Upper Limb Nerves, Brachial Plexus and Lesions MCQs

Anatomy · 81 free questions with answers & explanations.

1. A 25-year-old motorcyclist sustains a severe traction injury to the upper trunk of the brachial plexus (C5-C6). Which posture of the limb results?
2. Following a humeral shaft fracture, a patient cannot extend the wrist and fingers and has loss of sensation over the dorsum of the first web space. Which nerve is injured?
3. A patient with a median nerve lesion at the wrist has which classic hand deformity?
4. A fracture of the medial epicondyle of the humerus injures a nerve at the cubital tunnel. Which muscle is tested to confirm this injury?
5. Which root values of the brachial plexus are responsible for the biceps jerk reflex?
6. A 28-year-old motorcyclist is thrown from his bike, landing on the left side with violent lateral flexion of the head away from the shoulder. He presents with inability to abduct the arm, inability to flex the elbow, and the affected arm hangs limp in adduction and internal rotation ('porter's tip' posture). The lesion localises to:
7. A patient undergoes left axillary lymph node dissection for breast carcinoma and subsequently develops winging of the left scapula that is WORSENED by pushing against a wall. The injured nerve and its origin are:
8. A patient sustains a radial nerve injury in the radial groove of the humerus. Which movement is PRESERVED despite this high radial nerve lesion?
9. A 40-year-old lorry driver develops paraesthesia over the lateral three and a half fingers of the right hand that worsens at night. He also notices weakness and wasting of the thenar eminence. Surface anatomy for carpal tunnel release would place the skin incision along which landmark?
10. A patient sustains a mid-shaft humeral fracture and develops wrist drop. On examination, brachioradialis reflex is absent but the triceps reflex is intact. At which specific level of the radial nerve is the injury most likely?
11. In anterior interosseous nerve (AIN) syndrome, the patient is unable to make the 'OK sign'. Which specific muscles are paralysed?
12. A motorcyclist is involved in a high-speed collision and is found to have avulsion of C8 and T1 nerve roots. Which unique physical sign would indicate a root avulsion rather than a more distal traction lesion?
13. A patient with ulnar nerve injury at the wrist (Guyon's canal) will show which finding NOT seen with ulnar nerve injury at the elbow?
14. The lateral cord of the brachial plexus receives contributions from which spinal roots?
15. A construction worker sustains an injury with hyperabduction of the arm over a prolonged period. He presents with weak shoulder abduction and elbow flexion but preserved forearm and hand movements. Sensory loss is over the lateral forearm. Which nerve roots and trunk are injured?
16. In anterior shoulder dislocation, which nerve is most commonly injured due to its close relationship to the surgical neck of the humerus and its passage through the quadrangular space?
17. The anterior interosseous nerve is a branch of the median nerve arising just below the elbow. Isolated anterior interosseous nerve palsy produces which characteristic clinical finding?
18. In cubital tunnel syndrome (ulnar nerve entrapment at the elbow), which muscle is typically spared even in advanced cases, helping to localise the lesion?
19. The long thoracic nerve (nerve of Bell) arises from C5, C6, C7 roots and innervates serratus anterior. Injury to this nerve during radical mastectomy or thoracotomy produces:
20. A cricketer sustains a direct blow to the lateral aspect of the elbow. He develops weakness of wrist and finger extension and forearm supination with preserved triceps power and intact sensation over the dorsum of the hand. Which nerve and at which level?
21. A patient with a lesion of the medial cord of the brachial plexus would show which specific combination of deficits?
22. The flexor retinaculum (transverse carpal ligament) is attached medially to the pisiform and hamate hook and laterally to which structures?
23. A newborn is noted to have the arm adducted and internally rotated at shoulder, forearm pronated, and wrist flexed. Which nerve roots are injured and what is this called?
24. Anatomically, which muscle acts as a landmark separating the axillary artery into its three parts, and what are the two cords that give rise to the median nerve?
25. A 25-year-old motorcyclist is involved in a high-speed accident with forced depression of the right shoulder. He presents with inability to abduct the shoulder, flex the elbow, and supinate the forearm. Sensory loss is noted over the lateral arm and forearm. Which roots are most likely injured?
26. A patient with a deep laceration at the wrist cannot perform the 'O.K.' sign (opposition of thumb tip to index fingertip forming a circle). Which nerve is damaged and at which level?
27. A patient with a fracture of the medial epicondyle of the humerus is found to have weakness of finger abduction and adduction, hypothenar atrophy, and loss of sensation over the medial 1.5 fingers. Which of the following tests best demonstrates the ulnar claw hand deformity?
28. A 35-year-old woman develops winging of the scapula after a radical mastectomy. Which nerve is injured and what is the motor deficit?
