Upper Limb Practice Questions

Q: A sixteen-year-old boy receives a superficial cut on the thumb side of his forearm. Which superficial vein is most likely affected?

Cephalic vein. ### Explanation **Correct Option: B. Cephalic vein** The **cephalic vein** is the primary superficial vein on the **lateral (radial) side** of the forearm and arm. In anatomical terms, the "thumb side" corresponds to the lateral aspect. It originates from the radial side of the dorsal venous arch of the hand, winds around the radial border of the forearm, and ascends towards the deltopectoral groove. Therefore, a superficial cut on the thumb side of the forearm is most likely to involve the cephalic vein. **Analysis of Incorrect Options:** * **A. Basilic vein:** This vein runs on the **medial (ulnar) side** of the forearm and arm (the "little finger" side). * **C. Median antebrachial vein:** This vein ascends in the **midline** of the anterior aspect of the forearm, situated between the cephalic and basilic veins. * **D. Median cubital vein:** This is a communication between the cephalic and basilic veins located specifically in the **cubital fossa** (anterior to the elbow), not the forearm itself. **High-Yield NEET-PG Pearls:** 1. **Mnemonic:** **C**ephalic is **L**ateral (**CL**), **B**asilic is **M**edial (**BM**). 2. **The Deltopectoral Groove:** The cephalic vein travels here before piercing the **clavipectoral fascia** to drain into the axillary vein. 3. **Venepuncture:** The **median cubital vein** is the preferred site for venepuncture because it is fixed by the underlying bicipital aponeurosis and does not "roll" easily. 4. **Surgical Importance:** The cephalic vein is frequently used for creating arteriovenous (AV) fistulas for hemodialysis (e.g., Radio-cephalic fistula).

Q: Which of the following muscles is NOT supplied by the C8 T1 nerve roots?

Extensor indicis. ### Explanation The key to solving this question lies in understanding the **segmental innervation** of the upper limb. While most intrinsic muscles of the hand are supplied by the **C8 and T1** nerve roots (via the Median and Ulnar nerves), the muscles of the forearm—even those acting on the fingers—often have higher segmental origins. **1. Why Extensor Indicis is the Correct Answer:** The **Extensor indicis** is a deep muscle of the posterior compartment of the forearm [2]. It is supplied by the **Posterior Interosseous Nerve (PIN)**, which is a branch of the Radial nerve. The segmental innervation for the Extensor indicis is primarily **C7 and C8**. In the context of NEET-PG, the "extensors of the wrist and fingers" are classically associated with the **C7** root. **2. Analysis of Incorrect Options (C8-T1 Innervation):** * **Abductor pollicis brevis (A):** A thenar muscle supplied by the Recurrent branch of the Median nerve. All intrinsic hand muscles are primarily **T1** (with C8 contribution). * **Palmar interossei (C):** Supplied by the Deep branch of the Ulnar nerve. These are intrinsic hand muscles [1] and follow the **C8-T1** pattern. * **3rd and 4th lumbricals (D):** Supplied by the Ulnar nerve [1]. Like the interossei, these are intrinsic hand muscles supplied by **C8-T1**. **Clinical Pearls & High-Yield Facts:** * **T1 Root Lesion:** Results in "Claw Hand" due to paralysis of all intrinsic hand muscles (Klumpke’s Palsy). * **C7 Root Testing:** Clinically tested via the Triceps reflex and **finger extension**. * **The "Rule of Hand":** Remember that **T1** is the "master root" for the small muscles of the hand. If a muscle is located entirely within the hand (intrinsic), think T1; if it is in the forearm (extrinsic), think C6-C8.

Q: A 31-year-old patient complains of sensory loss over the anterior and posterior surfaces of the medial third of the hand and the medial one and one-half fingers. The patient is diagnosed with "funny bone" symptoms. Which of the following nerves is injured?

