中枢神经系统 - 浙江大学.pptVIP

The central nervous systemthe spinal cord The Spinal Cord 1. External features: Location: foramen magnum -- lower border of first lumbar vertebra Shape: A long cylindrical structure Enlargements: cervical enlargement lumbar enlargement Conus medullaris Filum terminale main longitudinal fissure and sulci on surface: Cauda equina posterior lateral posterior median sulcus anterior lateral anterior median Spinal segment: Its a part of spinal cord, which is connected with the rootlets of a pair of spinal nerve. 31 segments 8 cervical segments 12 thoracic segments 5 lumbar segments 5 sacral segments 1 coccygeal segments Corresponding relationship between spinal segments and vertebrae spinal segments correspond to vertebrae  C1-C4 C1-C4 C5 ~ T8, T l~ T4 C4 - C7, C7 ~ T3 T5 ~ T8 T3 ~ T6 T9-T12 T6-T9 L1-L5 T10-T12 S l~S5,Co1 LI? 2. Internal structure The central canal Gray matter: parts: Lateral horn (only extends from Tl to L3 segments.) gray commissure (anterior and posterior ) Main nuclei: anterior horn: medial group lateral group intermediate zone: intermediolateral nucleus intermediomedial nucleus posterior horn: the nucleus posteromarginalis the substantial gelatinosa the nucleus proprius: the dorsal nucleus (thoracic nucleus) White matter: parts: Main tracts (or fasciculi):long ascending tracts: fasciculus gracilis: come from sacral, lumbar and lower six thoracic nerves, terminate upon nucleus gracilis fascicules cunea