Upper Limb Practice Questions

Q: Flexion of the metacarpophalangeal joint is produced by all except?

Extensor pollicis longus. The primary action of the **Extensor Pollicis Longus (EPL)** is the **extension** of the interphalangeal and metacarpophalangeal (MCP) joints of the thumb. As a member of the extensor compartment of the forearm, its mechanical pull is dorsal to the joint axis, making it an antagonist to flexion. Therefore, it does not contribute to the flexion of any MCP joint [1]. **Analysis of Options:** * **Lumbricals:** These originate from the tendons of the Flexor Digitorum Profundus and insert into the extensor expansions [2]. Because they pass **palmar** to the deep transverse metacarpal ligament (the MCP joint axis), they act as primary flexors of the MCP joints while simultaneously extending the IP joints (the "Z-position") [2]. * **Dorsal Interossei (DAB):** While their primary role is abduction, their insertion into the extensor hoods palmar to the MCP joint axis allows them to assist in MCP flexion [2]. * **Palmar Interossei (PAD):** Similar to the dorsal interossei, their primary role is adduction, but their anatomical course also facilitates MCP joint flexion [2]. **Clinical Pearls for NEET-PG:** * **The "Z-movement":** Flexion at MCP + Extension at IP joints is the combined action of Lumbricals and Interossei [2]. * **Nerve Supply:** Lumbricals 1 & 2 (Median Nerve); Lumbricals 3 & 4 and all Interossei (Ulnar Nerve) [3]. * **Claw Hand:** Paralysis of these intrinsic muscles leads to the opposite deformity: hyperextension at MCP and flexion at IP joints. * **EPL Landmark:** It forms the ulnar (posterior) boundary of the **Anatomical Snuffbox** and hooks around **Lister’s tubercle** on the radius [1].

Q: Compression of nerve roots by a cervical rib, a cause of thoracic outlet syndrome, primarily affects which nerve roots?

C8, T1. ### Explanation **1. Why C8 and T1 are correct:** A cervical rib is an accessory rib originating from the C7 vertebra. Because of its anatomical position, it most commonly compresses the **lower trunk of the brachial plexus**, which is formed by the **C8 and T1 nerve roots**. These roots must arch over the cervical rib (or its fibrous band) to reach the axilla. Compression leads to the neurological symptoms of Thoracic Outlet Syndrome (TOS), specifically affecting the intrinsic muscles of the hand (T1) and sensation along the medial aspect of the forearm and hand (C8). **2. Why other options are incorrect:** * **A (C5, C6):** These roots form the upper trunk of the brachial plexus. They are located much higher in the neck and are typically involved in Erb’s palsy, not compression by a cervical rib. * **B (C6, C7):** These roots contribute to the upper and middle trunks. While they are proximal to the thoracic outlet, they are not in direct contact with the anomalous rib. * **C (C7, C8):** While C8 is involved, C7 forms the middle trunk and is generally spared in classic cervical rib compression, which specifically targets the structures resting directly on the rib. **3. High-Yield Clinical Pearls for NEET-PG:** * **Vascular Involvement:** The cervical rib can also compress the **Subclavian Artery** (rarely the vein), leading to a diminished radial pulse and positive **Adson’s Test**. * **Gilliatt-Sumner Hand:** This refers to the characteristic wasting of the thenar and hypothenar eminence seen in neurogenic TOS. * **Differential Diagnosis:** Must be distinguished from Pancoast tumor (which also affects C8-T1) and Ulnar nerve entrapment at the elbow. * **Embryology:** A cervical rib results from the elongation of the transverse process of the 7th cervical vertebra.

Q: A man cannot perform abduction and internal rotation of the arm. Which muscle is responsible for both these movements?