Ulnar. ### Explanation **1. Why the Correct Answer (Ulnar Nerve) is Right:** The ulnar nerve provides sensory innervation to the **medial one and one-half fingers** (little finger and medial half of the ring finger) and the corresponding **medial third of the hand** (hypothenar area) on both the palmar (anterior) and dorsal (posterior) aspects [1]. The "funny bone" refers to the ulnar nerve's vulnerable position as it passes behind the **medial epicondyle** of the humerus. Compression or trauma at this site leads to the classic paresthesia and sensory loss described in the question. **2. Why the Other Options are Incorrect:** * **Axillary Nerve:** Supplies the "regimental badge area" (skin over the lower part of the deltoid). It does not extend to the hand. * **Radial Nerve:** Primarily supplies the skin of the posterior arm, forearm, and the **lateral two-thirds of the dorsum of the hand** (excluding the fingertips, which are median nerve territory). * **Median Nerve:** Supplies the **lateral three and one-half fingers** and the lateral two-thirds of the palm [1]. It does not supply the medial side of the hand. **3. Clinical Pearls for NEET-PG:** * **Site of Injury:** The ulnar nerve is most commonly injured at the **elbow** (cubital tunnel/medial epicondyle) or the **wrist** (Guyon’s canal). * **Motor Deficit:** Injury leads to "Ulnar Claw Hand" (hyperextension at MCP joints and flexion at IP joints of the 4th and 5th digits). * **Froment’s Sign:** A positive test indicates ulnar nerve palsy due to paralysis of the Adductor Pollicis muscle. * **High-Yield Fact:** The ulnar nerve is known as the **"Musician’s Nerve"** because it controls most fine movements of the fingers.

Q: Which muscle is attached to the medial border of the scapula?

Rhomboidus Major. The medial (vertebral) border of the scapula serves as a critical attachment site for muscles that stabilize and move the scapula against the thoracic wall. ### **Explanation of the Correct Answer** **A. Rhomboidus Major:** This muscle originates from the spinous processes of T2–T5 vertebrae and inserts into the **medial border of the scapula**, specifically from the level of the spine to the inferior angle. Along with the Rhomboidus Minor (inserted at the base of the spine) and Serratus Anterior (inserted on the costal aspect of the medial border), it plays a vital role in retracting and rotating the scapula. ### **Analysis of Incorrect Options** * **B. Teres Major:** This muscle arises from the oval area on the dorsal surface of the **inferior angle** and the lower third of the **lateral border** of the scapula. It inserts into the medial lip of the bicipital groove of the humerus. * **C. Deltoid:** This large multipennate muscle originates from the lateral third of the clavicle, the acromion, and the lower lip of the **crest of the spine of the scapula**, not the medial border. * **D. Infraspinatus:** This muscle occupies the **infraspinous fossa** on the dorsal surface of the scapula and inserts into the middle facet of the greater tubercle of the humerus. ### **High-Yield Clinical Pearls for NEET-PG** * **Serratus Anterior:** Often tested alongside Rhomboids; it inserts into the **ventral (costal) aspect** of the medial border. Paralysis of this muscle (Long Thoracic Nerve injury) leads to **"Winging of Scapula."** * **Levator Scapulae:** Also attaches to the medial border, specifically from the superior angle to the root of the spine. * **The "Cuff" Rule:** Remember that the SITS muscles (Supraspinatus, Infraspinatus, Teres Minor, Subscapularis) attach to the humerus, whereas the Rhomboids are "extrinsic" muscles connecting the axial skeleton to the scapula.

Q: A 24-year-old medical student was bitten at the base of her thumb by her dog. The wound became infected and the infection spread into the radial bursa. The tendon(s) of which muscle will most likely be affected?

