Upper Limb Practice Questions

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: 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.

Q: What is the primary function of the deltoid muscle?

Abduction of the shoulder. ***Abduction of the shoulder*** - The **deltoid muscle** is the major muscle responsible for **abducting the arm** at the shoulder joint, particularly after the initial 15-20 degrees. - Its different parts (anterior, middle, posterior) also contribute to flexion, extension, and rotation, but **abduction** is its primary and most powerful action. *Adduction of the shoulder* - **Adduction of the shoulder** involves moving the arm towards the midline of the body, which is primarily performed by muscles such as the **latissimus dorsi** and **pectoralis major**. - While some fibers of the deltoid can assist in adduction from certain positions, it is not its primary function. *Flexion of the elbow* - **Flexion of the elbow** involves bending the arm at the elbow joint and is primarily performed by muscles like the **biceps brachii**, **brachialis**, and **brachioradialis**. - The deltoid muscle is located at the shoulder and has no direct action on the elbow joint. *Extension of the wrist* - **Extension of the wrist** involves bending the hand backward at the wrist joint and is primarily performed by muscles in the forearm such as the **extensor carpi radialis** and **extensor digitorum**. - The deltoid muscle is a shoulder muscle and does not act on the wrist joint.

Q: Which muscle's function is primarily assessed to evaluate damage to the axillary nerve?

Deltoid. ***Deltoid*** - The **axillary nerve** innervates the **deltoid muscle**, which is responsible for **shoulder abduction** (lifting the arm away from the body) and some flexion/extension. - Damage to the axillary nerve typically results in **weakness** or **paralysis** of the deltoid, leading to impaired shoulder abduction. *Teres major* - The teres major muscle is primarily innervated by the **lower subscapular nerve**, not the axillary nerve. - Its main actions are **adduction** and **internal rotation** of the humerus. *Pectoralis major* - The pectoralis major is innervated by the **medial and lateral pectoral nerves** [1]. - This muscle is responsible for **adduction**, **flexion**, and **internal rotation** of the humerus. *Latissimus dorsi* - The latissimus dorsi muscle is innervated by the **thoracodorsal nerve** [1]. - Its functions include **extension**, **adduction**, and **internal rotation** of the humerus.

Q: Which nerve supplies the rhomboid major and minor muscles?

Dorsal scapular nerve. Dorsal scapular nerve - The **dorsal scapular nerve** directly innervates the **rhomboid major** and **rhomboid minor** muscles, as well as the **levator scapulae** muscle. - This nerve originates from the C5 root of the brachial plexus. *Thoracodorsal nerve* - The **thoracodorsal nerve** primarily innervates the **latissimus dorsi** muscle, which is involved in adduction, extension, and internal rotation of the humerus [1]. - This nerve arises from the posterior cord of the brachial plexus. *Spinal accessory nerve* - The **spinal accessory nerve (CN XI)** is responsible for innervating the **sternocleidomastoid** and **trapezius** muscles. - It plays a crucial role in neck movement and shoulder elevation. *Suprascapular nerve* - The **suprascapular nerve** supplies the **supraspinatus** and **infraspinatus** muscles, which are part of the rotator cuff. - Damage to this nerve can impair shoulder abduction and external rotation.

Q: Posterior interosseous artery is a branch of?

Common interosseous artery. ***Common interosseous artery*** - The **common interosseous artery** is a short branch of the **ulnar artery** that quickly divides into the anterior and posterior interosseous arteries. - The **posterior interosseous artery** then supplies muscles in the posterior compartment of the forearm. *Radial artery* - The **radial artery** is one of the two terminal branches of the **brachial artery** and primarily supplies the lateral side of the forearm and hand. - It does not directly give off the posterior interosseous artery. *Median artery* - The **median artery** is a small artery that runs with the **median nerve** and is often a branch of the **anterior interosseous artery**. - It does not give rise to the posterior interosseous artery itself. *Brachial artery* - The **brachial artery** is the main artery of the upper arm, branching into the **radial** and **ulnar arteries** in the forearm. - While it's an upstream vessel, it does not directly give off the posterior interosseous artery; that branch comes from the common interosseous artery, which is a branch of the ulnar artery.

Q: Which muscle acting on the thumb is the only one among the options that has dual nerve supply?

