Upper Limb Practice Questions

Q: Which nerve runs along with the profunda brachii artery in the spiral groove?

Radial nerve. ***Radial nerve*** - The **radial nerve** courses through the **radial (spiral) groove** of the humerus in close association with the **profunda brachii artery** (also known as the deep brachial artery). - This anatomical relationship makes both structures vulnerable to injury in cases of **mid-shaft humeral fractures** [1]. *Ulnar nerve* - The **ulnar nerve** typically runs behind the **medial epicondyle of the humerus** and does not accompany the profunda brachii artery in the spiral groove. - Its main course in the arm is medial to the brachial artery, then it enters the forearm by passing posterior to the medial epicondyle. *Median nerve* - The **median nerve** travels in the anterior compartment of the arm, generally in close proximity to the **brachial artery**, but it does not enter the radial groove. - It maintains a superficial position in the cubital fossa before entering the forearm between the heads of pronator teres. *No nerve* - This option is incorrect because the **radial nerve** is well-documented to run alongside the profunda brachii artery in the radial groove. - This anatomical fact is clinically significant due to the risk of nerve injury with humeral fractures [1].

Q: Which of the following muscles is not in the pectoral region?

Infraspinatus. ***Infraspinatus*** - The **infraspinatus** muscle is located in the **posterior scapular region**, specifically on the posterior aspect of the scapula, filling the infraspinous fossa. - Its primary function is **external rotation** of the humerus, and it is a key component of the **rotator cuff**. *Pectoralis major* - The **pectoralis major** is a large, superficial muscle located in the **anterior chest wall**, forming the bulk of the chest. [1] - It plays a significant role in **adduction**, **flexion**, and **medial rotation** of the humerus. *Pectoralis minor* - The **pectoralis minor** is a smaller, triangular muscle situated beneath the pectoralis major in the **anterior thoracic wall**. [1] - Its functions include **stabilizing the scapula** by pulling it inferiorly and anteriorly, and assisting in forced inspiration. [1] *Subclavius* - The **subclavius** is a small, triangular muscle located inferior to the clavicle in the **pectoral region**. - Its primary role is to **depress and stabilize the clavicle**, protecting the underlying neurovascular structures.

Q: What is the largest branch of the brachial plexus?

Radial nerve. ***Radial nerve*** - The **radial nerve** is considered the largest branch of the brachial plexus due to its extensive innervation of numerous muscles in the posterior compartment of the arm and forearm. - It arises from the **posterior cord** of the brachial plexus and innervates all the extensors of the arm and forearm, including the triceps brachii and supinator. *Ulnar nerve* - The ulnar nerve is a significant branch, but it is **smaller** in cross-sectional area and muscular distribution compared to the radial nerve. - It mainly innervates muscles of the **hand** and some forearm flexors. *Median nerve* - The median nerve is a large and clinically important nerve, formed by contributions from both the **lateral and medial cords**, but it is generally *not* considered the largest in terms of overall bulk or number of muscular branches. - It primarily innervates the **flexor muscles of the forearm** and some muscles of the hand (thenar eminence). *Axillary nerve* - The axillary nerve is one of the **smaller** terminal branches of the brachial plexus. - It primarily innervates the **deltoid** and **teres minor muscles**, and a small area of skin over the shoulder.

Q: A person had injury to right upper limb, he is not able to extend fingers but able to extend wrist and elbow. Nerve injured is ?

Posterior interosseous. ***Posterior interosseous*** - This nerve supplies the muscles responsible for **finger extension**, such as the **extensor digitorum**, **extensor indicis**, and **extensor digiti minimi**. - A lesion here would spare wrist and elbow extension because the nerves to the **extensor carpi radialis longus/brevis** and **triceps brachii** branch off the radial nerve proximal to the origin of the posterior interosseous nerve. *Radial* - A more proximal **radial nerve injury** would result in the inability to extend the wrist (leading to **wrist drop**), fingers, and thumb, which is not seen here as wrist extension is preserved. - It also innervates the **triceps brachii**, and a high radial nerve injury would affect elbow extension; this patient can extend their elbow. *Median* - The **median nerve** primarily innervates muscles responsible for **flexion** of the wrist and fingers, as well as **thumb opposition** and **pronation**. - Its injury would not directly lead to an inability to extend the fingers, but rather weakness in flexion and specific thumb movements. *Ulnar* - The **ulnar nerve** innervates most of the **intrinsic hand muscles** and the **flexor carpi ulnaris**, leading to weakness in finger abduction/adduction and flexion of the 4th and 5th digits. - It does not control finger extension, so an injury would not cause this specific deficit.

