Lecture #18 - Spinal cord and nerves

Question 1

Where does spinal cord start?

Answer 1

Spinal cord starts at foramen magnum

Question 2

Where does spinal cord end?

Answer 2

Ends at 1st lumbar vertebra (L1)

Question 3

Meningeal sack

Answer 3

Spinal cord sits in here. Filled with CSF.

Question 4

Conus medularis

Answer 4

Spinal cord ends in a tapered cone

Question 5

Filum terminale

Answer 5

Extends from conus medularis to end of spinal cavity (anchors and extension of meninges). CT. So don’t suffer trauma.

Question 6

Where do spinal nerves exit?

Answer 6

At the level appropriate to their origin and destination They all EXIT at their own vertebrae but the lumbar and sacral spinal cord has to grow down (since spinal cord ends at L1). So only like until T10 is the spinal cord only thoracic (the nerves after this have to grow down)

Question 7

Where do the spinal cords that are still in register go to?

Answer 7

Arms and thorax - exit at cervical and thoracic level.

Question 8

Where do the spinal cords that exit the spinal cavity and vertebral column at the end of the spinal cord go?

Answer 8

Leg
Pelvis
Abdomen
(exit at lumbar, sacral, coccygeal levels)
In the caudal equina

Question 9

Cauda equina

Answer 9

Horse's tail
Filled with spinal nerves (the meningeal sack inferior to end of spinal cord) that exit at:
-lumbar
-sacral
-coccygeal levels

Question 10

Sulcus

Answer 10

Furrow

Question 11

Fissure

Answer 11

Deep sulcus

Question 12

Anterior median fissure

Answer 12

Ventral (in front of spinal cord)

Question 13

Posterior median sulcus

Answer 13

Dorsal (back of spinal)

Question 14

Grey matter

Answer 14

The butterfly of cell bodies in the spinal cord

Question 15

White matter

Answer 15

MYELINATED axons (called tracts in PNS)

Question 16

Dorsal columns

Answer 16

Columns of axons extending up to brain (white matter)

Question 17

Dorsal horn

Answer 17

Grey matter

Question 18

Dorsal nerve root (PNS)

Answer 18

Info comes in (afferent)

Question 19

Ventral horn

Answer 19

Grey matter

Question 20

Ventral columns

Answer 20

White matter

Question 21

Ventral nerve root (PNS)

Answer 21

Info goes out (efferent)

Question 22

Where are somatic motor neurons? (efferent)

Answer 22

In the ventral horn

Question 23

Where are autonomic neurons? (efferent)

Answer 23

In the lateral/ventrolateral horns (dorsal up, ventral down, lateral are sides)

Question 24

Spinal nerves - myelinated or unmyelinated

Answer 24

PNS so both (somatic efferent is one myelinated and autonomic efferent is unmyelinated #2 neuron)

Roots of dorsal and ventral combine to form spinal nerve

SPINAL CORD DOES NOT CONTAIN SPINAL NERVES. It contains sympathetic ner fibres for sure.

Question 25

Dorsal root ganglion

Answer 25

Cell bodies of sensory system

Question 26

Communicating rami

Answer 26

The ventral rams communicates with the sympathetic chain via two sympathetic rami

Question 27

Peripheral nerve

Answer 27

Un or myelinated

Axons covered in ENDONEURIUM

Endoneurium-covered axons bundle together to form a FASCICLE

Fasicles are covered with PERINEURIUM

Fascicles bundle together to form a NERVE

Nerves are covered with EPINEURIUM

Bundles of axons in the CNA are called a TRACT