Upper Limb Practice Questions

Q: Identify the muscle along with its action.

Dorsal interossei -abduction. ***Dorsal interossei -abduction*** - **Dorsal interossei** muscles are responsible for **abduction** of the fingers away from the midline of the middle finger. - These muscles are key intrinsic muscles of the hand and are supplied by the **deep branch of the ulnar nerve**. *Dorsal interossei -adduction* - This statement is incorrect as the **dorsal interossei** muscles primarily perform **abduction**, not adduction. - Adduction is functionally performed by the **palmar interossei** muscles. *Palmer interossei -adduction* - While this correctly identifies the primary action of **palmar interossei** (adduction of the fingers towards the midline), it is an incorrect option in the context of the provided choices as it is usually paired incorrectly in similar exam structures or distractor layouts, however, note that this statement is physiologically correct; but given the prompt's structure, the dorsal interossei-abduction is the primary target answer for the specific pairing required. - Correction: Please note that **Palmar interossei** *do* adduct the fingers, but in multiple-choice questions focusing on pairings, ensure you select the one explicitly tested as the primary association with **Dorsal Interossei**. *Palmer interossei -abduction* - **Palmar interossei** muscles are specifically designated for **adduction** of the fingers towards the central axis of the hand. - They do not possess the anatomical orientation to perform the **abduction** of the digits.

Q: Match the corresponding structures according to the labels in the given image.

A-Clavicle, B-Coracoid process, C -Scapula, D-Acromion. ***A-Clavicle, B-Coracoid process, C -Scapula, D-Acromion*** - The **clavicle** is the horizontal, S-shaped bone articulating medially with the manubrium and laterally with the **acromion**. - The **coracoid process** is a hook-like structure located anteriorly on the shoulder blade, while the acromion forms the bony prominence of the superior shoulder. *A-Clavicle, B-Coracoid process, C -Acromion, D -Scapula* - The **acromion** is not synonymous with the general body of the scapula; it is a specific extension. - Misidentifying anatomical landmarks in radiographic or schematic labeling leads to incorrect structural relationships. *A-Clavicle , B-Acromion, C -Coracoid process , D -Scapula* - The **acromion** is located superior and posterior to the coracoid process, not anterior to it. - This arrangement fails to correctly identify the lateral end of the clavicle's articulation point. *A-Clavicle, B-Acromion, C -Scapula, D-Coracoid process* - The **coracoid process** is distinct from the body of the **scapula** as it is a prominent bony projection. - Placing the acromion in the position of the coracoid process confuses the anterior and superior landmarks of the shoulder girdle.

Q: A person came in with difficulty to abduct his left arm above 15 degrees and loss of sensation over his left lateral arm. Xray of the affected arm is given. Which structure is most probably affected? (Badge sign was also mentioned in the question).

Axillary nerve. ***Axillary nerve*** - The **axillary nerve** innervates the **deltoid muscle**, which is responsible for arm abduction beyond the initial 15 degrees (initiated by the **supraspinatus**); injury results in weakness or paralysis of this movement. - Damage to this nerve causes loss of sensation over the 'regimental badge' area on the **lateral shoulder** and is commonly associated with **surgical neck fractures** of the humerus. *Radial nerve* - Injury to this nerve typically results in **wrist drop** due to paralysis of the **extensor muscles** of the forearm. - Sensory loss occurs on the **dorsum of the hand** and the posterior arm, not the lateral shoulder. *Musculocutaneous nerve* - This nerve innervates the **anterior compartment of the arm** (biceps, brachialis, coracobrachialis), responsible for **elbow flexion** and forearm supination. - Injury results in weakness in elbow flexion and sensory loss along the **lateral forearm**. *Subscapular nerve* - The **subscapular nerves** (upper and lower) innervate the **subscapularis** and **teres major**, which act as **medial rotators** and adductors of the arm. - Injury does not present with the characteristic loss of sensation over the lateral shoulder seen in axillary nerve palsy.

Q: What is true about the blood supply of the scaphoid bone?

