Upper Limb Practice Questions

Q: The radial nerve passes through the radial groove. Which of the following nerves also passes through the radial groove?

Lower lateral cutaneous nerve of arm. **Explanation:** The **radial groove** (also known as the spiral groove) is a shallow depression located on the posterior surface of the shaft of the humerus. It serves as a critical anatomical conduit for neurovascular structures passing from the medial to the lateral side of the arm. **Why the correct answer is right:** The radial nerve descends through the groove accompanied by the **profunda brachii artery**. While in the groove, the radial nerve gives off several branches. One of these is the **lower lateral cutaneous nerve of the arm**, which pierces the lateral head of the triceps and the lateral intermuscular septum to provide sensory innervation to the skin over the lower lateral part of the arm. Because it originates within or just as the nerve exits the groove, it is anatomically considered a resident of this space. **Why the incorrect options are wrong:** * **Ulnar nerve:** It travels in the medial compartment of the arm and passes posterior to the **medial epicondyle** of the humerus, not the radial groove. * **Median nerve:** It descends in the anterior compartment of the arm, lateral to the brachial artery initially, and crosses to the medial side; it has no relation to the posterior radial groove. * **Musculocutaneous nerve:** It 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 of the Humeral Shaft:** This is the most common site for radial nerve injury, leading to **wrist drop** due to paralysis of the extensors. * **Contents of Radial Groove:** 1. Radial Nerve, 2. Profunda brachii artery, 3. Lower lateral cutaneous nerve of arm, 4. Posterior cutaneous nerve of arm. * **Saturday Night Palsy:** Compression of the radial nerve in the spiral groove (e.g., leaning over a chair) results in temporary motor and sensory loss.

Q: A 34-year-old woman is admitted to the emergency department after a car crash. Radiographic studies show marked edema and hematoma of the arm, but there are no fractures. During physical examination the patient presents with inability to abduct her arm without first establishing lateral momentum of the limb, and inability to flex the elbow and shoulder. Which of the following portions of the brachial plexus is most likely injured?

Superior trunk. ### Explanation The clinical presentation describes a classic **Upper Brachial Plexus Injury (Erb-Duchenne Palsy)**, involving the **Superior Trunk (C5-C6 roots)**. **Why the Superior Trunk is correct:** The superior trunk gives rise to nerves that supply the rotator cuff, deltoid, and flexors of the arm. * **Inability to initiate abduction:** This indicates paralysis of the **Supraspinatus** (Suprascapular nerve, C5-C6) and **Deltoid** (Axillary nerve, C5-C6). The patient needs "lateral momentum" because they must use compensatory trunk movements to swing the arm into an abducted position. * **Inability to flex elbow and shoulder:** This indicates paralysis of the **Biceps brachii, Brachialis, and Coracobrachialis** (Musculocutaneous nerve, C5-C6-C7). **Why the other options are incorrect:** * **Middle Trunk (C7):** Primarily contributes to the radial nerve (extensors). Injury would lead to weakened elbow/wrist extension but would not abolish shoulder abduction or elbow flexion. * **Inferior Trunk (C8-T1):** Results in **Klumpke’s Palsy**. This affects the intrinsic muscles of the hand (claw hand) and potentially causes Horner’s syndrome, but does not affect the proximal shoulder/arm muscles. * **Lateral Cord:** While it contains fibers for the musculocutaneous nerve, it does not carry the C5 fibers for the Suprascapular or Axillary nerves (which branch off more proximally). **High-Yield Clinical Pearls for NEET-PG:** * **Erb’s Point:** A junction where six nerves meet (C5, C6, Nerve to Subclavius, Suprascapular n., Anterior and Posterior divisions of the Superior trunk). * **Waiters Tip Deformity:** The characteristic position in Erb's palsy—Arm is **Adducted** (loss of abductors), **Medially rotated** (loss of lateral rotators), and **Extended** at the elbow (loss of flexors). * **Mechanism:** Usually due to an increase in the angle between the neck and shoulder (e.g., birth trauma or falling on the shoulder).

Q: When withdrawing a blood sample from the median cubital vein, if the needle passes slightly deep and medial, which nerve might possibly be injured?

