Spinal Nerves Spinal nerves 31 pairs arise from
- Slides: 13
Spinal Nerves
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
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
Spinal Nerve Plexuses • • Cervical plexus Brachial plexus Lumbar plexus Sacral plexus
• C 1 – C 4 (+ C 5) – cutaneous nerves, mostly sensory from skin of neck & back of head – Phrenic nerve to diaphragm • Motor stimulation for breathing! Cervical plexus
Brachial plexus • C 5 – T 1 • Complex fusion, splitting, fusion, & division into nerves • Axillary Nerve – to deltoid • Musculocutaneous nerve – to biceps brachii, brachialis
• Radial nerve – to triceps brachii, extensors of wrist, hand, fingers • Wrist drop • Median nerve – to flexors of wrist, hand, fingers – can be compressed • Carpal Tunnel Syndrome • Ulnar nerve – (“funny bone”) – to flexors in hand • “Claw hand” Brachial plexus
• L 1 – L 4 (+ L 5) • Ilioinguinal nerve – mostly sensory from skin of thigh & genitals • Genitofemoral nerve – mostly sensory from scrotum, labia majora, ant. Thigh • Femoral Nerve – to quadriceps, sartorius Lumbar plexus
• L 4 – S 4 • Superior & inferior gluteal nerves – To gluteus muscles • Sciatic nerve – To hamstrings & other posterior thigh & leg muscles • Pudendal nerve – Sensory from penis, clitoris, labia minora, anus Sacral plexus
- Spinal cord anatomy
- Inferior gluteal nerve
- Cranial nerves mnemonic
- Spinal cover
- Spinal. nerves
- What is the spinal cord made of
- Frog spinal nerves
- Spinal nerves
- Spinal cord diagram
- Spinal segment
- Central. nervous system
- Figure 13-1 the spinal cord
- Lumbosacral enlargement
- Nerves branching beyond the spinal cord into the body