Major supply from the dorsal surface. The scaphoid is the most commonly fractured carpal bone [1], and its unique vascular anatomy is a high-yield topic for NEET-PG. [2] ### **Explanation of the Correct Answer** The scaphoid receives approximately **70–80% of its blood supply from the dorsal carpal branch of the radial artery**. These vessels enter the bone through the **dorsal ridge** (non-articular surface) and supply the proximal two-thirds of the bone via **retrograde flow**. This makes the dorsal surface the primary site of vascular entry. ### **Analysis of Incorrect Options** * **Option A:** The blood supply is derived almost exclusively from the **radial artery**, not the ulnar artery. * **Option B:** While some minor vessels enter the distal tubercle on the volar (ventral) side, the **major** supply is dorsal. * **Option C (Correct):** As stated, the dorsal carpal branch of the radial artery is the dominant source. * **Option D:** The blood supply to the proximal pole is **retrograde** (distal-to-proximal). There is no direct antegrade supply to the proximal pole, which is why it is highly susceptible to ischemia. [2] ### **Clinical Pearls for NEET-PG** * **Retrograde Blood Flow:** Because the vessels enter distally and travel proximally, a fracture at the **waist of the scaphoid** often severs the blood supply to the proximal fragment. [1] * **Avascular Necrosis (AVN):** The proximal pole is the most common site for AVN (Preiser’s disease is idiopathic AVN, but post-traumatic AVN is more common). [2] * **Anatomical Snuffbox:** Tenderness here is pathognomonic for a scaphoid fracture. * **Non-union:** Due to the precarious retrograde supply, scaphoid fractures have a high risk of non-union and delayed healing. [2]

Question 1

Identify the muscle along with its action.

Accepted Answer

Dorsal interossei -abduction

Answer

Dorsal interossei -adduction

Answer

Palmer interossei -adduction

Answer

Palmer interossei -abduction

Question 2

Match the corresponding structures according to the labels in the given image.

Accepted Answer

A-Clavicle, B-Coracoid process, C -Scapula, D-Acromion

Answer

A-Clavicle, B-Coracoid process, C -Acromion, D -Scapula

Answer

A-Clavicle , B-Acromion, C -Coracoid process , D -Scapula

Answer

A-Clavicle, B-Acromion, C -Scapula, D-Coracoid process

Question 3

A person came in with difficulty to abduct his left arm above 15 degrees and loss of sensation over his left lateral arm. Xray of the affected arm is given. Which structure is most probably affected? (Badge sign was also mentioned in the question).

Accepted Answer

Axillary nerve

Answer

Radial nerve

Answer

Musculocutaneous nerve

Answer

Subscapular nerve

Question 4

A 34-year-old man sustains a mid-shaft fracture of the humerus following a road traffic accident. During the axillary surgical approach for fixation, the operating surgeon identifies and tags a nerve (arrowed in Image 2) based on its intraoperative course and relationships — not solely on the fracture pattern. Postoperatively, the patient has weakness of elbow flexion and loss of sensation over the lateral forearm, consistent with injury to the tagged nerve. The nerve was identified intraoperatively as it pierced a muscle of the anterior axillary wall, and the image shows this tagged nerve with a clear arrow at the point of entry. Which statement best describes the course of the tagged nerve that accounts for both the motor and sensory deficits seen in this patient?

Accepted Answer

B. It arises from the lateral cord, pierces coracobrachialis, and continues as the lateral cutaneous nerve of the forearm

Answer

A. It arises from the medial cord, passes posterior to coracobrachialis, and terminates as the medial cutaneous nerve of the forearm

Answer

C. It arises from the posterior cord, passes anterior to the subscapularis, and supplies the lateral compartment of the arm

Answer

D. It arises from the lateral cord, passes superficial to coracobrachialis, and terminates as the posterior cutaneous nerve of the forearm

Question 5

What is true about the blood supply of the scaphoid bone?

Accepted Answer

Major supply from the dorsal surface

Answer

Mainly through the ulnar artery

Answer

Major supply from the ventral surface

Answer

Proximal supply in antegrade fashion

Upper Limb — MCQs

Upper Limb — MCQs

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