Overview Flashcards
How many pairs of spinal nerves?
31 pairs 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
Anterior (ventral) root
carry efferent axons from cell bodies located in the antrior or lateral horns
Posterior (dorsal) root
carry axons from cell bodies located in the posterior root of the spinal ganglion.
attaches to the cord at the posteriolateral sulcus
C1 and C2 spinal ganglia are located where?
on their respective vertebral arches
the sacral ganglia is located where?
within the vertebral canal
the coccygeal ganglia is located where?
inside the dura mater
what is given off after the spinal roots combine into a mixed spinal nerve?
a meningeal branch (present at all cord levels)
what is the function of the meningeal branch?
provide somatosensory and sympathetic supply to the dura, blood vessels, periostium, ligaments, and ivd in the anterior and lateral portions of the canal
the mixed spinal nerve divides into what rami?
anterior ramus and posterior ramus
posterior ramus
splits into lateral and medial branches (except C1)
smaller than anterior ramus (except for C1, S4, and S5)
motor innervation to the deep back muscles
sensory innervation to the skin on both sides of the spine
Anterior ramus
motor innervation to anterior and lateral trunk muscles
motor innervation to skeletal muscles of the extremities (contribute to the great plexuses)
sensory innervation to skin of extremities, and anterior and lateral trunk
Where are sympathetic chain communications located?
at or just medial to the bifurcation of the mixed spinal nerve
white ramus communicans
myelinated
carries axons from cell bodies located in the lateral horn at cord levels T1 - L2
Grey ramus communicans
unmyelinated
carries postganglionic sympathetic axons from cell bodies in the sympathetic chain to the spinal nerve (associated with each spinal nerve)
C1 posterior rami (suboccipital nerve)
motor supply to
rectus capitis posterior major and minor
obliquus capitis superior and inferior
semispinalis capitis
what cord levels give motor supply to semispinalis capitis?
C1, C2, and C3
posterior rami of C2
medial branch - greater occipital nerve, sensory innervation to neck an scalp
lateral branch - motor supply to semispinalis capitis, longissimus capitis, and splenius capitis muscles
posterior ramus of C3
medial branch - 3rd (least) occipital nerve, sensory supply from skin of posterior neck
Lateral branch - motor supply to semispinalis capitis, longissimus capitis, and splenius capitis
posterior ramus of C4 to C8
medial branch - sensory supply to skin of posterior neck
Lateral branch - motor supply to iliocostalis cervicis, longissimus cervicis and capitis
