Nervous System Anatomy: Neuron Soma Dendrites Axon Axolemma Axoplasm Axon Terminal Synaptic End Bulb Axon Hillock Trigger Zone Schwann Cell Myelin Sheath Node of Ranvier

Nervous System Anatomy: Spinal Cord Gray Matter White Matter Meninges Dura Mater (Outer) Subdural Space Arachnoid Mater Subarachnoid Space Denticulate Ligaments Pia Mater (Inner)

Nervous System Anatomy: Spinal Cord

Nervous System Anatomy: Spinal Cord

Nervous System Anatomy: Spinal Nerves Plexuses Cervical 8 Nerve Pairs Brachial 8 Nerves Lumbar 5 Nerve Pairs Sacral Thoracic Nerves 12 Pairs Coccygeal Nerves 1 Nerve Pair

Nervous System Anatomy: Spinal Column Horns: Gray & White, Anterior & Posterior Commisures: Gray & White, Anterior & Posterior Roots: Ventral & Dorsal Fissures & Sulci: Ventral & Dorsal Columns: Lateral, Anterior & Posterior Central Canal

Nervous System Anatomy Ventral & Dorsal Ramus Rami Communicantes

Nervous System Anatomy

Nervous System Anatomy

Nervous System Anatomy Most major nerves occur on both right and left sides Most major nerves carry both motor and sensory information, although they may be mostly one or the other Phrenic n. Innervates the diaphragm Emerges C3 - C5 Damage to the spinal cord above this point causes respiratory failure Supraclavicular n. Deep to the platysma Innervates skin in the neck, shoulder, & upper chest Cervical Plexus

Nervous System Anatomy Axillary n. Innervates deltoid & teres minor Suprascapular n. Innervates supraspinatus & infraspinatus Brachial Plexus

Nervous System Anatomy Radial n. Innervates extensors of arm & forearm Median n. Innervates flexors of forearm Ulnar n. Innervates flexors of wrist & hand Musculocutaneous n. Innervates coracobrachialis, biceps brachii, & brachialis Brachial Plexus

Nervous System Anatomy Genitofemoral n. Innervates skin over genitals & thighs Ilioinguinal n. Femoral n. Innervates flexors of thigh & extensors of leg Saphenous n. Branch of the Femoral n. Innervates skin over medial surface of leg Obturator n. Innervates adductors of leg Lumbar Plexus

Nervous System Anatomy Pudendal n. Innervates muscles of the perineum & skin of the genitals Sciatic n. Largest nerve in the body Splits into tibial & common peroneal nerves Innervates hamstrings & adductors Tibial n. Splits into lateral & medial plantar nerves Innervates gastrocnemius, soleus & other lower leg muscles Sacral Plexus

Nervous System Anatomy Common peroneal n. Splits into superficial & deep peroneal nerves Also known as the common fibular nerve Innervates tibialis anterior, peroneus (fibularis) longus & brevis, & other muscles of the lower leg & foot Sural n. Formed from branches of the Tibial & Common Peroneal nn. Innervates skin of lower leg & foot Medial & Lateral Plantar nn. Innervate muscles of the foot Sacral Plexus

Nervous System Anatomy The trigeminal nerve is Cranial Nerve V Largest cranial nerve, with three major divisions Many branches that provide somatic sensory information from the head & face Also has motor output to muscles of mastication Infraorbital n. Supraorbital n. Lingual n. Mental n. Branches of the Trigeminal Nerve (Cranial Nerve V)

Nervous System Anatomy Sensory and motor fibers travel along “highways” (tracts) in the spinal cord Sensory and motor tracts are landmarks for diagnosis & treatment of spinal cord damage