Flexor pollicis longus. The correct answer is **Flexor pollicis longus (FPL)**. This question tests your knowledge of the synovial sheaths of the hand and their clinical significance in the spread of infection (tenosynovitis). [1] **Why Flexor Pollicis Longus is correct:** The **radial bursa** is the synovial sheath that surrounds the tendon of the Flexor pollicis longus as it passes through the carpal tunnel into the thumb. Anatomically, the radial bursa starts proximal to the flexor retinaculum and extends distally to the insertion of the FPL at the base of the distal phalanx of the thumb. Therefore, an infection at the base of the thumb can easily track proximally through this continuous synovial channel. [1] **Why the other options are incorrect:** * **Flexor digitorum profundus (FDP) & Flexor digitorum superficialis (FDS):** These tendons are contained within the **ulnar bursa**. While the ulnar bursa and radial bursa communicate in about 80% of individuals (the "horseshoe bursa" communication), the primary resident of the radial bursa is the FPL. * **Flexor carpi radialis (FCR):** This tendon has its own separate synovial sheath as it passes through a groove on the trapezium; it does not reside within the radial bursa. **Clinical Pearls for NEET-PG:** * **The Horseshoe Bursa:** In many patients, the radial bursa and ulnar bursa communicate at the level of the wrist. An infection starting in the thumb (radial bursa) can spread to the little finger (ulnar bursa), creating a "horseshoe-shaped" abscess. [1] * **Kanavel’s Signs:** Used to diagnose infectious tenosynovitis: 1) Finger held in flexion, 2) Fusiform swelling, 3) Tenderness along the sheath, 4) Pain on passive extension. * **Space of Parona:** A potential space in the distal forearm where infections from both bursae can converge.

Q: Which of the following muscles is not a hybrid muscle?

Extensor digitorum. ### Explanation **Concept of Hybrid (Composite) Muscles** A **hybrid muscle** (also known as a composite muscle) is defined as a muscle that is supplied by more than one nerve. This dual nerve supply usually occurs because the muscle develops from more than one embryonic origin or spans different functional compartments. **Why Extensor Digitorum is the Correct Answer:** The **Extensor digitorum** is not a hybrid muscle. It is located in the posterior compartment of the forearm and is supplied solely by the **posterior interosseous nerve** (a branch of the radial nerve). It has a single functional role and a single nerve supply. **Analysis of Incorrect Options:** * **Pectoralis major:** It is a hybrid muscle supplied by both the **medial and lateral pectoral nerves**. * **Flexor digitorum profundus (FDP):** A classic hybrid muscle. The medial half (digits 4 and 5) is supplied by the **ulnar nerve**, while the lateral half (digits 2 and 3) is supplied by the **anterior interosseous nerve** (a branch of the median nerve). * **Brachialis:** It is a hybrid muscle. The majority is supplied by the **musculocutaneous nerve** (motor), but the lateral part is supplied by the **radial nerve** (proprioceptive/sensory). **High-Yield Clinical Pearls for NEET-PG:** * **Other common hybrid muscles:** * **Adductor magnus:** Obturator nerve and Sciatic nerve (Tibial part). * **Biceps femoris:** Long head (Tibial part of sciatic) and Short head (Common peroneal part of sciatic). * **Digastric:** Anterior belly (Nerve to mylohyoid - CN V3) and Posterior belly (Facial nerve - CN VII). * **Subscapularis:** Upper and lower subscapular nerves. * **Clinical Significance:** In nerve injuries (like a median nerve palsy), only the lateral half of the FDP is affected, leading to the "pointing sign" or "Ochsner’s clasping test" findings.

Q: Refer to the images. A patient presents with the condition shown in ![img-3.jpeg](img-3.jpeg). Which of the following nerve roots are primarily involved in this type of brachial plexus injury, often termed Erb's palsy, as indicated by Erb's point in the anatomical diagram ![img-2.jpeg](img-2.jpeg)?

C5 and C6. ***C5 and C6*** - Erb's palsy is an injury to the **upper trunk** of the brachial plexus, which is formed by the union of the **C5 and C6** nerve roots at a location known as Erb's point. - This injury classically results in a "**waiter's tip**" deformity, characterized by an adducted and internally rotated shoulder, extended elbow, and pronated forearm, due to paralysis of muscles like the deltoid, biceps, and brachialis. *C6 and C7* - The **C7** nerve root continues alone to form the **middle trunk** of the brachial plexus, while C6 joins C5 to form the upper trunk. - An injury involving C7 would primarily affect the extensors of the wrist and fingers, a different clinical picture than Erb's palsy. *C7 and C8* - The **C7** root forms the **middle trunk**, and the **C8** root contributes to the **lower trunk**, so an injury to both would not correspond to a classic upper plexus lesion. - Deficits would involve a combination of weak wrist/finger extension (C7) and weak finger flexion/intrinsic hand muscles (C8), which is not the presentation of Erb's palsy. *C8 and T1* - Injury to the **C8 and T1** nerve roots involves the **lower trunk** of the brachial plexus and results in a condition known as **Klumpke's palsy**. - This condition is characterized by paralysis of the intrinsic muscles of the hand, leading to a **claw hand** deformity, which is distinct from the "waiter's tip" posture.

