PSIO 5th Edition Lecture 29 Outline of Last Lecture SPINAL CORD Outline of Current Lecture I Spinal Cord Gross Anatomy II Spinal Meninges III White Matter IV Gray Matter V Current Lecture Objectives 1 Draw and label an accurate representation of the gross anatomy of the spinal cord 2 Draw a cross section through the spinal cord and label the internal anatomy as discussed in class 3 Trace the path taken by sensory information entering the spinal cord and motor information exiting the spinal cord Spinal Cord Gross Anatomy Enlargements 1 2 3 4 Cervical C4 T1 Nerves that exit here supply the shoulder girdle and upper limbs Lumbar T9 T12 Nerves that exit here supply pelvis and lower limbs Conus medullaris Around L2 Filum Terminale Extension of pia mater that anchors the spinal cord to the coccyx 5 Cauda Equina Extension of nerves exiting from end of spinal cord Spinal Tap Because the spinal cord proper ends at the level of L2 and the dura and arachnoid layers extend to S2 a cavity forms that can be used to withdraw CSF Distribution of Spinal Nerves Cervical plexus Brachial plexus Cervical enlargement Intercostal nerves Lumbar enlargement Lumbar plexus Sacral Plexus Cauda equine Spinal Meninges CSF flows in subarachnoid space same as cranial meninges Dura mater is not attached to the bony vertebral column creates epidural space anesthesia Internal anatomy of spinal cord Gray matter Central Canal small opening in center of SC contains CSF Posterior Horns cell bodies of somatic and visceral sensory neurons Gray Commisure connects posterior horns Anterior Horns cell bodies of somatic motor neurons Lateral Horns cell bodies of visceral motor neurons found only in thoracic lumbar and sacral regions of spinal cord Internal Anatomy of Spinal Cord White Matter Posterior Columns sensory tracts Lateral columns motor and sensory tracts Anterior Columns motor tracts Anterior White Commisure connects white matter on the left and right side of SC Input and Output to Spinal Cord Dorsal Root of Spinal Nerve carries afferent sensory information Dorsal Root Ganglion cluster of sensory cell bodies outside the CNS Ventral Root carries motor efferent information from the anterior portion of the cord Spinal Nerves joining of dorsal and ventral roots only 2 cm long are mixed nerves in that they contain both sensory and motor information Thirty one pairs of spinal nerves exit the cord
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