Flexor Pollicis Brevis. ***Flexor Pollicis Brevis (FPB)*** - The **Flexor Pollicis Brevis** is unique among thumb muscles because it commonly has a **dual nerve supply**. [1] - Its superficial head is innervated by the **median nerve**, while its deep head is innervated by the **ulnar nerve**. *Flexor Pollicis Longus (FPL)* - The **Flexor Pollicis Longus** is solely innervated by the **anterior interosseous nerve**, a branch of the **median nerve**. [1] - It does not receive any neural input from the ulnar nerve. *Adductor Pollicis* - The **Adductor Pollicis** muscle is exclusively innervated by the **deep branch of the ulnar nerve**. - It plays a crucial role in **adduction of the thumb** and does not share innervation with the median nerve. *Opponens Pollicis* - The **Opponens Pollicis** is primarily supplied by the **recurrent branch of the median nerve** (also known as the thenar motor branch). - Its function is **opposition of the thumb**, and it does not have dual innervation.

Q: Coracohumeral ligament inserts on?

Lesser and greater tuberosities. ***Lesser and greater tuberosities*** - The **coracohumeral ligament** originates from the **lateral border of the coracoid process** and inserts onto **both the greater and lesser tuberosities** of the humerus. - It divides into two bands: one inserts on the **greater tuberosity** and the other on the **lesser tuberosity**, effectively bridging across the **bicipital groove**. - This ligament strengthens the **superior part of the joint capsule** and limits inferior translation and external rotation of the humeral head. *Greater tuberosity* - While the coracohumeral ligament does insert partially on the **greater tuberosity**, this option is incomplete as it omits the insertion on the **lesser tuberosity** as well. - The greater tuberosity also serves as the attachment site for **supraspinatus**, **infraspinatus**, and **teres minor** muscles (rotator cuff). *Bicipital groove* - The **bicipital groove** (intertubercular sulcus) houses the **long head of the biceps tendon**. - The **transverse humeral ligament** spans this groove, holding the biceps tendon in place. - The coracohumeral ligament bridges across the groove but does not insert into it. *Anatomical neck of humerus* - The **anatomical neck** is the constriction below the humeral head, representing the old epiphyseal line. - The **joint capsule** attaches to the anatomical neck, but the coracohumeral ligament specifically inserts on the **tuberosities**, not the neck itself.

Q: Infraspinous fossa of scapula contains which of the following muscles?

Infraspinatus. ***Infraspinatus*** - The **infraspinous fossa** is a large depression on the posterior surface of the scapula, inferior to the spine. - As its name suggests, it is the origin for the **infraspinatus muscle**, which is a key component of the rotator cuff. - This muscle is responsible for **external rotation** of the humerus at the shoulder joint. *Subscapularis* - The **subscapularis muscle** originates from the **subscapular fossa**, which is on the anterior (costal) surface of the scapula. - This muscle is responsible for internal rotation of the humerus. *Teres major* - The **teres major muscle** originates from the inferior angle and lower part of the lateral border of the scapula. - It works to extend, adduct, and internally rotate the humerus, acting synergistically with the latissimus dorsi. *Supraspinatus* - The **supraspinatus muscle** originates from the **supraspinous fossa**, which is located above the spine of the scapula. - This muscle is primarily responsible for the initiation of abduction of the arm.

Question 1

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 2

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 3

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

Question 4

What is the primary function of the deltoid muscle?

Accepted Answer

Abduction of the shoulder

Answer

Adduction of the shoulder

Answer

Flexion of the elbow

Answer

Extension of the wrist

Question 5

Which muscle's function is primarily assessed to evaluate damage to the axillary nerve?

Accepted Answer

Deltoid

Answer

Teres major

Answer

Pectoralis major

Answer

Latissimus dorsi

Question 6

Which nerve supplies the rhomboid major and minor muscles?

Accepted Answer

Dorsal scapular nerve

Answer

Thoracodorsal nerve

Answer

Spinal accessory nerve

Answer

Suprascapular nerve

Question 7

Posterior interosseous artery is a branch of?

Accepted Answer

Common interosseous artery

Answer

Radial artery

Answer

Median artery

Answer

Brachial artery

Question 8

Which muscle acting on the thumb is the only one among the options that has dual nerve supply?

Accepted Answer

Flexor Pollicis Brevis

Answer

Flexor Pollicis Longus

Answer

Adductor Pollicis

Answer

Opponens Pollicis

Question 9

Coracohumeral ligament inserts on?

Accepted Answer

Lesser and greater tuberosities

Answer

Greater tuberosity

Answer

Bicipital groove

Answer

Anatomical neck of humerus

Question 10

Infraspinous fossa of scapula contains which of the following muscles?

Accepted Answer

Infraspinatus

Answer

Subscapularis

Answer

Teres major

Answer

Supraspinatus

Upper Limb — MCQs

Upper Limb — MCQs

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