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7. Hand and Wrist MCQs

Practice Set 129 of 266

This practice set contains high-yield board review questions covering key concepts in 7. Hand and Wrist. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 2561

Topic: 7. Hand and Wrist

The recurrent motor branch of the median nerve provides innervation to the thenar muscles. Which of the following is the most common anatomic variation of its course relative to the transverse carpal ligament?

. Extraligamentous
. Subligamentous
. Transligamentous
. Pre-ligamentous
. Ulnar to the hook of the hamate

Correct Answer & Explanation

. Extraligamentous

Explanation

The extraligamentous course is the most common variant of the recurrent motor branch of the median nerve, occurring in roughly 50-70% of individuals. The nerve typically branches off the median nerve just distal to the transverse carpal ligament and curves back to innervate the thenar musculature.

Question 2562

Topic: 7. Hand and Wrist

A 25-year-old gymnast presents with ulnar-sided wrist pain. MRI reveals a central tear of the triangular fibrocartilage complex (TFCC). Why is debridement preferred over repair for this specific injury pattern?

. The central portion is highly vascular and prone to arthrofibrosis if sutured
. The central portion is avascular and lacks healing potential
. Central tears invariably involve the extensor carpi ulnaris tendon
. The central portion is primarily muscular and heals poorly
. Repair of the central portion severely restricts pronation/supination

Correct Answer & Explanation

. The central portion is avascular and lacks healing potential

Explanation

The central articular disc of the TFCC is avascular, whereas the peripheral 15-20% receives blood supply from the ulnar artery branches. Consequently, central tears do not heal well and are typically treated with debridement.

Question 2563

Topic: Nerve & Tendon

A patient presents with an inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which nerve is most likely compressed or injured?

. Posterior interosseous nerve
. Ulnar nerve
. Anterior interosseous nerve
. Recurrent branch of the median nerve
. Superficial radial nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN) innervates the flexor pollicis longus, the flexor digitorum profundus to the index and long fingers, and the pronator quadratus. An AIN palsy presents with the classic inability to make an 'OK' sign.

Question 2564

Topic: 7. Hand and Wrist

During an open carpal tunnel release, the surgeon must be mindful of the superficial palmar arch. This structure is primarily formed by the continuation of which artery?

. Radial artery
. Ulnar artery
. Anterior interosseous artery
. Deep palmar branch of the radial artery
. Princeps pollicis artery

Correct Answer & Explanation

. Ulnar artery

Explanation

The superficial palmar arch is primarily the direct continuation of the ulnar artery, which anastomoses with the superficial palmar branch of the radial artery. It lies superficial to the flexor tendons and is at risk if the incision extends too far distally.

Question 2565

Topic: Nerve & Tendon

While performing an in situ decompression of the ulnar nerve at the elbow, the surgeon releases the aponeurosis connecting the two heads of the flexor carpi ulnaris (FCU). This aponeurotic band is classically known as:

. Arcade of Struthers
. Ligament of Struthers
. Osborne's ligament
. Lacertus fibrosus
. Arcade of Frohse

Correct Answer & Explanation

. Osborne's ligament

Explanation

Osborne's ligament connects the humeral and ulnar heads of the flexor carpi ulnaris, forming the roof of the cubital tunnel. The Arcade of Struthers is located more proximally in the arm and can be an independent site of ulnar nerve compression.

Question 2566

Topic: Wrist & Carpus

A patient presents with an attritional tendon rupture following a distal radius fracture. The ruptured tendon normally passes through the third dorsal extensor compartment. Which tendon is this?

. Extensor pollicis brevis
. Extensor carpi radialis longus
. Extensor pollicis longus
. Extensor indicis proprius
. Extensor digiti minimi

Correct Answer & Explanation

. Extensor pollicis longus

Explanation

The extensor pollicis longus (EPL) tendon is the sole occupant of the third dorsal extensor compartment and uses Lister's tubercle as a fulcrum.

Question 2567

Topic: 7. Hand and Wrist

Which of the following tendons are contained within the first dorsal compartment of the wrist?

. Extensor carpi radialis longus and brevis
. Extensor pollicis longus and extensor digitorum communis
. Abductor pollicis longus and extensor pollicis brevis
. Extensor carpi ulnaris and extensor digiti minimi
. Extensor indicis proprius and extensor pollicis longus

Correct Answer & Explanation

. Abductor pollicis longus and extensor pollicis brevis

Explanation

The first dorsal compartment of the wrist contains the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons. Stenosing tenosynovitis of this compartment is known as de Quervain's tenosynovitis.

