Upper Limb Practice Questions

Q: A clinician is assessing a patient for damage to the axillary nerve following a shoulder dislocation. Which clinical test should be performed to evaluate the integrity of this nerve?

Shoulder abduction test. ***Shoulder abduction test*** - The **axillary nerve** innervates the **deltoid muscle**, which is the primary muscle responsible for **shoulder abduction**. - Testing the patient's ability to abduct their shoulder against resistance directly assesses the motor function of the axillary nerve. *Elbow flexion test* - This test primarily evaluates the function of the **musculocutaneous nerve**, which innervates the **biceps brachii** and **brachialis muscles**. - It is not directly relevant to assessing the integrity of the axillary nerve. *Wrist extension test* - This test primarily assesses the function of the **radial nerve**, which innervates the extensors of the wrist and fingers. - Damage to the axillary nerve would not typically affect wrist extension. *Finger adduction test* - This test primarily evaluates the function of the **ulnar nerve**, which innervates the intrinsic muscles of the hand responsible for finger adduction. - This test is unrelated to the axillary nerve's distribution or function.

Q: A patient with a rotator cuff injury exhibits reduced external rotation. Which muscle is primarily involved in this movement?

Infraspinatus. ***Infraspinatus*** - The **infraspinatus** is a key muscle of the rotator cuff, primarily responsible for **external rotation of the humerus**. - Its tendon is frequently implicated in rotator cuff tears, which would lead to a reduction in this specific movement. *Supraspinatus* - The **supraspinatus** is primarily responsible for the **initiation of abduction** of the arm (first 15-30 degrees). - While it's part of the rotator cuff, its main function is not external rotation. *Teres minor* - The **teres minor** also contributes to **external rotation**, but the infraspinatus is the *primary* external rotator. - It is a smaller muscle and less frequently the primary source of isolated external rotation deficits compared to the infraspinatus in rotator cuff injuries. *Subscapularis* - The **subscapularis** is largely responsible for **internal rotation** of the humerus. - An injury to this muscle would cause a deficit in internal rotation, not external rotation.

Q: Identify the primary flexor of the elbow.

Brachialis. ***Brachialis*** - The **brachialis muscle** is the **most powerful flexor** of the elbow joint, originating from the anterior surface of the humerus and inserting onto the ulna. - It's often referred to as the "**workhorse**" of the elbow flexors because it acts on the elbow joint regardless of forearm position (pronation or supination). *Biceps brachii* - While the **biceps brachii** is a strong elbow flexor, it is also a powerful **supinator** of the forearm. - Its effectiveness as a flexor varies with forearm position and it is not the primary or sole flexor. *Triceps brachii* - The **triceps brachii** is the sole **extensor** of the elbow joint, located on the posterior aspect of the upper arm. - Its primary action is to straighten the arm, not to bend it. *Anconeus* - The **anconeus** is a small muscle on the posterior aspect of the elbow, primarily assisting the triceps in **elbow extension**. - It also helps to stabilize the elbow joint and abducts the ulna during pronation, but it does not contribute to elbow flexion.

Q: Rotator cuff tear with abduction weakness. Which muscle is primarily responsible for initiating abduction?

Supraspinatus; responsible for initiating abduction. ***Supraspinatus; responsible for initiating abduction*** - The **supraspinatus** muscle is the primary initiator of **shoulder abduction** for the first 15-20 degrees, making it crucial for lifting the arm away from the body. - A tear in this muscle often leads to significant **abduction weakness**, which is consistent with the clinical presentation. *Infraspinatus; responsible for external rotation* - The **infraspinatus** primarily contributes to **external rotation** of the shoulder joint and helps stabilize the humeral head. - While it is part of the rotator cuff, its main role is not in initiating abduction, and isolated tears would predominantly affect external rotation rather than abduction initiation. *Subscapularis; responsible for internal rotation* - The **subscapularis** muscle is the largest and most powerful rotator cuff muscle, primarily responsible for **internal rotation** of the shoulder. - Tears in the subscapularis would primarily manifest as weakness in internal rotation and may affect overhead activities, but not specifically the initiation of abduction. *Teres minor; responsible for external rotation* - The **teres minor** muscle, along with the infraspinatus, is primarily involved in **external rotation** of the humerus and contributes to stabilization of the shoulder joint. - Similar to the infraspinatus, its primary role is not in initiating abduction, and its injury would typically manifest as weakness in external rotation.

Q: A patient suffers from a fracture of the surgical neck of the humerus. Which nerve is most likely to be injured?

