Upper Limb Practice Questions

Q: A 21-year-old male with a fracture of the surgical neck of the humerus presents with a regimental badge sign and difficulty in abduction. What is the most likely nerve injury?

Axillary nerve injury. ### **Explanation** The correct answer is **Axillary nerve injury**. **1. Why Axillary Nerve Injury is Correct:** The axillary nerve (C5, C6) winds around the **surgical neck of the humerus** within the quadrangular space. Fractures at this site or anterior dislocations of the shoulder commonly result in its injury. * **Regimental Badge Sign:** The axillary nerve provides sensory innervation to the skin over the lower half of the deltoid muscle via the upper lateral cutaneous nerve of the arm. Loss of sensation in this specific area is known as the "Regimental Badge Sign." * **Difficulty in Abduction:** The nerve supplies the **deltoid** (the primary abductor of the arm after 15°) and the teres minor. Paralysis of the deltoid leads to significant weakness in abduction. **2. Why Other Options are Incorrect:** * **Ulnar Nerve Injury:** Typically occurs with fractures of the medial epicondyle of the humerus. It presents with "claw hand" and sensory loss in the medial 1.5 fingers, not abduction deficits. * **Klumpke's Paralysis:** This is a lower brachial plexus injury (C8-T1) usually caused by hyper-abduction of the arm. It results in a total claw hand and sensory loss along the ulnar aspect of the forearm and hand. * **Supraclavicular Nerve Injury:** These are cutaneous nerves from the cervical plexus (C3, C4) supplying the skin over the shoulder and clavicle. Injury would not cause motor weakness in abduction. **3. NEET-PG High-Yield Pearls:** * **Most common nerve injured in shoulder dislocation:** Axillary nerve. * **Most common nerve injured in mid-shaft humerus fracture:** Radial nerve (presents with wrist drop). * **Deltoid Atrophy:** Chronic axillary nerve palsy leads to the loss of the rounded contour of the shoulder, making it appear "flat." * **Abduction sequence:** 0–15° (Supraspinatus), 15–90° (Deltoid), >90° (Serratus anterior and Trapezius).

Q: Which muscle performs flexion, adduction, and medial rotation of the arm?

Pectoralis major. **Explanation:** The **Pectoralis Major** is a large, fan-shaped muscle of the anterior chest wall. Its primary actions are determined by its insertion into the **lateral lip of the bicipital groove** of the humerus. Because it crosses the shoulder joint anteriorly and laterally, its contraction pulls the humerus toward the midline (**adduction**), rotates it inward (**medial rotation**), and the clavicular fibers specifically assist in drawing the arm forward (**flexion**). **Analysis of Options:** * **Pectoralis Major (Correct):** It is the "climbing muscle" (along with Latissimus dorsi). Its dual nerve supply (Medial and Lateral pectoral nerves) and broad origin allow it to perform the triad of flexion, adduction, and medial rotation [1]. * **Serratus Anterior:** Known as the "boxer’s muscle," it originates from the ribs and inserts into the medial border of the scapula. Its primary role is **protraction** of the scapula and keeping it closely applied to the thoracic wall; it does not act directly on the humerus to cause rotation or flexion. * **Pectoralis Minor:** This muscle lies deep to the pectoralis major and inserts into the **coracoid process** of the scapula [1]. It stabilizes the scapula by pulling it anteriorly and inferiorly; it does not move the arm. * **Subclavius:** A small muscle that anchors and depresses the clavicle. It plays no role in the movements of the humerus. **High-Yield Clinical Pearls for NEET-PG:** * **Nerve Supply:** Pectoralis major is supplied by **both** medial (C8, T1) and lateral (C5-C7) pectoral nerves [1]. * **Surgical Significance:** It forms the anterior wall of the axilla. * **Testing:** To test the muscle, the patient is asked to press their hands against their hips or adduct the arm against resistance. * **Poland Syndrome:** A congenital condition characterized by the unilateral absence of the Pectoralis major, often associated with syndactyly.

Q: A patient attempts to make a fist, but the index and middle fingers remain partially extended. Which nerve is most likely involved?

