Upper Limb Practice Questions

Q: The oblique cord is related to which of the following muscles?

Flexor pollicis longus. The **oblique cord** (or chorda obliqua) is a small, flat ligamentous band that extends between the radius and the ulna. It originates from the lateral side of the **ulnar tuberosity** and runs downward and laterally to be inserted into the radius, just below the **radial tuberosity**. **Why Flexor Pollicis Longus (FPL) is correct:** The oblique cord lies in the same plane as the interosseous membrane but its fibers run in the opposite direction. Crucially, its lower border is continuous with the fascia covering the **Flexor pollicis longus**. In many individuals, the FPL takes a partial origin from the oblique cord itself. **Analysis of Incorrect Options:** * **A. Supinator:** The supinator muscle is located more superiorly and posteriorly in the forearm. While it relates to the radial tuberosity, it does not have a direct structural continuity with the oblique cord. * **C. Flexor digitorum profundus (FDP):** The FDP originates primarily from the anterior and medial surfaces of the ulna and the interosseous membrane, but it is medial to the site of the oblique cord. * **D. Flexor digitorum superficialis (FDS):** The FDS has a broad origin (humeroulnar and radial heads), but its radial head originates from the anterior oblique line of the radius, distal to the insertion of the oblique cord. **High-Yield Facts for NEET-PG:** * **Fiber Direction:** The fibers of the oblique cord run **downwards and laterally**, whereas the fibers of the interosseous membrane run **downwards and medially**. * **Gap:** There is a gap between the upper border of the interosseous membrane and the oblique cord through which the **posterior interosseous vessels** pass. * **Function:** It acts as a tie-beam to prevent displacement of the radius during forceful movements, though its functional significance is considered minimal compared to the interosseous membrane.

Q: A 21-year-old woman presents with shoulder and arm injury after a fall during horseback riding. Examination reveals inability to adduct her arm due to paralysis of which of the following muscles?

Latissimus dorsi. ### Explanation **Correct Option: C. Latissimus dorsi** The **Latissimus dorsi** is a powerful muscle of the posterior axillary wall. Its primary actions are **adduction, extension, and medial rotation** of the humerus (often remembered by the mnemonic "The Lady between two Majors"—it inserts into the floor of the bicipital groove between the Pectoralis major and Teres major). In the context of a shoulder injury, paralysis of this muscle significantly impairs the ability to pull the arm toward the midline (adduction) against resistance. **Analysis of Incorrect Options:** * **A. Teres minor:** This muscle is part of the rotator cuff. Its primary action is **lateral rotation** of the arm and stabilization of the glenohumeral joint. * **B. Supraspinatus:** This rotator cuff muscle is responsible for the **initiation of abduction** (first 0–15 degrees). It does not contribute to adduction. * **C. Infraspinatus:** Similar to the Teres minor, this muscle acts as a powerful **lateral rotator** of the arm. **Clinical Pearls for NEET-PG:** * **Nerve Supply:** Latissimus dorsi is supplied by the **Thoracodorsal nerve** (C6, C7, C8), a branch of the posterior cord of the brachial plexus. * **Clinical Testing:** To test the Latissimus dorsi, the patient is asked to adduct the elevated arm against resistance or to cough (it is an accessory muscle of expiration, hence the "Climbing muscle" or "Coughing muscle"). * **Surgical Significance:** The Latissimus dorsi flap is commonly used in reconstructive surgeries, such as breast reconstruction. * **Injury Association:** Damage to the thoracodorsal nerve often occurs during axillary lymph node dissection or surgeries in the inferior part of the axilla.

Q: Which nerve runs along with the profunda brachii artery in the spiral groove?

