Nerve Plexus and Major Nerves

Nerve Plexus:

During development, skeletal muscles commonly fuse, forming larger muscles innervated by nerve trunks containing axons derived from several spinal nerves. These compound nerve trunks originate at networks called nerve plexuses.

The cervical plexus innervates the muscles of the neck and extends into the thoracic cavity to control the diaphragm.

The brachial plexus innervates the shoulder girdle and upper limb.

The lumbosacral plexus supplies the pelvic girdle and lower limb. It can be further subdivided into a lumbar plexus and a sacral plexus.

Nerve plexus and major Nerves: (plexus; major nerve; distribution)

Cervical plexus – phrenic nerve – diaphragm
- C1-C8 – other branches – muscles of the neck and skin of upper chest, neck, and ears
Brachial plexus – axillary nerve – deltoid and teres minor muscles and skin of shoulder
- C5-T1:
  - Musculocutaneous nerve – flexor muscles of the arm and forearm – skin on lateral surface of forearm
  - Median nerve – flexor muscles of forearm and hand – skin over lateral surface of hand
  - Radial nerve – extensor muscles of the arm, forearm, and hand and skin on posterolateral surface of the arm
  - Ulnar nerve – flexor muscles of forearm and small digital muscles, as well as skin of medial surface of hand
Lumbosacral plexus – obturator nerve – adductors of hip and skin over medial surface of thigh
Lumbar plexus (T12-L4) – femoral nerve – adductors of hip, extensors of knee, and skin over medial surfaces of thigh and leg
Sacral plexus (L4-S4):
- Gluteal nerve – adductors and extensors of hip and skin over posterior surface of thigh
- Sciatic nerve – flexors of knee and ankle, flexors and extensors of toes, and skin over anterior and posterior surfaces of leg and foot
- Saphenous nerve - skin over medial surface of leg

This page was updated in December 2005.