocations more common. The deep acetabulum of the hip provides stability and reduces the risk of anterior dislocation. The ischiofemoral ligament is the weakest of the three capsular ligaments and does not play a significant role in hip stability. Therefore, the iliofemoral ligament is the most important factor in preventing hip dislocation.
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 6
Correct
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You are the junior doctor working in the emergency department. A 30-year-old male is brought in by ambulance after being caught in a house fire. He has significant burns spreading across his left arm, chest, abdomen and left thigh. During the A to E assessment, the consultant working with you asks you to give the patient aggressive fluid resuscitation using 1L of 0.9% sodium chloride over 30 minutes.
What is the rationale behind administering aggressive fluid resuscitation to this patient?Your Answer: Burns cause fluid loss via third spacing
Explanation:To determine the severity of a burn, a thorough examination is necessary. A superficial burn only affects the epidermis, while a partial thickness burn affects the dermis, and a full-thickness burn affects all layers of skin, including subcutaneous tissues, muscle, and bone if severe.
Third spacing occurs when fluid moves from the intravascular space to the interstitial or third space due to increased capillary permeability and loss of albumin. This can cause hypotension, making it crucial to replace intravascular volume in the management of severe burns.
While burns can cause fluid loss through evaporation, it is minimal and can be stopped by removing the source of the burn.
While adequate hydration is important for healing any injury, it is not the reason for aggressive fluid resuscitation. It is worth noting that a patient’s energy requirement increases during burn recovery, and they may require up to 6000 calories per day.
Maintenance fluids are given to patients who cannot drink enough to stay hydrated, such as those who are cognitively impaired or nil by mouth before surgery. Unlike resuscitation fluids, maintenance fluids provide the body with the necessary water, electrolytes, and glucose to function normally in a day based on weight.
Fluids do not affect the inflammatory process and therefore cannot reduce inflammation caused by burns.
First Aid and Management of Burns
Burns can be caused by heat, electricity, or chemicals. Immediate first aid involves removing the person from the source of the burn and irrigating the affected area with cool water. The extent of the burn can be assessed using Wallace’s Rule of Nines or the Lund and Browder chart. The depth of the burn can be determined by its appearance, with full-thickness burns being the most severe. Referral to secondary care is necessary for deep dermal and full-thickness burns, as well as burns involving certain areas of the body or suspicion of non-accidental injury.
Severe burns can lead to tissue loss, fluid loss, and a catabolic response. Intravenous fluids and analgesia are necessary for resuscitation and pain relief. Smoke inhalation can result in airway edema, and early intubation may be necessary. Circumferential burns may require escharotomy to relieve compartment syndrome and improve ventilation. Conservative management is appropriate for superficial burns, while more complex burns may require excision and skin grafting. There is no evidence to support the use of antimicrobial prophylaxis or topical antibiotics in burn patients.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 7
Incorrect
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A 68-year-old female comes in with a sudden onset of back pain that radiates down her lower limb while she was gardening and bending forward. During a neurological examination of her lower limb, it was discovered that she has reduced power when flexing her hip and extending her knee. Her patellar reflex was also reduced, and there is decreased sensation in the anteromedial aspect of her thigh. Can you determine the level at which the intervertebral disc herniation is located based on these examination findings?
Your Answer: L2-L3
Correct Answer: L3-L4
Explanation:If there is a disc herniation at the L3-L4 level, it can impact the L4 spinal nerve and lead to issues with the femoral nerve’s function. A herniation at the L2-L3 level can cause L3 radiculopathy and result in weakness in hip adduction. On the other hand, a herniation at the L3-L4 level can cause L4 radiculopathy and lead to weakness in knee extension, with a greater contribution from L4 than L3, as well as a decrease in the patellar reflex.
Understanding Prolapsed Disc and its Features
A prolapsed disc in the lumbar region can cause leg pain and neurological deficits. The pain is usually more severe in the leg than in the back and worsens when sitting. The features of the prolapsed disc depend on the site of compression. For instance, compression of the L3 nerve root can cause sensory loss over the anterior thigh, weak quadriceps, reduced knee reflex, and a positive femoral stretch test. On the other hand, compression of the L4 nerve root can cause sensory loss in the anterior aspect of the knee, weak quadriceps, reduced knee reflex, and a positive femoral stretch test.