Radial. **Explanation:** The **Radial nerve** is the correct answer because of its specific anatomical course in the posterior compartment of the arm. After originating from the posterior cord of the brachial plexus, the radial nerve enters the **spiral (radial) groove** on the posterior surface of the humerus. It is accompanied here by the **profunda brachii artery** (deep artery of the arm). This neurovascular bundle lies directly against the bone, making it highly vulnerable to injury in mid-shaft fractures of the humerus. **Analysis of Incorrect Options:** * **Ulnar Nerve:** Runs in the medial compartment and passes behind the medial epicondyle of the humerus (cubital tunnel), not the spiral groove. It is accompanied by the superior ulnar collateral artery. * **Median Nerve:** Descends in the anterior compartment of the arm within the medial bicipital groove, lateral to the brachial artery initially, then crossing to its medial side. It has no relation to the spiral groove. * **Musculocutaneous Nerve:** Pierces the coracobrachialis muscle and travels between the biceps brachii and brachialis muscles in the anterior compartment. **High-Yield Clinical Pearls for NEET-PG:** * **Fracture Correlation:** Mid-shaft humerus fractures commonly injure the radial nerve in the spiral groove, leading to **"Wrist Drop"** due to paralysis of the extensors of the wrist and digits. * **Saturday Night Palsy:** Compression of the radial nerve in the spiral groove (e.g., hanging an arm over a chair) leads to temporary loss of function. * **Triangular Space:** The profunda brachii artery and radial nerve enter the posterior compartment via the **lower triangular space** (bounded by teres major, long head of triceps, and humerus).

Q: Erb's palsy involves which nerve roots?

C5, C6. **Explanation:** **1. Why C5 and C6 are correct:** Erb’s palsy (Upper Brachial Plexus Injury) results from damage to the **upper trunk** of the brachial plexus, which is formed by the union of the **C5 and C6 nerve roots**. This injury typically occurs due to an excessive increase in the angle between the neck and the shoulder (e.g., birth trauma during difficult labor or a fall on the shoulder) [1]. The site of injury is known as **Erb’s point**, where six nerves meet. **2. Why other options are incorrect:** * **C8, T1 (Option B):** These roots form the lower trunk. Injury here leads to **Klumpke’s palsy**, characterized by a "claw hand" due to the involvement of intrinsic hand muscles. * **T1, T2 (Option C):** T2 is not a primary component of the brachial plexus (which spans C5-T1). T1 is involved in Klumpke’s, but T2 primarily contributes to the intercostobrachial nerve. * **C6, C7 (Option D):** While C6 is involved in the upper trunk, C7 forms the middle trunk in isolation. Isolated middle trunk injuries are clinically rare. **3. Clinical Pearls for NEET-PG:** * **Deformity:** The classic presentation is the **"Policeman’s tip hand"** or **"Waiter’s tip hand."** * **Position of the limb:** The arm is **Adducted** (loss of abductors), **Medially rotated** (loss of lateral rotators), and the forearm is **Extended** (loss of biceps) and **Pronated** (loss of supinator). * **Muscles paralyzed:** Mainly Biceps brachii, Deltoid, Brachialis, and Brachioradialis (partially Supraspinatus and Infraspinatus) [1]. * **Reflexes:** The Biceps and Supinator reflexes are lost.

Q: Which of the following is NOT a function of the Latissimus Dorsi muscle?

External rotation of the shoulder. **Explanation:** The **Latissimus Dorsi** (often called the "Climber's Muscle") is a large, fan-shaped muscle of the back. To understand its functions, one must look at its insertion: it attaches to the **floor of the bicipital groove** (intertubercular sulcus) of the humerus. **1. Why "External Rotation" is the correct answer:** Because the Latissimus Dorsi inserts on the **anterior** aspect of the humerus (the bicipital groove) after wrapping around from the back, its contraction pulls the humerus medially. Therefore, it acts as a **medial (internal) rotator**, not an external rotator. External rotation is primarily performed by the Infraspinatus and Teres Minor. **2. Analysis of incorrect options:** * **Extension (Option B):** As it originates from the posterior trunk (T7-L5 vertebrae, iliac crest, and thoracolumbar fascia) and pulls the humerus backward, it is a powerful extensor of the flexed arm. * **Adduction (Option C):** Its fibers pull the humerus toward the midline of the body, making it a primary adductor of the shoulder. * **Medial Rotation (Option D):** As explained above, its anterior insertion point allows it to rotate the humerus inward. **High-Yield NEET-PG Pearls:** * **Mnemonic for Bicipital Groove:** "A Lady between two Majors." The **L**atissimus dorsi (Lady) inserts into the floor, while the Pectoralis **Major** and Teres **Major** insert into the lateral and medial lips, respectively. * **Nerve Supply:** Thoracodorsal nerve (C6, **C7**, C8), a branch of the posterior cord of the brachial plexus [1]. * **Clinical Significance:** It is commonly used as a pedicled flap in reconstructive breast surgery (Latissimus Dorsi Flap) [2]. * **Functional Role:** It is crucial for activities like swimming, rowing, and climbing.

