Question | Answer |
How many spinal nerves are there? | 31 |
How far does the spinal cord go down to? | L2 |
How many cervical segments? | 8 |
How many coccygeal segements? | 1 |
Which fibers are sensory? | dorsal root |
Which fibers are motor? | ventral |
What is in great matter? | cell bodies |
What is in white matter? | bundles of axons |
How many layers of lamina are in the grey matter? | 10 |
Where is lamina I of the grey matter? | dorsal |
Where is lamina IX of the grey matter? | ventral |
Where is lamina X? | surrounds the central cannal |
How is white matter divided? | 3 paired funiculi |
What are the 3 funiculi? | posterior, lateral and anterior |
Where is the posterior funiculaus? | lises between posterior median sulcus and posterior horn |
Where is lateral funiculus? | lies between dorsal root entry zone and site where ventral root fibers emerge from spinal cord |
Where is the anterior funiculus? | lies between emerging ventral rootlets and anterior median fissue |
What is the anterior median fissure? | midline of spinal cord on anterior surface. Contains anterior spinal artery |
What is the posterior median sulcus? | less distinct groove in posterior midline that separates 2 posterior columns and contains the posterior spinal vein |
What is the posterior intermediate sulcus? | divides each posterior funiculus into 2 white columns. Only present in cervical and upper thoracic segments |
How does spinal cord anatomy vary at different levels? | size and shape, relative amounts of gray/white matter and amount/configuration of gray matter |
What are the characteristics of the sacral cord? | small diameter with large amounts of gray compared to white matter. Short, thick gray commissure and large anterior and posterior horns |
What 4 white matter tracts are we responsible to know the location of? | Gracile fasciculus, dorsolateral tract, lateral corticospinal tract and anteriolateral system |
What is the function of the gracile fasciculus? | ascending sensory axons below T7 |
What is the function of the dorsolateral tract? | pain |
What is the function of the lateral corticospinal tract? | main motor pathway |
What is the function of the anterolateral system? | pain/temperature pathway |
What are the characteristics of the lumbar cord? | nearly circular, massive horns, less white matter than cervical segments, and L1 and L3 resemble lower thoracic levels with a lateral horn |
What are the characteristics of a thoracic cord? | small diameter due ot marked reduction in grey matter. Small horns. Lateral horn containing intermediolateral cell columns present at all thoracic levels. Dorsal nucleus of Clarke |
What is the Dorsal nucleus of Clarke? | rounded collection of large cells at base of medial aspect of posterior horn. Present at all thoracic levels |
What are the characteristics of the cervical cord? | large size with a lot of white matter. Oval shape with prominent posterior intermediate septum |
What does the posterior intermediate septum? | divides the posterior funiculus into fasciulus gracilis and fasciculus cuneatus |
What is the cuneate fasciculus? | white matter lateral to the posterior intermediate sulcus |
What is the cuneate fasciculus? | Relays ascending sensory axons from spinal levels T7 and up |
What cell type are primary sensory neuron? | psuedounipolar neuron |
What nerves have faster conduction velocity? | those nerves with larger diameter |
What fiber type is proprioception? | A alpha, fastest conduction |
What fiber type is touch, pressure? | A beta |
What fiber type is moter to muscle spindles? | A gamma |
What fiber type is pain, temperature and touch? | A delta |
What fiber type is preganglionic autonomic? | B |
What fiber type is pain, reflex responses? | C Dorsal root |
What fiber type is postganglionic sympathethetics? | C sympathetic |
Which fibers are myelinated? | A and B |
Which fibers are unmyelinated? | C |