Similarly, compression of the L5 nerve root can cause sensory loss in the dorsum of the foot, weakness in foot and big toe dorsiflexion, intact reflexes, and a positive sciatic nerve stretch test. Lastly, compression of the S1 nerve root can cause sensory loss in the posterolateral aspect of the leg and lateral aspect of the foot, weakness in plantar flexion of the foot, reduced ankle reflex, and a positive sciatic nerve stretch test.
The management of prolapsed disc is similar to that of other musculoskeletal lower back pain, which includes analgesia, physiotherapy, and exercises. However, if the symptoms persist even after 4-6 weeks, referral for an MRI is appropriate. Understanding the features of prolapsed disc can help in early diagnosis and prompt management.
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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 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: Sternoclavicular junction
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 9
Incorrect
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A 70-year-old man with a history of untreated hypertension and diabetes mellitus presents to the clinic with worsening bone and joint pain. Upon examination, diffuse muscular tenderness is noted but is otherwise unremarkable. The following blood test results are obtained:
Calcium 1.9 mmol/L (2.1-2.6)
Phosphate 2.0 mmol/L (0.8-1.4)
ALP 170 IU/L (44-147)
Parathyroid Hormone 70 pg/mL (15-65)
What is the most likely diagnosis?Your Answer: Humoral hypercalcemia of malignancy
Correct Answer: Secondary hyperparathyroidism
Explanation:The patient’s low serum calcium, high serum phosphate, high ALP, and high PTH levels suggest that they have chronic kidney disease leading to secondary hyperparathyroidism. This occurs when the kidneys are unable to synthesize enough vitamin D, resulting in low calcium levels. Additionally, poor kidney function leads to high phosphate levels. As a compensatory mechanism, the parathyroid hormone levels increase, causing lytic bone lesions and high ALP, which explains the patient’s diffuse musculoskeletal tenderness.
Humoral hypercalcemia of malignancy is a condition where parathyroid hormone-related peptide acts similarly to parathyroid hormone, leading to high calcium levels. However, phosphate levels would be low or normal due to the effect of this hormone. In contrast, this patient’s parathyroid hormone levels are high, indicating secondary hyperparathyroidism.
Liver disease alone does not typically cause disturbances in calcium metabolism.
Primary hyperparathyroidism is characterized by excess secretion of parathyroid hormone, resulting in high serum calcium and parathyroid hormone levels. However, in this condition, phosphate levels are low due to the effect of high parathyroid hormone. This patient’s blood work does not suggest primary hyperparathyroidism.
Tertiary hyperparathyroidism occurs in end-stage renal disease, where longstanding secondary hyperparathyroidism leads to excess production of parathyroid hormone and eventual hypercalcemia, rather than 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.
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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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Which of the following structures separates the posterior cruciate ligament from the popliteal artery?
Your Answer: Oblique popliteal ligament
Explanation:The oblique popliteal ligament separates the origin of the posterior cruciate ligament from the popliteal vessels, while the transverse ligament is situated in front.
The knee joint is the largest and most complex synovial joint in the body, consisting of two condylar joints between the femur and tibia and a sellar joint between the patella and femur. The degree of congruence between the tibiofemoral articular surfaces is improved by the presence of the menisci, which compensate for the incongruence of the femoral and tibial condyles. The knee joint is divided into two compartments: the tibiofemoral and patellofemoral compartments. The fibrous capsule of the knee joint is a composite structure with contributions from adjacent tendons, and it contains several bursae and ligaments that provide stability to the joint. The knee joint is supplied by the femoral, tibial, and common peroneal divisions of the sciatic nerve and by a branch from the obturator nerve, while its blood supply comes from the genicular branches of the femoral artery, popliteal, and anterior tibial arteries.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 11
Correct
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Samantha, a 65-year-old female, visits a vascular clinic and complains of leg pain while walking, which subsides when she rests. However, she has recently experienced night pain in her leg that wakes her up. She has a medical history of hypertension, diabetes, and hypercholesterolemia, and her BMI is 29kg/m².
The surgeon suspects peripheral vascular disease and conducts a peripheral vascular exam. During the exam, the surgeon finds it difficult to palpate the posterior tibial pulse.
