Upper Limb — MCQs

Upper Limb Indian Medical PG Practice Questions and MCQs

Question 701: Which of the following is not a flexor of the forearm?

A. Brachialis
B. Anconeus (Correct Answer)
C. Pronator teres
D. Brachioradialis

Explanation: ***Anconeus*** - The **anconeus muscle** assists the **triceps** in extending the elbow and is not involved in forearm flexion. - It is located posteriorly to the elbow joint, originating from the **lateral epicondyle of the humerus** and inserting onto the ulna. *Brachialis* - The **brachialis muscle** is a primary **flexor of the elbow joint** and acts to flex the forearm at the elbow. - It is often considered the **workhorse of elbow flexion** as it provides pure flexion regardless of forearm pronation or supination. *Pronator teres* - The **pronator teres** is a muscle in the forearm that primarily functions to **pronate the forearm** (turn the palm downwards). - It also acts as a **weak flexor of the elbow joint**, contributing to forearm flexion. *Brachioradialis* - The **brachioradialis muscle** is located in the superficial layer of the posterior compartment of the forearm but acts as a **flexor of the elbow joint**. - It is particularly active during rapid or resisted elbow flexion, especially when the forearm is in a **neutral position** (thumb up).

Question 702: What are the attachments of the ulnar collateral ligament?

A. Lateral epicondyle of humerus to annular ligament
B. Lateral epicondyle of humerus to radial notch of ulna
C. Medial epicondyle of humerus to radial tuberosity
D. Medial epicondyle of humerus to coronoid process of ulna (Correct Answer)

Explanation: ***Medial epicondyle of humerus to coronoid process of ulna*** - The **ulnar collateral ligament (UCL)** complex is a primary stabilizer of the **elbow joint**, preventing valgus stress. - It consists of anterior, posterior, and transverse bundles, with the **anterior bundle** being the strongest and most important, extending from the **medial epicondyle of the humerus** to the **coronoid process of the ulna**. *Lateral epicondyle of humerus to annular ligament* - This description corresponds to a portion of the **radial collateral ligament (RCL)** complex, specifically connecting the lateral epicondyle to structures around the radial head. - The **annular ligament** encircles the radial head, but the UCL is on the medial side of the elbow. *Lateral epicondyle of humerus to radial notch of ulna* - This anatomical location describes part of the **radial collateral ligament** or structures related to the radiohumeral joint. - The **UCL** is on the medial side of the elbow and connects to the ulna, but not to the **radial notch**. *Medial epicondyle of humerus to radial tuberosity* - While the UCL originates from the **medial epicondyle of the humerus**, it inserts onto the ulna, not the **radial tuberosity**. - The **radial tuberosity** is an insertion site for the biceps brachii muscle, located on the radius.

Question 703: Power grip of hand depends on?

A. Long flexors of the fingers (Correct Answer)
B. Lumbricals of hand
C. Short flexor of fingers
D. Palmaris brevis

Explanation: ***Long flexors of the fingers*** - The **power grip** involves strong flexion of the **metacarpophalangeal (MCP)** and **interphalangeal (IP) joints**, primarily accomplished by the **flexor digitorum profundus** and **flexor digitorum superficialis**. - These muscles originate in the forearm and insert into the fingers, providing the **necessary force** for firmly grasping objects. *Lumbricals of hand* - The lumbricals primarily **flex the MCP joints** and **extend the IP joints** (intrinsic plus action) [1]. - While they contribute to precise movements, they are not the main drivers of the strong, forceful flexion required for a **power grip**. *Short flexor of fingers* - There are no primary "short flexors of the fingers" apart from the intrinsic muscles already discussed (lumbricals and interossei), which perform precise movements rather than **power grip**. - The primary flexors for power are the **long flexors**. *Palmaris brevis* - The **palmaris brevis** is a superficial muscle in the hypothenar eminence that tenses the palmar aponeurosis. - Its main function is to **deepen the hollow of the palm** to improve grip with small objects, not to provide the essential force for a **power grip** [1].

Question 704: In a vehicle accident, the musculocutaneous nerve was completely severed, but still the person was able to weakly flex the elbow joint. All of the following muscles are responsible for this flexion, EXCEPT:

A. Flexor carpi ulnaris
B. Flexor carpi radialis
C. Pronator quadratus (Correct Answer)
D. Brachioradialis

Explanation: ***Pronator quadratus*** - The **pronator quadratus** primarily functions in **pronation of the forearm** and has no role in elbow flexion. - It is innervated by the **anterior interosseous nerve**, a branch of the median nerve, and not involved with elbow flexion. *Flexor carpi ulnaris* - While its main actions are **wrist flexion** and **adduction**, it can contribute *weakly* to elbow flexion due to its origin partially spanning the elbow joint. - It is innervated by the **ulnar nerve**. *Flexor carpi radialis* - The **flexor carpi radialis** acts as a primary **flexor of the wrist** and also assists in **abduction of the wrist**. - It provides a *minor* contribution to elbow flexion because it crosses the elbow joint, and is innervated by the **median nerve**. *Brachioradialis* - The **brachioradialis** is a significant elbow flexor, particularly when the forearm is in a **mid-prone position**. - It is innervated by the **radial nerve**, which explains why elbow flexion is still possible despite musculocutaneous nerve damage.