Median nerve. The clinical presentation described is known as the **"Hand of Benediction"** (or Preacher’s Hand). This occurs due to a high lesion of the **Median nerve** (typically at the elbow or supracondylar region). [1] **1. Why the Median Nerve is Correct:** To make a fist, one must flex the Interphalangeal (IP) and Metacarpophalangeal (MCP) joints. The Median nerve innervates the **Flexor Digitorum Superficialis (FDS)** and the radial half of the **Flexor Digitorum Profundus (FDP)**. [1] When the Median nerve is damaged, the patient cannot flex the index and middle fingers at the IP joints. Consequently, when asked to make a fist, these two fingers remain extended, while the ring and little fingers flex normally (as their portion of the FDP is supplied by the Ulnar nerve). [1] **2. Why Other Options are Incorrect:** * **Musculocutaneous nerve:** Supplies the coracobrachialis, biceps brachii, and brachialis. Injury results in loss of forearm flexion and supination, not finger extension issues. * **Radial nerve:** Supplies the extensors. Injury typically leads to **Wrist Drop**. If the radial nerve were injured, the patient would have trouble extending fingers, not flexing them. * **Ulnar nerve:** Injury causes **Ulnar Claw Hand** (seen at rest). While it affects the ring and little fingers, it does not prevent the index and middle fingers from flexing. [1] **Clinical Pearls for NEET-PG:** * **Hand of Benediction:** Seen only when the patient **attempts to make a fist** (Active sign). * **Ulnar Claw Hand:** Seen when the hand is **at rest** (Passive sign). * **Point to remember:** The "Pointing Index" (Ochsner’s Clasping Test) is also a diagnostic sign for Median nerve palsy. * **Million Dollar Nerve:** The recurrent branch of the Median nerve (supplies thenar muscles); injury leads to "Ape Thumb" deformity.

Q: Several weeks after surgical dissection of her left axilla for the removal of lymph nodes for staging and treatment of her breast cancer, a 32-year-old woman presented with "winging" of her left scapula when pushed against resistance. She also reported difficulty raising her right arm above her head. A nerve was accidentally injured during the surgical procedure, causing the scapular abnormality and inability to raise her arm normally. What was the origin of this injured nerve?

Roots of the brachial plexus. **Explanation:** The clinical presentation of **"winging of the scapula"** following axillary surgery is a classic sign of injury to the **Long Thoracic Nerve**. This nerve innervates the **Serratus Anterior** muscle, which is responsible for protracting the scapula and holding its medial border against the thoracic wall. It also assists the Trapezius in rotating the scapula upward to allow for abduction of the arm above 90 degrees. **1. Why the Correct Answer is Right:** The Long Thoracic Nerve (Nerve of Bell) originates directly from the **Roots (ventral rami) of the brachial plexus**, specifically **C5, C6, and C7**. Because it arises so proximally and descends along the lateral thoracic wall, it is vulnerable during axillary lymph node dissection (ALND) or radical mastectomies [1]. **2. Why Incorrect Options are Wrong:** * **Option A (Upper Trunk):** The Suprascapular nerve and Nerve to Subclavius arise from the upper trunk, not the long thoracic nerve. * **Option B (Posterior Division):** Divisions of the plexus do not give off any branches; they merely redistribute fibers to the cords. * **Option D (Posterior Cord):** The posterior cord gives rise to the Axillary, Radial, Upper/Lower Subscapular, and Thoracodorsal nerves [1]. Injury to the Thoracodorsal nerve would cause weakness in extension and adduction (Latissimus dorsi), not winging. **Clinical Pearls for NEET-PG:** * **Mnemonic for Long Thoracic Nerve:** "C5, 6, 7 raise your arms to heaven." * **Winging Test:** Ask the patient to push against a wall; the medial border of the scapula becomes prominent (wings). * **Nerve at Risk:** During axillary surgery, two nerves are at high risk: the **Long Thoracic** (leading to winging) and the **Thoracodorsal** [1] (leading to "climbing" weakness/Latissimus dorsi palsy).

Q: Which ligament transfers weight from the peripheral to the axial skeleton?

Coracoclavicular ligament. **Explanation:** The **Coracoclavicular ligament** is the primary structure responsible for transferring the weight of the upper limb (peripheral skeleton) to the clavicle and subsequently to the axial skeleton. It consists of two parts: the **conoid** and **trapezoid** ligaments. While the upper limb is suspended from the scapula, the scapula itself is attached to the clavicle via this ligament. Therefore, the weight of the arm is transmitted from the scapula to the clavicle through the coracoclavicular ligament, and then to the sternum via the sternoclavicular joint. **Analysis of Incorrect Options:** * **Acromioclavicular ligament:** This ligament strengthens the capsule of the acromioclavicular joint but is relatively weak and does not play a major role in weight transmission. * **Ligament of Bigelow (Iliofemoral ligament):** This is a Y-shaped ligament of the hip joint. It is the strongest ligament in the body and prevents hyperextension of the hip, but it is located in the lower limb. * **Sternoclavicular ligament:** While the sternoclavicular joint is the only bony attachment of the upper limb to the axial skeleton, the *ligament* itself primarily stabilizes the joint rather than acting as the primary weight-transferring bridge from the limb. **High-Yield NEET-PG Pearls:** * The **Conoid** part is medially placed and fan-shaped; the **Trapezoid** part is laterally placed and quadrilateral. * In **Acromioclavicular joint dislocation** (Shoulder separation), the tearing of the coracoclavicular ligament is the clinical hallmark of a severe (Grade II/III) injury. * The clavicle is the first bone to ossify (intramembranous) and is the most commonly fractured bone in the body, typically at the junction of its medial 2/3 and lateral 1/3 [1].