Where is the posterior tibial pulse located anatomically?Your Answer: Inferior posteriorly to the medial malleolus
Explanation:The posterior tibial pulse is located inferiorly and posteriorly to the medial malleolus. It is not found superiorly or anteriorly to the medial malleolus, nor is it located posterior to the lateral malleolus. It is important to accurately locate the pulse for proper assessment and diagnosis.
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 12
Incorrect
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A 16-year-old male presents to the physician with severe right dorsoradial wrist pain, which had a gradual onset over the past week. He had tripped over the pavement one month ago, breaking his fall with his outstretched right hand. However, he did not seek medical attention for it as the pain was not severe then.
Clinical examination reveals tenderness in the anatomical snuffbox, and the range of motion of the wrist is limited by pain. There is no overlying skin changes. His sensation over the median, radial and ulnar distributions of the hand was intact.
Radiographs of the wrist show collapse and fragmentation. The patient was diagnosed with a scaphoid fracture and informed that he has a complication due to delaying medical attention. He is then promptly scheduled for surgery.
What is the reason for the development of this complication in a 16-year-old male with a scaphoid fracture who delayed seeking medical attention?Your Answer: Blood supply towards the radial vein is disrupted, resulting in avascular necrosis of the scaphoid.
Correct Answer: Blood supply from the dorsal carpal branch is disrupted, resulting in avascular necrosis of the scaphoid.
Explanation:The radial vein is not involved in avascular necrosis of the scaphoid. The abductor pollicis brevis muscle, which is responsible for thumb movement and located near the scaphoid bone, is supplied by the superficial palmar arch and is not typically affected by avascular necrosis in scaphoid fractures. Nonunion refers to the failure of bony union beyond a certain period of time, but as it has only been one month since the injury and only one radiograph has been taken, it is premature to diagnose non-union in this patient.
A scaphoid fracture is a type of wrist fracture that usually occurs when a person falls onto an outstretched hand or during contact sports. It is important to identify scaphoid fractures as they can lead to avascular necrosis due to the unusual blood supply of the scaphoid bone. Patients with scaphoid fractures typically experience pain along the radial aspect of the wrist and loss of grip or pinch strength. Clinical examination involves checking for tenderness over the anatomical snuffbox, wrist joint effusion, pain on telescoping of the thumb, tenderness of the scaphoid tubercle, and pain on ulnar deviation of the wrist. Plain film radiographs and scaphoid views are used to diagnose scaphoid fractures, but MRI is considered the definitive investigation. Initial management involves immobilization with a splint or backslab and referral to orthopaedics. Orthopaedic management depends on the type of fracture, with undisplaced fractures typically treated with a cast and displaced fractures requiring surgical fixation. Complications of scaphoid fractures include non-union and avascular necrosis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 13
Correct
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During a soccer match, a young player is tackled and suffers a twisting injury to their knee. They are diagnosed with a soft tissue knee injury. What is the name of the structure that originates from the medial surface of the lateral femoral condyle and inserts onto the anterior intercondylar area of the tibial plateau?
Your Answer: Anterior cruciate ligament
Explanation:To recall the attachments of the ACL, one can imagine placing their hand in their pocket and moving from the superolateral to inferomedial direction. Conversely, for the PCL, the movement would be from inferolateral to superomedial.
The ACL originates from the medial surface of the lateral condyle, while the PCL originates from the lateral surface of the medial condyle.
Located in the medial compartment of the knee, beneath the medial condyle of the femur, is the medial meniscus.
The knee joint is the largest and most complex synovial joint in the body, consisting of two condylar joints between the femur and tibia and a sellar joint between the patella and femur. The degree of congruence between the tibiofemoral articular surfaces is improved by the presence of the menisci, which compensate for the incongruence of the femoral and tibial condyles. The knee joint is divided into two compartments: the tibiofemoral and patellofemoral compartments. The fibrous capsule of the knee joint is a composite structure with contributions from adjacent tendons, and it contains several bursae and ligaments that provide stability to the joint. The knee joint is supplied by the femoral, tibial, and common peroneal divisions of the sciatic nerve and by a branch from the obturator nerve, while its blood supply comes from the genicular branches of the femoral artery, popliteal, and anterior tibial arteries.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 14
Correct
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The Trendelenburg test evaluates the integrity of which muscle?
Your Answer: Gluteus medius
Explanation: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 15
Correct
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A 42-year-old man falls onto an outstretched hand and is evaluated in the emergency department. During the examination, tenderness is noted in the base of his anatomical snuffbox upon palpation. What injury is most likely in this situation?