Q: Which nerve passes through the medial epicondyle?

Ulnar. **Explanation:** The **Ulnar nerve** (C8–T1) is the correct answer because of its specific anatomical course in the distal humerus [1]. After piercing the medial intermuscular septum in the mid-arm, it descends to the posterior aspect of the **medial epicondyle**. It passes through the **cubital tunnel** (formed by the medial epicondyle, the medial collateral ligament, and the arcuate ligament of Osborne), making it easily palpable and vulnerable to injury at this site [1]. **Analysis of Incorrect Options:** * **Radial Nerve:** This nerve travels in the spiral groove of the humerus and passes **anterior** to the **lateral epicondyle** before dividing into superficial and deep branches. * **Median Nerve:** This nerve descends in the anterior compartment of the arm and passes through the cubital fossa, medial to the brachial artery, but well **anterior** to the elbow joint, not behind the epicondyles [1]. * **Posterior Interosseous Nerve (PIN):** This is the deep branch of the radial nerve. It passes through the **supinator muscle** (Arcade of Frohse) and is related to the neck of the radius, not the medial epicondyle. **Clinical Pearls for NEET-PG:** 1. **Funny Bone Sensation:** Compression of the ulnar nerve against the medial epicondyle causes the characteristic tingling sensation. 2. **Cubital Tunnel Syndrome:** The most common site of ulnar nerve entrapment is at the medial epicondyle. 3. **Fracture Association:** Medial epicondyle fractures or Supracondylar fractures of the humerus (with posterolateral displacement) frequently result in **Ulnar nerve palsy**, leading to "Claw Hand" deformity.

Q: Allen's test is used for detecting the integrity of which of the following?

Palmar arch. **Explanation:** The **Allen’s test** is a clinical bedside assessment used to evaluate the **patency of the palmar arterial arches** and the adequacy of collateral circulation in the hand. **1. Why "Palmar arch" is correct:** The hand receives a dual blood supply from the radial and ulnar arteries, which anastomose to form the **superficial and deep palmar arches**. The test involves compressing both arteries at the wrist until the palm blanches, then releasing one artery while keeping the other compressed. If the palm flushes (reperfuses) within 5–15 seconds, it confirms that the released artery is patent and, crucially, that the **palmar arch is intact**, allowing blood to cross over and supply the entire hand. Therefore, the test evaluates the functional integrity of the entire anastomotic system (the arch) rather than just a single vessel. **2. Why other options are incorrect:** * **Radial/Ulnar Artery (Options A & B):** While the test involves compressing these individual vessels, its primary purpose is to ensure that if one artery is damaged or cannulated, the *other* can support the hand via the collateral circulation of the arch [1]. Testing an artery in isolation without considering the arch's integrity would not provide the necessary clinical information regarding collateral safety. **3. Clinical Pearls for NEET-PG:** * **Modified Allen’s Test:** This is the standard version used today, performed on one hand at a time before **Radial Artery Cannulation** or **Arterial Blood Gas (ABG)** sampling to prevent ischemic complications [1]. * **Positive vs. Negative:** A "normal" test (rapid flush) indicates a patent arch. * **Anatomy:** The **superficial palmar arch** is primarily a continuation of the **ulnar artery**, while the **deep palmar arch** is primarily formed by the **radial artery**.

