SPINAL NERVES
- 31 Pairs. Mixed type. Total weight 150 gms.
- At the base of origin of spinal nerves gland of swammardon or calcarious ganglion is present.
- Composed of medulated nerve fibres.
- Classified into five groups -
1. Cervical - 8 pairs
2. Thoracic - 12 pairs
3. Lumber - 5 pairs
4. Sacral - 5 pairs
5. Coccygeal - 1 pair
- Each spinal nerve is originated from spinal cord from dorsal root and ventral root.
- In dorsal root, root ganglion is present. Both roots fuse in neural canal to form spinal nerve.
- It comes out of vertebral column from inter vertebral foramen.
- Out side vertebral column each spinal nerve is divided into three parts -
(i) Dorsal branch or Ramus dorsalis
(ii) Ventral branch or Ramus ventralis
(iii) Visceral branch or Ramus communicans
- Dorsal branch to skin and muscle of dorsal side.
- Ventral branch to skin & muslce of ventral side.
- Visceral branch is attached to ganglions of A.N.S.
- In rabbit 37 pairs spinal nerves present -
1. Cervical - 8 pairs
2. Thoracic - 12 pairs
3. Lumber - 7 pairs
4. Sacral - 4 pairs
5. Caudal - 6 pairs
In rabbit caudal nerves combine with filum terminalis to form cauda equina.