Knowledge of the segmental cutaneous innervation of the skin of the lower extremity is important in determining the level of intervertebral disc disease. Thus, S1 nerve root irritation will result in pain located along the -
S1 nerve root impairment results in

Weak plantar flexion
Weak eversion of the foot
Depressed ankle jerk
Sensory loss along lateral border of foot
Anterior aspect of the thigh
Medial aspect of the thigh
Anteromedial aspect of the leg
Lateral side of the foot