Upper Limb Practice Questions

Q: Traumatic anterior dislocation of shoulder with sensory loss in lateral side of forearm and weakness of flexion of elbow joint, most likely injured nerve is:

Musculocutaneous nerve. ***Musculocutaneous nerve*** - The **musculocutaneous nerve** innervates the biceps brachii and brachialis muscles, responsible for **elbow flexion**. - It also provides sensory innervation to the **lateral forearm** via the **lateral cutaneous nerve of the forearm**, explaining the sensory loss described. *Ulnar nerve* - The ulnar nerve primarily innervates muscles of the **hand** and gives sensory supply to the medial 1 and 1/2 digits. - Its injury would typically lead to weakness in **finger adduction/abduction** and sensory loss in the medial hand, not the lateral forearm. *Axillary nerve* - The axillary nerve innervates the **deltoid** and **teres minor** muscles, causing weakness in **shoulder abduction** and external rotation upon injury. - Sensory loss would be over the **regimental badge area** (lateral shoulder), not the lateral forearm. *Radial nerve* - The radial nerve innervates the **extensor muscles of the wrist and fingers**, and the triceps. - Injury would result in **wrist drop** and sensory loss over the **posterior arm, forearm, and hand**, not lateral forearm sensory loss.

Q: Posterolateral Anconeus triangle is formed by all, except

Medial epicondyle. ***Medial epicondyle*** - The **medial epicondyle** is part of the **medial column** of the distal humerus and is therefore not involved in forming the posterolateral anconeus triangle. - This triangle is specifically defined by structures on the posterior and lateral aspects of the elbow joint. *Lateral epicondyle* - The **lateral epicondyle** forms the **apex** or superior boundary of the anconeus triangle when viewed from the posterior aspect. - It serves as a key bony landmark for the posterolateral region of the elbow. *Olecranon* - The **olecranon** of the ulna constitutes the **inferomedial** boundary of the anconeus triangle. - It forms a prominent point on the posterior aspect of the elbow. *Head of the radius* - The **head of the radius** forms the **inferior-lateral** boundary of the anconeus triangle. - It is an important structure for defining the lateral and distal limits of this anatomical region.

Q: Crutch palsy is injury to which nerve?

Radial nerve. ***Radial nerve*** - **Crutch palsy** is a form of **compression neuropathy** that specifically affects the **radial nerve** due to improper crutch use. - The crutch top places pressure on the **axilla**, compressing the radial nerve in the **axillary region** as it travels along the posterior cord. - This results in **wrist drop** and weakness of finger/thumb extension due to paralysis of extensor muscles. *Ulnar nerve* - The **ulnar nerve** is commonly injured at the **cubital tunnel** (medial epicondyle) or Guyon's canal in the wrist. [1] - Injuries typically result in **claw hand deformity** and sensory loss in the medial 1.5 digits, not associated with crutch pressure. [1] *Musculocutaneous nerve* - The **musculocutaneous nerve** innervates the **biceps brachii** and **brachialis** muscles, responsible for elbow flexion. - Injury to this nerve is rare from external compression and would primarily affect **forearm flexion** and sensation on the lateral forearm. *Median nerve* - The **median nerve** is most commonly entrapped in the **carpal tunnel** at the wrist, leading to carpal tunnel syndrome. - Injury typically results in **ape hand deformity** and sensory loss in the lateral 3.5 digits, not compression in the axilla from crutches.

Q: Surgical neck fracture leads to all EXCEPT

Teres major palsy. ***Teres major palsy*** - The **teres major** muscle is innervated by the **lower subscapular nerve** (C5-C7). - A surgical neck fracture of the humerus typically injures the **axillary nerve**, which does not innervate the teres major. *Deltoid muscle palsy* - The **axillary nerve**, which innervates the **deltoid muscle**, is commonly injured in a surgical neck fracture due to its proximity. - Injury to the axillary nerve would result in **deltoid muscle palsy**, leading to weakness in shoulder abduction and external rotation. *Weakness of abduction* - The **deltoid muscle** is the primary abductor of the arm after the initial 15 degrees, and it is innervated by the **axillary nerve**. - A surgical neck fracture carries a high risk of **axillary nerve injury**, compromising deltoid function and causing significant weakness in abduction. *Teres minor palsy* - The **teres minor muscle** is innervated by the **axillary nerve**, which is vulnerable in surgical neck fractures. - Palsy of the teres minor would impair **external rotation** of the shoulder.

