Cutaneous Nerve Supply: Dermatomes and Peripheral Nerves for Face and Body

Skin sensation is mediated by dorsal root ganglia neurons projecting via spinal nerves (and cranial nerves for face).

Cranial Nerves (Face/Head)

• V1 (Ophthalmic): Forehead, scalp, cornea.
• V2 (Maxillary): Midface, upper lip, maxillary teeth.
• V3 (Mandibular): Lower face, jaw, mandibular teeth, tongue (anterior 2/3).
• VII (Facial): Small ear region (taste anterior tongue via chorda tympani).
• IX (Glossopharyngeal): Posterior tongue, pharynx, ear.
• X (Vagus): External auditory canal, pharynx, larynx.

Spinal Nerves (Dermatomes)

• C2–C4: Neck, shoulder cape, supraclavicular.
• C5–T1: Upper limb (brachial plexus) — C6 thumb, C7 middle finger, C8 pinky.
• T2–T12: Trunk (intercostal nerves) — T4 nipple, T10 umbilicus.
• L1–S5: Lower limb (lumbosacral plexus) — L4 medial leg, L5 dorsum foot, S1 lateral foot.

Key Concepts

• Dermatome: Skin area supplied by one spinal nerve root.
• Overlap: Adjacent dermatomes overlap; complete anesthesia requires 3 contiguous root blocks.
• Autonomic zones: Non-overlapping core areas for single-root testing.

Clinical Use

Sensory level localization (spinal cord injury), radiculopathy diagnosis, regional anesthesia planning, shingles (dermatomal herpes zoster).