Q: Which nerve originates from the trunk of the brachial plexus?

Suprascapular nerve. ### Explanation The brachial plexus is organized into Roots, Trunks, Divisions, Cords, and Branches. Understanding the specific level at which nerves arise is a frequent high-yield topic for NEET-PG. **Why Suprascapular Nerve is Correct:** The **Suprascapular nerve (C5, C6)** is one of only two nerves that originate directly from the **Superior Trunk** of the brachial plexus (the other being the Nerve to Subclavius). It provides motor innervation to the supraspinatus and infraspinatus muscles and sensory fibers to the shoulder joint. **Analysis of Incorrect Options:** * **A. Long thoracic nerve (C5, C6, C7):** This nerve originates directly from the **Roots** (ventral rami) of the brachial plexus. It innervates the serratus anterior. * **B. Dorsal scapular nerve (C5):** This nerve also originates from the **Roots** (specifically the C5 root) before the formation of the trunks. It innervates the rhomboids and levator scapulae. * **C. Axillary nerve (C5, C6):** This is a terminal branch of the **Posterior Cord**, not the trunk. It innervates the deltoid and teres minor. **High-Yield Clinical Pearls for NEET-PG:** * **Erb’s Point:** This is the site on the Superior Trunk where six nerves meet. Injury here (Erb's Palsy) involves the Suprascapular nerve, leading to the loss of lateral rotation and abduction (Waitor's tip deformity). * **Suprascapular Notch:** The suprascapular nerve passes *under* the superior transverse scapular ligament (the artery passes *over* it), a common site for nerve entrapment. * **Mnemonic for Roots vs. Trunk:** Remember that **D**orsal scapular and **L**ong thoracic come from the **D**eep **L**evel (Roots), while **S**uprascapular and **S**ubclavius come from the **S**uperior Trunk.

Question 1

The oblique cord is related to which of the following muscles?

Accepted Answer

Flexor pollicis longus

Answer

Supinator

Answer

Flexor digitorum profundus

Answer

Flexor digitorum superficialis

Question 2

Loss of sensation in the lateral 3 and 1/2 fingers is indicative of injury to which nerve(s)?

Accepted Answer

Median nerve and radial nerve

Answer

Only median nerve

Answer

Median nerve and ulnar nerve

Answer

Ulnar and radial nerve

Question 3

A 21-year-old woman presents with shoulder and arm injury after a fall during horseback riding. Examination reveals inability to adduct her arm due to paralysis of which of the following muscles?

Accepted Answer

Latissimus dorsi

Answer

Teres minor

Answer

Supraspinatus

Answer

Infraspinatus

Question 4

Which nerve runs along with the profunda brachii artery in the spiral groove?

Accepted Answer

Radial

Answer

Ulnar

Answer

Median

Answer

Musculocutaneous nerve

Question 5

Which of the following structures is present in the lateral wall of the axilla?

Accepted Answer

Axillary vessels

Answer

Subscapular vessel

Answer

Brachial plexus

Answer

Long thoracic nerve

Question 6

Erb's palsy involves which nerve roots?

Accepted Answer

C5, C6

Answer

C8, T1

Answer

T1, T2

Answer

C6, C7

Question 7

Which of the following is NOT a function of the Latissimus Dorsi muscle?

Accepted Answer

External rotation of the shoulder

Answer

Extension of the shoulder

Answer

Adduction of the shoulder

Answer

Medial rotation of the shoulder

Question 8

Which nerve passes through the medial epicondyle?

Accepted Answer

Ulnar

Answer

Radial

Answer

Median

Answer

Posterior interosseus

Question 9

Allen's test is used for detecting the integrity of which of the following?

Accepted Answer

Palmar arch

Answer

Radial artery

Answer

Ulnar artery

Answer

None of the above

Question 10

Which nerve originates from the trunk of the brachial plexus?

Accepted Answer

Suprascapular nerve

Answer

Long thoracic nerve

Answer

Dorsal scapular nerve

Answer

Axillary nerve

Upper Limb — MCQs

Upper Limb — MCQs

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