Upper Limb Practice Questions

Q: Midpalmar space ends distally in which structure?

Into the web space. ***Into the web space*** - The **midpalmar space** extends distally to the level of the **web spaces** between the fingers (at the metacarpal heads) [1]. - It is bounded distally by **vertical fibrous septa** that connect the palmar aponeurosis to the deep transverse metacarpal ligament at the web spaces. - These septa prevent distal spread of infections beyond the web space level. - This anatomical boundary is clinically important in understanding the spread of **midpalmar space infections** [1]. *Distal palmar crease* - The **distal palmar crease** is a surface landmark that lies **more proximal** than the actual distal extent of the midpalmar space. - While it's a useful clinical landmark, it does not represent the true anatomical distal boundary of the midpalmar space. - The space extends beyond this crease to reach the web spaces. *Along the digital sheaths* - While infections in the midpalmar space can potentially support spread to involve the fingers, the space itself does not directly terminate "along" the digital sheaths. - The **digital flexor tendon sheaths** are distinct anatomical structures within the fingers. *Into the flexor tendon sheaths* - The midpalmar space surrounds the flexor tendons but is separated from the **flexor tendon sheaths** by synovial membranes. - While infections can spread between these spaces in severe cases, the midpalmar space does not anatomically "end" in the tendon sheaths.

Q: A person reaches for something on the kitchen shelf, falls on his arm laterally, after which he is unable to extend his wrist, unable to make a strong hand grip, and there is loss of sensation on the dorsum of the hand and fingers. Which of the following structures is involved?

Radial nerve injury. ***Radial nerve injury*** - The inability to **extend the wrist** (**wrist drop**) and loss of sensation on the **dorsum of the hand** and fingers are classic signs of **radial nerve injury**. - The radial nerve innervates the **extensor muscles** of the forearm and hand and provides sensory innervation to the dorsal aspect of the hand. - The mechanism of injury (lateral fall on arm) suggests injury to the radial nerve in the **spiral groove** of the humerus, which is the most common site for radial nerve compression injury. *Brachial plexus* - A brachial plexus injury typically presents with more widespread neurological deficits affecting multiple nerves and muscle groups, often involving the entire arm or specific parts depending on the plexus level affected. - While it could lead to radial nerve dysfunction, the specific constellation of symptoms points directly to the radial nerve rather than a broader plexus injury. *C7 radiculopathy* - **C7 radiculopathy** primarily affects the **triceps (extension of the elbow)**, wrist flexors, and some finger extensors, but the sensory loss pattern is typically along the C7 dermatome (middle finger) and may not include the entire dorsum of the hand. - The prominent **wrist drop** is more characteristic of radial nerve injury. *Posterior cord injury* - The **posterior cord** gives rise to the radial and axillary nerves. An injury here would affect both the **radial nerve** and the **axillary nerve**. - An **axillary nerve injury** manifests as **deltoid weakness** (inability to abduct the arm), which is not described in this patient's symptoms.

Q: What type of joints are the metacarpophalangeal joints?

Condylar. Condylar - The metacarpophalangeal (MCP) joints are classified as condylar (condyloid) joints. - The rounded metacarpal head (condyle) articulates with the shallow concave surface of the proximal phalanx base. - This allows movement in two planes: flexion/extension and abduction/adduction, plus some circumduction. - This is the standard anatomical classification used in major anatomy references. *Ellipsoid* - Ellipsoid is sometimes used interchangeably with condylar, but it is a less specific descriptive term. - The term emphasizes the oval shape of the articular surface. - While not incorrect, condylar is the preferred anatomical classification for MCP joints. *Saddle* - Saddle joints have articular surfaces that are concave in one direction and convex in the perpendicular direction (saddle-shaped). - The classic example is the carpometacarpal joint of the thumb (1st CMC joint) [1]. - This configuration allows greater range of motion including opposition [1]. *Hinge* - Hinge joints permit movement in only one plane (uniaxial): flexion and extension. - Examples include the interphalangeal (IP) joints of the fingers and the humeroulnar joint of the elbow. - MCP joints have additional movements beyond simple hinging.

Q: Which ligament transmits the weight of the upper limb to the axial skeleton?

Costoclavicular ligament. ***Costoclavicular ligament*** - The **costoclavicular ligament** is a strong, fibrous band connecting the first rib's superior surface and its costal cartilage to the inferior surface of the medial clavicle. - This ligament plays a crucial role in anchoring the **medial end of the clavicle** to the axial skeleton, thereby transmitting the weight of the upper limb. *Coracoacromial ligament* - This ligament connects the **coracoid process** to the **acromion** of the scapula, forming an arch over the glenohumeral joint. - Its primary function is to protect the underlying structures, such as the rotator cuff tendons, from trauma and to prevent superior displacement of the humeral head, not to transmit weight to the axial skeleton. *Coracoclavicular ligament* - The **coracoclavicular ligament** consists of two parts: the **conoid** and **trapezoid ligaments**, connecting the coracoid process of the scapula to the clavicle. - While it helps stabilize the clavicle and scapula, its main role is to suspend the scapula from the clavicle and transmit forces within the shoulder girdle, not directly to the axial skeleton. *Coracohumeral ligament* - This ligament extends from the **coracoid process** to the **greater and lesser tuberosities** of the humerus. - It strengthens the superior part of the **glenohumeral joint capsule** and helps support the weight of the upper limb when the arm is adducted, but it does not transmit weight directly to the axial skeleton.

