Spinal Cord

Question 1

What are cervical and lumbar enlargements?

Answer 1

Cervical: C3-T2 nerves, Lumbar: L1-S3 nerves (begins @ ~ T11 vertebra)
handle increased sensory input & motor output from the upper & lower limbs respectively.

Question 2

What is lordosis & kyphosis?

Answer 2

Question 3

What make up the meninges?

Answer 3

From outside-in: epidural fat (surround dura mater, contains posterior internal vertebral plexus), dura mater, arachnoid, (subarachnoid space containing CSF produced by choroid plexus in brain (functions as shock absorber & circulates nutrients & removes waste)), pia. Denticulate ligaments on pia mater connect spinal cord to dural sac (arachnoid & dura)

Question 4

What are the spinal pathway basics?

Answer 4

Not pictured: dorsal and ventral rami (occur after the spinal nerve, mixed, go to dorsal and ventral structures).

Notes: Sympathetic chain/trunk (same thing)

Sympathetic nerves originate from lateral horn. White rami communicans (presynaptic), grey (postsynaptic).

spinal nerve exits the spinal cord via the intervertebral foramen.

Question 5

Parasympathetic vs sympathetic?

Answer 5

Parasympathetic: craniocaudal (brain and S2, 3, 4 (keeps the penis off the floor)), long 1st order neuron, short 2nd order synapses at target site

Sympathetic: T1-L2 origination

Question 6

How are the spinal nerves numbered?

Answer 6

C1 spinal nerve is above C1 vertebra, C8 spinal nerve is below C7 vertebra. C1 is motor only (suboccipital nerve is the dorsal ramus of C1), the rest of the spinal nerves are mixed.

Question 7

What are the conus medullaris, cauda equina and filum terminale?

Answer 7

Conus medullaris is the tapered lower end of the spinal cord occurring @ L1, L2.

Cauda equina is a bundle of spinal nerve roots occuring after L1 and extending past the end of the spinal cord.

Filum terminale: fibrous tissue continuation of pia mater extending from conus medullaris to coccyx (provides longitudinal support for spinal cord).

Question 8

What are the anterior & posterior longitudinal ligaments, ligamentum flavum?

Answer 8

anterior: strong, wide band
posterior: weak, narrow band

ligamentum flavum: yellow d/t elastin, connects adjacent laminae

Question 9

What is the spinal reflex?

Answer 9

Afferent neuron can synapse directly on efferent neuron or via an interneuron. Spinal reflex does NOT involve the brain, only spinal cord (fast).