Chapter 9: Upper Limb
A 54-year-old male is brought to the emergency department after a motor vehicle accident. Physical examination reveals some sensory loss from the upper limb and radiologic imaging confirms herniation of the C5-C6 intervertebral disc. Which nerve carries sensory fibers from the affected dermatome?
B. Lateral cutaneous nerve of forearm
D. Medial cutaneous nerve of forearm
Answer B. The intervertebral disc herniation affects the C6 spinal nerve and its dermatome. This dermatome is located along the lateral aspect of the forearm, which is supplied by the lateral cutaneous nerve of the forearm (the terminal branch of the musculocutaneous nerve).
A 54-year-old male is brought to the emergency department after a motor vehicle accident. Physical examination reveals some sensory loss from the upper limb and radiologic imaging confirms herniation of the C5-C6 intervertebral disc. Which actions would also be likely impaired by this injury?
A. Elbow flexion and thumb opposition
B. Shoulder abduction and wrist adduction
C. Shoulder abduction and elbow flexion
D. Shoulder abduction and shoulder elevation
Answer C. Motor fibers from the C6 spinal cord enter nerves that supply muscles that control shoulder abduction (deltoid and rotator cuff muscles) and elbow flexion (biceps brachii and brachialis).
A 44-year-old woman is diagnosed with breast cancer. Following mastectomy and dissection of axillary lymph nodes, the patient is unable to raise her arm over her head. Which nerve is most likely damaged?
B. Pectoral branch of thoraco-acromial
Answer A. The long thoracic nerve supplies the serratus anterior muscle, which is necessary for the upward rotation of the scapula when raising the abducted arm above the head.
Which clinical sign would not be associated with injury of the ulnar nerve due to fracture of the medial epicondyle?
A. Hypesthesia from proximal part of the medial half of the palm
B. Hypesthesia from the middle finger