Upper Limb Practice Questions

Q: Which carpal bone articulates with the radius?

Scaphoid. **Explanation:** The wrist joint (radiocarpal joint) is a synovial joint of the ellipsoid variety. It is formed by the articulation between the distal end of the **radius** (and the articular disc of the inferior radioulnar joint) and the proximal row of carpal bones. **Why Scaphoid is Correct:** The distal surface of the radius has two distinct articular facets: a lateral triangular facet for the **scaphoid** and a medial quadrangular facet for the **lunate**. Therefore, the scaphoid directly articulates with the radius to transmit forces from the hand to the forearm. **Analysis of Incorrect Options:** * **Trapezium (A):** This is a distal row carpal bone. It articulates with the scaphoid proximally and the first metacarpal distally (forming the thumb CMC joint), but it has no contact with the radius. * **Capitate (C):** The largest carpal bone, located in the distal row. It occupies a central position, articulating with the scaphoid and lunate proximally, but not the radius. * **Hamate (D):** A distal row bone characterized by its hook (uncus). It articulates with the triquetrum proximally and the 4th/5th metacarpals distally. **High-Yield Clinical Pearls for NEET-PG:** * **Fracture Scaphoid:** It is the most commonly fractured carpal bone. Tenderness in the **Anatomical Snuffbox** is a classic sign. Due to retrograde blood supply, it is prone to **Avascular Necrosis (AVN)**. * **Lunate Dislocation:** The lunate is the most commonly dislocated carpal bone, often resulting in Median nerve compression. * **The Ulna:** Note that the ulna does **not** articulate directly with any carpal bones; it is separated from them by the triangular fibrocartilage complex (TFCC).

Q: Which of the following arteries is present in the anatomical snuff box?

Radial artery. **Explanation:** The **Radial artery** is the correct answer because of its specific course through the wrist. After giving off the superficial palmar branch, the radial artery winds dorsally around the lateral aspect of the carpus, deep to the tendons of the abductor pollicis longus and extensor pollicis brevis. It then enters the **anatomical snuff box**, where it lies on the floor (formed by the scaphoid and trapezium bones). This is a high-yield clinical site where the radial pulse can be palpated against the scaphoid. **Analysis of Incorrect Options:** * **Anterior interosseous artery:** This is a branch of the common interosseous artery (from the ulnar artery). It travels deep in the forearm on the interosseous membrane and ends by joining the dorsal carpal arch; it does not enter the snuff box. * **Brachial artery:** This artery terminates in the cubital fossa by dividing into the radial and ulnar arteries. It is located far proximal to the wrist. * **Ulnar artery:** This artery enters the hand via **Guyon’s canal**, superficial to the flexor retinaculum and medial to the pisiform bone. It remains on the anterior (palmar) aspect of the wrist. **NEET-PG High-Yield Pearls:** * **Boundaries of Snuff Box:** Lateral (Abductor pollicis longus, Extensor pollicis brevis); Medial (Extensor pollicis longus). * **Contents:** Radial artery, Cephalic vein (superficial), and branches of the Superficial Radial Nerve. * **Clinical Significance:** Tenderness in the snuff box post-trauma is highly suggestive of a **Scaphoid fracture**, the most commonly fractured carpal bone.

Q: Which muscle arises from the supraglenoid tubercle?

Long head of biceps. The **supraglenoid tubercle** is a small bony prominence located at the superior aspect of the glenoid cavity of the scapula. It serves as the specific site of origin for the **long head of the biceps brachii**. ### Why Option A is Correct: The **long head of the biceps brachii** arises from the supraglenoid tubercle. Its tendon is unique because it is **intracapsular but extrasynovial**; it passes over the head of the humerus within the shoulder joint capsule before exiting through the bicipital groove. ### Why the Other Options are Incorrect: * **Short head of biceps (B):** Arises from the apex of the **coracoid process** of the scapula (along with the coracobrachialis). * **Long head of triceps (C):** Arises from the **infraglenoid tubercle** of the scapula. A common mnemonic to distinguish these is: **B**iceps is **S**uperior (Supraglenoid) and **T**riceps is **I**nferior (Infraglenoid). * **Coracobrachialis (D):** Arises from the apex of the **coracoid process** via a common tendon with the short head of the biceps. ### High-Yield Clinical Pearls for NEET-PG: * **SLAP Lesion:** Superior Labrum Anterior to Posterior lesions often involve the attachment site of the long head of the biceps at the supraglenoid tubercle/superior labrum. * **Nerve Supply:** The biceps brachii and coracobrachialis are supplied by the **Musculocutaneous nerve (C5-C7)**, while the triceps is supplied by the **Radial nerve (C6-C8)**. * **Yergason’s Test:** Used clinically to detect tendonitis or stability of the long head of the biceps tendon in the bicipital groove.

