GENERAL ANATOMY-1 Reviewer
Peripheral Nervous System
For Dentistry
Spinal Nerves
• Bundles of nerves attached to the spinal cord
• Classified as:
a. Sensory nerve fibers
b. Motor nerve fibers
• 31 pairs attached along the vertebral canal
• Emerge through intervertebral foramina
Number of Spinal Nerves
• 8 cervical
• 12 thoracic
• 5 lumbar
• 5 sacral
• 1 coccygeal
Attachment to Spinal Cord
• Dorsal root: sensory fibers
• Ve nt r a l ro o t : m o t o r f i b e rs
• Both roots join to form the spinal nerve
Plexuses
• Groups of nerve fibers from ventral rami
• Posterior rami do not form plexuses
• Plexuses arise from cervical, lumbar, sacral, and brachial spinal nerves
Thoracic nerves
• T1 to T11: intercostal nerves (do not form plexus)
• T12: subcostal nerve (does not form plexus)
Cervical Plexus
• From C1 to C4
• Supplies back and sides of head, front of neck (sensory)
• Most important branch: phrenic nerve (motor to diaphragm)
Brachial Plexus
• From C5 to C8 and T1
• Supplies skin and muscles of upper limb
• Major branches:
a. Radial nerve
b. Ulnar nerve
c. Median nerve
Lumbar Plexus
• From L1 to L4
• Gives rise to:
a. Femoral nerve (anterior thigh)