29. Thoracic outlet syndrome compressing the lower trunk of the brachial plexus (C8, T1) typically produces which pattern of weakness and sensory loss?
30. A 28-year-old motorcyclist sustains a complete avulsion injury of C8 and T1 nerve roots. In addition to claw hand deformity, which other specific finding would indicate preganglionic (root avulsion) injury rather than postganglionic traction injury?
31. A patient is unable to oppose the thumb after a deep laceration of the palm. Testing reveals intact flexor pollicis brevis and adductor pollicis. Which specific muscle and its nerve supply are most likely damaged?
32. Anterior interosseous nerve (AIN) syndrome specifically involves which combination of muscles?
33. During a Kocher's approach to the elbow for lateral condyle fracture repair in a child, the surgeon inadvertently injures the posterior interosseous nerve (PIN). Which movements would be specifically lost?
34. A 24-year-old patient presents with weakness of all intrinsic hand muscles (both thenar and hypothenar), loss of sensation over the entire hand and medial forearm, and no Horner's syndrome. This pattern of deficit is most consistent with which level of injury?
35. A motorcyclist suffers a forceful lateral flexion injury of the neck to the right. Examination shows loss of shoulder abduction, elbow flexion, and lateral forearm sensation on the right. The paralysed muscles are in a position of medial rotation and adduction — the 'waiter's tip' posture. Which roots are involved?
36. A patient cannot extend the wrist and fingers (wrist drop) after a fracture of the mid-shaft of the humerus. Testing reveals preserved extension of MCP joints of index and middle fingers via the ulnar nerve, but loss of sensation on the dorsum of the hand in the distribution of the first dorsal web space. Which nerve is injured and at what level?
37. A patient has a lesion of the median nerve at the wrist (carpal tunnel). Which specific intrinsic hand function is MOST likely to be preserved?
38. A patient with a deep laceration at the medial epicondyle level presents with clawing of ring and little fingers, weakness of finger abduction and adduction, and loss of sensation on the medial 1.5 fingers. Flexion of the DIP joint of the little finger is also lost. What is the level of ulnar nerve injury?
39. During shoulder arthroplasty, the surgeon identifies a nerve running along the posterior aspect of the surgical neck of humerus. Injury to this nerve would result in which combination of deficits?
40. During an axillary node dissection for breast cancer, the long thoracic nerve is inadvertently sectioned. Which specific functional deficit would the surgeon MOST likely observe postoperatively?
41. A motorcyclist falls and sustains a severe traction injury to the upper trunk (C5-C6) of the brachial plexus — an Erb's palsy. Which nerve's autonomous zone will demonstrate reduced pinprick sensation?
42. A patient presents with inability to extend the wrist and fingers, with the hand hanging down ('wrist drop'). Sensory testing reveals loss only on the dorsum of the hand between the 1st and 2nd metacarpals. Where is the radial nerve most likely injured?
43. A 40-year-old woman presents with carpal tunnel syndrome. Which specific nerve compression causes thenar muscle wasting and loss of sensation over the thumb, index, middle finger, and radial half of the ring finger?
44. A patient with a supracondylar fracture of the humerus in childhood develops a delayed onset 'claw hand' affecting all four fingers, with wasting of all intrinsic hand muscles. What is the most likely explanation?
45. A 28-year-old carpenter develops progressive weakness of thumb opposition and thenar wasting. Nerve conduction studies show prolonged distal motor latency with preserved palmar cutaneous sensation. The compression most likely involves which specific anatomical location?
46. Following a penetrating shoulder injury, a patient cannot abduct the arm beyond 15 degrees, has loss of sensation over the lateral arm (regimental badge area), and wasting of the deltoid. The posterior cord of the brachial plexus is disrupted. Which nerve is injured and at what spinal levels does it originate?
47. In a Klumpke's palsy (C8, T1 avulsion), which specific deformity is seen and why?
48. Anterior interosseous nerve (AIN) palsy selectively paralyses which muscles and produces what characteristic clinical sign?
49. The long thoracic nerve (nerve of Bell) is vulnerable during axillary lymph node dissection in breast cancer surgery. Which muscle does it supply, and what deformity results from its injury?
50. A patient after shoulder dislocation presents with inability to initiate abduction of the arm and loss of sensation over the 'regimental badge' area. Which nerve is damaged and at what anatomical site?
51. In thoracic outlet syndrome (TOS) causing neurogenic compression of the lower trunk of the brachial plexus (C8–T1), which of the following findings is MOST characteristic?
52. The posterior interosseous nerve (deep branch of the radial nerve) can be compressed at the arcade of Frohse. Which movement is specifically lost while wrist extension is preserved?