Q: What is the nerve supply to the muscles of the flexor compartment of the arm?

Musculocutaneous nerve. ***Musculocutaneous nerve*** - The **musculocutaneous nerve** is the primary nerve supplying all three muscles in the **flexor compartment of the arm**: the **biceps brachii**, **brachialis**, and **coracobrachialis**. - Its motor branches innervate these muscles, allowing for **flexion at the elbow** and **supination of the forearm**. *Median nerve* - The **median nerve** primarily innervates most muscles in the **flexor compartment of the forearm**, not the arm. - It plays a crucial role in **wrist and finger flexion**, as well as movements of the **thenar eminence**. *Radial nerve* - The **radial nerve** is the main nerve for the **extensor compartment of the arm and forearm**. - It is responsible for **elbow, wrist, and finger extension**. *Ulnar nerve* - The **ulnar nerve** primarily supplies intrinsic muscles of the hand and some flexor muscles in the forearm. - It has no motor supply to the muscles of the **flexor compartment of the arm**.

Q: Which of the following structures is not found in the midpalmar space?

1st lumbrical. ***1st lumbrical*** - The **1st lumbrical** is typically found within the **thenar space** or the **central compartment of the palm**, not the midpalmar space [1]. - Its position is associated with the **index finger's flexor tendons**, which do not traverse the midpalmar space. *2nd lumbrical* - The **2nd lumbrical** is located in the **midpalmar space**, situated on the radial side of the **flexor digitorum profundus (FDP) tendon** to the third digit [1]. - It arises from the radial side of the **FDP tendon** of the **middle finger** [1]. *FDP of 3rd finger* - The **flexor digitorum profundus (FDP) tendon** to the **third finger** (middle finger) passes through the **midpalmar space** [1]. - These tendons, along with their associated lumbricals, are key components of the **midpalmar space**. *FDP of 4th finger* - The **flexor digitorum profundus (FDP) tendon** to the **fourth finger** (ring finger) also travels through the **midpalmar space** [1]. - The midpalmar space contains the **FDP tendons** for the middle, ring, and little fingers, as well as their corresponding lumbricals (2nd, 3rd, and 4th).

Q: Which is the primary muscle causing supination of the forearm?

Supinator. ***Supinator*** - The **supinator muscle** is the **primary muscle** responsible for **supination** of the forearm, rotating the palm anteriorly or superiorly. - It is a deep muscle of the **posterior compartment** of the forearm. - Its action is especially prominent when **supinating against resistance** or in very slow movements, as it works synergistically with the biceps brachii. *Biceps brachii* - While the **biceps brachii** is also a powerful **supinator** of the forearm, especially when the elbow is flexed, it is a **secondary supinator**. - It is primarily a major **flexor** of the elbow, whereas the supinator is dedicated specifically to supination. *Brachioradialis* - The **brachioradialis** is primarily a **flexor** of the forearm at the elbow joint. - It helps to bring the forearm into a **mid-prone or mid-supine position** from either full pronation or full supination, but does not actively supinate. *Anconeus* - The **anconeus** is a small muscle that assists the **triceps brachii** in **extension of the forearm** at the elbow. - It helps to **stabilize the elbow joint** and slightly abducts the ulna during pronation, but has no role in supination.

Q: All of the following muscles have dual nerve supply except which one?

