Upper Limb Practice Questions

Q: Following a radical mastectomy, there is injury to the long thoracic nerve. How can the integrity of this nerve be tested at the bedside?

Raise the arm above the head on the affected side. The **long thoracic nerve (Nerve of Bell)** arises from the roots of the brachial plexus (C5, C6, C7) and supplies the **serratus anterior** muscle. This muscle is the primary protractor of the scapula and is essential for rotating the scapula upward. **Why Option B is Correct:** To raise the arm above the head (abduction beyond 90 degrees), the scapula must undergo **upward rotation** to reposition the glenoid cavity. This action is performed by the coordinated effort of the serratus anterior and the trapezius. If the long thoracic nerve is injured, the serratus anterior is paralyzed, making it impossible for the patient to raise their arm above the horizontal level. At the bedside, this is often demonstrated as **"winging of the scapula"** when the patient is asked to push against a wall. **Why Other Options are Incorrect:** * **A. Shrug the shoulders:** This tests the **Trapezius** muscle, which is supplied by the Spinal Accessory Nerve (CN XI). * **C. Touch the opposite shoulder:** This involves adduction and internal rotation, primarily testing the **Pectoralis major** (Lateral and Medial pectoral nerves). * **D. Lift a heavy object:** While this requires general upper limb strength, it specifically tests the **Biceps brachii** (Musculocutaneous nerve) and back extensors, rather than the specific integrity of the long thoracic nerve. **NEET-PG High-Yield Pearls:** * **Clinical Scenario:** Injury most commonly occurs during **radical mastectomy** (axillary lymph node dissection) or chest tube insertion because the nerve runs superficially on the lateral wall of the thorax. * **Deformity:** "Winging of the Scapula" occurs because the medial border and inferior angle of the scapula move postero-medially away from the rib cage. * **Mnemonic:** "C5, 6, 7 raise your arms to heaven" (refers to the nerve roots and the action of overhead abduction).

Q: Deformity associated with ulnar nerve injury is:

Claw hand. The **Ulnar Nerve** (C8-T1) is often referred to as the "Musician’s Nerve" because it controls the fine movements of the fingers. [1] **Why Claw Hand is correct:** The characteristic deformity of ulnar nerve injury is the **Claw Hand (Main en Griffe)**. This occurs due to the paralysis of the **medial two lumbricals** and all **interossei** muscles. * **Mechanism:** Normally, lumbricals flex the metacarpophalangeal (MCP) joints and extend the interphalangeal (IP) joints. Loss of these muscles leads to the opposite: **hyperextension at the MCP joints** (due to unopposed action of long extensors) and **flexion at the IP joints** (due to unopposed action of long flexors). This is most prominent in the ring and little fingers. **Analysis of Incorrect Options:** * **A. Wrist drop:** Caused by **Radial nerve** injury (typically at the spiral groove), leading to paralysis of the wrist extensors. * **B. Simon hand:** This is a distractor term; however, "Simeon hand" is an older synonym for Ape hand. * **D. Ape thumb deformity:** Caused by **Median nerve** injury. [1] It results from paralysis of the thenar muscles, leading to the loss of thumb opposition and the thumb falling into the same plane as the fingers. **High-Yield Clinical Pearls for NEET-PG:** 1. **Ulnar Paradox:** A high ulnar nerve lesion (at the elbow) results in a *less* prominent clawing than a low lesion (at the wrist). This is because, in high lesions, the Flexor Digitorum Profundus is also paralyzed, reducing the flexion at the IP joints. 2. **Froment’s Sign:** A positive test for ulnar nerve palsy where the patient flexes the thumb IP joint (using the median nerve) to compensate for the paralyzed Adductor Pollicis while holding a piece of paper. 3. **Point of compression:** Most common site is the **Cubital Tunnel** (behind the medial epicondyle) or **Guyon’s Canal** (at the wrist). [1]

Q: Which muscle causes flexion at the elbow joint when the forearm is semi-pronated?