Question 1

A 24-year-old construction worker presents after an injury to his left hand. Physical examination reveals marked flexion of the ring and little fingers. Which of the following additional findings would most likely be found on physical examination?

Accepted Answer

Wasting of the dorsal interosseous muscles

Answer

Loss of sensation on the back of the thumb

Answer

Loss of sensation on the palmar side of the forefinger

Answer

Wasting of the thenar eminence

Question 2

A 19-year-old male sustained an injury to the C8-T1 spinal nerve roots after a fall. Which of the following nerves, when demonstrating sensory loss in the area it supplies, would confirm the nature of his neurologic injury?

Accepted Answer

Medial antebrachial cutaneous nerve

Answer

Lower lateral brachial cutaneous nerve

Answer

Musculocutaneous nerve

Answer

Intercostobrachial nerve

Question 3

A sixteen-year-old boy receives a superficial cut on the thumb side of his forearm. Which superficial vein is most likely affected?

Accepted Answer

Cephalic vein

Answer

Basilic vein

Answer

Median antebrachial vein

Answer

Median cubital vein

Question 4

Which of the following muscles is NOT supplied by the C8 T1 nerve roots?

Accepted Answer

Extensor indicis

Answer

Abductor pollicis brevis

Answer

Palmar interossei

Answer

3rd and 4th lumbricals

Question 5

A 31-year-old patient complains of sensory loss over the anterior and posterior surfaces of the medial third of the hand and the medial one and one-half fingers. The patient is diagnosed with "funny bone" symptoms. Which of the following nerves is injured?

Accepted Answer

Ulnar

Answer

Axillary

Answer

Radial

Answer

Median

Question 6

A 23-year-old female sustained an injury to her right index finger while making a bed. She experienced sudden, severe pain over the base of the terminal phalanx, followed by swelling and inability to completely extend the terminal interphalangeal joint. Which one of the following structures within the digit was most likely injured?

Accepted Answer

The insertion of the tendon of the extensor digitorum onto the base of the distal phalanx

Answer

The proper palmar digital branch of the median nerve

Answer

The vinculum longa

Answer

The insertion of the flexor digitorum profundus tendon

Question 7

Which muscle is attached to the medial border of the scapula?

Accepted Answer

Rhomboidus Major

Answer

Teres Major

Answer

Deltoid

Answer

Infraspinatus

Question 8

A 24-year-old medical student was bitten at the base of her thumb by her dog. The wound became infected and the infection spread into the radial bursa. The tendon(s) of which muscle will most likely be affected?

Accepted Answer

Flexor pollicis longus

Answer

Flexor digitorum profundus

Answer

Flexor digitorum superficialis

Answer

Flexor carpi radialis

Question 9

Which of the following muscles is not a hybrid muscle?

Accepted Answer

Extensor digitorum

Answer

Pectoralis major

Answer

Flexor digitorum profundus

Answer

Brachialis

Question 10

Refer to the images. A patient presents with the condition shown in ![img-3.jpeg](img-3.jpeg). Which of the following nerve roots are primarily involved in this type of brachial plexus injury, often termed Erb's palsy, as indicated by Erb's point in the anatomical diagram ![img-2.jpeg](img-2.jpeg)?

Accepted Answer

C5 and C6

Answer

C6 and C7

Answer

C7 and C8

Answer

C8 and T1

Upper Limb — MCQs

Upper Limb — MCQs

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