Question 705: If median nerve is injured at the wrist then loss of function of all of the following will take place except

A. Lumbrical muscles to the middle finger
B. Lumbrical muscles to the Index finger
C. Adductor pollicis (Correct Answer)
D. Muscles of the thenar eminence

Explanation: ***Adductor pollicis*** - The **adductor pollicis** muscle is primarily innervated by the **ulnar nerve**, not the median nerve [1]. - A median nerve injury at the wrist would therefore **not affect** the function of the adductor pollicis [1]. *Lumbrical muscles to the middle finger* - The **first and second lumbricals** (to the index and middle fingers) are typically innervated by the **median nerve** [1]. - An injury to the median nerve at the wrist would cause loss of function in these muscles. *Lumbrical muscles to the Index finger* - Similar to the middle finger lumbrical, the **lumbrical muscle to the index finger** is innervated by the **median nerve** [1]. - Its function would be compromised with a median nerve injury at the wrist. *Muscles of the thenar eminence* - Most muscles of the **thenar eminence** (e.g., abductor pollicis brevis, flexor pollicis brevis, opponens pollicis) are innervated by the **recurrent branch of the median nerve** [1]. - An injury to the median nerve at the wrist, which provides this branch, would lead to significant loss of function in these muscles, affecting **thumb abduction, flexion, and opposition** [1].

Question 706: In a 24 year old man, weight of the upper limb is transmitted to the axial skeleton by:

A. Coracoacromial ligament
B. Costoclavicular ligament
C. Coracoclavicular ligament (Correct Answer)
D. Coracohumeral ligament

Explanation: ***Coracoclavicular ligament*** - The **coracoclavicular ligament** is a strong extra-articular ligament that connects the **coracoid process** of the scapula to the **inferior surface of the clavicle**, effectively suspending the scapula from the clavicle. - This ligament plays the **primary and crucial role** in transmitting forces from the upper limb through the **scapula and clavicle** to the **axial skeleton**, particularly during weight-bearing activities. - It is the key structure that maintains the connection between the upper limb (via scapula) and the axial skeleton (via clavicle). *Coracoacromial ligament* - The **coracoacromial ligament** forms the roof of the **subacromial space** and is primarily involved in preventing superior displacement of the humeral head. - It does not transmit the weight of the upper limb to the axial skeleton but rather protects structures within the subacromial space by forming the coracoacromial arch. *Costoclavicular ligament* - The **costoclavicular ligament** connects the **first rib to the clavicle**, stabilizing the **sternoclavicular joint**. - While it provides important stability at the sternoclavicular joint (part of the transmission pathway), the primary transmission of upper limb weight occurs through the **coracoclavicular ligament** connecting the scapula to clavicle. *Coracohumeral ligament* - The **coracohumeral ligament** connects the **coracoid process of the scapula** to the **greater and lesser tubercles of the humerus**, reinforcing the shoulder joint capsule. - It primarily helps support the weight of the upper limb when the arm is adducted, but it does not transmit this weight to the axial skeleton.

Question 707: Which artery becomes the axillary artery at the lateral border of the first rib?

A. Radial
B. Brachial
C. Ulnar
D. Subclavian (Correct Answer)

Explanation: ***Subclavian*** - The **subclavian artery** passes posterior to the clavicle and becomes the axillary artery once it crosses the **lateral border of the first rib**. [1] - This transition marks the beginning of the arterial supply to the upper limb in the axillary region. [1] *Radial* - The **radial artery** is a terminal branch of the brachial artery in the forearm, supplying the lateral forearm and hand. - It does not contribute to the formation of the axillary artery. *Brachial* - The **brachial artery** is a continuation of the axillary artery in the arm, beginning at the inferior border of the teres major muscle. - It does not precede or become the axillary artery. *Ulnar* - The **ulnar artery** is another terminal branch of the brachial artery in the forearm, supplying the medial forearm and hand. - Like the radial artery, it is a distal artery and is not involved in the formation of the axillary artery.

Question 708: Which nerve is affected if a patient has weakness in wrist and finger extension?

