Upper Limb — MCQs

Upper Limb Indian Medical PG Practice Questions and MCQs

Question 781: What type of joint is the 1st carpometacarpal joint?

A. Pivot
B. Hinge
C. Ball and Socket
D. Saddle (Correct Answer)

Explanation: ***Saddle*** - The **1st carpometacarpal joint** (thumb CMC joint) is a classic example of a **saddle joint** due to the reciprocal concave-convex opposing surfaces of the trapezium and the first metacarpal [1]. - This unique shape allows for a wide range of motion, including **flexion/extension**, **abduction/adduction**, and **opposition**, which is crucial for thumb function. *Pivot* - A **pivot joint** allows for rotational movement around a single axis, like the **atlantoaxial joint** (C1-C2) or the **proximal radioulnar joint**. - This type of motion is not characteristic of the 1st carpometacarpal joint. *Hinge* - A **hinge joint** permits movement in only one plane, like the **elbow** or **interphalangeal joints**, allowing for **flexion and extension**. - The 1st carpometacarpal joint has a greater degree of freedom than a hinge joint. *Ball and Socket* - A **ball and socket joint** offers the greatest range of motion, allowing for movement in all planes, including **circumduction and rotation**, such as the **shoulder** and **hip joints**. - While the 1st carpometacarpal joint is highly mobile, it does not achieve the full range of motion of a ball and socket joint.

Question 782: Sensory supply of the palm is from which nerves?

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

Explanation: **Ulnar nerve and Median nerve** *(Correct)* - The **median nerve** provides sensory innervation to the lateral palm, including the thumb, index, middle, and radial half of the ring finger [1]. - The **ulnar nerve** supplies sensory innervation to the medial palm, including the little finger and the ulnar half of the ring finger [1]. - Together, these two nerves provide complete sensory coverage of the palm [1]. *Median nerve and Radial nerve* (Incorrect) - While the **median nerve** innervates a significant portion of the palm, the **radial nerve** primarily supplies the dorsal aspect of the hand and a small area of the thenar eminence, not the entire palm. - The radial nerve's sensory supply to the palm is usually limited to a very small area at the base of the thumb. - This combination does not provide complete palmar sensory coverage. *Radial nerve and ulnar nerve* (Incorrect) - The **radial nerve** mainly supplies the dorsum of the hand and digits, with minimal palmar contribution, making this option incorrect for primary palmar sensory supply. - The **ulnar nerve** does innervate part of the palm, but the combination with the radial nerve for complete palmar supply is inaccurate. - The median nerve, not the radial nerve, is the other major contributor to palmar sensation. *Musculocutaneous nerve and Radial nerve* (Incorrect) - The **musculocutaneous nerve** primarily innervates the lateral aspect of the forearm (as the lateral antebrachial cutaneous nerve) and does not contribute to the sensory supply of the palm. - The **radial nerve** also has a limited role in palmar sensation. - Neither of these nerves provides significant sensory innervation to the palm.

Question 783: Long thoracic nerve arises from which nerve roots?

A. C6 C7 T1
B. C7 T1 T2
C. C5 C6 C7 (Correct Answer)
D. C5 C6 C7 T1

Explanation: ***C5 C6 C7*** - The long thoracic nerve is formed from the **anterior rami** of the fifth, sixth, and seventh **cervical nerves (C5, C6, C7)**. - This nerve uniquely descends posterior to the **brachial plexus** and innervates the **serratus anterior muscle**. *C6 C7 T1* - While these roots contribute to other brachial plexus nerves, the **long thoracic nerve** specifically excludes T1. - T1 is more commonly associated with the **lower trunk** of the brachial plexus and nerves like the **ulnar nerve**. *C7 T1 T2* - The long thoracic nerve arises primarily from **cervical roots** and does not typically include T2. - **T2 involvement** in neural innervation of the upper limb is less common for the main nerves. *C5, C6, C7, T1* - The inclusion of T1 in this option makes it incorrect for the **long thoracic nerve**. - The T1 root contributes to other nerves of the **brachial plexus**, not the long thoracic nerve.

Question 784: Which muscle initiates abduction at the shoulder joint?

