Upper Limb Practice Questions

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.

Q: A diabetic worker sustains a stab injury to the central region of his palm. After 3 days, he develops swelling, severe pain, and inability to extend his middle and ring fingers. Pus accumulation is suspected in one of the palmar spaces. Which of the following spaces is most likely involved?

B (Midpalmar space). ***B (Midpalmar space)*** - A stab wound to the central palm directly accesses the **midpalmar space**, which lies deep to the palmar aponeurosis and contains the flexor tendons for the middle, ring, and little fingers. - Infection and pus accumulation in this space lead to **flexor tenosynovitis**, causing severe pain, swelling, and inability to extend the middle and ring fingers, as their tendon sheaths are directly involved. *A (Hypothenar space)* - The **hypothenar space** is located on the ulnar side of the palm and is associated with the intrinsic muscles of the little finger. - An infection in this area would primarily cause swelling and tenderness over the hypothenar eminence and affect the **little finger**, not the middle and ring fingers. *C (Thenar space)* - The **thenar space** is on the radial side of the palm, containing the intrinsic muscles of the thumb and often the flexor tendon sheath of the index finger. - Infection here would cause significant swelling at the base of the thumb (thenar eminence) and primarily affect the function of the **thumb and index finger**. *D (Dorsal subaponeurotic space)* - This space is on the **dorsum (back) of the hand**, whereas the injury occurred on the palm. - While deep palmar space infections can cause significant dorsal swelling due to loose tissue, the primary site of pus collection from a palmar wound is a **palmar space**, not a dorsal one.

Q: Identify the nerve roots involved in the condition depicted in the image.

C5 and C6. ***C5 and C6*** - The image displays a "waiter's tip" or "porter's tip" posture, which is the classic presentation of **Erb's palsy** (or Erb-Duchenne palsy). - This condition results from an injury to the **upper trunk** of the brachial plexus, which is formed by the union of the **C5 and C6** nerve roots, leading to paralysis of shoulder abductors/external rotators and elbow flexors. *C6 and C7* - An injury involving the C7 nerve root, which forms the **middle trunk**, primarily results in weakness of the wrist and finger extensors, a condition known as **wrist drop**. - While C6 is involved in Erb's palsy, the classic "waiter's tip" deformity is not seen with a C7 lesion. *C7 and C8* - A lesion affecting C7 and C8 would involve the middle and part of the lower trunk, leading to a combination of weak wrist extension and weak finger flexion. - This pattern of injury does not correspond to a recognized brachial plexus syndrome and would not produce the specific posture shown. *C8 and T1* - Injury to the C8 and T1 nerve roots affects the **lower trunk** of the brachial plexus, causing **Klumpke's palsy**. - This condition presents with paralysis of the intrinsic muscles of the hand, leading to a **"claw hand"** deformity, which is distinct from the posture seen in the image.

Q: A man fell on his shoulder with his head pushed in the opposite direction. He presented with the following deformity. Which nerve root values are most likely affected?

C5 and C6. ***C5 and C6*** - The clinical presentation of an adducted, internally rotated arm with an extended elbow and pronated forearm is known as the "**waiter's tip**" or "**porter's tip**" position. This is the classic sign of an upper brachial plexus injury, specifically **Erb's Palsy**. - This type of injury typically occurs from trauma that increases the angle between the neck and shoulder, such as a fall or during childbirth, affecting the **C5 and C6** nerve roots. This leads to paralysis of shoulder abductors (deltoid), external rotators (infraspinatus), and elbow flexors (biceps brachii). *C6 and C7* - An injury involving the **C7** root would predominantly cause weakness in the extensors of the elbow, wrist, and fingers, a condition often referred to as "**wrist drop**". - While the C6 root is involved, the primary features of the "waiter's tip" deformity (loss of shoulder abduction and external rotation) are most characteristic of a C5-C6 lesion, not a C6-C7 lesion. *C7 and C8* - A lesion of the **C7 and C8** nerve roots would primarily affect the muscles responsible for finger extension and wrist flexion. - This pattern of weakness does not align with the observed posture, which is defined by deficits in shoulder and elbow movements controlled by C5 and C6. *C8 and T1* - Injury to the **C8 and T1** roots results in a lower brachial plexus injury, known as **Klumpke's Palsy**, which typically occurs from a hyperabduction injury of the arm. - This condition affects the intrinsic muscles of the hand, leading to a "**claw hand**" deformity, which is clinically distinct from the deformity shown in the image.

Question 1

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 2

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 3

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 4

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

Accepted Answer

Rhomboidus Major

Answer

Teres Major

Answer

Deltoid

Answer

Infraspinatus

Question 5

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 6

Which of the following muscles is not a hybrid muscle?

Accepted Answer

Extensor digitorum

Answer

Pectoralis major

Answer

Flexor digitorum profundus

Answer

Brachialis

Question 7

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

Question 8

A diabetic worker sustains a stab injury to the central region of his palm. After 3 days, he develops swelling, severe pain, and inability to extend his middle and ring fingers. Pus accumulation is suspected in one of the palmar spaces. Which of the following spaces is most likely involved?

Accepted Answer

B (Midpalmar space)

Answer

A (Hypothenar space)

Answer

D (Dorsal subaponeurotic space)

Answer

C (Thenar space)

Question 9

Identify the nerve roots involved in the condition depicted in the image.

Accepted Answer

C5 and C6

Answer

C6 and C7

Answer

C7 and C8

Answer

C8 and T1

Question 10

A man fell on his shoulder with his head pushed in the opposite direction. He presented with the following deformity. Which nerve root values are most likely affected?

Accepted Answer

C5 and C6

Answer

C7 and C8

Answer

C6 and C7

Answer

C8 and T1

Upper Limb — MCQs

Upper Limb — MCQs

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