Lower Extremity Dermatomes and Myotomes

Reflexes: 

 • Knee - L2, L3, L4

 • Ankle - S1

 • Biceps - C5, C6

 • Triceps - C6, C7, C8

 • Supinator - C5, C6

Important Conditions:

 • Cauda Equina Syndrome - Low back pain, sciatica, saddle (perineal) anesthesia, genitourinary dysfunction, and bilateral leg paresis. Medical Emergency

 • Peroneal Neuropathy - Foot drop and sensory disturbance over dorsum of foot and lateral calf. Inversion reserved. Commonly caused by damage to peroneal nerve at fibular neck such as fibular fracture or prolonged compression

 • Spinal Stenosis - Narrowing of spinal canal and neural foramina. Results in dysaesthesia, neurogenic claudication and weakness. Claudication classically is relieved by sitting rather than stopping walking (vascular claudication)



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