Q: Which of the following structures passes through the triangular interval of the arm?

Radial nerve. The **triangular interval** (also known as the lower triangular space) is a critical anatomical gateway located in the posterior region of the arm. ### **Anatomical Basis** The boundaries of the triangular interval are: * **Superior:** Lower border of the Teres major muscle. * **Medial:** Long head of the Triceps brachii. * **Lateral:** Lateral head of the Triceps or the shaft of the humerus. The **Radial nerve** and the **Profunda brachii artery** pass through this space to reach the spiral groove of the humerus. Therefore, Option A is correct. ### **Analysis of Incorrect Options** * **B. Axillary nerve:** This nerve passes through the **quadrangular space** (along with the posterior circumflex humeral artery), which is located superior to the triangular interval. * **C. Median nerve:** This nerve travels in the anterior compartment of the arm within the medial bicipital groove; it does not pass through any posterior scapular spaces. * **D. Ulnar nerve:** Initially located in the anterior compartment, it pierces the medial intermuscular septum to enter the posterior compartment but does not traverse the triangular interval. ### **High-Yield Clinical Pearls for NEET-PG** * **Radial Nerve Injury:** Because the radial nerve lies directly against the humerus after exiting the triangular interval, it is highly susceptible to injury in **mid-shaft fractures of the humerus**, leading to "wrist drop." * **Space Differentiation:** * *Quadrangular Space:* Axillary nerve. * *Upper Triangular Space:* Circumflex scapular artery. * *Lower Triangular Space (Interval):* Radial nerve. * **Mnemonic:** Remember **"T-R-P"** for the Triangular Interval: **T**riceps, **R**adial nerve, **P**rofunda brachii.

Q: The superficial palmar arch is related to which anatomical landmark?

The distal end of the fully extended thumb. The superficial palmar arch is a critical arterial network in the hand, primarily formed by the terminal part of the ulnar artery, usually completed by the superficial palmar branch of the radial artery. [1] **1. Why Option A is Correct:** In surface anatomy, the convexity of the superficial palmar arch lies at the level of a transverse line drawn across the palm from the distal border of the fully extended thumb. This landmark is essential for surgeons to avoid accidental injury to the arch during palmar incisions. **2. Why the Other Options are Incorrect:** * **Options B & C:** The "flexed thumb" positions move the thumb's tip toward the center or base of the palm. These landmarks are inconsistent and do not align with the anatomical projection of the arch. * **Option D:** The proximal end (base) of the extended thumb corresponds more closely to the **deep palmar arch**, which lies approximately one finger-breadth (1–1.5 cm) proximal to the superficial arch. **3. High-Yield NEET-PG Clinical Pearls:** * **Formation:** The superficial arch is mainly ulnar; the deep arch is mainly radial. * **Location:** The superficial arch lies deep to the palmar aponeurosis but **superficial** to the long flexor tendons. * **Deep Palmar Arch Landmark:** It lies at the level of the proximal border of the extended thumb (or the bases of the metacarpal bones). * **Allen’s Test:** Used clinically to assess the patency of the radial and ulnar arteries before performing arterial blood gas (ABG) sampling, ensuring the palmar arches are intact. * **Nerve Relation:** The superficial arch is closely related to the common palmar digital branches of the **median nerve**. [1]

Q: What is the primary action of the highlighted muscle?

Flexion and adduction of the shoulder joint. ***Flexion and adduction of the shoulder joint*** - The highlighted muscle is the **pectoralis major**, which originates from the clavicle, sternum, and costal cartilages and inserts on the intertubercular sulcus (bicipital groove) of the humerus. - Its primary functions include **flexion, adduction, and medial rotation of the shoulder joint** and it is innervated by the **medial and lateral pectoral nerves**. *Supination of the forearm and flexion of the elbow* - This describes the action of the **biceps brachii** muscle, which acts on the forearm and elbow joint. - The pectoralis major has no involvement in **forearm supination** or **elbow flexion** as it acts specifically on the shoulder joint. *Protraction of the scapula forward around the thorax* - This action is primarily performed by the **serratus anterior** muscle, which inserts on the medial border of the scapula. - The pectoralis major does not directly protract the scapula but rather acts on the **glenohumeral joint** via its insertion on the humerus. *None of the above* - This option is incorrect as the pectoralis major does indeed perform **flexion and adduction of the shoulder joint**. - The muscle is also known as the **"sternal head"** and **"clavicular head"** portions contributing to different ranges of shoulder movement.