A. Deltoid
B. Supraspinatus (Correct Answer)
C. Infraspinatus
D. Subscapularis

Explanation: ***Supraspinatus*** - The **supraspinatus muscle** is responsible for initiating abduction of the arm at the shoulder joint, specifically for the first 15-30 degrees. - Its tendon passes through the **subacromial space**, making it vulnerable to impingement and tears. *Subscapularis* - The **subscapularis** is primarily involved in **internal rotation** of the shoulder. - It also contributes to stabilization of the **glenohumeral joint**. *Deltoid* - The **deltoid muscle** is the principal abductor of the arm, but it takes over *after* the initial 15-30 degrees of abduction. - It is powerful for abduction from approximately **30 to 180 degrees**. *Infraspinatus* - The **infraspinatus muscle** is a key muscle for **external rotation** of the shoulder. - It also aids in stabilizing the **humeral head** within the glenoid cavity.

Question 785: The lateral boundary of the anatomical snuff box is formed by?

A. FPL
B. EPB (Correct Answer)
C. Abductor Pollicis Brevis (APB)
D. EPL

Explanation: ***EPB*** - The **anatomical snuff box** is a triangular depression on the radial side of the wrist. - Its **lateral boundary** is formed by the tendons of **extensor pollicis brevis (EPB)** and **abductor pollicis longus (APL)**, which run together superficially [1]. - EPB is the primary structure cited in most exam contexts for the lateral boundary. *EPL* - The **extensor pollicis longus (EPL)** forms the **medial boundary** of the anatomical snuff box [1]. - It crosses obliquely over the wrist, lying deeper and medial to the EPB and APL tendons. *FPL* - The **flexor pollicis longus (FPL)** is located in the anterior compartment of the forearm [2]. - Its tendon crosses the wrist joint **anteriorly** and does not contribute to the boundaries of the anatomical snuff box [2]. - It flexes the interphalangeal joint of the thumb [2]. *Abductor Pollicis Brevis (APB)* - The **abductor pollicis brevis (APB)** is a thenar muscle in the palm of the hand. - It abducts the thumb at the carpometacarpal joint but does not form any boundary of the anatomical snuff box.

Question 786: The clavipectoral fascia is penetrated by which artery?

A. Anterior circumflex humeral artery
B. Axillary artery
C. Subscapular artery
D. Thoracoacromial artery (Correct Answer)

Explanation: The clavipectoral fascia is penetrated by which artery? ***Thoracoacromial artery*** - The **thoracoacromial artery** is a branch of the **axillary artery (second part)** that pierces the **clavipectoral fascia** along with other structures like the **cephalic vein**, **lateral pectoral nerve**, and **lymphatics**. - It then divides into four terminal branches: **pectoral**, **deltoid**, **acromial**, and **clavicular**, which supply relevant muscles and joints. *Anterior circumflex humeral artery* - This artery typically arises from the **third part of the axillary artery** and wraps around the surgical neck of the humerus. - It does not penetrate the **clavipectoral fascia** as it runs posterior to the coracobrachialis and biceps brachii muscles. *Axillary artery* - The **axillary artery** itself gives rise to branches that penetrate the clavipectoral fascia, but the main trunk of the axillary artery is located superficial to it, traversing the axilla. - It does not penetrate the fascia but rather gives off branches that do. *Subscapular artery* - The **subscapular artery** is the largest branch of the **axillary artery (third part)** and gives rise to the **circumflex scapular** and **thoracodorsal arteries**. - It runs along the inferior border of the subscapularis muscle and does not penetrate the **clavipectoral fascia**.

Question 787: Which of the following structures passes deep to the flexor retinaculum at the wrist along with the tendon of flexor digitorum profundus?

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

Explanation: ***Median nerve*** - The **median nerve** passes through the **carpal tunnel**, deep to the **flexor retinaculum**, along with the tendons of the **flexor digitorum superficialis**, **flexor digitorum profundus**, and **flexor pollicis longus** [1]. - Compression of the **median nerve** in this confined space leads to **carpal tunnel syndrome**. *Ulnar nerve* - The **ulnar nerve** passes *superficial* to the **flexor retinaculum** within **Guyon's canal**, not deep to it [1]. - It accompanies the **ulnar artery** in this canal. *Radial nerve* - The **radial nerve** typically passes over the **anatomical snuffbox** or more proximally around the lateral epicondyle; it does not pass *deep* to the **flexor retinaculum** at the wrist. - Its superficial branch can be found on the dorsum of the hand. *Ulnar artery* - The **ulnar artery** passes *superficial* to the **flexor retinaculum**, alongside the **ulnar nerve**, within **Guyon's canal** [1]. - It contributes to the blood supply of the hand, forming the superficial palmar arch.

Question 788: Which statement considering the relations of nerves to the humerus is the most accurate?

