Presentation on theme: "Spinal Nerves. Spinal nerves 31 pairs arise from spinal cord Five groups correspond to regions of spinal cord and vertebrae –Cervical 8 pr. –Thoracic."— Presentation transcript:
Spinal nerves 31 pairs arise from spinal cord Five groups correspond to regions of spinal cord and vertebrae –Cervical 8 pr. –Thoracic 12 pr. –Lumbar 5 pr. –Sacral 5 pr. –Coccygeal 1 pr.
Structure of a Nerve Bundle of axons Layers of connective tissue –Epineurium –Perineurium –Endoneurium
Structure of a spinal nerve Tree analogy Dorsal root & ventral root fuse lateral to dorsal root ganglion Whole nerve "trunk" lies in intervertebral foramen
Structure of a spinal nerve Branches Dorsal ramus Ventral ramus Communicating rami to sympathetic chain ganglion (ANS)
Spinal Nerve Plexuses
Ventral rami of spinal nerves fuse and form networks with ventral rami of other spinal nerves. –Crossing of fibers A peripheral nerve may contain axons from several spinal segments. T 2 – T 12 do not form plexuses