Upper Limb Practice Questions

Q: Which of the following muscles is not attached to the medial border of the scapula?

Teres major. ***Teres major*** - The **teres major** muscle originates from the **inferior angle and lower part of the lateral border** of the scapula, NOT the medial border. - It inserts into the medial lip of the intertubercular groove of the humerus. - This is the correct answer as it does not attach to the medial border of the scapula. *Serratus anterior* - The **serratus anterior** muscle originates from the outer surfaces of the upper 8-9 ribs and inserts along the **entire medial border** of the scapula on its anterior (costal) surface. - It plays a crucial role in protraction and upward rotation of the scapula, keeping it applied to the thoracic wall. *Levator scapulae* - The **levator scapulae** muscle originates from the transverse processes of the C1-C4 vertebrae and inserts into the **superior angle and upper part of the medial border** of the scapula. - Its primary actions are to elevate the scapula and assist in downward rotation. *Rhomboid major* - The **rhomboid major** muscle originates from the spinous processes of T2-T5 vertebrae and attaches to the **medial border** of the scapula between the spine and inferior angle. - It acts to retract, elevate, and rotate the scapula downward.

Q: Which nerve roots are primarily involved in Erb's palsy?

C5, C6. C5, C6 - **Erb's palsy** primarily involves injury to the **upper trunk of the brachial plexus**, which is formed by the ventral rami of **C5 and C6** spinal nerves. - This lesion results in a characteristic "waiter's tip" posture due to paralysis of muscles supplied by these nerve roots, including the **deltoid**, **biceps**, and **brachialis**. *C4, C5* - While C5 is involved, **C4** is typically associated with the **phrenic nerve** and diaphragm function, and its primary involvement is not characteristic of Erb's palsy. - Injury to C4 and C5 alone would not produce the comprehensive motor deficits seen in Erb's palsy involving shoulder and elbow flexion. *C5, C7* - This option includes C5 but also **C7**, which is more commonly associated with the **middle trunk** of the brachial plexus. - While C7 can be involved in extended brachial plexus injuries, its primary involvement alone is not the classic presentation of Erb's palsy. *C6, C8* - This combination includes C6 but introduces **C8**, which is part of the **lower trunk** of the brachial plexus. - Injuries involving C8 and T1 are characteristic of **Klumpke's palsy**, affecting intrinsic hand muscles and causing a "claw hand" deformity, which is distinct from Erb's palsy.

Q: A person is not able to extend his metacarpophalangeal joint. Injury to which of the following nerve result in this?

Posterior Interosseous nerve injury. Posterior Interosseous Nerve (PIN) injury - The Posterior Interosseous Nerve is the deep motor branch of the radial nerve that specifically innervates the extensor muscles of the fingers and thumb - These muscles include: Extensor Digitorum, Extensor Indicis, Extensor Digiti Minimi, Extensor Pollicis Longus and Brevis [1] - PIN injury causes inability to extend the MCP joints and interphalangeal joints of the fingers [1] - Wrist extension is preserved because the Extensor Carpi Radialis Longus (ECRL) and often ECRB are innervated by the radial nerve proper before it gives off the PIN [1] - This results in a characteristic finger drop without wrist drop Radial nerve injury - A high radial nerve injury (proximal, above the elbow) would cause both wrist drop AND finger extension loss - However, radial nerve injury at the spiral groove (most common site) typically spares the PIN or affects it less severely - The question asks specifically about isolated inability to extend MCP joints, which is the hallmark of PIN injury, not general radial nerve injury - Radial nerve proper gives branches to triceps, brachioradialis, and ECRL before dividing into PIN and superficial branch Ulnar nerve injury - The ulnar nerve innervates intrinsic hand muscles (interossei, lumbricals to digits 4-5, hypothenar muscles, adductor pollicis) [1] - Ulnar nerve injury causes claw hand deformity with MCP hyperextension (not loss of extension) and IP joint flexion - This is the opposite of what is described in the question Median nerve injury - The median nerve innervates the thenar muscles, lateral two lumbricals, and forearm flexors [1] - Median nerve injury causes ape hand deformity with loss of thumb opposition and flexion - It does not affect MCP joint extension, which is an extensor function

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: 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.

Q: Which muscle is not part of the superficial anterior compartment of the forearm?

Flexor pollicis longus (FPL). **Flexor pollicis longus (FPL)** - The **FPL** is located in the **deep anterior compartment** of the forearm, differentiating it from the superficial muscles [1]. - Its primary function is **flexion of the thumb's interphalangeal joint**, requiring a deeper anatomical position for mechanical advantage [1]. *FDS* - The **Flexor digitorum superficialis (FDS)** is a key muscle of the superficial anterior compartment, visible just beneath the skin and fascia. - It is responsible for **flexing the middle phalanges** of the medial four digits. *FCR* - The **Flexor carpi radialis (FCR)** is situated in the superficial anterior compartment, running obliquely across the forearm. - It functions in **flexion and abduction of the wrist**. *Palmaris longus* - The **Palmaris longus** is a superficial anterior compartment muscle, though it is absent in a significant portion of the population. - When present, its main action is **flexion of the wrist** and tightening of the palmar aponeurosis.

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 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: 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**.

Question 1

Which of the following muscles is not attached to the medial border of the scapula?

Accepted Answer

Teres major

Answer

Serratus anterior

Answer

Levator scapulae

Answer

Rhomboid major

Question 2

Which nerve roots are primarily involved in Erb's palsy?

Accepted Answer

C5, C6

Answer

C4, C5

Answer

C5, C7

Answer

C6, C8

Question 3

A person is not able to extend his metacarpophalangeal joint. Injury to which of the following nerve result in this?

Accepted Answer

Posterior Interosseous nerve injury

Answer

Radial nerve injury

Answer

Ulnar nerve injury

Answer

Median nerve injury

Question 4

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 5

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

Accepted Answer

Infraspinatus

Answer

Pectoralis major

Answer

Pectoralis minor

Answer

Subclavius

Question 6

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 7

Which muscle is not part of the superficial anterior compartment of the forearm?

Accepted Answer

Flexor pollicis longus (FPL)

Answer

FDS

Answer

FCR

Answer

Palmaris longus

Question 8

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 9

What is the largest branch of the brachial plexus?

Accepted Answer

Radial nerve

Answer

Ulnar nerve

Answer

Axillary nerve

Answer

Median nerve

Question 10

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

Upper Limb — MCQs

Upper Limb — MCQs

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