Upper Limb Practice Questions

Q: Insertion of levator scapulae is?

Superior part of medial scapula border. ***Superior part of medial scapula border*** - The **levator scapulae muscle** originates from the **transverse processes of C1-C4 vertebrae** and **inserts** onto the superior part of the medial border of the scapula, between the **superior angle and the spine of the scapula**. - Its main actions are to **elevate** and **rotate** the scapula downward. *Lateral border of scapula* - The **lateral border of the scapula** primarily serves as the attachment site for muscles that move the **humerus**, such as the **teres major** and **teres minor**. - The levator scapulae has no direct insertion on the lateral border. *Suprolateral part of scapula* - This general description is vague and does not precisely identify the insertion point of the levator scapulae. - While it's located superiorly, the specific insertion is on the **medial border**, not broadly "suprolateral." *Inferior angle of scapula* - The **inferior angle of the scapula** is the insertion point for muscles like the **latissimus dorsi** (occasionally) and a key landmark for muscles involved in **scapular rotation**, such as the **serratus anterior**. - The levator scapulae is located much more superiorly and inserts onto the medial border at a higher level than the inferior angle.

Q: Which artery passes through the anatomical snuffbox?

Radial artery. ***Radial artery*** - The **radial artery** is palpable within the **anatomical snuffbox**, as it courses over the scaphoid and trapezium bones towards the deep palmar arch. - This location is clinically significant for feeling the pulse and is vulnerable to injury, especially during **scaphoid fractures**. *Brachial artery* - The **brachial artery** is found in the **arm**, typically running in the cubital fossa, well proximal to the anatomical snuffbox. - It bifurcates into the radial and ulnar arteries at the level of the elbow, not within the wrist structures. *Ulnar artery* - The **ulnar artery** typically lies on the **medial side of the forearm** and wrist, contributing to the superficial palmar arch. - It does not pass through the anatomical snuffbox, which is located on the lateral aspect of the wrist. *Interosseus artery* - The **interosseus arteries** (anterior and posterior) run between the radius and ulna in the forearm, supplying muscles and bones. - These arteries are deep within the forearm compartments and do not traverse the superficial anatomical snuffbox at the wrist.

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 patient has a herniated intervertebral disc impinging on the right C5 nerve roots. Which of the following movements would most likely be affected?

Flexion of the elbow. ***Flexion of the elbow*** - The **C5 nerve root** is a primary contributor to the innervation of the **biceps brachii** and **brachialis** muscles, which are the prime movers for elbow flexion. - The C5 myotome specifically includes elbow flexion as one of its key motor functions. - Impingement of the C5 nerve root would therefore most directly impact the strength and function of **elbow flexion**, leading to weakness in this movement. *Extension of the fingers* - Finger extension is primarily mediated by the **C7 and C8 nerve roots** via the posterior interosseous nerve (branch of the radial nerve). - C5 does not significantly contribute to finger extension. *Extension of the shoulder* - Shoulder extension involves muscles primarily innervated by the **C6, C7, and C8 nerve roots** (e.g., latissimus dorsi via thoracodorsal nerve, teres major). - While C5 contributes to some shoulder movements (particularly **shoulder abduction** via the deltoid), it is not primarily responsible for shoulder extension. *Flexion of the wrist* - Wrist flexion is primarily served by muscles innervated by the **C6, C7, and C8 nerve roots** (e.g., flexor carpi radialis - C6/C7, flexor carpi ulnaris - C7/C8). - The C5 nerve root has minimal to no role in wrist flexion.

Q: What is the characteristic upper limb deformity seen in Erb's palsy?

Adduction and medial rotation of arm. ***Adduction and medial rotation of arm*** - Erb's palsy, resulting from injury to the **upper brachial plexus** (C5-C6 nerve roots), primarily affects the **deltoid**, **supraspinatus**, **infraspinatus**, and **biceps** muscles. - The unopposed action of unaffected muscles, such as the **pectoris major** and **latissimus dorsi**, leads to the characteristic **waiter's tip position**, involving **adduction** and **medial rotation** of the arm. *Adduction and lateral rotation of arm* - This position would imply weakness of the **pectoralis major** and **latissimus dorsi** and stronger activity of the **infraspinatus** and **teres minor**, which is contrary to the muscle deficits in Erb's palsy. - **Lateral rotation** of the arm is typically impaired in Erb's palsy due to weakness of the **infraspinatus** and **teres minor**. *Abduction and lateral rotation of arm* - **Abduction** is severely impacted in Erb's palsy due to paralysis of the **deltoid** and **supraspinatus**. - This position would suggest intact function of muscles that are explicitly weakened or paralyzed in Erb's palsy. *Abduction and medial rotation of arm* - While **medial rotation** can be a component of the deformity, **abduction** is a movement that is significantly impaired in Erb's palsy, making this option incorrect. - The inability to abduct the arm is a hallmark of the condition due to weakness of the **deltoid** and **supraspinatus**.

