Spinal Cord Medical Neuroscience Dr. Wiegand

Spinal Cord Medical Neuroscience Dr. Wiegand

Directions dorsal dorsal rostral rostral ventral ventral caudal caudal

Terms rostral - toward the “beak” caudal - toward the “tail” ventral - toward the front (anterior) dorsal - toward the back (posterior) superior - above inferior - below

Spinal Cord Central gray nuclei and outer white matter (tracts) Descending Descending Cell bodies Celltracts bodies tracts Peripheral Peripheral nerve nerve fibers fibers Ascending Ascending tracts tracts

Peripheral and Central Nervous System PNS PNS sensory sensory motor motor Lesions CNS CNS

Spinal nerves & cord 31 pairs with anterior and posterior root C1 often doesn’t have posterior root Spinal cord enlarged in C5 – T1 and L2 – S3 levels Spinal cord ends at L1 vertebral level

Dermatomes & Myotomes Dermatome – an area of skin innervated by a single posterior root Myotome – a group of muscles innervated by a single anterior root

C4 T4 T10 L3 Dermatomes Dermatomes L5 Myotomes Myotomes

Stretch Reflexes Examples: C5-6 biceps tendon C6 brachioradialis C7-8 triceps tendon L2-4 patellar tendon S1-2 Achilles tendon

External Spinal Cord Conusmedullaris medullaris Conus Filumterminale terminale Filum Caudaequina equina Cauda Duramater mater Dura

External Structure – Spinal Cord PosteriorMedian MedianSulcus Sulcus Posterior Lateralsulci sulci Lateral Posterior Posterior Intermediate Intermediate Sulci Sulci AnteriorMedian MedianFissure Fissure Anterior

Internal Structure – White Matter Posterior Posterior Funiculi Funiculi Lateral Lateral Anterior Anterior

White Matter Organization: Ascending Pathways f. gracilis tus nea f. cu Lateral& & Lateral Anterior Anterior Spinothalamic Spinothalamic Tracts Tracts Posterior PosteriorColumns Columns Posterior Posterior& & Anterior Anterior Spinocerebellar Spinocerebellar Tracts Tracts

White Matter Organization: Descending Pathways Lateral Lateral Corticospinal Corticospinal Tract Tract Anterior Anterior Corticospinal Corticospinal Tract Tract Rubrospinal Rubrospinal Tract Tract Reticulospinal Reticulospinal Tracts Tracts Vestibulospinal Vestibulospinal Tracts Tracts

White Matter Organization: Intersegmental Pathways Lissauer’s Lissauer’s Tract Tract Intersegmental Intersegmental Tracts Tracts

White Matter Organization: Ascending Pathways Posterior PosteriorColumns Columns LTA Lateral& & Lateral Anterior Anterior Spinothalamic Spinothalamic Tracts Tracts L N N

White Matter Organization: Descending Pathways Legs T A Neck

Grey Matter Organization Posterior Posterior MotorGroups Groups Motor Intermediate Intermediate Anterior Anterior Lateral Lateral Medial Medial

Grey Matter Organization: Anterior Cell Columns

Grey Matter Organization: Lateral Grey Horns: T1 – L2/3 AKA AKA Intermediolateral Intermediolateral CellColumn Column Cell

Grey Matter Organization: Posterior Cell Column Dorsomarginalnucleus nucleus Dorsomarginal Substantiagelatinosa gelatinosa Substantia Nucleusproprius proprius Nucleus Nucleusdorsalis dorsalis Nucleus (Clarke’scolumn) column) (Clarke’s

From FromPritchard Pritchard& & Alloway: Alloway:Fig. Fig.3-7 3-7

http:// lansing.bellarmine.edu/pt/atl as/cover.html

Rexed Lamina Dorsomarginaln. n. Dorsomarginal Substantiagelatinosa gelatinosa Substantia Nucleusproprius proprius Nucleus Nucleusdorsalis dorsalis Nucleus (Clarke’scolumn) column) (Clarke’s Motornuclei nuclei Motor

Brown-Sequard Syndrome