A. Median nerve
B. Radial nerve (Correct Answer)
C. Ulnar nerve
D. Musculocutaneous nerve

Explanation: ***Radial nerve*** - The **radial nerve** innervates the muscles responsible for **wrist and finger extension**, such as the extensor digitorum and extensor carpi radialis [2]. - Weakness in these movements, often described as **wrist drop**, is a classic sign of radial nerve injury [2]. *Median nerve* - The **median nerve** primarily innervates muscles responsible for **flexion of the wrist and fingers**, as well as movements of the thumb [1],[2]. - Injury to the median nerve would typically result in weakness of thumb opposition, flexion of the index and middle fingers, and sensory deficits over the palmar aspect of the first three and a half digits [1]. *Ulnar nerve* - The **ulnar nerve** innervates most of the **intrinsic hand muscles** that control fine movements of the fingers, particularly abduction and adduction, and also controls flexion of the 4th and 5th digits [2]. - Damage to the ulnar nerve often leads to a "claw hand" deformity, which doesn't primarily manifest as weakness in wrist or finger extension [2]. *Musculocutaneous nerve* - The **musculocutaneous nerve** innervates the **biceps brachii** and brachialis muscles, which are primarily responsible for **elbow flexion**. - Weakness due to musculocutaneous nerve injury would therefore affect elbow flexion, and sensation over the lateral forearm.

Question 709: A 25-year-old male presents with weakness in his right arm and difficulty lifting it. An MRI reveals a lesion in the lateral cord of the brachial plexus. Which muscle is most likely to be affected?

A. Pectoralis major
B. Triceps brachii
C. Deltoid
D. Biceps brachii (Correct Answer)

Explanation: ***Biceps brachii*** - The **lateral cord** of the brachial plexus gives rise to the **musculocutaneous nerve**, which innervates the biceps brachii, coracobrachialis, and brachialis. - The biceps brachii is **entirely dependent** on the musculocutaneous nerve for its innervation. - Injury to the lateral cord would lead to complete weakness in elbow flexion and forearm supination, which aligns with the clinical presentation of weakness and difficulty lifting the arm. *Pectoralis major* - The **pectoralis major** receives **dual innervation** from both the **lateral pectoral nerve** (from lateral cord, C5-C7) and **medial pectoral nerve** (from medial cord, C8-T1). - The lateral pectoral nerve primarily supplies the **clavicular head** of pectoralis major. - While a lateral cord lesion would affect the pectoralis major partially, the muscle would retain some function through its medial pectoral nerve supply, making isolated weakness less likely than with biceps brachii. *Deltoid* - The **deltoid muscle** is innervated by the **axillary nerve**, which arises from the **posterior cord** of the brachial plexus (C5-C6). - A lesion in the lateral cord would not directly affect the deltoid's function. *Triceps brachii* - The **triceps brachii** is innervated by the **radial nerve**, which is a terminal branch of the **posterior cord** of the brachial plexus (C6-C8). - A lesion in the lateral cord would not affect the triceps brachii's function.

Question 710: Which ligament is primarily involved in stabilizing the acromioclavicular joint?

A. Coracoacromial ligament
B. Coracoclavicular ligament (Correct Answer)
C. Glenohumeral ligament
D. Transverse humeral ligament

Explanation: ***Coracoclavicular ligament*** - The **coracoclavicular ligament** is the primary stabilizer of the **acromioclavicular (AC) joint**, connecting the coracoid process of the scapula to the clavicle. - It consists of two parts, the **conoid** and **trapezoid ligaments**, which prevent superior displacement of the clavicle relative to the acromion. *Coracoacromial ligament* - The **coracoacromial ligament** forms the **coracoacromial arch** and protects the superior aspect of the glenohumeral joint, often implicated in impingement syndromes. - It does not directly stabilize the integrity of the **AC joint** itself against separation. *Glenohumeral ligament* - The **glenohumeral ligaments** (superior, middle, and inferior) are crucial for stabilizing the **glenohumeral joint** (shoulder joint), preventing dislocation of the humerus from the glenoid fossa. - These ligaments are internal to the shoulder joint capsule and do not have a direct role in the stability of the **AC joint**. *Transverse humeral ligament* - The **transverse humeral ligament** spans the bicipital groove of the humerus, holding the **long head of the biceps tendon** in place. - It plays no role in the stability of the **acromioclavicular joint**.

Practice by Chapter

Pectoral Region and Axilla

Practice Questions

Arm and Cubital Fossa

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Forearm and Hand

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Joints of Upper Limb

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Nerves of Upper Limb

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Arterial Supply and Venous Drainage

Practice Questions

Lymphatic Drainage

Practice Questions

Muscles and Their Actions

Practice Questions

Applied Anatomy and Clinical Correlations

Practice Questions

Surface Anatomy and Landmarks

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Upper Limb — MCQs

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