Q: Which muscle is inserted into the floor of the intertubercular sulcus of the humerus?

Latissimus dorsi. The **intertubercular sulcus (bicipital groove)** of the humerus is a critical landmark for the insertion of three major muscles of the upper limb. A high-yield mnemonic to remember their arrangement from lateral to medial is **"The Lady between two Majors."** ### 1. Why Latissimus Dorsi is Correct The **Latissimus dorsi** (the "Lady") inserts into the **floor** of the intertubercular sulcus. It originates from the lower thoracic vertebrae and iliac crest, acting as a powerful adductor, extensor, and internal rotator of the arm [1]. ### 2. Analysis of Incorrect Options * **Pectoralis major (Option C):** This muscle inserts into the **lateral lip** of the bicipital groove [1]. It forms the anterior wall of the axilla. * **Teres major (Option B):** This muscle inserts into the **medial lip** of the bicipital groove. Along with the latissimus dorsi, it helps in internal rotation. * **Deltoid (Option D):** This muscle does not insert into the sulcus; it inserts into the **deltoid tuberosity** on the lateral aspect of the mid-shaft of the humerus. ### 3. NEET-PG High-Yield Pearls * **Contents of the Sulcus:** The intertubercular sulcus contains the **long head of the biceps brachii tendon** (enclosed in a synovial sheath) and the **ascending branch of the anterior circumflex humeral artery**. * **The "Lady" Mnemonic:** * **Lateral lip:** Pectoralis **Major** [1] * **Floor:** Latissimus **Dorsi** (The Lady) * **Medial lip:** Teres **Major** * **Clinical Significance:** The bicipital groove is a common site for **bicipital tendinitis**, often seen in athletes performing overhead throwing motions.

Q: A rock climber falls on their shoulder, resulting in a chipping off of the lesser tubercle of the humerus. Which of the following structures would most likely have structural and functional damage?

Subscapularis muscle. **Explanation:** The correct answer is **Subscapularis muscle**. **1. Why Subscapularis is correct:** The humerus has two primary bony projections at its proximal end: the greater and lesser tubercles. The **Subscapularis** is the only member of the rotator cuff (SITS) muscles that inserts onto the **lesser tubercle**. It originates from the subscapular fossa and acts as the primary internal rotator of the humerus. A fracture or "chipping off" of the lesser tubercle directly compromises the insertion point of the subscapularis, leading to both structural damage and functional loss of internal rotation. **2. Why the other options are incorrect:** The remaining three rotator cuff muscles insert onto the **greater tubercle** of the humerus in a specific superior-to-inferior sequence: * **A. Supraspinatus:** Inserts onto the highest impression of the greater tubercle (responsible for initiating abduction). * **B. Infraspinatus:** Inserts onto the middle impression of the greater tubercle (responsible for external rotation). * **D. Teres minor:** Inserts onto the lowest impression of the greater tubercle (responsible for external rotation). **Clinical Pearls for NEET-PG:** * **SITS mnemonic:** **S**upraspinatus, **I**nfraspinatus, **T**eres minor (Greater tubercle) and **S**ubscapularis (Lesser tubercle). * **Bicipital Groove:** Located between the two tubercles; it houses the long head of the biceps brachii tendon. * **Lift-off Test:** A clinical exam used to assess subscapularis integrity. If the patient cannot lift their hand away from their lower back, it indicates subscapularis weakness or injury. * **Nerve Supply:** Subscapularis is supplied by the upper and lower subscapular nerves (C5, C6).

Q: A patient has a tiny (0.2 cm), but exquisitely painful tumor under the nail of her index finger. Prior to surgery to remove it, local anesthetic block to a branch of which of the following nerves would be most likely to achieve adequate anesthesia?

