Lecture #18 - Spinal cord and nerves Flashcards
Where does spinal cord start?
Spinal cord starts at foramen magnum
Where does spinal cord end?
Ends at 1st lumbar vertebra (L1)
Meningeal sack
Spinal cord sits in here. Filled with CSF.
Conus medularis
Spinal cord ends in a tapered cone
Filum terminale
Extends from conus medularis to end of spinal cavity (anchors and extension of meninges). CT. So don’t suffer trauma.
Where do spinal nerves exit?
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)
Where do the spinal cords that are still in register go to?
Arms and thorax - exit at cervical and thoracic level.
Where do the spinal cords that exit the spinal cavity and vertebral column at the end of the spinal cord go?
Leg Pelvis Abdomen (exit at lumbar, sacral, coccygeal levels) In the caudal equina
Cauda equina
Horse's tail Filled with spinal nerves (the meningeal sack inferior to end of spinal cord) that exit at: -lumbar -sacral -coccygeal levels
Sulcus
Furrow
Fissure
Deep sulcus
Anterior median fissure
Ventral (in front of spinal cord)
Posterior median sulcus
Dorsal (back of spinal)
Grey matter
The butterfly of cell bodies in the spinal cord
White matter
MYELINATED axons (called tracts in PNS)
Dorsal columns
Columns of axons extending up to brain (white matter)
Dorsal horn
Grey matter
Dorsal nerve root (PNS)
Info comes in (afferent)
Ventral horn
Grey matter
Ventral columns
White matter
Ventral nerve root (PNS)
Info goes out (efferent)
Where are somatic motor neurons? (efferent)
In the ventral horn
Where are autonomic neurons? (efferent)
In the lateral/ventrolateral horns (dorsal up, ventral down, lateral are sides)
Spinal nerves - myelinated or unmyelinated
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.
Dorsal root ganglion
Cell bodies of sensory system
Communicating rami
The ventral rams communicates with the sympathetic chain via two sympathetic rami
Peripheral nerve
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
