PSIO 5th Edition Lecture 29Outline of Last Lecture SPINAL CORD Outline of Current Lecture I. Spinal Cord Gross AnatomyII. Spinal MeningesIII. White MatterIV. Gray Matter V.Current LectureObjectives: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) Cervical - C4-T1- Nerves that exit here supply the shoulder girdle and upper limbs2) Lumbar- T9-T12- Nerves that exit here supply pelvis and lower limbs3) Conus medullaris- Around L24) Filum Terminale – - Extension of pia mater that anchors the spinal cord to the coccyx5) 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 CSFDistribution of Spinal Nerves- Cervical plexus- Brachial plexus- Cervical enlargement - Intercostal nerves- Lumbar enlargement- Lumbar plexus- Sacral Plexus- Cauda equineSpinal MeningesCSF flows in subarachnoid space- same as cranial meningesDura 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 neuronsGray Commisure: connects posterior hornsAnterior Horns: cell bodies of somatic motor neuronsLateral Horns: cell bodies of visceral motor neurons; found only in thoracic, lumbar and sacral regions of spinal cordInternal Anatomy of Spinal Cord (White Matter)-Posterior Columns: sensory tractsLateral columns: motor and sensory tractsAnterior Columns: motor tractsAnterior White Commisure: connects white matter on the left and right side of SCInput 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
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