Medial antebrachial cutaneous nerve. ### Explanation **1. Why the Correct Answer is Right:** The **median cubital vein** is the most common site for venipuncture. It lies superficial to the bicipital aponeurosis in the cubital fossa. Anatomically, the **medial antebrachial cutaneous nerve** (a branch of the medial cord of the brachial plexus) runs in close proximity to the medial side of this vein. If a needle passes too deep or is angled medially during the procedure, it can pierce this nerve, leading to pain or paresthesia along the ulnar (medial) aspect of the forearm. **2. Analysis of Incorrect Options:** * **A. Dorsal ulnar cutaneous nerve:** This is a branch of the ulnar nerve that arises in the distal third of the forearm to supply the skin of the dorsum of the hand. It is not located near the cubital fossa. * **B. Lateral antebrachial cutaneous nerve:** This is the terminal continuation of the **musculocutaneous nerve**. While it is also superficial in the cubital fossa, it lies **lateral** to the cephalic vein and the median cubital vein. * **C. Posterior antebrachial cutaneous nerve:** A branch of the **radial nerve**, it supplies the skin on the posterior aspect of the forearm and is located far from the anteriorly situated median cubital vein. **3. Clinical Pearls for NEET-PG:** * **Bicipital Aponeurosis:** This structure acts as a protective "safety shield" separating the median cubital vein from the deeper **brachial artery** and **median nerve**. * **H-shaped vs. M-shaped patterns:** The venous anatomy of the cubital fossa varies, but the relationship of the cutaneous nerves to the veins remains a high-yield surgical landmark. * **Nerve Injury Risk:** The medial antebrachial cutaneous nerve is the most frequently injured nerve during routine venipuncture at the cubital fossa.

Q: A 55-year-old female choreographer had been treated in the emergency department after she fell from the stage into the orchestra pit. Radiographs revealed fracture of the styloid process of the ulna. Disruption of the triangular fibrocartilage complex is suspected. With which of the following bones does the ulna normally articulate at the wrist?

Radius. The correct answer is **Radius**. This question tests your understanding of the anatomy of the wrist joint (radiocarpal joint) and the distal radioulnar joint. **1. Why Radius is Correct:** The ulna is unique because it **does not articulate directly with any carpal bones** at the wrist. Instead, the distal end of the ulna articulates with the **ulnar notch of the radius** to form the distal radioulnar joint (a pivot joint allowing pronation and supination). The ulna is separated from the carpal bones (specifically the triquetrum and lunate) by the **Triangular Fibrocartilage Complex (TFCC)**. Therefore, the only bone the ulna articulates with at the wrist level is the radius. **2. Why Incorrect Options are Wrong:** * **Triquetrum & Lunate (Options A & C):** While these bones are located distal to the ulna, they articulate with the **radius** and the **TFCC**, not the ulna itself. The TFCC acts as a physical barrier preventing ulnar-carpal contact. * **Hamate (Option B):** The hamate is a distal row carpal bone. It articulates with the triquetrum, capitate, and the 4th and 5th metacarpals, but has no anatomical relationship with the ulna. **3. NEET-PG High-Yield Pearls:** * **The Wrist Joint (Radiocarpal Joint):** Formed by the distal end of the radius and the TFCC proximally, and the scaphoid, lunate, and triquetrum distally. * **TFCC Components:** Includes the articular disc (triangular fibrocartilage), palmar and dorsal radioulnar ligaments, and the ulnar collateral ligament. * **Clinical Correlation:** A fracture of the ulnar styloid often indicates a TFCC tear, leading to ulnar-sided wrist pain and instability during rotation. * **Memory Aid:** The Ulna is "**U**nable" to touch the carpal bones!

Q: Which of the following movements will be affected if the greater tubercle of the humerus is lost?

Abduction and lateral rotation. The **greater tubercle** of the humerus serves as the insertion site for three of the four rotator cuff muscles (SITS). Understanding the muscles attached here is key to determining the functional loss: 1. **Supraspinatus:** Inserts on the superior impression. It initiates **abduction** (first 0-15°). 2. **Infraspinatus:** Inserts on the middle impression. It is a powerful **lateral rotator**. 3. **Teres Minor:** Inserts on the inferior impression. It also assists in **lateral rotation**. If the greater tubercle is lost (e.g., due to a fracture), these muscles lose their leverage, leading to a deficit in **abduction and lateral rotation**. **Analysis of Incorrect Options:** * **B, C, and D:** These options involve **adduction and medial rotation**. These movements are primarily performed by muscles that insert on the **lesser tubercle** (Subscapularis) or the **intertubercular sulcus/bicipital groove** (Pectoralis major, Latissimus dorsi, and Teres major). These structures remain intact if only the greater tubercle is lost. **High-Yield Clinical Pearls for NEET-PG:** * **Rotator Cuff (SITS):** Only the **Subscapularis** inserts on the **lesser tubercle**; the other three insert on the greater tubercle. * **Fracture Displacement:** In greater tubercle fractures, the fragment is typically displaced superiorly and posteriorly due to the pull of the supraspinatus and infraspinatus. * **Nerve Supply:** Supraspinatus and Infraspinatus are supplied by the **Suprascapular nerve** (C5, C6), while Teres minor is supplied by the **Axillary nerve** (C5, C6). * **The "Lady between two Majors":** Latissimus dorsi (the Lady) inserts into the floor of the bicipital groove, flanked by Pectoralis major and Teres major on the lips.