Q: Which of the following muscles is innervated by both the musculocutaneous and radial nerve?

Brachialis. ***Brachialis*** - The **brachialis muscle** lies deep to the biceps and is the primary flexor of the elbow. - It receives dual innervation from the **musculocutaneous nerve** (primarily) and a small contribution from the **radial nerve** laterally. *Biceps brachii* - The **biceps brachii** is solely innervated by the **musculocutaneous nerve** (C5, C6). - Its main actions are **supination** of the forearm and **flexion of the elbow**. *Coracobrachialis* - The **coracobrachialis** is also exclusively innervated by the **musculocutaneous nerve** (C5, C6, C7). - Its primary function is to **flex** and **adduct** the arm at the shoulder joint. *Brachioradialis* - The **brachioradialis** muscle is innervated by the **radial nerve** (C5, C6, C7). - It functions as an elbow flexor, particularly during **rapid movements** and when the forearm is in a **neutral position**.

Q: A patient is found to have a melanoma originating in the skin of the left forearm. After removal of the tumor from the forearm, all axillary lymph nodes lateral to the medial edge of the pectoralis minor muscle are removed. Which axillary nodes would not be removed?

Apical lymph nodes. ***Apical lymph nodes*** - The **apical lymph nodes** are located **medial** to the **medial border of the pectoralis minor muscle**, at the apex of the axilla (Level III) [2]. - Since the removal was restricted to nodes **lateral** to the medial edge of the pectoralis minor, the apical nodes would **not be removed**. - These nodes receive lymph from all other axillary node groups and drain into the subclavian lymphatic trunk. *Central lymph nodes* - **Central lymph nodes** are located **posterior to (deep to)** the pectoralis minor muscle, within the axillary fat (Level II) [1]. - They lie between the medial and lateral borders of the pectoralis minor and are generally considered to be **lateral** to the medial edge of the pectoralis minor, so they would be removed in this dissection. *Lateral lymph nodes* - **Lateral (humeral) lymph nodes** are found along the **lateral border** of the axilla, following the axillary vein (Level I) [1]. - These nodes drain the majority of the upper limb and are clearly **lateral** to the pectoralis minor muscle, so hese would be included in the dissection. *Pectoral lymph nodes* - **Pectoral (anterior) lymph nodes** lie along the **lower border** of the pectoralis minor muscle and the lateral thoracic vessels (Level I). - They receive lymph from the anterior and lateral thoracic walls and much of the breast. - These nodes are located **lateral** to the medial edge of the pectoralis minor and would be removed as part of the surgical procedure.

Q: Boundaries of the anatomical snuff box are all except

ECU. ***ECU*** - The **extensor carpi ulnaris (ECU)** is not a boundary of the anatomical snuff box. Its tendon inserts into the base of the 5th metacarpal, medial to the snuffbox [1][2]. - The ECU's function is **wrist extension** and **ulnar deviation**, and it does not form part of the snuffbox's borders [1]. *APL* - The **abductor pollicis longus (APL)** tendon forms the **anterior (radial) boundary** of the anatomical snuff box [1][2]. - It inserts into the base of the 1st metacarpal and is responsible for **abducting the thumb** [1]. *EPL* - The **extensor pollicis longus (EPL)** tendon forms the **posterior (ulnar) boundary** of the anatomical snuff box [1][2]. - It inserts into the distal phalanx of the thumb and is responsible for **extending the thumb interphalangeal joint**. *EPB* - The **extensor pollicis brevis (EPB)** tendon forms part of the **anterior (radial) boundary** along with the APL [1][2]. - It inserts into the proximal phalanx of the thumb and aids in **extending the thumb metacarpophalangeal joint** [1].

Q: Which spinal nerves are affected in Klumpke's paralysis?

C8-T1. ***C8-T1*** - **Klumpke's paralysis** results from damage to the lower trunks of the brachial plexus, specifically involving the **C8 and T1 spinal nerves**. - This injury often leads to a characteristic "claw hand" deformity due to paralysis of the **intrinsic hand muscles** and **flexors of the wrist and fingers**, along with potential **Horner's syndrome** if the T1 sympathetic fibers are affected. *C3-C6* - Involvement of these spinal nerves would typically affect the **upper and middle trunks of the brachial plexus**, leading to different patterns of paralysis, such as those seen in **Erb's palsy**. - This range does not specifically define Klumpke's paralysis, which is localized to the lower brachial plexus. *C6-C7* - Injury to these nerves primarily affects the **upper and middle trunks**, responsible for movements like shoulder abduction and elbow flexion. - This pattern of involvement is associated with different neurological deficits and is not characteristic of Klumpke's paralysis. *C4-C5* - Damage to these spinal nerves would primarily affect the **upper trunk of the brachial plexus**, leading to conditions like **Erb's palsy**. - This would result in paralysis of the shoulder and biceps muscles, distinct from the hand and wrist deficits seen in Klumpke's paralysis.