Biceps brachii. ***Biceps brachii*** - The **biceps brachii** muscle is solely innervated by the **musculocutaneous nerve (C5, C6, C7)**. - This muscle is a prime mover for forearm supination and elbow flexion and does not receive nerve supply from any other nerve. *Subscapularis* - The **subscapularis** muscle has a dual nerve supply from both the **upper and lower subscapular nerves (C5, C6)**. - This dual innervation ensures motor control of the subscapularis, which is an important medial rotator of the humerus. *Pectoralis major* - The **pectoralis major** muscle receives a dual nerve supply from both the **medial and lateral pectoral nerves** [1]. - The **lateral pectoral nerve** primarily supplies the clavicular head, while the **medial pectoral nerve** supplies both the sternocostal head and a portion of the clavicular head [1]. *Flexor digitorum profundus* - The **flexor digitorum profundus** muscle has a dual nerve supply from the **median nerve** (innervating the lateral half for digits 2 and 3) and the **ulnar nerve** (innervating the medial half for digits 4 and 5). - This dual innervation allows for independent or coordinated flexion of the distal phalanges of the fingers.

Q: Which muscle in the hand is unique for originating from the tendon of another muscle?

Lumbricals. ***Lumbricals*** - The **lumbrical muscles** in the hand are unique as they originate from the **tendons of the flexor digitorum profundus muscle** [1]. - This unusual origin allows them to act on both the metacarpophalangeal (MCP) joints (flexion) and the interphalangeal (IP) joints (extension) [1]. *Palmaris longus* - The **palmaris longus** muscle originates from the **medial epicondyle of the humerus**, not from the tendon of another muscle. - It inserts into the **palmar aponeurosis** and is absent in a significant portion of the population. *Flexor carpi radialis (FCR)* - The **flexor carpi radialis** originates from the **medial epicondyle of the humerus**. - It is a primary flexor and abductor of the wrist, inserting into the bases of the second and third metacarpal bones. *Adductor pollicis* - The **adductor pollicis** has two heads, transverse and oblique, both originating from the **carpal bones** and **metacarpals**, not from the tendon of another muscle. - Its main function is to adduct the thumb, pulling it towards the palm.

Question 1

Which nerve runs along with the profunda brachii artery in the spiral groove?

Accepted Answer

Radial nerve

Answer

Ulnar nerve

Answer

Median nerve

Answer

No nerve

Question 2

Which of the following muscles is not in the pectoral region?

Accepted Answer

Infraspinatus

Answer

Pectoralis major

Answer

Pectoralis minor

Answer

Subclavius

Question 3

What is the largest branch of the brachial plexus?

Accepted Answer

Radial nerve

Answer

Ulnar nerve

Answer

Axillary nerve

Answer

Median nerve

Question 4

A person had injury to right upper limb, he is not able to extend fingers but able to extend wrist and elbow. Nerve injured is ?

Accepted Answer

Posterior interosseous

Answer

Median

Answer

Ulnar

Answer

Radial

Question 5

What is the nerve supply to the muscles of the flexor compartment of the arm?

Accepted Answer

Musculocutaneous nerve

Answer

Median nerve

Answer

Radial nerve

Answer

Ulnar nerve

Question 6

Which of the following structures is not found in the midpalmar space?

Accepted Answer

1st lumbrical

Answer

2nd lumbrical

Answer

FDP of 4th finger

Answer

FDP of 3rd finger

Question 7

Which is the primary muscle causing supination of the forearm?

Accepted Answer

Supinator

Answer

Brachioradialis

Answer

Anconeus

Answer

Biceps brachii

Question 8

All of the following muscles have dual nerve supply except which one?

Accepted Answer

Biceps brachii

Answer

Pectoralis major

Answer

Flexor digitorum profundus

Answer

Subscapularis

Question 9

Which muscle in the hand is unique for originating from the tendon of another muscle?

Accepted Answer

Lumbricals

Answer

Palmaris longus

Answer

Adductor pollicis

Answer

Flexor carpi radialis (FCR)

Question 10

In axillary nerve paralysis, which of the following statements is false?

Accepted Answer

Extension of shoulder with arm abducted to 90 degrees is impossible

Answer

Deltoid muscle is wasted

Answer

Small area of numbness is present over the shoulder region

Answer

Patient cannot initiate abduction

Upper Limb — MCQs

Upper Limb — MCQs

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