Q: Which of the following is the only shoulder girdle muscle that is not innervated by the brachial plexus?

Pectoralis minor. ### Explanation The correct answer is **C. Pectoralis minor**. **Why it is correct:** The question asks for a shoulder girdle muscle **not** innervated by the brachial plexus. However, based on standard anatomical teaching, the **Pectoralis minor** is supplied by the **Medial Pectoral Nerve (C8, T1)** [1]. The Medial Pectoral Nerve arises directly from the **Medial Cord** of the brachial plexus [1]. Therefore, Pectoralis minor *is* innervated by the brachial plexus. *Note on Question Context:* In many competitive exams, if the options provided are Coracobrachialis, Pectoralis major, and Pectoralis minor, all of these are innervated by branches of the brachial plexus. If the question intended to identify a muscle *not* supplied by the brachial plexus, the classic answer is the **Trapezius** (innervated by the Spinal Accessory Nerve/CN XI). Given the options provided, there appears to be a technical error in the question stem or key; however, among the choices, all are derivatives of the brachial plexus. **Why the other options are incorrect:** * **Coracobrachialis:** Innervated by the **Musculocutaneous nerve** (C5-C7), which is a terminal branch of the Lateral Cord of the brachial plexus. * **Pectoralis major:** Innervated by both the **Lateral and Medial Pectoral nerves**, both of which originate from the cords of the brachial plexus [1]. **High-Yield NEET-PG Pearls:** 1. **Trapezius:** The most high-yield "shoulder" muscle NOT supplied by the brachial plexus (Spinal Accessory Nerve). 2. **Levator Scapulae & Rhomboids:** Supplied by the **Dorsal Scapular Nerve** (Branch from the C5 root). 3. **Serratus Anterior:** Supplied by the **Long Thoracic Nerve of Bell** (C5, C6, C7 roots); injury leads to "winging of scapula." 4. **Pectoralis Minor Landmark:** It serves as the key landmark to divide the **Axillary Artery** into three parts.

Q: A 39-year-old woman complains of an inability to reach the top of her head to brush her hair. History reveals that she had undergone a bilateral mastectomy procedure 2 months earlier. Physical examination demonstrates winging of both of her scapulae. Which nerves were most likely damaged during surgery?

Long thoracic. The clinical presentation of **winging of the scapula** following a mastectomy is a classic board-exam scenario. The **long thoracic nerve** (C5, C6, C7) is anatomically vulnerable during axillary lymph node dissection, a common component of mastectomy [1]. This nerve innervates the **serratus anterior** muscle, which is responsible for protracting the scapula and holding its medial border against the thoracic wall. When paralyzed, the medial border of the scapula "wings" outward. Furthermore, the serratus anterior is essential for rotating the scapula upward to allow **abduction of the arm above 90 degrees** (explaining her inability to brush her hair). **Analysis of Incorrect Options:** * **Axillary Nerve:** Innervates the deltoid and teres minor. Damage results in loss of rounded shoulder contour and inability to abduct the arm to 90 degrees, but does not cause scapular winging. * **Spinal Accessory Nerve:** Innervates the trapezius. Damage can cause "lateral" winging (the scapula moves downward and laterally), but it is less commonly injured in mastectomy compared to the long thoracic nerve. * **Dorsal Scapular Nerve:** Innervates the rhomboids and levator scapulae. Damage results in difficulty retracting the scapula but does not cause prominent winging. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Origin:** "C5, 6, 7 raise your wings to heaven" (Long thoracic nerve roots). * **Nerve of Bell:** Another name for the long thoracic nerve. * **Thoracodorsal Nerve:** Also at risk during mastectomy; damage leads to weakness in internal rotation and extension of the arm (Latissimus dorsi) [1]. * **Serratus Anterior Test:** Ask the patient to push against a wall; winging becomes more pronounced.

Q: All of the following muscles of the pectoral girdle are innervated by branches from the brachial plexus, except?