Deltoid. ### Explanation The **Deltoid muscle** is a multipennate muscle with three distinct sets of fibers that act on the glenohumeral joint. Its unique functional anatomy allows it to participate in multiple, sometimes opposing, movements: 1. **Abduction:** The **multipennate acromial (middle) fibers** are the primary abductors of the arm from 15° to 90°. 2. **Internal Rotation:** The **anterior (clavicular) fibers** act as flexors and internal rotators of the humerus. 3. **External Rotation:** The **posterior (spinal) fibers** act as extensors and external rotators. Since the question specifies a muscle capable of *both* abduction and internal rotation, the Deltoid is the only option that fits both criteria. #### Analysis of Incorrect Options: * **Pectoralis major:** A powerful adductor and internal rotator. It cannot perform abduction (except for weak assistance in flexion by the clavicular head). * **Subscapularis:** Part of the rotator cuff; it is the primary internal rotator of the arm but does not perform abduction. * **Teres major:** Known as the "Lat's little helper," it performs adduction, internal rotation, and extension, but not abduction. #### NEET-PG High-Yield Pearls: * **Nerve Supply:** The Deltoid is supplied by the **Axillary Nerve (C5, C6)**. Damage to this nerve (e.g., surgical neck of humerus fracture) leads to loss of the rounded contour of the shoulder and inability to abduct the arm beyond 15°. * **Abduction Sequence:** * 0°–15°: Supraspinatus (Suprascapular nerve). * 15°–90°: Deltoid (Axillary nerve). * Above 90°: Serratus anterior and Trapezius (Scapular rotation). * **Intramuscular Injection:** The deltoid is a common site for IM injections; the needle is typically aimed at the middle of the muscle to avoid the axillary nerve, which winds around the surgical neck of the humerus.

Q: The synovial cavity of the glenohumeral joint communicates with the subdeltoid bursa after the rupture of which structure?

Supraspinatus Tendon. The **glenohumeral joint** and the **subdeltoid (subacromial) bursa** are normally two distinct, non-communicating anatomical spaces. They are separated by the **Rotator Cuff**, a musculotendinous sheath formed by the SITS muscles (Supraspinatus, Infraspinatus, Teres minor, and Subscapularis). The **Supraspinatus tendon** forms the superior part of the rotator cuff and lies directly beneath the subdeltoid bursa and above the joint capsule. When the Supraspinatus tendon undergoes a full-thickness rupture (often due to chronic impingement or trauma), a pathological communication is established. This allows synovial fluid to pass from the joint cavity into the bursa, a sign often visualized on MRI or arthrography. **Analysis of Incorrect Options:** * **Infraspinatus & Subscapularis Tendons:** While these are part of the rotator cuff, their rupture is less common than the supraspinatus and typically does not lead to the classic communication with the subdeltoid bursa in the same clinical context. * **Middle Glenohumeral Ligament:** This is an intrinsic thickening of the anterior joint capsule. Its rupture would lead to joint instability (dislocation) rather than communication with the subdeltoid bursa. **High-Yield Clinical Pearls for NEET-PG:** * **Supraspinatus** is the most commonly injured muscle of the rotator cuff (the "Critical Zone" of hypovascularity near its insertion). * **Painful Arc Syndrome:** Pain between 60°–120° of abduction usually indicates supraspinatus tendinitis or subacromial bursitis. * The **Subscapularis bursa** (unlike the subdeltoid) *normally* communicates with the joint cavity through an opening between the superior and middle glenohumeral ligaments.

Q: All of the following structures pass through Guyon's canal, EXCEPT:

Flexor carpi ulnaris. Guyon’s canal (ulnar canal) is a fibro-osseous tunnel located on the medial side of the wrist. It serves as a passage for the ulnar neurovascular bundle from the forearm into the hand. **Why Flexor Carpi Ulnaris (FCU) is the correct answer:** The **Flexor carpi ulnaris** muscle does not pass *through* Guyon’s canal. Instead, it inserts onto the **pisiform bone**, which forms the medial boundary (wall) of the canal. The tendon of the FCU remains superficial and proximal to the canal entrance, acting as a landmark rather than a content. **Analysis of Incorrect Options:** * **Ulnar Nerve (A):** This is the primary neural content of the canal. It travels to the radial side of the pisiform and passes to the ulnar side of the hook of the hamate [1]. It divides within or just distal to the canal into superficial and deep branches. * **Ulnar Artery (B):** The ulnar artery enters the canal lateral to the ulnar nerve and provides the blood supply to the deep palmar arch. * **Ulnar Vein (C):** Venae comitantes of the ulnar artery accompany the artery through the canal. **High-Yield Clinical Pearls for NEET-PG:** * **Boundaries:** The roof is formed by the **palmar carpal ligament** and palmaris brevis; the floor is formed by the **flexor retinaculum** and hypothenar muscles [1]. * **Guyon’s Canal Syndrome:** Compression of the ulnar nerve here (often due to handlebar palsy in cyclists or ganglion cysts) leads to sensory loss in the medial 1.5 fingers and weakness of intrinsic hand muscles, but **spares the long flexors** and the dorsal cutaneous sensation of the hand. * **Mnemonic:** The contents are simply the **Ulnar Nerve and Vessels.**

