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NERVES OF THE UPPER EXTREMITIES

Axillary Nerve

Radial Nerve

Musculocutaneous

Median Nerve

Ulnar Nerve

BRACHIAL PLEXUSES

Networks of nerves that supply the upper limb

Formed by spinal nerves C5-T1

Innervates the pectoral girdle and entire upper limb of one side

Right and Left sides

UPPER EXTREMITY: AXILLARY NERVE

Traverses through the axilla and posterior to the surgical neck of the humerous.

Emerges from the posterior cord of the brachial plexus.

Innervates both the deltoid and teres minor muscles.

Receives sensory information from the superolateral part of the arm.

UPPER EXTREMITY: MEDIAN NERVE

Formed from medial and lateral cords of the brachial plexus.

Travels along the midline of the arm and forearm

Deep to the carpal tunnel of the wrist.

Innervates most of the anterior forearm muscles, the thenar muscles, and the lateral two lumbricals.

Receives sensory information from palmar side of lateral 3-1/2 fingers (thumb, index finger, middle finger and lateral one-half of ring finger) and from dorsal tips of these same fingers.

UPPER EXTREMITY: MUSCULOCUTANEOUS

Arises from the lateral cord of the brachial plexus.

Innervates the anterior arm muscles (coracobrachialis, biceps brachii, and brachialis).

Receives sensory information from the lateral surface of the forearm.

UPPER EXTREMITY: RADIAL NERVE

Arises from posterior cord of the brachial plexus.

Travels along the posterior side of the arm and then along the radial side of the forearm.

Innervates the posterior arm muscles (forearm extensors) and the posterior forearm muscles (extensors of the wrist and digits and supinator of forearm).

Receives sensory information from the posterior arm and forearm surface and dorsolateral side of hand.

UPPER EXTREMITY: ULNAR NERVE

Arises from the medial cord of the brachial plexus and descends along medial side of arm.

Wraps posterior to the medial epicondyle of the humerus and then runs along the ulnar side of the forearm.

Innervates some of the anterior forearm muscles (medial region of the flexor digitorum profundus and all of the flexor carpi ulnaris), most intrinsic hand muscles including hypothenar muscles, the palmar and dorsal interossei, and the medial two lumbricals.

Receives sensations from skin of the dorsal and palmar aspects of the medial 3-1/2 fingers (pinky, and medial half of ring finger).

NERVES OF THE LOWER EXTREMITIES

Femoral Nerve

Obturator Nerve

Sciatic Nerve

LUMBAR PLEXUSES

Formed from anterior rami of spinal nerves L1-L4 located lateral to the L1-L4 vertebrae and within the psoas major muscle in the posterior abdominal wall.

Structurally less complex than the brachial plexus.

Is subdivided into anterior division and posterior division.

LOWER EXTREMITY: FEMORAL NERVE

Innervates anterior thigh muscles (quadriceps femoris, sartorius and iliopsosas).

Receives sensory information from the anterior and inferomedial thigh as well as the medial aspect of the leg.

LOWER EXTREMITY: OBTURATOR NERVE

Travels through the obturator foramen to the medial thigh.

Innervates the medial thigh muscles (which adduct the thigh).

Receives sensory information from the superomedial skin of thigh.

SACRAL PLEXUSES

Formed from anterior rami of spinal nerves L4-L5.

Located immediately inferior to lumbar plexuses.

Lumbar and sacral plexuses are sometimes considered together as the lumbosacral plexus.

Nerves from Sacral Plexus innervate the gluteal region, pelvis, perineum, posterior thigh and almost all of the leg and foot.

LOWER EXTREMITY: SCIATIC NERVE

AKA the ischiadic nerve.

Largest and longest nerve in human body.

Extends into posterior region of thigh.

Actually composed of two nerves: common fibular nerve and tibial nerve.

Posterior to popliteal fossa, the sciatic nerve splits into two nerves.

LOWER EXTREMITY: TIBIAL NERVE

Formed from the anterior divisions of sciatic nerve.

Innervates the hamstrings (except for short head of biceps femoris) and the hamstring part of the adductor magnus, plantar flexors of the foot and toe flexors.

In the foot, the tibial nerve splits into the lateral and medial plantar nerves, which innervate the plantar muscles of the foot and conduct sensory impulses from the skin on sole of foot.

LOWER EXTREMITY: COMMON FIBULAR NERVE

Formed from the posterior division of the sciatic nerve.

Innervates short head of biceps femoris muscle.

Along the lateral knee, splits into two main branches: deep fibular nerve and superficial fibular nerve.

LOWER EXTREMITY: DEEP FIBULAR NERVE

Travels in the anterior compartment of the leg and terminates between the first and second toes.

Innervates the anterior leg muscles (which dorsiflex foot and extend toes) and muscles of the dorsum of the foot (extend toes).

Receives sensory innervation from the skin between first and second toes on the dorsum of the foot.

LOWER EXTREMITY: SUPERFICIAL FIBULAR NERVE

Travels in the lateral compartment of the leg.

Just proximal to ankle, this nerve becomes superficial along the anterior part of the ankle and dorsum of the foot.

Innervates the lateral compartment muscles of the leg (foot evertors and weak plantar flexors).

Receives sensory impulses from most of the dorsal surface of the foot.