Trapezius. ### Explanation The correct answer is **Trapezius**. The pectoral girdle is connected to the axial skeleton by several muscles. The key to answering this question lies in distinguishing between muscles innervated by the **brachial plexus (C5–T1)** and those innervated by **cranial nerves**. **Why Trapezius is the correct answer:** The Trapezius is a large, superficial muscle of the back that acts on the pectoral girdle. Unlike the other options, it is **not** innervated by the brachial plexus. Its motor supply is derived from the **Spinal Accessory Nerve (Cranial Nerve XI)**. Its sensory (proprioceptive) fibers come from the ventral rami of **C3 and C4**. **Analysis of Incorrect Options:** * **Subclavius:** Innervated by the **nerve to subclavius**, which arises from the **upper trunk** of the brachial plexus (C5, C6). * **Serratus anterior:** Innervated by the **long thoracic nerve** (Nerve of Bell), which arises from the **roots** of the brachial plexus (C5, C6, C7). * **Rhomboid major:** Innervated by the **dorsal scapular nerve**, which arises from the **C5 root** of the brachial plexus. **Clinical Pearls for NEET-PG:** 1. **Winged Scapula:** Damage to the long thoracic nerve (Serratus anterior) causes medial winging [1]. Damage to the spinal accessory nerve (Trapezius) causes lateral winging. 2. **Triangle of Auscultation:** The Trapezius forms the medial boundary of this triangle, which is the best site to listen to lung sounds due to the relative thinning of muscles. 3. **Testing CN XI:** Shrugging the shoulders against resistance tests the Trapezius, while turning the head against resistance tests the Sternocleidomastoid (also supplied by CN XI).

Question 1

The radial nerve passes through the radial groove. Which of the following nerves also passes through the radial groove?

Accepted Answer

Lower lateral cutaneous nerve of arm

Answer

Ulnar nerve

Answer

Median nerve

Answer

Musculocutaneous nerve

Question 2

Following surgical removal of a firm nodular swelling in the right breast and exploration of the right axilla, a winged right scapula was noted on examination. Most likely, this occurred due to injury to which of the following structures?

Accepted Answer

Long thoracic nerve

Answer

Subscapular muscle

Answer

Coracoid process of scapula

Answer

Circumflex scapular artery

Question 3

A 34-year-old woman is admitted to the emergency department after a car crash. Radiographic studies show marked edema and hematoma of the arm, but there are no fractures. During physical examination the patient presents with inability to abduct her arm without first establishing lateral momentum of the limb, and inability to flex the elbow and shoulder. Which of the following portions of the brachial plexus is most likely injured?

Accepted Answer

Superior trunk

Answer

Middle trunk

Answer

Inferior trunk

Answer

Lateral cord

Question 4

When withdrawing a blood sample from the median cubital vein, if the needle passes slightly deep and medial, which nerve might possibly be injured?

Accepted Answer

Medial antebrachial cutaneous nerve

Answer

Dorsal ulnar cutaneous nerve

Answer

Lateral antebrachial cutaneous nerve

Answer

Posterior antebrachial cutaneous nerve

Question 5

Injury to the radial nerve in the lower part of the spiral groove results in which of the following?

Accepted Answer

Leaves extension at the elbow joint intact

Answer

Spares nerve supply to extensor carpi radialis longus

Answer

Results in paralysis of the anconeus muscle

Answer

Weakens pronation movement

Question 6

A 55-year-old female choreographer had been treated in the emergency department after she fell from the stage into the orchestra pit. Radiographs revealed fracture of the styloid process of the ulna. Disruption of the triangular fibrocartilage complex is suspected. With which of the following bones does the ulna normally articulate at the wrist?

Accepted Answer

Radius

Answer

Triquetrum

Answer

Hamate

Answer

Radius and lunate

Question 7

Which of the following movements will be affected if the greater tubercle of the humerus is lost?

Accepted Answer

Abduction and lateral rotation

Answer

Adduction and flexion

Answer

Adduction and medial rotation

Answer

Flexion and medial rotation

Question 8

Which of the following is the only shoulder girdle muscle that is not innervated by the brachial plexus?

Accepted Answer

Pectoralis minor

Answer

Coracobrachialis

Answer

Pectoralis major

Answer

None of the above

Question 9

A 39-year-old woman complains of an inability to reach the top of her head to brush her hair. History reveals that she had undergone a bilateral mastectomy procedure 2 months earlier. Physical examination demonstrates winging of both of her scapulae. Which nerves were most likely damaged during surgery?

Accepted Answer

Long thoracic

Answer

Axillary

Answer

Spinal accessory

Answer

Dorsal scapular

Question 10

All of the following muscles of the pectoral girdle are innervated by branches from the brachial plexus, except?

Accepted Answer

Trapezius

Answer

Subclavius

Answer

Serratus anterior

Answer

Rhomboid major

Upper Limb — MCQs

Upper Limb — MCQs

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