Spinal Cord 2 PDF

Faculty of Medicine Medicine and Surgery Spinal Cord Ass. Prof. Rabab A. Rasheed 1/10/2024  Learning outcomes q By the end of the lecture, the students will be able to: 1. Enumerate divisions of the nervous system. 2. Describe the general features of the spinal cord. 3....

Faculty of Medicine Medicine and Surgery Spinal Cord Ass. Prof. Rabab A. Rasheed 1/10/2024  Learning outcomes q By the end of the lecture, the students will be able to: 1. Enumerate divisions of the nervous system. 2. Describe the general features of the spinal cord. 3. Describe the components of the grey matter. 4. Describe the components of the white matter. 5. Differentiate the various levels of the spinal cord.  Nervous system CNS PNS Peripheral nerves Brain Spinal cord 1. Cerebral Cortex 1. Cervical level 2. Cerebellum 2. Thoracic level 3. Brain stem 3. Lumbar level  Spinal cord Central Grey matter Peripheral White matter Nuclei [Cell Bodies] Nerve Fibers [Axons]  Spinal Cord Grey Matter White Matter Central Canal Ø Dorsal Horn Ø Dorsal Column Ø In the centre of Ø Ventral Horn Ø Ventral Column grey matter Ø Lateral Horn Ø Lateral Column Ø Contain Nuclei Ø Contain Tracts Ø Contain CSF  Spinal Cord Grey Matter White Matter Dorsal [Posterior] column Dorsal Horn Lateral column Lateral Horn Central Canal Lateral column Ventral Horn  Grey matter Nuclei Dorsal horn N. Lateral horn N. Ventral horn N. (sensory) (autonomic) (motor) -Posteromarginal N. 2 Medial motor N. In All Sympathetic N. (for trunk). -SGR. Levels Parasympath. N. 2 Lateral motor N. -MSN (N. Proprius). (for limbs). Thoracic -Clarke’s (dorsal) N. level  Grey Matter Nuclei Substantia Gelatinosa of Rolandi [SGR] Posteromarginal Nuc. Main Sensory Nucleu [MSN] Clake’s [dorsal] Nuc. [C8-L2] Parasympathetic Nuc. [S2-4] Sympathetic Nuc. [T1-L2] Dorsolateral Nuc. Dorsomedial Nuc. Ventrolateral Nuc. Ventromedial Nuc.  Histology of Grey Matter 1. Nerve cells [Nuclei] → 2 types: Golgi type I: with long axons → form the long tracts. Golgi type II: with short axons → their axons end in the same segment or in adjacent segments. 2. Non-myelinated nerve fibers: the beginning of the axons arising from the nerve cells and the termination of the fibers entering the grey matter. 3. Neuroglial cells and fibers. 4. Blood capillaries.  White matter Short tracts (coordinate the function of Long tracts different spinal cord segments) -Fasciculus proprius tract (all levels) -Ascending sensory tracts -Lissauer’s tract (all levels) (carry sensations to higher centers) -Comma–shaped tract à upper ½ -Descending motor tracts -Septomarginal tract à lower ½ (carry motor orders to the body) Short tracts Septomarginal Comma tract Fasciculus proprius Lissauer’s tract  Ascending tracts (carry sensations from the body to higher centers) Conscious sensations Unconscious sensations 1. Lateral spinothalamic T. (pain & temperature). 1. Dorsal spino-cerebellar T. 2. Ventral spinothalamic T. (crude touch). 2. Ventral spino-cerebellar T. 3. Gracile T. (proprioception & fine 3. Spino-olivary T. touch from lower ½ of the body). 4. Spino-tectal T 4. Cuneate T. (proprioception & fine touch from upper ½ of the body).  Ascending Gracile T [Sensory] tracts Cuneate T Lateral Spinothalamic T Ventral Spinothalamic T  Descending tracts (carry motor orders from higher centers to the body) Pyramidal tract Extrapyramidal tract 1. Corticospinal T. 1. Olivospinal T. (to AHCs of spinal cord). 2. Tectospinal T. à crossed pyramidal T. (80%) 3. Rubro-spinal T. à direct pyramidal T (20%) 4. Reticulo-spinal T. (medial & lateral) 2. Corticobulbar T. 5. Vestibulospinal T. (to cranial nerves motor nuclei)  Descending [Motor] tracts Lateral CorticospinaL T Ventral CorticospinaL T  Spinal Cord Levels Cervical Thoracic Lumbar Ø Oval Ø Rounded Ø Rounded Ø Much white matter Ø Much white matter Ø Much grey matter Ø Less grey matter Ø Less grey matter Ø Less white matter Ø Thick ventral horns Ø Thin ventral and dorsal horns Ø Thick ventral and Ø Thin dorsal horns Ø Lateral horn is present dorsal horns Practical  Spinal Cord Levels Cervical Thoracic Lumbar Acknowledgment Prof Dr. Salwa Gawish Dr. Ahmed Elmansy Cervical Level Nuclei PMN PSM SGR MSN LMN MMN Motor N.  Cervical Level Short tracts Lissauer’s tract Comma shaped tract Fasciculus proprius Cervical Level Sensory tracts G C DSCT LSTT VSCT STT SOT VSTT  Cervical Level Pyramidal tracts Crossed pyramidal T Direct pyramidal T  Cervical Level Extrapyramidal tracts RST LRST VST MRST TST OST Cervical Level Complete  Upper Thoracic Level Appear 2 Disappear 4 ROT 1-Clarke’s N X Rubrospinal T 2-Sympathetic N. X Olivospinal T. (lateral horn) X Tectospinal T. X Lateral motor N X X X  Lower Thoracic Level Disappear Appear X X CCD Septomarginal T X Cuneate T X Comma-shaped T X Direct pyramidal T X Lumbar Level Appear Lateral motor N.  Summary and wrap up Spinal cord is a part of the CNS connecting the brain with the PNS. It is formed of grey matter (nerve cell bodies) and white matter (nerve fibers) Grey matter contained sensory and motor nuclei. White matter contained short and long tracts. Long tracts are either ascending carrying sensory stimuli to the brain or descending carrying motor orders from the brain to the striated muscles. The spinal cord is divided into 3 levels, cervical, thoracic, and lumbar.