Spinal Meninges Three membranes surround all of CNS 3) Pia mater 1) __________- "tough mother", strong 2) _________- spidery looking, carries blood vessels, etc. Subarachnoid space 3) ________- "delicate mother", adheres tightly to surface of spinal cord 3) Pia mater 2) Arachnoid 1) Dura mater

Sectional anatomy of the spinal cord __________________________and unmyelinated axons Gray matter is cell bodies, unmyelinated axons and neuroglia Projections of gray matter toward outer surface of cord are horns

The Sectional Organization of the Spinal Cord

Organization of Cord Cross Section _________- interior horns posterior - somatic and visceral sensory nuclei anterior (and lateral) gray horns – somatic and visceral motor control gray commissures - axons carrying information from side to side _________- tracts or columns posterior white column - anterior white column lateral white column anterior white commissure functions ascending tracts - sensory toward brain descending tracts - motor from brain Fig 14-5

Horns of spinal cord Posterior gray horn contains somatic and visceral sensory nuclei Anterior gray horns deal with somatic motor control Lateral gray horns contain visceral motor neurons Gray commissures contain axons that cross from one side to the other

Peripheral Nerves Definition: bundles of axons. AKA tracts in CNS Organization – coverings: _____________ wraps entire nerve ___________ wraps fascicles of tracts _____________ wraps individual axons

31 pairs of spinal nerves Nerves consist of: Epineurium Perineurium Endoneurium

Dermatomes Sensory innervations by specific spinal nerves  Each pair of spinal nerves monitors specific region of body surface. Clinical significance ?

Nerve plexus Complex interwoven network of nerves Four large plexuses Cervical plexus __________ Lumbar plexus _____________

Peripheral Nerves and Nerve Plexus

The Brachial Plexus

The Branchial Plexus

The Branchial Plexus

The Lumbar and Sacral Plexuses

The Lumbar and Sacral Plexuses