Median nerve. ### Explanation **Correct Option: B. Median nerve** The clinical presentation describes a **Glomus tumor**, a benign but highly painful vascular neoplasm typically found in the subungual (under the nail) region of the fingers [3]. The **Median nerve** provides sensory innervation to the palmar aspect of the lateral three and a half digits (thumb, index, middle, and lateral half of the ring finger) [2]. Crucially, it also supplies the **dorsal aspect of the distal phalanges (nail beds)** of these same fingers. Therefore, to anesthetize the nail bed of the index finger, a block of the median nerve (or its digital branches) is required [1]. **Why other options are incorrect:** * **A. Axillary nerve:** Supplies the deltoid and teres minor muscles and the skin over the lower deltoid (regimental badge area). It does not extend to the hand. * **C. Musculocutaneous nerve:** Continues as the lateral cutaneous nerve of the forearm. It provides sensation to the lateral forearm but does not supply the digits. * **D. Radial nerve:** While the superficial branch of the radial nerve supplies the dorsal skin of the lateral hand, it only reaches the proximal and middle phalanges. It does **not** supply the nail beds of the index, middle, or ring fingers. **High-Yield Clinical Pearls for NEET-PG:** * **Glomus Tumor Triad:** Paroxysmal pain, pinpoint tenderness, and cold hypersensitivity [3]. * **Nerve Supply of Nail Beds:** * Index, Middle, and Lateral half of Ring finger: **Median Nerve**. * Little finger and Medial half of Ring finger: **Ulnar Nerve**. * Thumb: **Median Nerve**. * **Safe Anesthesia:** When performing a digital nerve block, **never use epinephrine** (adrenaline) with the local anesthetic, as it can cause vasoconstriction of end-arteries leading to digital gangrene.

Q: Which nerve passes through the spiral groove of the humerus?

Radial Nerve. Explanation: 1. Correct Answer: Radial Nerve The Radial Nerve (C5-T1) is the correct answer because it travels within the spiral groove (also known as the radial groove) located on the posterior aspect of the shaft of the humerus. It is accompanied in this groove by the profunda brachii artery. The nerve enters the groove after passing through the triangular space and exits by piercing the lateral intermuscular septum to enter the anterior compartment of the arm. 2. Analysis of Incorrect Options: * Ulnar Nerve: This nerve passes posterior to the medial epicondyle of the humerus (the "funny bone" area), not the spiral groove. * Musculocutaneous Nerve: This nerve pierces the coracobrachialis muscle and travels between the biceps brachii and brachialis muscles in the anterior compartment. * Interosseous Nerve: The Anterior and Posterior interosseous nerves are branches of the Median and Radial nerves, respectively, and are located in the forearm, not the humeral shaft. 3. Clinical Pearls & High-Yield Facts for NEET-PG: * Fracture Site: Mid-shaft humerus fractures commonly injure the radial nerve in the spiral groove, leading to Wrist Drop (loss of extension of the wrist and metacarpophalangeal joints). * Sparing of Triceps: In mid-shaft fractures, the long and medial heads of the triceps are often spared because their nerve branches arise proximal to the spiral groove. * Saturday Night Palsy: Compression of the radial nerve in the spiral groove (e.g., leaning over a chair) leads to temporary palsy. * Rule of Three: Remember the nerves related to the humerus: Axillary (Surgical neck), Radial (Spiral groove), Ulnar (Medial epicondyle) — Mnemonic: ARU.

Q: What is the nerve injury that causes a "claw hand" deformity as shown in the image?

Ulnar nerve injury. ***Ulnar nerve injury*** - The **ulnar nerve** innervates the **lumbricals to the ring and little fingers**, and when injured, causes **hyperextension at MCP joints** and **flexion at IP joints**, creating the characteristic **claw hand deformity**. - Loss of **interosseous muscles** and medial lumbricals results in inability to flex MCP joints and extend IP joints of the 4th and 5th digits. *Radial nerve injury* - Causes **wrist drop** due to loss of **wrist extensors** and **finger extensors** at the MCP joints. - Results in inability to extend the wrist and fingers, not the claw hand deformity seen with ulnar nerve injury. *Median nerve injury* - Causes **ape hand deformity** with loss of **thenar muscles** and inability to oppose the thumb. - Affects **lumbricals to index and middle fingers** but does not produce the characteristic claw hand involving ring and little fingers. *Axillary nerve injury* - Primarily affects the **deltoid muscle** causing inability to abduct the arm beyond 15 degrees. - Does not cause any hand deformities as it does not innervate muscles of the hand or forearm.