Your Answer: Scaphoid fracture
Explanation:If there is tenderness in the base of the anatomical snuffbox, a scaphoid fracture should be suspected as it is a common injury caused by a fall onto an outstretched hand. It is important to note that bony tenderness would not be a symptom of a tendon rupture.
The scaphoid bone has various articular surfaces for different bones in the wrist. It has a concave surface for the head of the capitate and a crescentic surface for the lunate. The proximal end has a wide convex surface for the radius, while the distal end has a tubercle that can be felt. The remaining articular surface faces laterally and is associated with the trapezium and trapezoid bones. The narrow strip between the radial and trapezial surfaces and the tubercle gives rise to the radial collateral carpal ligament. The tubercle also receives part of the flexor retinaculum and is the only part of the scaphoid bone that allows for the entry of blood vessels. However, this area is commonly fractured and can lead to avascular necrosis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 16
Incorrect
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A 16-year-old adolescent is brought to the emergency department by his father after falling off his skateboard on an outstretched hand. The patient complains of pain at the base of the thumb which is worse with the use of the hand.
Upon examination, there is swelling and tenderness over the anatomical snuffbox.
The emergency physician is concerned about avascular necrosis of the scaphoid bone. The physician explains to the patient that the scaphoid bone receives its blood supply through a specific part of the bone and fracture to this area can result in bone death. Therefore, an urgent scaphoid x-ray is necessary.
Which part of the scaphoid bone, when fractured, increases the risk of avascular necrosis?Your Answer: Capitate end
Correct Answer: Tubercle
Explanation:The scaphoid bone’s blood supply is only through the tubercle, and a fracture in this area can lead to avascular necrosis. It attaches to the trapezium and trapezoid bones at the greater and lesser multangular ends, respectively.
The scaphoid bone has various articular surfaces for different bones in the wrist. It has a concave surface for the head of the capitate and a crescentic surface for the lunate. The proximal end has a wide convex surface for the radius, while the distal end has a tubercle that can be felt. The remaining articular surface faces laterally and is associated with the trapezium and trapezoid bones. The narrow strip between the radial and trapezial surfaces and the tubercle gives rise to the radial collateral carpal ligament. The tubercle also receives part of the flexor retinaculum and is the only part of the scaphoid bone that allows for the entry of blood vessels. However, this area is commonly fractured and can lead to avascular necrosis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 17
Correct
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A 67-year-old retired firefighter visits the clinic complaining of recurring burning chest pain. He reports that the pain worsens after consuming take-away food and alcohol, and he experiences increased belching. The patient has a medical history of high cholesterol, type two diabetes, and osteoarthritis. He is currently taking atorvastatin, metformin, gliclazide, naproxen, and omeprazole, which he frequently forgets to take. Which medication is the probable cause of his symptoms?
Your Answer: Naproxen
Explanation:Peptic ulcers can be caused by the use of NSAIDs as a medication. Symptoms of peptic ulcer disease include a burning pain in the chest, which may be accompanied by belching, alcohol consumption, and high-fat foods. However, it is important to rule out any cardiac causes of the pain, especially in patients with a medical history of high cholesterol and type two diabetes.
Other medications that can cause peptic ulcer disease include aspirin and corticosteroids. Each medication has its own specific side effects, such as myalgia with atorvastatin, hypoglycemia with gliclazide, abdominal pain with metformin, and bradycardia with propranolol.
Understanding Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and COX-2 Selective NSAIDs
Non-steroidal anti-inflammatory drugs (NSAIDs) are medications that work by inhibiting the activity of cyclooxygenase enzymes, which are responsible for producing key mediators involved in inflammation such as prostaglandins. By reducing the production of these mediators, NSAIDs can help alleviate pain and reduce inflammation. Examples of NSAIDs include ibuprofen, diclofenac, naproxen, and aspirin.
However, NSAIDs can also have important and common side-effects, such as peptic ulceration and exacerbation of asthma. To address these concerns, COX-2 selective NSAIDs were developed. These medications were designed to reduce the incidence of side-effects seen with traditional NSAIDs, particularly peptic ulceration. Examples of COX-2 selective NSAIDs include celecoxib and etoricoxib.