Axillary nerve. Providing an explanation for your question about nerve injury in a humeral neck fracture: ***Axillary nerve*** - The **axillary nerve** wraps around the **surgical neck of the humerus**, making it highly vulnerable to injury in fractures of this region. - Injury can lead to **deltoid muscle paralysis** (difficulty with shoulder abduction) and sensory loss over the **regimental badge area**. *Radial nerve* - The **radial nerve** courses in the **spiral groove of the humerus**, making it susceptible to injury in **mid-shaft humeral fractures**, not typically surgical neck fractures. - Injury would primarily affect **wrist and finger extensors**, leading to **wrist drop**. *Median nerve* - The **median nerve** travels along the medial side of the arm and is generally protected from injury in a surgical neck fracture. - Injury typically results in problems with **thumb opposition** and sensation over the **lateral palm and fingers (digits 1-3.5)**. *Ulnar nerve* - The **ulnar nerve** runs medially in the arm and passes behind the **medial epicondyle**, making it vulnerable to injury in elbow fractures or dislocations, and is usually spared in surgical neck fractures. - Injury would cause weakness in **intrinsic hand muscles** and sensory loss over the **medial 1.5 fingers**.

Q: In carpal tunnel syndrome, which of the following tendons does NOT pass through the carpal tunnel and therefore does NOT contribute to median nerve compression?

Flexor carpi radialis. ***Flexor carpi radialis*** - The **flexor carpi radialis tendon** runs in its own **separate fibro-osseous compartment** lateral to the carpal tunnel, between the flexor retinaculum and the trapezium bone [1]. - It does **NOT pass through the carpal tunnel** itself and therefore cannot contribute to compression of the median nerve [1]. - This anatomical distinction is clinically important in understanding carpal tunnel pathophysiology [3]. *Flexor digitorum superficialis* - The **four tendons of flexor digitorum superficialis** pass through the carpal tunnel anterior to the flexor digitorum profundus tendons. - Tenosynovitis of these tendons can contribute to increased pressure within the carpal tunnel and **median nerve compression**. *Flexor digitorum profundus* - The **four tendons of flexor digitorum profundus** pass through the carpal tunnel deep to the flexor digitorum superficialis tendons [2]. - Inflammation or swelling of these tendons can contribute to **carpal tunnel syndrome symptoms**. *Flexor pollicis longus* - The **flexor pollicis longus tendon** passes through the carpal tunnel on the radial side, anterior to the median nerve [2]. - Tenosynovitis of this tendon can also contribute to **space-occupying pathology** within the carpal tunnel.

Q: A child presents with a 'claw hand' deformity after a fall. Which nerve is most likely to be injured?

Ulnar nerve. ***Ulnar nerve*** - A **claw hand deformity** (or ulnar claw) is characterized by **hyperextension of the metacarpophalangeal joints** and **flexion of the interphalangeal joints** of the 4th and 5th digits, due to paralysis of the **interossei** and **lumbricals** to these digits. - The ulnar nerve innervates most of the intrinsic hand muscles, including the **interossei** and the medial two **lumbricals**, which are crucial for flexing the MCP joints and extending the IP joints of the ring and little fingers. *Median nerve* - Injury to the median nerve would typically result in a **"hand of benediction"** or **ape hand deformity**, where the thumb is adducted and externally rotated, and there is an inability to flex the index and middle fingers. - It primarily affects the **thenar muscles** and lateral two **lumbricals**, which would not cause a claw hand deformity of the 4th and 5th digits. *Radial nerve* - Damage to the radial nerve leads to **wrist drop** and an inability to extend the wrist and fingers. - This nerve is responsible for innervating the **extensor muscles** of the forearm and hand, not the intrinsic hand muscles that cause a claw hand. *Musculocutaneous nerve* - The musculocutaneous nerve primarily innervates the muscles of the anterior compartment of the arm, such as the **biceps brachii** and **brachialis**. - Injury would result in weakness in **forearm flexion** and **supination**, not hand deformities.

Q: A 35-year-old female with carpal tunnel syndrome undergoes surgical release. Which structure is incised during the procedure?

Flexor retinaculum. ***Flexor retinaculum*** - The **flexor retinaculum** (also known as the **transverse carpal ligament**) forms the roof of the carpal tunnel. - Incising this ligament during surgery relieves pressure on the **median nerve**, which is entrapped in carpal tunnel syndrome. *Extensor retinaculum* - The **extensor retinaculum** is located on the dorsal aspect of the wrist and holds the extensor tendons in place. - It is not involved in carpal tunnel syndrome, which affects structures on the palmar side. *Palmar aponeurosis* - The **palmar aponeurosis** is a thick fibrous fascia in the palm of the hand, superficial to the carpal tunnel. - While it can be involved in conditions like Dupuytren's contracture, it does not form the boundaries of the carpal tunnel directly. *Ulnar bursa* - The **ulnar bursa** is a synovial sheath that encloses the flexor digitorum superficialis and profundus tendons within the carpal tunnel. - It lies within the carpal tunnel but incising it would not relieve the primary compression on the median nerve.

Q: A 35-year-old patient presents with weakness in wrist flexion and numbness in the little finger following elbow trauma. Which nerve is most likely to be affected?

