Lab 9 Nervous System

Brachial Plexus

these nerves supply the neck muscles, shoulder muscles and entire upper extremities. (Be sure to check out the online text for examples of this plexus) Nerves arising from this plexus are the musculocutaneous (motor nerve) innervating anterior arm muscles, axillary bringing motor fibers to deltoid, median nerve bring motor fibers to flexor muscles of forearm and hand, ulnar nerve bringing fibers to flexor muscles of forearm and hand and radial nerve bringing motor fibers to posterior aspect of arm, forearm and hand.

Sacral plexus

largest nerve arising from this plexus is the sciatic nerve formed from the tibial nerve and the common fibular nerve. All the skeletal muscles in the thigh, leg and foot are innervated by these nerves. The gluteus medius and gluteus maximus are innervated by the superior and inferior gluteal nerves arising from the sacral plexus

Intercostal nerves

not a plexus, nerves arising from anterior rami of 2nd through 12th thoracic spinal nerve innervate the are between the ribs (intercostal area).

Lumbar plexus

one of the nerves leaving this plexus is the femoral nerve bringing nerve fibers to the quadraceps femoris and iliopsoas muscles.

Cervical Plexus

phrenic nerve arises from this plexus and innervates the diaphragm. The phrenic nerve arises from the 3rd, 4th and 5th cervical spinal nerves. If the spinal cord is severed above the third cervical vertebra, death results because signals from the brain can no longer reach the diaphragm and breathing ceases.