Q: The axis of abduction and adduction of digits passes through the center of which metacarpal bone?

3rd metacarpal. ### Explanation **1. Why the 3rd Metacarpal is Correct:** In the hand, the functional axis for movements of the fingers (digits 2–5) is defined by the **3rd digit (middle finger)** and its corresponding **3rd metacarpal**. * **Abduction** is defined as movement away from this central axis. * **Adduction** is defined as movement toward this axis. Because the 3rd digit *is* the axis, it can abduct to both the radial and ulnar sides (via the two dorsal interossei attached to it) but cannot technically "adduct" in the same way other fingers do, as it is already at the midline. **2. Why Other Options are Incorrect:** * **2nd Metacarpal (Index Finger):** This digit abducts away from the 3rd digit (radially) and adducts toward it. It serves as a boundary but not the reference axis. * **4th and 5th Metacarpals (Ring and Little Fingers):** These digits abduct away from the 3rd digit (ulnarly) and adduct toward it. The 5th digit has its own specific abductor (Abductor digiti minimi), but the reference point remains the 3rd metacarpal. **3. High-Yield Clinical Pearls for NEET-PG:** * **Muscle Mnemonics:** * **DAB:** **D**orsal interossei **AB**duct (4 muscles). * **PAD:** **P**almar interossei **AD**duct (3 muscles; the 3rd digit lacks a palmar interosseous because it is the axis). * **Nerve Supply:** All interossei (DAB and PAD) are supplied by the **Deep branch of the Ulnar Nerve (C8, T1)** [1]. * **Thumb Exception:** The axis for the thumb is different; its abduction/adduction occurs in a plane perpendicular to the palm (at the 1st CMC joint). * **Foot Comparison:** In the foot, the axis of abduction/adduction passes through the **2nd toe/metacarpal**, not the 3rd. This is a frequent point of confusion in exams.

Q: The axillary nerve is a branch of which part of the brachial plexus?

Posterior cord. The axillary nerve (C5, C6) arises directly from the posterior cord of the brachial plexus. The posterior cord is formed by the union of the posterior divisions of all three trunks (upper, middle, and lower), representing the dorsal aspect of the limb's nerve supply. **Why the Posterior Cord is correct:** The posterior cord gives off five branches, easily remembered by the mnemonic **ULTRA**: * **U**pper subscapular nerve * **L**ower subscapular nerve * **T**horacodorsal nerve [1] * **R**adial nerve (Terminal branch) * **A**xillary nerve (Terminal branch) **Why other options are incorrect:** * **Trunk:** The trunks (Upper, Middle, Lower) primarily give off branches like the suprascapular nerve and nerve to subclavius (from the upper trunk), but not the axillary nerve. * **Medial Cord:** This cord gives rise to the ulnar nerve, medial cutaneous nerves of the arm/forearm, and the medial head of the median nerve. * **Lateral Cord:** This cord gives rise to the musculocutaneous nerve, lateral pectoral nerve, and the lateral head of the median nerve. **Clinical Pearls for NEET-PG:** 1. **Site of Injury:** The axillary nerve is most commonly injured during **fractures of the surgical neck of the humerus** or **anterior dislocation of the shoulder joint**. 2. **Clinical Presentation:** Injury leads to paralysis of the **deltoid** (loss of abduction from 15–90 degrees) and **teres minor**, along with sensory loss over the "regimental badge area" (lower half of the deltoid). 3. **Quadrangular Space:** The axillary nerve passes through this space along with the posterior circumflex humeral artery.

