The dermatomes of S4 and S5 are tested in the perineum.
Selected joint movements are used to test myotomes (Fig. 6.17). For example:
Flexion of the hip is controlled primarily by L1 and L2.
Extension of the knee is controlled mainly by L3 and L4.
Knee flexion is controlled mainly by L5 to S2.
Plantarflexion of the foot is controlled predominantly by S1 and S2.