Despite their potential benefits, COX-2 selective NSAIDs are not widely used due to ongoing concerns about cardiovascular safety. This led to the withdrawal of rofecoxib (‘Vioxx’) in 2004. As with any medication, it is important to discuss the potential risks and benefits of NSAIDs and COX-2 selective NSAIDs with a healthcare provider before use.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 18
Correct
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A one-year-old is brought to the paediatric team for assessment. The parents report that the child's right arm hangs loosely and does not move in coordination with the other limbs.
Upon examination, an adducted, internally rotated right upper limb with an extended elbow is observed. However, movement of the right wrist appears normal.
Based on these findings, where is the most likely location of the lesion?Your Answer: C5 and C6
Explanation:The infant’s arm is observed to be hanging loosely after a difficult forceps delivery, with adduction and internal rotation and extension of the elbow, indicating an injury to the upper trunk of the brachial plexus involving nerve roots C5 and C6. This is known as Erb’s palsy, which is commonly associated with difficult forceps deliveries and requires specialized management. Lower brachial plexus injuries affecting nerve roots C7 and C8 are less frequent and would cause wrist and forearm pathology rather than shoulder and elbow weakness. Isolated damage to the C6 nerve root is unlikely, as it is typically affected alongside the C5 nerve root.
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 19
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: Iliac crest
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 20
Incorrect
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Which of the muscles below does not cause lateral rotation of the hip?
Your Answer: Quadratus femoris
Correct Answer: Pectineus
Explanation:P-GO-GO-Q is a mnemonic for remembering the lateral hip rotators in order from top to bottom: Piriformis, Gemellus superior, Obturator internus, Gemellus inferior, Obturator externus, and Quadratus femoris.
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 21
Incorrect
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Sarah, a 23-year-old female, complains of worsening pain in her right lower leg after it was casted for a fibular fracture. The medical team suspects compartment syndrome and initiates prompt treatment. Besides pain, what is another early symptom of compartment syndrome?
Your Answer: Pulselessness
Correct Answer: Paresthesia
Explanation:Compartment syndrome is characterized by the 6 P’s: pain, paresthesia, paresis, pallor, perishingly cold, and pulselessness. Pain is an early symptom that is often not relieved by pain medication and is particularly noticeable during passive stretching. Paresthesia, which includes abnormal sensations like tingling, numbness, and burning, may progress to anesthesia.
Compartment syndrome is a complication that can occur after fractures or vascular injuries. It is characterized by increased pressure within a closed anatomical space, which can lead to tissue death. Supracondylar fractures and tibial shaft injuries are the most common fractures associated with compartment syndrome. Symptoms include pain, numbness, paleness, and possible paralysis of the affected muscle group. Even if a pulse is present, compartment syndrome cannot be ruled out. Diagnosis is made by measuring intracompartmental pressure, with pressures over 20 mmHg being abnormal and over 40 mmHg being diagnostic. X-rays typically do not show any pathology. Treatment involves prompt and extensive fasciotomies, with careful attention to decompressing deep muscles in the lower limb. Patients may experience myoglobinuria and require aggressive IV fluids. In severe cases, debridement and amputation may be necessary, as muscle death can occur within 4-6 hours.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 22
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 23
Correct
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In a confrontation, a 35-year-old woman was stabbed in the medial aspect of her left thigh. Upon examination, there is a noticeable decrease in knee extension. Additionally, there is a reduction in sensation over the anterior thigh.
Which anatomical structure has been affected by the stabbing?Your Answer: Femoral nerve
Explanation:The femoral nerve is responsible for loss of knee extension and sensory loss to the anterior and medial aspect of the thigh following a stab injury. The muscles innervated by the femoral nerve are responsible for hip flexion and knee extension, while the nerve is responsible for sensation over the anterior thigh. Injury to the inferior gluteal nerve would result in loss of hip extension, while injury to the obturator nerve would result in a loss of sensation to the medial thigh and impaired hip adduction. Although the quadriceps tendon is vital to knee extension, it would not explain the sensory deficit and the location of the injury.