Q: All of the following are true statements about the joints of the upper limb EXCEPT:

Sternoclavicular joint - Hinge joint. ### Explanation The **Sternoclavicular (SC) joint** is anatomically and functionally a **Saddle-type synovial joint**, not a hinge joint. It is unique because it is the only bony attachment between the upper limb and the axial skeleton. Despite being a saddle joint, it functions almost like a ball-and-socket joint due to the presence of a fibrocartilaginous articular disc that divides the joint cavity, allowing for multi-axial movement (elevation/depression, protraction/retraction, and rotation). **Analysis of Options:** * **A. Acromioclavicular joint:** This is correctly identified as a **Plane synovial joint**. It allows gliding movements between the acromion of the scapula and the lateral end of the clavicle, facilitating scapular rotation during arm abduction. * **B. Shoulder joint:** This is a classic **Ball and socket joint** (Glenohumeral joint). It provides the greatest range of motion of any joint in the body at the expense of stability. * **D. Intercarpal and midcarpal joints:** These are **Plane synovial joints**. They allow small gliding movements between individual carpal bones, which contribute to the overall flexibility of the wrist complex. **NEET-PG High-Yield Pearls:** * **Sternoclavicular Joint:** It is the only joint in the upper limb that contains a complete **intra-articular disc**, which acts as a shock absorber and prevents medial displacement of the clavicle. * **Hinge Joints in Upper Limb:** The primary examples are the **Humeroulnar (Elbow) joint** and the **Interphalangeal joints**. * **Pivot Joints:** The **Proximal and Distal Radioulnar joints** are pivot joints, essential for supination and pronation. * **Ellipsoid Joint:** The **Wrist (Radiocarpal) joint** is an ellipsoid/condyloid joint.

Q: A 16-year-old boy sustained a severe radial nerve injury due to a midshaft humerus fracture following a motorcycle fall. Which of the following conditions would most likely result from this injury?

Loss of wrist extension leading to wrist drop. **Explanation:** **1. Why Option A is Correct:** The radial nerve (C5-T1) travels in the **spiral groove** of the humerus, making it highly susceptible to injury in midshaft humerus fractures. This nerve innervates the extensors of the forearm. A lesion at this level results in paralysis of the *Extensor Carpi Radialis Longus/Brevis* and the *Extensor Digitorum*, leading to an inability to extend the wrist against gravity—a clinical condition known as **Wrist Drop**. **2. Why the Other Options are Incorrect:** * **Option B:** Forearm pronation is primarily controlled by the **Median Nerve** (*Pronator Teres* and *Pronator Quadratus*). Radial nerve injury affects supination (via the *Supinator* muscle), though the *Biceps Brachii* (Musculocutaneous nerve) can still perform supination when the elbow is flexed. * **Option C:** Sensory loss in radial nerve injury typically occurs on the **dorsal** aspect of the first web space. Sensory loss on the **ventral (palmar)** aspect of the thumb is characteristic of a **Median Nerve** injury. * **Option D:** Opposition of the thumb is the function of the *Opponens Pollicis*, which is part of the thenar eminence and is supplied by the **Recurrent branch of the Median Nerve**. **3. High-Yield Clinical Pearls for NEET-PG:** * **Saturday Night Palsy:** Compression of the radial nerve in the axilla (e.g., crutch palsy) presents with wrist drop **plus** loss of triceps function (extension of the elbow). * **Midshaft Fracture:** Triceps function is usually **spared** because the branches to the long and medial heads of the triceps arise proximal to the spiral groove. * **PIN Palsy:** Injury to the Posterior Interosseous Nerve (a branch of the radial nerve) causes

Q: The fourth dorsal interosseous muscle is innervated by?

