Nerve Plexuses/Spinal Nerves

Cervical plexus

- plexus formed by ventral rami of C1-C5 - innervates skin and muscles of the head, neck, and superior part of the shoulders and chest - nerves to know: phrenic

Brachial plexus

- plexus formed by ventral rami of C5-C8, T1 - innervates skin and muscles of pectoral girdle and upper limbs - nerves to know: axillary, musculocutaneous, radial, median, ulnar

Lumbar plexus

- plexus formed by ventral rami of L1-L4 - innervates skin and muscles of abdominal wall, external genitalia, part of lower limbs - nerves to know: femoral, obturator

Sacral plexus

- plexus formed by ventral rami of L4-L5, S1-S4 - innervates skin and muscles of buttocks, perineum, lower limbs - nerves to know: superior gluteal, inferior gluteal, sciatic (branches into tibial and common fibular), pudendal

Coccygeal plexus

- plexus formed by ventral rami of S4-S5 and coccygeal nerves - innervates skin in coccygeal region - nerves to know: none

Sciatic nerve

- specific nerve (group of two nerves) that innervates hamstring muscles and adductor magnus - no sensory function - part of sacral plexus

Tibial nerve

- specific nerve (part of sciatic nerve) that innervates gastrocnemius, soleus, flexor digitorum longus, flexor hallucis longus (posterior leg muscles) - sensory info for skin over plantar surface of foot

Common fibular nerve (both superficial and deep)

- specific nerve (part of sciatic nerve) that innervates tibialis anterior, extensor hallucis longus, extensor digitorum longus (anterior leg muscles) - sensory info for skin over distal 1/3 of anterior aspect of leg and dorsum of foot; skin on adjacent sides of great and second toes - part of sacral plexus

Obturator nerve

- specific nerve that innervates adductors of hip joint - sensory info for medial aspect of thigh - part of lumbar plexus

Musculocutaneous nerve

- specific nerve that innervates anterior muscles of arm (biceps brachii, brachialis, etc) - no sensory function - part of brachial plexus

Axillary nerve

- specific nerve that innervates deltoid and teres minor - sensory info for skin over deltoid and superior/posterior aspect of arm - part of brachial plexus

Ulnar nerve

- specific nerve that innervates flexor carpi ulnaris, part of flexor digitorum profundus, most intrinsic hand muscles (lumbricals, dorsal/palmar interossei) - sensory info for skin of medial side of hand, little finger and medial half of ring finger - part of brachial plexus

Femoral nerve

- specific nerve that innervates flexor muscles of hip joint and extensors of knee joint - sensory info for skin over anterior and medial aspect of thigh, medial side of leg and foot - part of lumbar plexus

Inferior gluteal nerve

- specific nerve that innervates gluteus maximus - no sensory function - part of sacral plexus

Superior gluteal nerve

- specific nerve that innervates gluteus medius, gluteus minimus, tensor fasciae latae - no sensory function - part of sacral plexus

Median nerve

- specific nerve that innervates most (6.5 out of 8) anterior forearm muscles (flexors of the wrist, etc) - sensory info for skin of lateral 2/3 of palm of hand and fingers - part of brachial plexus ** runs through carpal tunnel **

Pudendal nerve

- specific nerve that innervates muscles of perineum (bulbospongiosus, external anal and urethral sphincters) - sensory info for skin of penis and scrotum in males; clitoris, labia minora, labia majora, and vagina in females

Radial nerve

- specific nerve that innervates muscles on posterior aspect of arm/forearm (triceps brachii, extensors of wrist, etc) - sensory info for skin of posterior arm/forearm, lateral 2/3 of dorsum of hand and fingers over proximal and middle phalanges - part of brachial plexus

Phrenic nerve

- specific nerve that innervates the diaphragm (breathing) - no sensory function - part of cervical plexus