Lower limb anatomy is an important topic that often appears in examinations. One aspect of this topic is the nerves that control motor and sensory functions in the lower limb. The femoral nerve controls knee extension and thigh flexion, and provides sensation to the anterior and medial aspect of the thigh and lower leg. It is commonly injured in cases of hip and pelvic fractures, as well as stab or gunshot wounds. The obturator nerve controls thigh adduction and provides sensation to the medial thigh. It can be injured in cases of anterior hip dislocation. The lateral cutaneous nerve of the thigh provides sensory function to the lateral and posterior surfaces of the thigh, and can be compressed near the ASIS, resulting in a condition called meralgia paraesthetica. The tibial nerve controls foot plantarflexion and inversion, and provides sensation to the sole of the foot. It is not commonly injured as it is deep and well protected, but can be affected by popliteral lacerations or posterior knee dislocation. The common peroneal nerve controls foot dorsiflexion and eversion, and can be injured at the neck of the fibula, resulting in foot drop. The superior gluteal nerve controls hip abduction and can be injured in cases of misplaced intramuscular injection, hip surgery, pelvic fracture, or posterior hip dislocation. Injury to this nerve can result in a positive Trendelenburg sign. The inferior gluteal nerve controls hip extension and lateral rotation, and is generally injured in association with the sciatic nerve. Injury to this nerve can result in difficulty rising from a seated position, as well as difficulty jumping or climbing stairs.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 24
Incorrect
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A 25-year-old male patient is diagnosed with appendicitis and requires an appendicectomy. The surgical procedure begins with a 5cm incision at McBurney's point. What is the first structure that will be encountered during the dissection?
Your Answer: Rectus sheath
Correct Answer: External oblique aponeurosis
Explanation:The rectus sheath is located more medially than the external oblique, which is encountered first. The external oblique muscle is the most superficial muscle of the abdominal wall and originates from the 5th to 12th ribs. It inserts into the linea alba, pubic tubercle, and anterior half of the iliac crest by passing inferomedially. The muscle is innervated by the thoracoabdominal nerves (T7-T11) and subcostal nerves.
Muscles and Layers of the Abdominal Wall
The abdominal wall is composed of various muscles and layers that provide support and protection to the organs within the abdominal cavity. The two main muscles of the abdominal wall are the rectus abdominis and the quadratus lumborum. The rectus abdominis is located anteriorly, while the quadratus lumborum is located posteriorly.
The remaining abdominal wall is made up of three muscular layers, each passing from the lateral aspect of the quadratus lumborum to the lateral margin of the rectus sheath. These layers are muscular posterolaterally and aponeurotic anteriorly. The external oblique muscle lies most superficially and originates from the 5th to 12th ribs, inserting into the anterior half of the outer aspect of the iliac crest, linea alba, and pubic tubercle. The internal oblique arises from the thoracolumbar fascia, the anterior 2/3 of the iliac crest, and the lateral 2/3 of the inguinal ligament, while the transversus abdominis is the innermost muscle, arising from the inner aspect of the costal cartilages of the lower 6 ribs, the anterior 2/3 of the iliac crest, and the lateral 1/3 of the inguinal ligament.
During abdominal surgery, it is often necessary to divide either the muscles or their aponeuroses. It is desirable to divide the aponeurosis during a midline laparotomy, leaving the rectus sheath intact above the arcuate line and the muscles intact below it. Straying off the midline can lead to damage to the rectus muscles, particularly below the arcuate line where they may be in close proximity to each other. The nerve supply for these muscles is the anterior primary rami of T7-12.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 25
Incorrect
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As a junior doctor in orthopaedic surgery, you are tasked with evaluating a 42-year-old woman who is scheduled for surgery tomorrow to repair an open radial fracture resulting from a bike accident. The patient has a medical history of severe psoriasis, gastro-oesophageal reflux disease, polycystic ovary syndrome, and depression. Routine blood tests were ordered before the surgery, and the results are surprising:
- Bilirubin: 17 µmol/L (normal range: 3 - 17)
- ALP: 89 u/L (normal range: 30 - 100)
- ALT: 354 u/L (normal range: 3 - 40)
- γGT: 61 u/L (normal range: 8 - 60)
- Albumin: 34 g/L (normal range: 35 - 50)
Which medication is most likely responsible for this abnormality?Your Answer: Fluoxetine
Correct Answer: Methotrexate
Explanation:Hepatotoxicity is a potential side effect of using Methotrexate to treat severe psoriasis. The use of combined oral contraceptive pills may increase the risk of venous thromboembolism and breast cancer. Fluoxetine may cause serotonin syndrome, while morphine can lead to respiratory depression and overdose, both of which are serious risks.