A. Deltoid may atrophy following shoulder dislocation. (Correct Answer)
B. The median nerve runs in the spiral groove.
C. The axillary nerve runs around the anatomical neck.
D. Mid-shaft humeral fractures will usually result in complete paralysis of triceps.

Explanation: **Deltoid may atrophy following shoulder dislocation.** - **Shoulder dislocations**, particularly anterior dislocations, frequently injure the **axillary nerve** due to its close proximity to the humeral head and surgical neck. - Damage to the axillary nerve, which innervates the **deltoid muscle**, can lead to deltoid paralysis and subsequent **atrophy**, resulting in a flattened shoulder contour and impaired abduction. *The median nerve runs in the spiral groove.* - The **radial nerve**, not the median nerve, runs in the **spiral groove** (radial groove) of the humerus [1]. - The median nerve travels more anteriorly in the arm, alongside the brachial artery. *The axillary nerve runs around the anatomical neck.* - The **axillary nerve** wraps around the **surgical neck** of the humerus, not the anatomical neck. - The surgical neck is a common site for fractures, making the axillary nerve vulnerable to injury in such cases. *Mid-shaft humeral fractures will usually result in complete paralysis of triceps.* - Mid-shaft humeral fractures primarily risk damage to the **radial nerve**, which innervates the lateral and medial heads of the triceps [1]. - However, the **long head of the triceps** is innervated by the radial nerve more proximally and may remain partially functional, preventing complete paralysis of the entire triceps muscle.

Question 789: Which of the following is not a content of the cubital fossa?

A. Bicipital aponeurosis (Correct Answer)
B. Brachial artery
C. Biceps brachii tendon
D. Median nerve

Explanation: ***Bicipital aponeurosis*** - The **bicipital aponeurosis** is part of the **roof** of the cubital fossa, not a content within the fossa itself. - It arises from the biceps brachii tendon and fans out medially to blend with the deep fascia of the forearm, protecting the underlying neurovascular structures (brachial artery and median nerve). - As a roof structure, it is distinct from the actual contents of the fossa. *Brachial artery* - The **brachial artery** is a key content of the cubital fossa, lying medial to the biceps tendon. - It bifurcates within the cubital fossa into the radial and ulnar arteries at the level of the radial neck. *Biceps brachii tendon* - The **biceps brachii tendon** is a central content of the cubital fossa, being the most lateral structure. - It inserts on the radial tuberosity and is responsible for powerful supination and flexion of the forearm. *Median nerve* - The **median nerve** is a content of the cubital fossa, running medial to the brachial artery (most medial structure). - It continues into the forearm between the two heads of pronator teres, providing motor innervation to most forearm flexors.

Question 790: Which of the following is not a branch of the posterior cord of the brachial plexus?

A. Thoracodorsal nerve
B. Axillary nerve
C. Long thoracic nerve (Correct Answer)
D. Radial nerve

Explanation: ### Long thoracic nerve - The **long thoracic nerve** originates directly from the **nerve roots C5, C6, C7** of the brachial plexus, **NOT from the posterior cord**. - It innervates the **serratus anterior muscle**, crucial for scapular protraction and upward rotation. - Damage causes **winged scapula** deformity. ### Axillary nerve - The **axillary nerve** is a **terminal branch of the posterior cord**, formed from C5-C6. - It supplies the **deltoid** and **teres minor muscles**, and provides sensory innervation to the lateral shoulder (regimental badge area). - Commonly injured in anterior shoulder dislocations or humeral surgical neck fractures. ### Thoracodorsal nerve - The **thoracodorsal nerve** (nerve to latissimus dorsi) is a **branch of the posterior cord**, deriving from C6-C8 [1]. - It exclusively innervates the **latissimus dorsi muscle**, responsible for shoulder adduction, extension, and internal rotation [1]. - Important in breast reconstruction surgery (latissimus dorsi flap). ### Radial nerve - The **radial nerve** is the **largest terminal branch of the posterior cord**, formed from C5-T1. - It innervates the **triceps brachii** and all extensor muscles of the forearm (wrist and finger extensors). - Provides sensory innervation to the posterior arm, forearm, and anatomical snuffbox. - Most commonly injured nerve of the upper limb (spiral groove fractures).

Practice by Chapter

Pectoral Region and Axilla

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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

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Muscles and Their Actions

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Applied Anatomy and Clinical Correlations

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Surface Anatomy and Landmarks

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Upper Limb — MCQs

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