Brachioradialis. The **Brachioradialis** is the correct answer because it is uniquely positioned to act as a powerful flexor of the elbow when the forearm is in the **mid-prone (semi-pronated) position**. This is often referred to as the "beer-drinking muscle" position. While it originates from the lateral supracondylar ridge of the humerus and inserts into the radial styloid process, its mechanical advantage is maximized when the forearm is neutral between supination and pronation. **Analysis of Options:** * **Biceps brachii:** This is the chief supinator of the forearm. It acts as a powerful flexor primarily when the forearm is **supinated**. In pronation, its tendon wraps around the radius, reducing its efficiency as a flexor. * **Brachialis:** Known as the "workhorse" of the elbow, it is the primary flexor of the elbow in **all positions** (supination, pronation, or neutral) because it inserts into the ulna, which does not rotate. However, it is not specifically associated with the semi-pronated position like the brachioradialis. * **Coracobrachialis:** This muscle acts on the **shoulder joint** (glenohumeral joint), causing flexion and adduction of the arm; it has no action on the elbow joint. **High-Yield NEET-PG Pearls:** * **Innervation Paradox:** The Brachioradialis is a flexor of the elbow but is innervated by the **Radial nerve** (typically the nerve of extensors). * **Shunt Muscle:** It acts as a "shunt muscle," providing compression of the joint surfaces to stabilize the elbow during rapid movements. * **Testing:** To test the Brachioradialis, ask the patient to flex the elbow against resistance with the forearm in the mid-prone position; the muscle belly will become prominent.

Q: Intracapsular articular disc is present in which joint?

Sternoclavicular joint. **Explanation:** The presence of an **intracapsular fibrocartilaginous articular disc** is a characteristic feature of specific synovial joints where it serves to increase stability, absorb shock, and allow for complex movements by dividing the joint cavity into two separate compartments. 1. **Sternoclavicular Joint (Correct):** This is a saddle-type synovial joint that contains a complete fibrocartilaginous disc. This disc divides the joint into two distinct synovial cavities. It acts as a hinge during elevation/depression of the clavicle and as a pivot during protraction/retraction. It also prevents the medial end of the clavicle from being driven upwards and medially during compressive forces. 2. **Elbow Joint (Incorrect):** This is a pure hinge joint (ginglymus) consisting of the humeroulnar and humeroradial articulations. It does not contain an articular disc. 3. **Hip Joint (Incorrect):** While it contains a **labrum** (to deepen the socket) and the **ligamentum teres** (intracapsular ligament), it does not possess a fibrocartilaginous disc that partitions the joint cavity. 4. **Knee Joint (Incorrect):** The knee contains **menisci** (semilunar cartilages). While menisci are fibrocartilaginous structures within the capsule, they are incomplete rings and do not fully divide the joint into two separate compartments like a true articular disc. **High-Yield Facts for NEET-PG:** * **Other joints with articular discs:** Temporomandibular joint (TMJ), Acromioclavicular joint (often incomplete), and the Distal Radioulnar joint (Triangular fibrocartilage complex). * **Sternoclavicular Joint:** It is the only bony attachment between the upper limb and the axial skeleton. * **Clinical Pearl:** Dislocation of the sternoclavicular joint is rare due to the strength of the disc and ligaments; however, posterior dislocation is a medical emergency due to potential compression of the trachea or great vessels.

Q: All the muscles are used to abduct the shoulder except?

Pectoralis major. Explanation: The movement of shoulder abduction is a coordinated effort involving multiple muscles acting at different stages. The **Pectoralis major** is the correct answer because it is primarily an **adductor** and internal rotator of the humerus. Its fibers are positioned to pull the arm toward the midline, making it an antagonist to abduction. **Analysis of Options:** * **Supraspinatus:** This muscle initiates the first **0–15 degrees** of abduction. It stabilizes the humeral head in the glenoid cavity, allowing the deltoid to act effectively. * **Deltoid (Multipennate middle fibers):** This is the principal abductor of the arm from **15–90 degrees**. * **Serratus anterior:** Along with the Trapezius, this muscle facilitates abduction **beyond 90 degrees** by causing upward rotation of the scapula. This shift in the glenoid cavity's position is essential for overhead reaching. **Clinical Pearls for NEET-PG:** 1. **The Scapulohumeral Rhythm:** For every 2° of humeral abduction, there is 1° of scapular rotation (2:1 ratio). 2. **Nerve Injuries:** * Injury to the **Axillary nerve** affects the Deltoid (loss of abduction from 15-90°). * Injury to the **Long thoracic nerve** affects the Serratus anterior, leading to "Winged Scapula" and inability to abduct above the horizontal plane. 3. **Rotator Cuff:** The Supraspinatus is the most commonly injured muscle in rotator cuff tears, leading to difficulty in initiating abduction (the "Painful Arc" syndrome).