Q: Which among the following muscles receives dual nerve supply?

Flexor digitorum profundus. **Explanation:** The correct answer is **Flexor digitorum profundus (FDP)**. In the context of the upper limb, certain muscles are known as "hybrid" or "composite" muscles because they are supplied by more than one nerve, typically reflecting their complex functional roles. **1. Why Flexor Digitorum Profundus is correct:** The FDP is a classic example of a hybrid muscle in the forearm [1]. It has a dual nerve supply: * **Medial half (digits 4 and 5):** Supplied by the **Ulnar nerve** (C8, T1). * **Lateral half (digits 2 and 3):** Supplied by the **Anterior Interosseous Nerve** (a branch of the Median nerve). This dual innervation explains why a high ulnar nerve palsy results in the "Ulnar Claw" (affecting the ring and little fingers), while the index and middle fingers remain functional. **2. Why the other options are incorrect:** * **Flexor digitorum superficialis:** Supplied solely by the **Median nerve**. * **Palmaris longus:** A vestigial muscle supplied solely by the **Median nerve**. * **Extensor carpi radialis:** The ECR Longus is supplied by the **Radial nerve**, and the ECR Brevis is supplied by the **Deep branch of the radial nerve** (or PIN) [3]; however, neither receives dual innervation from two different primary nerves. **3. NEET-PG High-Yield Clinical Pearls:** * **Other Hybrid Muscles of the Upper Limb:** * **Brachialis:** Musculocutaneous nerve (motor) and Radial nerve (proprioceptive). * **Pectoralis Major:** Medial and Lateral pectoral nerves. * **Adductor Magnus (Lower Limb):** Obturator and Sciatic (Tibial) nerves. * **Clinical Sign:** In **Median nerve palsy** at the wrist, the patient cannot flex the index finger at the DIP joint because the lateral half of the FDP is paralyzed [2].

Question 1

Axillary abscess is safely drained by which approach?

Accepted Answer

Floor

Answer

Medial

Answer

Anterior & posterior circumflex humeral

Answer

Lateral

Question 2

Which carpal bone articulates with the radius?

Accepted Answer

Scaphoid

Answer

Trapezium

Answer

Capitate

Answer

Hamate

Question 3

Which of the following arteries is present in the anatomical snuff box?

Accepted Answer

Radial artery

Answer

Anterior interosseous artery

Answer

Brachial artery

Answer

Ulnar artery

Question 4

Which muscle arises from the supraglenoid tubercle?

Accepted Answer

Long head of biceps

Answer

Short head of biceps

Answer

Long head of triceps

Answer

Coracobrachialis

Question 5

Which muscle is inserted into the floor of the intertubercular sulcus of the humerus?

Accepted Answer

Latissimus dorsi

Answer

Teres major

Answer

Pectoralis major

Answer

Deltoid

Question 6

A rock climber falls on their shoulder, resulting in a chipping off of the lesser tubercle of the humerus. Which of the following structures would most likely have structural and functional damage?

Accepted Answer

Subscapularis muscle

Answer

Supraspinatus muscle

Answer

Infraspinatus muscle

Answer

Teres minor muscle

Question 7

A patient has a tiny (0.2 cm), but exquisitely painful tumor under the nail of her index finger. Prior to surgery to remove it, local anesthetic block to a branch of which of the following nerves would be most likely to achieve adequate anesthesia?

Accepted Answer

Median nerve

Answer

Axillary nerve

Answer

Musculocutaneous nerve

Answer

Radial nerve

Question 8

Which nerve passes through the spiral groove of the humerus?

Accepted Answer

Radial Nerve

Answer

Ulnar Nerve

Answer

Musculocutaneous Nerve

Answer

Interosseous Nerve

Question 9

What is the nerve injury that causes a "claw hand" deformity as shown in the image?

Accepted Answer

Ulnar nerve injury

Answer

Radial nerve injury

Answer

Median nerve injury

Answer

Axillary nerve injury

Question 10

Which among the following muscles receives dual nerve supply?

Accepted Answer

Flexor digitorum profundus

Answer

Flexor digitorum superficialis

Answer

Palmaris longus

Answer

Extensor carpi radialis

Upper Limb — MCQs

Upper Limb — MCQs

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