Question 2568

Topic: 7. Hand and Wrist
A 2-year-old boy is evaluated for congenital scoliosis secondary to a fully segmented hemivertebra at T8. What screening studies are mandatory prior to definitive orthopedic management?
. CT scan of the chest to rule out pulmonary hypoplasia
. Renal ultrasound and echocardiogram
. MRI of the brain for Chiari malformation
. Genetic karyotyping for Down syndrome
. DEXA scan for bone density

Correct Answer & Explanation

. Renal ultrasound and echocardiogram

Explanation

Congenital scoliosis is highly associated with VACTERL anomalies. A renal ultrasound and echocardiogram are mandatory to rule out genitourinary and cardiovascular abnormalities, which occur in up to 30% and 10% of these patients, respectively.

Question 2569

Topic: Nerve & Tendon

A 13-year-old gymnast sustains a fall and presents with an elbow dislocation.

Following closed reduction, radiographs reveal an associated medial epicondyle fracture. Which of the following is an absolute indication for operative fixation of the medial epicondyle?

. Displacement of 5 mm
. Displacement of 10 mm
. Incarceration of the fragment within the joint
. Ulnar nerve paresthesias
. Valgus instability on stress testing

Correct Answer & Explanation

. Incarceration of the fragment within the joint

Explanation

An incarcerated medial epicondyle fragment within the ulnohumeral joint that cannot be extracted by closed means is an absolute indication for open reduction and internal fixation. Ulnar nerve symptoms and displacement >5-10 mm are relative indications.

Question 2570

Topic: Nerve & Tendon

A 12-year-old boy presents with an acute elbow dislocation. After closed reduction, radiographs reveal a medial epicondyle fracture fragment incarcerated within the joint. Which nerve is most at risk of injury or entrapment in this scenario?

. Median nerve
. Radial nerve
. Ulnar nerve
. Anterior interosseous nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Ulnar nerve

Explanation

The ulnar nerve courses posterior to the medial epicondyle in the cubital tunnel. It is the most commonly injured nerve in medial epicondyle fractures, especially when the fracture fragment becomes incarcerated within the ulnohumeral joint.

Question 2571

Topic: 7. Hand and Wrist

When a patient uses a cane in the hand contralateral to an osteoarthritic hip, what is the primary biomechanical reason for the observed reduction in joint reaction force at the affected hip?

. Decreased body weight transmission through the pelvis
. Increased moment arm of the body weight relative to the hip center
. Decreased force required by the ipsilateral hip abductors to maintain a level pelvis
. Direct load transfer from the contralateral arm to the ipsilateral leg
. Shift of the center of gravity away from the cane

Correct Answer & Explanation

. Decreased force required by the ipsilateral hip abductors to maintain a level pelvis

Explanation

Using a cane in the contralateral hand provides an upward force with a long moment arm. This massively reduces the force the ipsilateral hip abductors must exert to keep the pelvis level during stance, which accounts for the majority of the hip joint reaction force.

Question 2572

Topic: Nerve & Tendon

During a volar approach to the forearm for plating a radius fracture, the surgeon must be cautious of the anterior interosseous nerve (AIN). Which of the following muscles is innervated by the AIN?

. Flexor carpi radialis
. Flexor pollicis longus
. Abductor pollicis longus
. Pronator teres
. Flexor digitorum superficialis

Correct Answer & Explanation

. Flexor pollicis longus

Explanation

The AIN innervates the flexor pollicis longus, the radial half of the flexor digitorum profundus, and the pronator quadratus. The other listed muscles are innervated by the median nerve proper or the radial nerve.

Question 2573

Topic: 7. Hand and Wrist

Increasing the inner (root) diameter of a cortical screw primarily improves which of the following mechanical properties?

. Pull-out strength
. Bending strength
. Torsional strength
. Pitch
. Lead

Correct Answer & Explanation

. Bending strength

Explanation

The bending strength of a screw is proportional to the inner (root) diameter to the third power. Pull-out strength, on the other hand, is primarily determined by the outer diameter, thread pitch, and bone quality.

Question 2574

Topic: 7. Hand and Wrist

A 32-year-old man has intense right hand and wrist pain, a deformed wrist, and numbness in his fingers after falling off his motorcycle. This is an isolated injury. Examination reveals a swollen wrist, normal capillary refill to all fingers, and limited flexion of all fingers. Radiographs are shown in Figures 21a and 21b. Neurologic examination of the hand will most likely reveal

. lack of extension of the thumb.
. lack of abduction of the little finger.
. decreased sensation on the volar surface of the index finger.
. decreased sensation on the volar surface of the little finger.
. inability to extend the metacarpophalangeal joints of the fingers.

Correct Answer & Explanation

. decreased sensation on the volar surface of the index finger.

Explanation

The patient has a perilunate dislocation. A volar dislocation of the lunate is often associated with median nerve dysfunction. This injury to the wrist is often overlooked because of its benign clinical appearance and the presence of other injuries, as it is caused by high-energy mechanisms. Ruby LK, Cassidy C: Fractures and dislocations of the carpus, in Browner BD (ed): Skeletal Trauma, ed 3. Philadelphia, PA, WB Saunders, 2003, pp 1297-1300.

