1. Cervical Enlargement 2. Thoracic Region 3. Lumbar Enlargement 4. Medullaris blunt cone at inferior end of spinal cord. (L1/L2) – 5. Filum Terminale thin filament of pia mater and arachnoid mater extending from the – spinal cord to the upper portion of the coccyx 6. Cauda Equina Horse’s Tail Spinal Nerves extending downward from the lower lumbar and sacral areas of the vertebral canal. C. Spinal Nerves (31 Pairs Total) 1. 8 Pairs of Cervical Nerves (C1 C8) *Note….there are 7 cervical vertebrae but 8 pairs – of cervical nerves 2. 12 Pairs of Thoracic Nerves (T1 T12) – 3. 5 Pairs of Lumbar Nerves (L1 L5) – 4. 5 Pairs of Sacral Nerves (S1 S5) – 5. 1 Pair of Coccygeal Nerves (Co) D. Cross Section of the Spinal Cord 1. Grooves divides spinal cord into left and right halves – a. Anterior Median Fissure b. Posterior Median Sulcus 2. Gray Matter unmyelinated tissue – a. Anterior Horn contains cell bodies of motor neurons. – b. Posterior Horn c. Lateral Horn present between T1 L2 regions of the spinal cord – – d. Gray Commissure common site for decussation (crossing over) of sensory – neurons. 3. White Matter myelinated axons – a. Anterior Funiculus (column) b. Posterior Funiculus (column) c. Lateral Funiculus (column)
1. Cervical Enlargement 2. Thoracic Region 3. Lumbar Enlargement 4. Medullaris – blunt cone at inferior end of spinal cord. (L1/L2) 5. Filum Terminale – thin filament of pia mater and arachnoid mater extending from the spinal cord to the upper portion of the coccyx 6. Cauda Equina Horse’s Tail Spinal Nerves extending downward from the lower lumbar and sacral areas of the vertebral canal. C. Spinal Nerves (31 Pairs Total) 1. 8 Pairs of Cervical Nerves (C1 – C8) *Note….there are 7 cervical vertebrae but 8 pairs of cervical nerves 2. 12 Pairs of Thoracic Nerves (T1 – T12) 3. 5 Pairs of Lumbar Nerves (L1 – L5) 4. 5 Pairs of Sacral Nerves (S1 – S5) 5. 1 Pair of Coccygeal Nerves (Co) D. Cross Section of the Spinal Cord 1. Grooves – divides spinal cord into left and right halves a. Anterior Median Fissure b. Posterior Median Sulcus 2. Gray Matter – unmyelinated tissue a. Anterior Horn – contains cell bodies of motor neurons. b. Posterior Horn c. Lateral Horn – present between T1 – L2 regions of the spinal cord d. Gray Commissure – common site for decussation (crossing over) of sensory neurons. 3. White Matter – myelinated axons a. Anterior Funiculus (column) b. Posterior Funiculus (column) c. Lateral Funiculus (column)
chapter-11-nervous-system-ii.docx