Q: A lesion involving the C8 nerve root will affect which of the following?

Flexors of the wrist and fingers. ### Explanation The **C8 nerve root** is a critical component of the lower trunk of the brachial plexus. It primarily contributes to the **ulnar nerve** and the **median nerve**, which together supply the long flexors of the forearm and the intrinsic muscles of the hand [1]. **1. Why Option B is Correct:** The long flexors of the wrist and fingers (such as the Flexor Digitorum Superficialis, Flexor Digitorum Profundus, and Flexor Carpi Ulnaris) are predominantly innervated by the C8 and T1 nerve roots. A lesion at C8 specifically weakens finger flexion and wrist flexion, as these muscles rely heavily on this segment for motor output [1]. **2. Why Other Options are Incorrect:** * **Option A (Extensors):** While C8 does contribute to the radial nerve (which supplies extensors), the **C7** root is the primary functional driver for wrist and finger extension. * **Option C (Small muscles of the hand):** These are primarily supplied by the **T1** nerve root (via the ulnar and median nerves). While C8 contributes, T1 is the "classic" root associated with intrinsic hand muscle wasting (e.g., in Klumpke’s palsy). * **Option D (Supinators):** Supination is performed by the Biceps Brachii (**C5, C6**) and the Supinator muscle (**C6, C7**). **3. NEET-PG High-Yield Pearls:** * **Root Value Mnemonic:** * C5, C6: "Pick up the sticks" (Elbow flexion/Deltoid). * C7: "Push to heaven" (Elbow/Wrist extension). * **C8: "Close the gate" (Finger flexion).** * T1: "Paper between fingers" (Finger abduction/adduction). * **Clinical Correlation:** A C8 radiculopathy often presents with pain/numbness radiating down the medial aspect of the arm to the little finger (medial antebrachial cutaneous distribution). * **Klumpke’s Palsy:** Involves C8 and T1, leading to a "Claw Hand" deformity due to the loss of intrinsic muscles and long flexors [1].

Q: Which nerve supplies the deltoid muscle?

Axillary nerve. The **Axillary nerve (C5, C6)** is the correct answer. It is a terminal branch of the posterior cord of the brachial plexus. It enters the quadrangular space alongside the posterior circumflex humeral artery to supply the **deltoid** and **teres minor** muscles. It also provides sensory innervation to the skin over the lower half of the deltoid (the "regimental badge area"). **Analysis of Incorrect Options:** * **Upper subscapular nerve (C5, C6):** Arises from the posterior cord and supplies only the upper part of the **subscapularis** muscle. * **Lower subscapular nerve (C5, C6):** Also arises from the posterior cord but supplies the lower part of the **subscapularis** and the **teres major** muscle. * **Thoracodorsal nerve (C6, C7, C8):** Also known as the nerve to **latissimus dorsi**, it supplies that specific muscle, which is responsible for adduction, extension, and internal rotation of the humerus [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Site of Injury:** The axillary nerve is most commonly injured during **dislocation of the shoulder joint** (anterior-inferior) or **fracture of the surgical neck of the humerus**. * **Clinical Presentation:** Injury leads to atrophy of the deltoid (loss of rounded shoulder contour) and inability to **abduct the arm from 15° to 90°**. * **Quadrangular Space Boundaries:** Superior (Teres minor), Inferior (Teres major), Medial (Long head of triceps), and Lateral (Surgical neck of humerus). This space contains the axillary nerve and posterior circumflex humeral vessels.

Q: Which of the following structures is present in the posterior axillary wall?

