- Peripheral Nervous System—Sensory Maps 73
Cutaneous Nerves — Trunk (Advanced)
■ Th e posterior ramus derives the posterior cutaneous
branch.
■ Th e anterior ramus derives the intercostal nerve,
which provides the lateral cutaneous branch and the
anterior cutaneous branch.
■ Th e thoracic anterior and lateral cutaneous branches
cover the midline thorax and abdomen and the
lateral thorax and abdomen, respectively.
■ Th e iliohypogastric, ilioinguinal, genitofemoral,
and pudendal nerves cover the abdomino-pelvic
region.
■ Th e posterior cutaneous rami cover the posterior
trunk, posterior neck, and posterior head.
■ Th e greater occipital nerve, specifi cally, covers
the back of the head.Referred Pain
■ Innervation of the diaphragm comes from C3, C4,
and C5, which cover the neck, shoulders, and upper
lateral arm.
■ Use the mnemonic: C3, C4, C5 keeps the diaphragm
alive!
■ Innervation of the heart comes from T1–T5, which
cover the chest and medial upper arm and forearm.
■ Innervation of the appendix comes from T10, which
covers the umbilicus.FIGURE 5-1 Dermatomal maps based on O. Foerster’s work (1933).Used with permission from Haymaker, Webb, and Barnes Woodhall. Peripheral
Nerve Injuries, Principles of Diagnosis. 2nd ed. Philadelphia: Saunders, 1953.