Deep branch of the ulnar nerve. **Explanation:** The **fourth dorsal interosseous muscle** is one of the intrinsic muscles of the hand. The fundamental rule for hand innervation is that **all interossei (both dorsal and palmar)** are supplied by the **deep branch of the ulnar nerve (C8, T1).** **1. Why the correct answer is right:** The ulnar nerve enters the hand through Guyon’s canal and divides into superficial and deep branches [1]. The **deep branch** is purely motor; it follows the course of the deep palmar arch and supplies all interossei, the two medial lumbricals, the hypothenar muscles, and the adductor pollicis [2]. Since the fourth dorsal interosseous is located in the fourth intermetacarpal space, it falls under this motor distribution. **2. Why the incorrect options are wrong:** * **Option A:** The recurrent branch of the median nerve supplies the "TH" muscles of the thenar eminence (Abductor pollicis brevis, Flexor pollicis brevis, and Opponens pollicis). * **Option C:** The dorsal branch of the ulnar nerve is **purely sensory**, providing cutaneous innervation to the medial half of the dorsum of the hand and the proximal parts of the medial 2.5 fingers [1]. * **Option D:** The superficial branch of the radial nerve is **purely sensory**, supplying the skin over the lateral part of the dorsum of the hand and the base of the thumb. **High-Yield Clinical Pearls for NEET-PG:** * **DAB & PAD:** **D**orsal interossei **AB**duct (4 muscles); **P**almar interossei **AD**duct (3 muscles). * **Ulnar Paradox:** Higher lesions of the ulnar nerve (at the elbow) result in less prominent clawing than lower lesions (at the wrist) because the medial half of the Flexor Digitorum Profundus is also paralyzed. * **Froment’s Sign:** Tests for adductor pollicis palsy (ulnar nerve) where the patient compensates by flexing the thumb IP joint (median nerve/FPL).

Question 1

Flexion of the metacarpophalangeal joint is produced by all except?

Accepted Answer

Extensor pollicis longus

Answer

Lumbricals

Answer

Dorsal interossei

Answer

Palmar interossei

Question 2

Compression of nerve roots by a cervical rib, a cause of thoracic outlet syndrome, primarily affects which nerve roots?

Accepted Answer

C8, T1

Answer

C5, C6

Answer

C6, C7

Answer

C7, C8

Question 3

A man cannot perform abduction and internal rotation of the arm. Which muscle is responsible for both these movements?

Accepted Answer

Deltoid

Answer

Pectoralis major

Answer

Subscapularis

Answer

Teres major

Question 4

The synovial cavity of the glenohumeral joint communicates with the subdeltoid bursa after the rupture of which structure?

Accepted Answer

Supraspinatus Tendon

Answer

Infraspinatus Tendon

Answer

Middle glenohumeral ligament

Answer

Subscapularis Tendon

Question 5

All of the following structures pass through Guyon's canal, EXCEPT:

Accepted Answer

Flexor carpi ulnaris

Answer

Ulnar nerve

Answer

Ulnar artery

Answer

Ulnar vein

Question 6

The axis of abduction and adduction of digits passes through the center of which metacarpal bone?

Accepted Answer

3rd metacarpal

Answer

2nd metacarpal

Answer

4th metacarpal

Answer

5th metacarpal

Question 7

The axillary nerve is a branch of which part of the brachial plexus?

Accepted Answer

Posterior cord

Answer

Trunk

Answer

Medial cord

Answer

Lateral cord

Question 8

All of the following are true statements about the joints of the upper limb EXCEPT:

Accepted Answer

Sternoclavicular joint - Hinge joint

Answer

Acromioclavicular joint - Plane synovial joint

Answer

Shoulder joint - Ball and socket joint

Answer

Intercarpal and midcarpal joints - Plane synovial joint

Question 9

A 16-year-old boy sustained a severe radial nerve injury due to a midshaft humerus fracture following a motorcycle fall. Which of the following conditions would most likely result from this injury?

Accepted Answer

Loss of wrist extension leading to wrist drop

Answer

Weakness in pronating the forearm

Answer

Sensory loss over the ventral aspect of the thumb

Answer

Inability to oppose the thumb

Question 10

The fourth dorsal interosseous muscle is innervated by?

Accepted Answer

Deep branch of the ulnar nerve

Answer

Recurrent (motor) branch of the median nerve

Answer

Dorsal branch of the ulnar nerve

Answer

Superficial branch of the radial nerve

Upper Limb — MCQs

Upper Limb — MCQs

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