Subscapular artery. ### Explanation The **axilla** is a pyramidal space between the upper limb and the thorax. Understanding its boundaries is high-yield for NEET-PG. **1. Why the Subscapular Artery is Correct:** The **posterior wall** of the axilla is formed by the Subscapularis (superiorly), Teres major, and Latissimus dorsi (inferiorly). The **Subscapular artery**, the largest branch of the third part of the axillary artery, descends along the lower border of the subscapularis muscle. Therefore, it lies directly on the posterior axillary wall before dividing into the circumflex scapular and thoracodorsal arteries. **2. Analysis of Incorrect Options:** * **Thoracodorsal artery (Option A):** While it is a branch of the subscapular artery, it typically enters the substance of the Latissimus dorsi [1]. In standard anatomical descriptions of the axillary walls, the parent **Subscapular artery** is the primary landmark associated with the posterior wall. * **Long thoracic nerve (Option B):** This nerve (C5-C7) descends on the external surface of the Serratus anterior muscle, which forms the **medial wall** of the axilla. * **Axillary artery (Option C):** The axillary artery and the cords of the brachial plexus are contained within the **axillary sheath**, which constitutes the **contents** of the axilla, rather than forming its walls. **3. Clinical Pearls & High-Yield Facts:** * **Medial Wall:** Serratus anterior and upper 4-5 ribs. * **Lateral Wall:** Bicipital groove of the humerus (very narrow). * **Anterior Wall:** Pectoralis major, Pectoralis minor, and Clavipectoral fascia. * **Nerve to Latissimus Dorsi (Thoracodorsal nerve):** Also lies on the posterior wall and is at risk during axillary lymph node dissection [1]. It crosses the axilla to reach the medial surface of the latissimus dorsi. * **Apex of Axilla:** Also known as the *cervico-axillary canal*, bounded by the clavicle, first rib, and upper border of the scapula.

Question 1

Following a radical mastectomy, there is injury to the long thoracic nerve. How can the integrity of this nerve be tested at the bedside?

Accepted Answer

Raise the arm above the head on the affected side

Answer

Shrug the shoulders

Answer

Touch the opposite shoulder

Answer

Lift a heavy object from the ground

Question 2

Deformity associated with ulnar nerve injury is:

Accepted Answer

Claw hand

Answer

Wrist drop

Answer

Simon hand

Answer

Ape thumb deformity

Question 3

Which muscle causes flexion at the elbow joint when the forearm is semi-pronated?

Accepted Answer

Brachioradialis

Answer

Biceps brachii

Answer

Brachialis

Answer

Coracobrachialis

Question 4

Intracapsular articular disc is present in which joint?

Accepted Answer

Sternoclavicular joint

Answer

Elbow

Answer

Hip joint

Answer

Knee joint

Question 5

All the muscles are used to abduct the shoulder except?

Accepted Answer

Pectoralis major

Answer

Deltoid

Answer

Supraspinatus

Answer

Serratus anterior

Question 6

Which muscle is typically spared in a lateral epicondyle fracture?

Accepted Answer

Extensor carpi radialis longus

Answer

Extensor digitorum

Answer

Extensor pollicis longus

Answer

Extensor carpi radialis brevis

Question 7

Which of the following is least likely to be involved in a collateral anastomosis which bypasses an obstruction of the first part of the axillary artery?

Accepted Answer

Posterior humeral circumflex artery

Answer

Suprascapular artery

Answer

Subscapular artery

Answer

Dorsal scapular artery

Question 8

A lesion involving the C8 nerve root will affect which of the following?

Accepted Answer

Flexors of the wrist and fingers

Answer

Extensors of the wrist and fingers

Answer

Small muscles of the hand

Answer

Supinators

Question 9

Which nerve supplies the deltoid muscle?

Accepted Answer

Axillary nerve

Answer

Upper subscapular nerve

Answer

Lower subscapular nerve

Answer

Thoracodorsal nerve

Question 10

Which of the following structures is present in the posterior axillary wall?

Accepted Answer

Subscapular artery

Answer

Thoracodorsal artery

Answer

Long thoracic nerve

Answer

Axillary artery

Upper Limb — MCQs

Upper Limb — MCQs

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