53. A patient with a posterior cord brachial plexus injury has wrist drop and weakness of shoulder abduction. However, elbow flexion is intact. Which muscles are selectively weakened?
54. Long thoracic nerve (nerve of Bell) palsy causes winging of the scapula because it denervates the serratus anterior. In which direction does the inferior angle of the scapula deviate when winging is present?
55. In carpal tunnel syndrome, the median nerve at the wrist is compressed under the flexor retinaculum. The motor branch to thenar muscles (recurrent thenar branch) typically arises:
56. A 30-year-old motorcyclist suffers a forced depression of the right shoulder with lateral neck deviation, resulting in weakness of shoulder abduction, elbow flexion, and external rotation of the arm. Sensation is lost over the lateral arm. Which roots are most likely injured?
57. Injury to the posterior interosseous nerve (deep branch of radial nerve) at the radial neck causes which specific pattern?
58. A patient has weakness of the intrinsic hand muscles on both the ulnar and median nerve distributions, with sparing of the thenar muscles. The injury is most likely at which level?
59. The long thoracic nerve (nerve to serratus anterior) arises from which roots of the brachial plexus?
60. Radial nerve entrapment at the radial tunnel (radial tunnel syndrome / posterior interosseous nerve syndrome) causes weakness of which specific muscles without sensory loss?
61. A patient has complete paralysis and wasting of the intrinsic hand muscles (both thenar and hypothenar), loss of sensation over the entire palm and all fingers (including the dorsum of the medial three and a half fingers), but preserved wrist and finger flexor power. Which nerve is injured and where?
62. The posterior interosseous nerve (deep branch of radial nerve) enters the posterior compartment of the forearm by passing through the radial tunnel. It does NOT supply which of the following muscles?
63. A newborn has the right arm held in adduction, medial rotation, and pronation with loss of flexion at the elbow and absence of the Moro reflex on the right side. Grip reflex is present. This is Erb-Duchenne palsy. The avulsed roots are:
64. A patient with a penetrating wound to the axilla has the following findings: inability to abduct the arm past 90° (deltoid and supraspinatus paralysed), loss of arm external rotation, loss of forearm flexion (biceps), and lateral forearm sensory loss. Which component of the brachial plexus is injured?
65. The anterior interosseous nerve (AIN) is a branch of the median nerve that supplies no cutaneous area but innervates specific muscles. Which motor deficit best identifies an isolated AIN palsy?
66. In a high radial nerve palsy at the level of the spiral groove of the humerus, which function is typically preserved compared to a radial nerve injury at the axillary level?
67. A patient cannot extend the wrist or fingers but has intact brachioradialis and normal elbow flexion. Sensation is lost over the dorsum of the hand in the first web space. The radial nerve injury is most likely located at:
68. In a high median nerve lesion at the elbow (anterior interosseous nerve involvement), which specific grip is lost and which test assesses this?
69. Compression of the lower trunk of the brachial plexus (C8–T1) by a cervical rib produces the characteristic neurological and vascular features of thoracic outlet syndrome. Which muscles show wasting in neurogenic TOS?
70. A 28-year-old man sustains a fracture of the medial epicondyle of the humerus. Which of the following functional deficits would be expected?
71. The long thoracic nerve (nerve of Bell) is formed from which roots?
72. Injury to which part of the brachial plexus is responsible for Klumpke's palsy, and which root(s) are involved?
73. The anterior interosseous nerve is a branch of the median nerve that can be selectively injured. Which specific muscles does it innervate?
74. A patient has a lesion of the posterior cord of the brachial plexus. Which combination of deficits is expected?
75. In Saturday night palsy (radial nerve compression in the spiral groove of humerus), which muscle action is PRESERVED?
76. The 'Froment's sign' is positive in ulnar nerve palsy. It tests for weakness of which specific muscle and which action?
77. A 35-year-old carpenter sustains a mid-shaft fracture of the humerus after a fall. On examination, he is unable to extend his wrist and fingers, and the dorsum of the hand has diminished sensation. Which nerve is most likely injured?
78. During surgical repair of a supracondylar fracture in a 7-year-old child, the anterior interosseous nerve is inadvertently damaged. Which functional deficit would be expected?
79. A woman presents with weakness of adduction of all fingers and wasting of the interossei following a fracture of the hook of hamate. Which nerve territory is compromised?
80. The long head of the biceps brachii is an important stabilizer of the glenohumeral joint. Where does its tendon of origin attach?
81. A patient undergoing axillary lymph node dissection for breast cancer develops a winged scapula postoperatively. Which nerve was most likely injured during the procedure?