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: Root value of the thoracodorsal nerve

C6, C7, C8. ***C6, C7, C8*** - The **thoracodorsal nerve**, also known as the middle subscapular nerve, originates from the **posterior cord of the brachial plexus**. - Its specific root values are **C6, C7, and C8**, which supply motor innervation to the **latissimus dorsi muscle** [1]. - This nerve is one of the three subscapular nerves arising from the posterior cord [1]. *C5, C6, C7* - While these roots contribute to the **posterior cord**, the thoracodorsal nerve specifically arises from **C6, C7, C8**. - **C5** primarily contributes to the **upper and middle trunk** and is more associated with nerves like the **suprascapular** and **axillary nerves**. *C6, T1* - These root values contribute to various nerves of the **brachial plexus**, but not specifically the thoracodorsal nerve. - **T1** contributes mainly to the **medial cord** and its branches like the **ulnar nerve**, not the posterior cord from which the thoracodorsal nerve arises. *T1, T2* - These are typical root values for **intercostal nerves** and contribute to the **sympathetic trunk**, not the **brachial plexus** or its branches like the thoracodorsal nerve. - The brachial plexus predominantly arises from **C5 to T1 spinal nerve roots**, and **T2** is not part of the brachial plexus.

Q: A nerve injured during axillary lymph node dissection leads to loss of sensation in the medial side of the arm. Which nerve is injured?

Intercostobrachial nerve. ***Intercostobrachial nerve*** - The **intercostobrachial nerve** (T2) is the nerve most commonly injured during **axillary lymph node dissection** - It provides **sensory innervation to the medial side of the upper arm**, specifically the skin over the medial and posterior aspects of the arm [1] - This nerve arises from the **lateral cutaneous branch of the second intercostal nerve** and crosses the axilla to reach the arm [1] - Injury during axillary surgery results in **numbness or paresthesia** in the medial upper arm region, which is a well-recognized complication of breast cancer surgery with axillary node dissection [1] - Studies show **30-80% of patients** undergoing axillary dissection experience intercostobrachial nerve injury *Long thoracic nerve* - The **long thoracic nerve** (C5-C7) innervates the **serratus anterior muscle**, which is crucial for scapular protraction and rotation - Damage to this nerve causes **"winged scapula"**, where the scapula protrudes posteriorly - This is a **motor nerve**, not sensory, so injury does not result in sensory deficits in the arm *Medial pectoral nerve* - The **medial pectoral nerve** (C8-T1) primarily innervates the **pectoralis major** and **pectoralis minor** muscles [1] - This is a **motor nerve** playing a role in muscle function rather than sensation [1] - Injury would result in weakness of these muscles, not sensory loss *Accessory nerve* - The **accessory nerve** (cranial nerve XI) innervates the **sternocleidomastoid** and **trapezius muscles** - This nerve is located in the **posterior triangle of the neck**, not in the axilla - Injury would lead to weakness in shrugging the shoulders or turning the head, not sensory loss in the arm during axillary dissection

Q: Which of the following statements about the lumbrical muscles is correct?

Flex MCP joints and extend IP joints. Flex MCP joints and extend IP joints - The lumbrical muscles are unique in their attachment, originating from tendons and inserting into the extensor hood, allowing them to perform simultaneous metacarpophalangeal (MCP) joint flexion and interphalangeal (IP) joint extension [1]. - This specific action is crucial for fine motor movements of the fingers, particularly in precision grip. All lumbricals are supplied by the median nerve - This statement is incorrect as only the first and second lumbricals (of the index and middle fingers) are typically supplied by the median nerve. - The third and fourth lumbricals are innervated by the ulnar nerve. All lumbricals are supplied by the ulnar nerve - This statement is incorrect because the first and second lumbricals receive innervation from the median nerve. - Only the third and fourth lumbricals are consistently supplied by the deep branch of the ulnar nerve. Origin from the tendons of flexor digitorum superficialis - This statement is incorrect. The lumbricals originate from the tendons of the flexor digitorum profundus, not the superficialis [1]. - They are unique in that they are the only muscles in the human body that originate from a tendon and insert into a tendon (extensor expansion) [1].

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

Question 1

Insertion of levator scapulae is?

Accepted Answer

Superior part of medial scapula border

Answer

Lateral border of scapula

Answer

Suprolateral part of scapula

Answer

Inferior angle of scapula

Question 2

Which artery passes through the anatomical snuffbox?

Accepted Answer

Radial artery

Answer

Brachial artery

Answer

Ulnar artery

Answer

Interosseus artery

Question 3

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

Accepted Answer

C5, C6

Answer

C4, C5

Answer

C5, C7

Answer

C6, C8

Question 4

A patient has a herniated intervertebral disc impinging on the right C5 nerve roots. Which of the following movements would most likely be affected?

Accepted Answer

Flexion of the elbow

Answer

Extension of the fingers

Answer

Extension of the shoulder

Answer

Flexion of the wrist

Question 5

What is the characteristic upper limb deformity seen in Erb's palsy?

Accepted Answer

Adduction and medial rotation of arm

Answer

Adduction and lateral rotation of arm

Answer

Abduction and lateral rotation of arm

Answer

Abduction and medial rotation of arm

Question 6

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 7

Root value of the thoracodorsal nerve

Accepted Answer

C6, C7, C8

Answer

T1, T2

Answer

C5, C6, C7

Answer

C6, T1

Question 8

A nerve injured during axillary lymph node dissection leads to loss of sensation in the medial side of the arm. Which nerve is injured?

Accepted Answer

Intercostobrachial nerve

Answer

Long thoracic nerve

Answer

Medial pectoral nerve

Answer

Accessory nerve

Question 9

Which of the following statements about the lumbrical muscles is correct?

Accepted Answer

Flex MCP joints and extend IP joints

Answer

All lumbricals are supplied by the median nerve

Answer

Origin from the tendons of flexor digitorum superficialis

Answer

All lumbricals are supplied by the ulnar nerve

Question 10

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

Upper Limb — MCQs

Upper Limb — MCQs

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