Q: Which muscle is affected in winging of the scapula?

Serratus anterior. ***Serratus anterior*** - Damage to the **long thoracic nerve**, which innervates the serratus anterior muscle, leads to paralysis of this muscle. - The **serratus anterior** is crucial for holding the scapula against the thoracic wall and for **scapular protraction**, so its weakness results in a prominent medial border of the scapula, known as **winging**. *Latissimus dorsi* - The **latissimus dorsi** is an important muscle for **adduction**, **extension**, and **internal rotation** of the shoulder. - Injury to this muscle or its innervation (thoracodorsal nerve) primarily affects these movements, not causing scapular winging. *Subscapularis* - The **subscapularis** is part of the rotator cuff and is primarily involved in **internal rotation** of the humerus. - Dysfunction of the subscapularis would manifest as weakness in internal rotation and possibly shoulder instability, but not scapular winging. *Teres minor* - The **teres minor** is another rotator cuff muscle responsible for **external rotation** and stabilization of the humeral head. - Weakness of the teres minor would impair external rotation and contribute to rotator cuff dysfunction, but it is not associated with scapular winging.

Q: Which muscle originates from tendon of other muscle?

Lumbricals. Lumbricals - The lumbrical muscles are unique in the hand because they originate from the tendons of the flexor digitorum profundus (FDP), not from bone [1]. - This attachment allows them to flex the metacarpophalangeal (MCP) joints while extending the interphalangeal (IP) joints [1]. FCR - The flexor carpi radialis (FCR) muscle originates from the medial epicondyle of the humerus, a bony origin. - Its primary function is flexion and radial deviation of the wrist. Adductor pollicis - The adductor pollicis muscle has two heads, the oblique and transverse heads, both originating from various carpal bones and the third metacarpal. - It plays a crucial role in adducting the thumb. Palmaris longus - The palmaris longus muscle originates from the medial epicondyle of the humerus, similar to the FCR. - It contributes to wrist flexion and is absent in a significant portion of the population.

Q: Winging of scapula is seen in paralysis of which muscle?

Serratus anterior. **Serratus anterior** - The **serratus anterior muscle** is crucial for holding the scapula against the thoracic wall and enabling upward rotation, protraction, and abduction of the arm. - Paralysis of the serratus anterior, typically due to damage to the **long thoracic nerve (of Bell)**, causes the medial border of the scapula to protrude posteromedially, known as **"winging of the scapula."** *Infraspinatus* - The **infraspinatus** is a rotator cuff muscle primarily responsible for **external rotation** of the humerus. - Paralysis of this muscle would lead to weakness in external rotation and potentially some shoulder instability, but not scapular winging. *Pectoralis major* - The **pectoralis major** is a large chest muscle responsible for **adduction, medial rotation, and flexion** of the humerus. - Its paralysis would impair these movements but would not directly cause the scapula to wing. *Supraspinatus* - The **supraspinatus** is another rotator cuff muscle, primarily responsible for initiating **abduction** of the humerus (first 0-15 degrees). - Paralysis would result in difficulty with arm abduction but would not cause scapular winging.

Q: What is the normal orientation of the humeral head relative to the transepicondylar axis of the elbow?

Anteversion of 15 degrees. ***Anteversion of 15 degrees*** - The humeral head normally exhibits approximately **15-30 degrees of anteversion** (also called torsion) relative to the **transepicondylar axis of the elbow**. - This **anteversion** means the humeral head is rotated **anteriorly (forward)** compared to the plane of the elbow. - This orientation allows for optimal range of motion at the glenohumeral joint, particularly during **internal and external rotation**. - The value of **15 degrees falls within the normal anatomical range** and represents the lower end of normal variation. *Anteversion of 50 degrees* - While anteversion is the correct direction, **50 degrees is excessive** and beyond the normal range (typically 15-30 degrees). - Excessive anteversion can lead to **anterior instability** of the shoulder and altered biomechanics. *Retroversion of 80 degrees* - **Retroversion** means posterior rotation, which is the **opposite direction** from normal humeral anatomy. - The humerus normally demonstrates **anteversion, not retroversion**. - 80 degrees would be an extremely abnormal orientation. *Retroversion of 30 degrees* - This option confuses the direction: the humerus exhibits **anteversion (forward rotation), not retroversion (backward rotation)**. - While 30 degrees is within the normal magnitude, the **direction is incorrect**.

