Dermatomes and their surface landmarks

What it is

Each dermatome carries its own characteristic:

• C2: posterior half of the skull
• C3: high turtleneck shirt. Diaphragm and gallbladder pain is referred to the right shoulder via the phrenic nerve. C3, 4, 5 keeps the diaphragm alive
• C4: low-collar shirt
• C6: includes the thumbs. The thumbs up sign on the left hand looks like a 6
• T4: at the nipple. T4 at the teat pore
• T7: at the xiphoid process
• T10: at the umbilicus, and an important point of referred pain in early appendicitis
• L1: at the inguinal ligament
• L4: includes the kneecaps. Down on ALL 4's
• S2, S3, S4: sensation of the penile and anal zones. S2, 3, 4 keep the penis off the floor