Nerve |
Mechanism |
Clinical Findings |
Axillary Nerve (Circumflex) (C5/6) |
Shoulder dislocation, humeral neck fracture, or trauma to the shoulder region |
Loss of sensation over the outer border of the shoulder, reduced abduction from 30 to 90 degrees. Weakness in deltoid and teres minor muscles, affecting shoulder stability and abduction. |
Suprascapular Nerve (C5/6) |
Shoulder trauma, entrapment in the suprascapular notch, or repetitive overhead activities |
Weakness in supraspinatus and infraspinatus muscles, impaired initiation of abduction (first 30 degrees), and external rotation of the shoulder. |
Long Thoracic Nerve (C5-7) |
Heavy lifting, carrying heavy bags, trauma, radical mastectomy, or axillary surgery |
Burning pain and winging of the scapula due to serratus anterior muscle weakness. Difficulty with shoulder elevation and pushing against resistance. |
Radial Nerve (C5-T1) |
Humeral shaft fracture, compression in the axilla (e.g., "Saturday night palsy"), or improper use of crutches |
Wrist drop (inability to extend wrist and fingers), loss of sensation over the dorsal hand and posterior arm, weakened grip strength. |
Median Nerve (C5-T1) |
Carpal tunnel syndrome, wrist laceration, or supracondylar fracture of the humerus |
Weakness in thumb opposition and flexion, "ape hand" deformity, loss of sensation in the lateral 3.5 fingers, and hand clumsiness. Inability to make an "OK" sign with thumb and index finger. |
Ulnar Nerve (C8-T1) |
Elbow trauma (cubital tunnel syndrome), fracture of the medial epicondyle, or compression at Guyon's canal |
Claw hand deformity, weakness in finger abduction and adduction, loss of sensation over the medial 1.5 fingers. Difficulty with fine motor tasks. |
Femoral Nerve (L2-L4) |
Pelvic fracture, prolonged lithotomy position, or hip surgery |
Weakness in hip flexion and knee extension, loss of patellar reflex, and decreased sensation over the anterior thigh and medial leg. |
Sciatic Nerve (L4-S3) |
Hip dislocation, pelvic trauma, or prolonged compression |
Weakness in knee flexion and all movements below the knee. Loss of sensation over the posterior thigh, leg, and foot. Foot drop if common peroneal nerve is affected. |
Common Peroneal (Fibular) Nerve (L4-S2) |
Fracture of the fibular head, leg crossing, or prolonged squatting |
Foot drop (inability to dorsiflex the foot), loss of sensation over the dorsum of the foot and lateral shin, difficulty with ankle eversion and dorsiflexion. |
Tibial Nerve (L4-S3) |
Knee trauma, compression at the tarsal tunnel, or ankle injury |
Weakness in plantarflexion, inversion, and toe flexion. Loss of sensation over the sole of the foot. Difficulty with walking and foot stability. |
Obturator Nerve (L2-L4) |
Pelvic trauma or surgery |
Weakness in thigh adduction, sensory loss over the medial thigh. Difficulty crossing legs. |