Q: The first primary ossification centre to appear of the carpal bones is

Capitate. The first primary ossification centre to appear of the carpal bones is ***Capitate*** - The **capitate** is the first carpal bone to show an ossification center, typically appearing around **1-3 months of age**. [1] - This early ossification is an important marker in assessing **bone age** in children. *Scaphoid* - The **scaphoid** ossifies later than the capitate, usually between **4 and 6 years of age**. - Its ossification center is often **bi-lobed** and can be confused with a fracture on X-ray if not recognized. *Triquetral* - The **triquetral** ossification center generally appears between **2 and 4 years of age**. - This makes it a mid-range ossifier among the carpal bones, not the first. *Pisiform* - The **pisiform** is typically the last carpal bone to ossify, with its center appearing between **8 and 12 years of age**. - Its delayed ossification makes it a useful indicator for assessing **skeletal maturity** in older children and adolescents.

Q: What structure passes through the rotator interval?

Long head of Biceps tendon. ***Long head of Biceps tendon*** - The **rotator interval** is a triangular space in the shoulder capsule bounded superiorly by the anterior edge of the **supraspinatus tendon**, inferiorly by the superior edge of the **subscapularis tendon**, and laterally by the **coracoid process** base. - The **long head of the biceps tendon** passes through this interval, enclosed within its synovial sheath, as it courses from the supraglenoid tubercle to enter the intertubercular groove. *Long head of Triceps tendon* - The **long head of the triceps tendon** originates from the infraglenoid tubercle of the scapula and is located at the posterior aspect of the humerus, not passing through the rotator interval. - Its primary function is **elbow extension**, distinct from shoulder joint components related to the rotator interval. *Coracohumeral ligament* - The **coracohumeral ligament** forms the superior border and roof of the rotator interval but does not pass through it. - It plays a role in restricting **external rotation** and **inferior subluxation** of the humeral head. *Short head of Biceps tendon* - The **short head of the biceps tendon** originates from the coracoid process and courses medially to the shoulder joint, not entering the articular capsule or passing through the rotator interval. - It is located entirely **outside** the joint capsule.

Question 1

Midpalmar space ends distally in which structure?

Accepted Answer

Into the web space

Answer

Along the digital sheaths

Answer

Into the flexor tendon sheaths

Answer

Distal palmar crease

Question 2

A person reaches for something on the kitchen shelf, falls on his arm laterally, after which he is unable to extend his wrist, unable to make a strong hand grip, and there is loss of sensation on the dorsum of the hand and fingers. Which of the following structures is involved?

Accepted Answer

Radial nerve injury

Answer

Brachial plexus

Answer

C7 radiculopathy

Answer

Posterior cord injury

Question 3

What type of joints are the metacarpophalangeal joints?

Accepted Answer

Condylar

Answer

Ellipsoid

Answer

Saddle

Answer

Hinge

Question 4

Which ligament transmits the weight of the upper limb to the axial skeleton?

Accepted Answer

Costoclavicular ligament

Answer

Coracoclavicular ligament

Answer

Coracohumeral ligament

Answer

Coracoacromial ligament

Question 5

Which of the following muscles is innervated by both the musculocutaneous and radial nerve?

Accepted Answer

Brachialis

Answer

Coracobrachialis

Answer

Brachioradialis

Answer

Biceps brachii

Question 6

A patient is found to have a melanoma originating in the skin of the left forearm. After removal of the tumor from the forearm, all axillary lymph nodes lateral to the medial edge of the pectoralis minor muscle are removed. Which axillary nodes would not be removed?

Accepted Answer

Apical lymph nodes

Answer

Central lymph nodes

Answer

Lateral lymph nodes

Answer

Pectoral lymph nodes

Question 7

Boundaries of the anatomical snuff box are all except

Accepted Answer

ECU

Answer

APL

Answer

EPL

Answer

EPB

Question 8

Which spinal nerves are affected in Klumpke's paralysis?

Accepted Answer

C8-T1

Answer

C3-C6

Answer

C6-C7

Answer

C4-C5

Question 9

The first primary ossification centre to appear of the carpal bones is

Accepted Answer

Capitate

Answer

Pisiform

Answer

Triquetral

Answer

Scaphoid

Question 10

What structure passes through the rotator interval?

Accepted Answer

Long head of Biceps tendon

Answer

Coracohumeral ligament

Answer

Long head of Triceps tendon

Answer

Short head of Biceps tendon

Upper Limb — MCQs

Upper Limb — MCQs

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