Methotrexate is an antimetabolite that hinders the activity of dihydrofolate reductase, an enzyme that is crucial for the synthesis of purines and pyrimidines. It is a significant drug that can effectively control diseases, but its side-effects can be life-threatening. Therefore, careful prescribing and close monitoring are essential. Methotrexate is commonly used to treat inflammatory arthritis, especially rheumatoid arthritis, psoriasis, and acute lymphoblastic leukaemia. However, it can cause adverse effects such as mucositis, myelosuppression, pneumonitis, pulmonary fibrosis, and liver fibrosis.
Women should avoid pregnancy for at least six months after stopping methotrexate treatment, and men using methotrexate should use effective contraception for at least six months after treatment. Prescribing methotrexate requires familiarity with guidelines relating to its use. It is taken weekly, and FBC, U&E, and LFTs need to be regularly monitored. Folic acid 5 mg once weekly should be co-prescribed, taken more than 24 hours after methotrexate dose. The starting dose of methotrexate is 7.5 mg weekly, and only one strength of methotrexate tablet should be prescribed.
It is important to avoid prescribing trimethoprim or co-trimoxazole concurrently as it increases the risk of marrow aplasia. High-dose aspirin also increases the risk of methotrexate toxicity due to reduced excretion. In case of methotrexate toxicity, the treatment of choice is folinic acid. Overall, methotrexate is a potent drug that requires careful prescribing and monitoring to ensure its effectiveness and safety.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 26
Incorrect
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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.
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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 35-year-old woman presents to the emergency department after falling off her bike and landing on her outstretched hand. She experiences tenderness in the anatomical snuffbox and is treated conservatively before being discharged. However, when she returns for outpatient follow-up several weeks later, she reports ongoing wrist pain. What is the probable complication that has arisen from her initial injury?
Your Answer: Carpal tunnel syndrome
Correct Answer: Avascular necrosis
Explanation:A scaphoid fracture can result in avascular necrosis due to the bone’s limited blood supply through the tubercle. This complication is often seen in patients who have fallen on an outstretched hand and may not be immediately visible on X-ray. Carpal tunnel syndrome, compartment syndrome, and Guyon canal syndrome are not typically associated with a scaphoid fracture and present with different symptoms and causes.
The scaphoid bone has various articular surfaces for different bones in the wrist. It has a concave surface for the head of the capitate and a crescentic surface for the lunate. The proximal end has a wide convex surface for the radius, while the distal end has a tubercle that can be felt. The remaining articular surface faces laterally and is associated with the trapezium and trapezoid bones. The narrow strip between the radial and trapezial surfaces and the tubercle gives rise to the radial collateral carpal ligament. The tubercle also receives part of the flexor retinaculum and is the only part of the scaphoid bone that allows for the entry of blood vessels. However, this area is commonly fractured and can lead to avascular necrosis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 28
Incorrect
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Which of the metastatic bone tumours mentioned below is most susceptible to pathological fracture?
Your Answer: Proximal humeral lesion from a carcinoma of the breast
Correct Answer: Peritrochanteric lesion from a carcinoma of the breast
Explanation:Fracture risks are highest in peritrochanteric lesions due to loading. Lytic lesions from breast cancer are at greater risk of fracture compared to the sclerotic lesions from prostate cancer.
Understanding the Risk of Fracture in Metastatic Bone Disease
Metastatic bone disease is a condition where cancer cells spread to the bones from other parts of the body. The risk of fracture in this condition varies depending on the type of metastatic bone tumour. Osteoblastic metastatic disease has the lowest risk of spontaneous fracture compared to osteolytic lesions of a similar size. However, lesions affecting the peritrochanteric region are more prone to spontaneous fracture due to loading forces at that site. To stratify the risk of spontaneous fracture for bone metastasis of varying types, the Mirel Scoring system is used. This system takes into account the site of the lesion, radiographic appearance, width of bone involved, and pain. Depending on the score, the treatment plan may involve prophylactic fixation, consideration of fixation, or non-operative management. Understanding the risk of fracture in metastatic bone disease is crucial in determining the appropriate treatment plan for patients.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 29
Correct
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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 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 30
Incorrect
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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: Clavipectoral fascia
Correct 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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