Question 2575

Topic: 7. Hand and Wrist

A 65-year-old female sustains a significantly displaced distal radius fracture. Upon presentation, she has profound numbness in her thumb, index, and long fingers. The fracture is reduced and splinted, but her neurologic symptoms progressively worsen over the next 2 hours. What is the most appropriate next step?

. Reassurance and re-evaluation in 24 hours
. Administration of oral corticosteroids
. Urgent open carpal tunnel release
. Application of a tighter cast
. Electromyography (EMG)

Correct Answer & Explanation

. Urgent open carpal tunnel release

Explanation

Progressive or unrelenting median nerve symptoms after closed reduction of a distal radius fracture indicate acute carpal tunnel syndrome. This requires urgent surgical decompression of the carpal tunnel to prevent permanent nerve damage.

Question 2576

Topic: 7. Hand and Wrist

A 55-year-old female presents with a displaced fracture of the distal radius treated with a volar locking plate. Six months postoperatively, she suddenly loses the ability to actively flex the interphalangeal joint of her thumb. What is the most likely cause of this complication?

. FDP rupture due to dorsal screw prominence
. FPL rupture due to plate prominence at the watershed line
. EPL rupture due to untreated Lister's tubercle fracture
. FCR tendinopathy from the surgical approach
. Median nerve compression at the carpal tunnel

Correct Answer & Explanation

. FPL rupture due to plate prominence at the watershed line

Explanation

Flexor pollicis longus (FPL) tendon rupture is a well-documented complication of volar locking plates used for distal radius fractures. This attritional rupture occurs when the plate is placed too distally, prominent beyond the anatomical watershed line of the distal radius.

Question 2577

Topic: 7. Hand and Wrist

A 68-year-old man with known cervical spondylosis presents after a hyperextension injury. He has 2/5 motor strength in his bilateral upper extremities, particularly the hands, and 4/5 strength in his lower extremities. He has variable sensory loss but retains bladder function. What is the classic mechanism and diagnosis?

. Flexion-distraction injury causing anterior cord syndrome
. Hyperextension injury causing central cord syndrome
. Axial loading causing Brown-Sequard syndrome
. Hyperflexion injury causing posterior cord syndrome
. Rotational injury causing crucial paralysis

Correct Answer & Explanation

. Hyperextension injury causing central cord syndrome

Explanation

Central cord syndrome typically occurs after a hyperextension injury in a patient with pre-existing cervical spondylosis. It affects the medially located cervical motor tracts more than the laterally located sacral/lumbar tracts, causing upper extremity weakness out of proportion to the lower extremities.

Question 2578

Topic: 7. Hand and Wrist

A 48-year-old man presents with right arm pain, numbness in his index and middle fingers, and weakness with triceps extension and wrist flexion. His triceps reflex is diminished. Which cervical nerve root is most likely compressed?

. C5
. C6
. C7
. C8
. T1

Correct Answer & Explanation

. C7

Explanation

Compression of the C7 nerve root classically presents with weakness in elbow extension (triceps) and wrist flexion. Sensory changes are typically noted in the middle finger, along with an absent or diminished triceps reflex.

Question 2579

Topic: 7. Hand and Wrist

A 65-year-old man with underlying cervical stenosis presents with weakness in his upper and lower extremities following a hyperextension injury to his neck during a fall. His exam shows 2/5 strength in his hands bilaterally and 4/5 strength in his legs, with preserved sacral sensation. Which of the following best describes the typical expected pattern of neurologic recovery in this condition?

. Fine motor function of the hands typically recovers fully before proximal muscles
. Lower extremity strength and ambulatory capacity recover before hand dexterity
. Bowel and bladder dysfunction are typically permanent despite motor recovery
. The upper extremities recover completely, while lower extremity spasticity remains permanent
. Recovery occurs equally and simultaneously across all extremities

Correct Answer & Explanation

. Lower extremity strength and ambulatory capacity recover before hand dexterity

Explanation

In Central Cord Syndrome, the typical sequence of neurologic recovery occurs in the following order: lower extremity function first, followed by bowel/bladder function, then proximal upper extremities, and finally distal upper extremity fine motor function (which often remains permanently impaired).

Question 2580

Topic: 7. Hand and Wrist

A 60-year-old man with a known history of severe cervical spondylosis presents after sustaining a hyperextension injury in a motor vehicle collision. He has severe motor weakness in his hands and arms (1/5) but can still move his lower extremities against gravity (4/5). He retains intact perineal sensation. What is the most likely diagnosis?

. Anterior cord syndrome
. Central cord syndrome
. Brown-Sequard syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome classically occurs following a hyperextension injury in older patients with pre-existing cervical spondylosis. It presents with disproportionately greater motor impairment in the upper extremities compared to the lower extremities.

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