Dermatomes
Dermatomes
UPPER EXTREMITY
- C7 covers the middle finger,
- C8 the medial hand.
- C6 the lateral hand and lateral forearm.
- C5 covers the upper lateral arm.
- T1 covers the medial forearm.
- T2 covers the medial upper arm.
ANTERIOR TRUNK & PELVIS
- T4 covers the nipple line.
- T10 covers the umbilicus.
- T12 covers the suprapubic area.
- L1 covers the inguinal region.
- S2 covers the proximal external genitalia.
- S3 covers the distal external genitalia.
LOWER EXTREMITY
- L2 begins its descent from the superolateral anterior lower extremity.
- L3 and L4 cross the knee.
- L5 covers the great toe.
- S1 covers the ankle and little toe.
- The coccyx covers the center of the anus and the following dermatomes form rings that surround it:
- the innermost is S5,
- then going outward is S4,
- then S3,
- and then S2 encircles S3 but also extends down the posteromedial lower limb.
- S1 extends down the posterolateral lower limb and covers the Achilles.
HEAD & NECK
- The posterior ramus of C2 covers the back of the head and is known as the greater occipital nerve.
- C3 and C4 cover the posterior neck.
POSTERIOR TRUNK
- T2-L5 cover the upper back to the buttocks.