Ulnar nerve. ***Ulnar nerve*** - The **ulnar nerve** innervates the **flexor carpi ulnaris** and the medial half of the **flexor digitorum profundus**, responsible for wrist flexion and flexion of the 4th and 5th digits. [1] - It also provides sensory innervation to the **little finger** and the ulnar half of the ring finger, explaining the reported numbness. [1] The **cubital tunnel** at the elbow is a common site of ulnar nerve compression or injury following trauma. *Median nerve* - The **median nerve** primarily innervates the forearm flexors (excluding the flexor carpi ulnaris and medial flexor digitorum profundus) and most of the thenar muscles. - Sensory innervation of the **median nerve** includes the thumb, index finger, middle finger, and radial half of the ring finger. [1] Injury would typically affect these areas and spare the little finger. *Radial nerve* - The **radial nerve** is responsible for **wrist and finger extension**, not flexion. - Injury to the **radial nerve** would result in **wrist drop** and sensory deficits over the dorsum of the hand, not numbness in the little finger. *Musculocutaneous nerve* - The **musculocutaneous nerve** innervates the biceps brachii and brachialis muscles, responsible for **elbow flexion** and forearm supination. - It provides sensory innervation to the lateral forearm, but not the little finger or wrist flexion.

Q: A patient reports a loss of sensation along the medial side of their hand. This symptom suggests an injury to which nerve?

Ulnar nerve. ***Ulnar nerve*** - The **ulnar nerve** innervates the **medial side of the hand**, including the little finger and the medial half of the ring finger [1]. - A loss of sensation in this area, often described as the **"ulnar side"** of the hand, is a classic sign of ulnar nerve injury [1]. *Radial nerve* - The **radial nerve** primarily supplies sensation to the **posterior surface of the arm and forearm**, and the **dorsal aspect of the lateral 3.5 fingers**. - Injury typically results in wrist drop and sensory loss over the dorsal aspect of the hand. *Median nerve* - The **median nerve** provides sensation to the **lateral side of the palm**, thumb, index finger, middle finger, and the lateral half of the ring finger [1]. - Injury to this nerve leads to sensory deficits in this distribution, often associated with carpal tunnel syndrome [1]. *Musculocutaneous nerve* - The **musculocutaneous nerve** solely innervates the skin of the **lateral forearm** as the lateral cutaneous nerve of the forearm. - It does not supply any sensory innervation to the hand itself.

Question 1

A clinician is assessing a patient for damage to the axillary nerve following a shoulder dislocation. Which clinical test should be performed to evaluate the integrity of this nerve?

Accepted Answer

Shoulder abduction test

Answer

Elbow flexion test

Answer

Wrist extension test

Answer

Finger adduction test

Question 2

A patient with a rotator cuff injury exhibits reduced external rotation. Which muscle is primarily involved in this movement?

Accepted Answer

Infraspinatus

Answer

Teres minor

Answer

Subscapularis

Answer

Supraspinatus

Question 3

Identify the primary flexor of the elbow.

Accepted Answer

Brachialis

Answer

Biceps brachii

Answer

Triceps brachii

Answer

Anconeus

Question 4

Rotator cuff tear with abduction weakness. Which muscle is primarily responsible for initiating abduction?

Accepted Answer

Supraspinatus; responsible for initiating abduction

Answer

Infraspinatus; responsible for external rotation

Answer

Subscapularis; responsible for internal rotation

Answer

Teres minor; responsible for external rotation

Question 5

A patient suffers from a fracture of the surgical neck of the humerus. Which nerve is most likely to be injured?

Accepted Answer

Axillary nerve

Answer

Radial nerve

Answer

Median nerve

Answer

Ulnar nerve

Question 6

In carpal tunnel syndrome, which of the following tendons does NOT pass through the carpal tunnel and therefore does NOT contribute to median nerve compression?

Accepted Answer

Flexor carpi radialis

Answer

Flexor digitorum profundus

Answer

Flexor pollicis longus

Answer

Flexor digitorum superficialis

Question 7

A child presents with a 'claw hand' deformity after a fall. Which nerve is most likely to be injured?

Accepted Answer

Ulnar nerve

Answer

Median nerve

Answer

Radial nerve

Answer

Musculocutaneous nerve

Question 8

A 35-year-old female with carpal tunnel syndrome undergoes surgical release. Which structure is incised during the procedure?

Accepted Answer

Flexor retinaculum

Answer

Extensor retinaculum

Answer

Palmar aponeurosis

Answer

Ulnar bursa

Question 9

A 35-year-old patient presents with weakness in wrist flexion and numbness in the little finger following elbow trauma. Which nerve is most likely to be affected?

Accepted Answer

Ulnar nerve

Answer

Median nerve

Answer

Radial nerve

Answer

Musculocutaneous nerve

Question 10

A patient reports a loss of sensation along the medial side of their hand. This symptom suggests an injury to which nerve?

Accepted Answer

Ulnar nerve

Answer

Radial nerve

Answer

Median nerve

Answer

Musculocutaneous nerve

Upper Limb — MCQs

Upper Limb — MCQs

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