Q: Which nerve is injured in a fracture of the medial epicondyle of the humerus?

Ulnar nerve. **Explanation:** The **ulnar nerve** is the correct answer because of its specific anatomical course in the elbow. It descends along the medial side of the arm, pierces the medial intermuscular septum, and passes posteriorly through the **retrocondylar groove** (ulnar groove) located directly behind the **medial epicondyle** of the humerus. Due to this close proximity, any fracture or trauma involving the medial epicondyle frequently results in ulnar nerve compression or laceration. **Analysis of Incorrect Options:** * **Median Nerve:** This nerve passes anterior to the elbow joint, medial to the brachial artery. It is most commonly injured in **supracondylar fractures** of the humerus, not medial epicondyle fractures. * **Anterior Interosseous Nerve (AIN):** A motor branch of the median nerve, the AIN is typically injured in supracondylar fractures (Gartland Type II/III). Injury results in the inability to make the "OK" sign. * **Radial Nerve:** This nerve runs in the spiral groove of the humerus and passes anterior to the **lateral epicondyle**. It is most commonly injured in **mid-shaft humeral fractures**. **Clinical Pearls for NEET-PG:** * **Ulnar Nerve (C8-T1):** Injury at the medial epicondyle leads to "Claw Hand" (main en griffe) due to paralysis of the medial half of the flexor digitorum profundus and intrinsic hand muscles. * **Tardy Ulnar Palsy:** A delayed ulnar nerve palsy that occurs years after a lateral condyle fracture due to resultant cubitus valgus deformity. * **High-Yield Sites:** * Mid-shaft fracture → Radial nerve. * Surgical neck fracture → Axillary nerve. * Supracondylar fracture → Median nerve.

Question 1

A 21-year-old male with a fracture of the surgical neck of the humerus presents with a regimental badge sign and difficulty in abduction. What is the most likely nerve injury?

Accepted Answer

Axillary nerve injury

Answer

Ulnar nerve injury

Answer

Klumpke's paralysis

Answer

Supraclavicular nerve injury

Question 2

Which muscle performs flexion, adduction, and medial rotation of the arm?

Accepted Answer

Pectoralis major

Answer

Serratus Anterior

Answer

Pectoralis minor

Answer

Subclavius

Question 3

A patient attempts to make a fist, but the index and middle fingers remain partially extended. Which nerve is most likely involved?

Accepted Answer

Median nerve

Answer

Musculocutaneous nerve

Answer

Radial nerve

Answer

Ulnar nerve

Question 4

Several weeks after surgical dissection of her left axilla for the removal of lymph nodes for staging and treatment of her breast cancer, a 32-year-old woman presented with "winging" of her left scapula when pushed against resistance. She also reported difficulty raising her right arm above her head. A nerve was accidentally injured during the surgical procedure, causing the scapular abnormality and inability to raise her arm normally. What was the origin of this injured nerve?

Accepted Answer

Roots of the brachial plexus

Answer

The upper trunk of the brachial plexus

Answer

The posterior division of the middle trunk

Answer

The posterior cord of the brachial plexus

Question 5

Which ligament transfers weight from the peripheral to the axial skeleton?

Accepted Answer

Coracoclavicular ligament

Answer

Acromioclavicular ligament

Answer

Ligament of Bigelow

Answer

Sternoclavicular ligament

Question 6

Which of the following structures passes through the triangular interval of the arm?

Accepted Answer

Radial nerve

Answer

Axillary nerve

Answer

Median nerve

Answer

Ulnar nerve

Question 7

The superficial palmar arch is related to which anatomical landmark?

Accepted Answer

The distal end of the fully extended thumb

Answer

The distal end of the fully flexed thumb

Answer

The proximal end of the fully flexed thumb

Answer

The proximal end of the fully extended thumb

Question 8

What is the primary action of the highlighted muscle?

Accepted Answer

Flexion and adduction of the shoulder joint

Answer

Supination of the forearm and flexion of the elbow

Answer

Protraction of the scapula forward around the thorax

Answer

None of the above

Question 9

Which nerve is injured in a fracture of the medial epicondyle of the humerus?

Accepted Answer

Ulnar nerve

Answer

Anterior interosseous nerve

Answer

Median nerve

Answer

Radial nerve

Question 10

Which of the following structures is located within the bicipital groove?

Accepted Answer

Ascending branch of the anterior circumflex artery

Answer

Synovial membrane of the shoulder joint

Answer

Ascending branch of the posterior circumflex artery

Answer

Radial artery

Upper Limb — MCQs

Upper Limb — MCQs

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