Q: All of the following muscles are paralyzed in trauma to median nerve at the wrist except -

Adductor pollicis. ***Adductor pollicis*** - The **adductor pollicis** muscle is primarily innervated by the **ulnar nerve**, specifically its deep branch [2]. - Therefore, it would **not be paralyzed** by a median nerve injury at the wrist [2]. *Muscles of the Thenar eminence* - The thenar muscles (**abductor pollicis brevis**, **flexor pollicis brevis** (superficial head), and **opponens pollicis**) are innervated by the **recurrent branch of the median nerve** [2]. - A median nerve injury at the wrist, especially involving the recurrent branch, would paralyze these muscles, leading to loss of thumb opposition and abduction [1]. *First two lumbicals* - The **first and second lumbrical muscles** are innervated by the **median nerve** [2]. - Trauma to the median nerve at the wrist would impair their function, affecting flexion of the metacarpophalangeal joints and extension of the interphalangeal joints of the index and middle fingers. *Abductor pollicis brevis* - The **abductor pollicis brevis** is a thenar muscle innervated by the **recurrent branch of the median nerve** [2]. - Its paralysis would be a direct consequence of a median nerve injury at the wrist, resulting in inability to abduct the thumb.

Q: Damage to median nerve produces:

Ape thumb. Ape thumb - Damage to the median nerve specifically affects the thenar muscles (via the recurrent branch): abductor pollicis brevis, opponens pollicis, and the superficial head of flexor pollicis brevis [1]. - Loss of these muscles results in the characteristic "ape thumb" deformity, where the thumb lies in the same plane as the palm and cannot be opposed [1]. - The patient loses the ability to perform thumb opposition, which is essential for precision grip and many hand functions [1]. Winging of scapula - Winging of the scapula is caused by damage to the long thoracic nerve, which innervates the serratus anterior muscle. - This condition is not associated with median nerve injury. Claw hand - A claw hand deformity is typically caused by damage to the ulnar nerve, affecting the lumbricals and interossei muscles. - It results in hyperextension of the metacarpophalangeal joints and flexion of the interphalangeal joints, particularly of the 4th and 5th digits. - This is distinct from median nerve pathology. Wrist drop - Wrist drop is a classic sign of radial nerve damage, affecting the extensor muscles of the wrist and fingers. - It results in the inability to extend the wrist and digits, which is not a feature of median nerve injury.

Question 1

Traumatic anterior dislocation of shoulder with sensory loss in lateral side of forearm and weakness of flexion of elbow joint, most likely injured nerve is:

Accepted Answer

Musculocutaneous nerve

Answer

Ulnar nerve

Answer

Axillary nerve

Answer

Radial nerve

Question 2

Posterolateral Anconeus triangle is formed by all, except

Accepted Answer

Medial epicondyle

Answer

Lateral epicondyle

Answer

Olecranon

Answer

Head of the radius

Question 3

Crutch palsy is injury to which nerve?

Accepted Answer

Radial nerve

Answer

Ulnar nerve

Answer

Musculocutaneous nerve

Answer

Median nerve

Question 4

Surgical neck fracture leads to all EXCEPT

Accepted Answer

Teres major palsy

Answer

Deltoid muscle palsy

Answer

Weakness of abduction

Answer

Teres minor palsy

Question 5

Which muscle is affected in winging of the scapula?

Accepted Answer

Serratus anterior

Answer

Latissimus dorsi

Answer

Subscapularis

Answer

Teres minor

Question 6

Which muscle originates from tendon of other muscle?

Accepted Answer

Lumbricals

Answer

FCR

Answer

Adductor pollicis

Answer

Palmaris longus

Question 7

Winging of scapula is seen in paralysis of which muscle?

Accepted Answer

Serratus anterior

Answer

Infraspinatus

Answer

Pectoralis major

Answer

Supraspinatus

Question 8

What is the normal orientation of the humeral head relative to the transepicondylar axis of the elbow?

Accepted Answer

Anteversion of 15 degrees

Answer

Anteversion of 50 degrees

Answer

Retroversion of 80 degrees

Answer

Retroversion of 30 degrees

Question 9

All of the following muscles are paralyzed in trauma to median nerve at the wrist except -

Accepted Answer

Adductor pollicis

Answer

Muscles of the Thenar eminence

Answer

First two lumbicals

Answer

Abductor pollicis brevis

Question 10

Damage to median nerve produces:

Accepted Answer

Ape thumb

Answer

Winging of scapula

Answer

Claw hand

Answer

Wrist drop

Upper Limb — MCQs

Upper Limb — MCQs

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