1. Spinal Cord, Spinal Nerves, Plexuses

2. Spinal Nerves There are 31 pairs of spinal nerves They each contain thousands of nerve fibers They arise from the spinal cord and supply all parts of the body except the head and some areas of the neck The nerves are named according to their point of issue from the spinal cord Spinal nerves are named as followed: C1 – C7 for the vertebrae below it C8 – C0 for the vertebrae above it

3. Spinal Nerves

4. Cervical Spinal Nerves (C1 – C8) C1 – C8

5. Thoracic Spinal Nerves (T1 – T12) T1- T12

6. Lumbar Spinal Nerves (L1- L5) L1 – L5

7. Sacral Spinal Nerves (S1- S5) S1 – S5

8. Coccygeal Nerve C0 C0

9. CaudaEquina Is the collective nerve roots at the end of the spinal cord. Looks like a horse’s tail The spinal cord ends between L1 and L2 and the roots of L3 – C0 make up the Cauda Equina

10. ConusMedullaris Conus Medullaris is the tapered cone shaped portion at the inferior end of the spinal cord Filum Terminale Connects the conus medullaris to the upper coccyx. Is a fibrous extension of the conus covered in pia mater. It anchors the spinal cord and prevents damage from movement

11. Lumbar Puncture Is the insertion of a sterile needle into the sub arachnoid space, usually between the 3rd and 4th lumbar vertebrae. The procedure is used to detect increased intercranial pressure or the presence of blood in the CSF

12. Lumbar Puncture The insertion of the needle occurs at this point because there is no spinal cord present after L3 and therefore there is little chance of spinal cord damage but CSF is still present in the sub arachnoid space.

13. Plexuses A plexus is an interlacing group of nerve fibers which occur in the cervical, brachial, lumbar and sacral regions The plexuses primarily serve the limbs This means that each muscle in a limb is supplied with impulses from more then one spinal nerve

14. CervicalPlexus C1 – C4 Formed by the first four cervical nerves Most branches are cutaneous nerves Others innervate muscles of the anterior neck Cervical Plexus

15. CervicalPlexus C3, C4 and C5 give rise to the phrenic nerve which innervates the diaphragm.

16. Brachial Plexus C5- T1 formed by the last four cervical and the 1st Thoracic nerve. It is situated in the neck and partially in the upper arm (axillary region) It gives rise to virtually all the nerves that innervate the arm Brachial Plexus

17. Brachial Plexus

18. Brachial Plexus

19. Nerves from the Brachial Plexus Axillary Nerve Innervates the deltoid muscle Musculocutaneous Nerve Innervates the biceps brachii Musculocutaneous nerve Axillary Nerve

20. Nerves from the Brachial Plexus Radial Nerve Innervates the triceps and the extensors Ulnar Nerve Innervates the flexor carpi ulnaris Radial Nerve Ulnar Nerve

21. Nerves from the Brachial Plexus Median Nerve Innervates the flexors of the palm and forearm Median Nerve

22. Carpal Tunnel Syndrome Occurs when the median nerve, which runs from the forearm to the hand becomes compressed or damaged. Some symptoms include : Pain, weakness, numbness, tingling in the hand The nerve is squeezed against the bones and ligaments Treatment Most commonly treated by cutting the transverse carpal ligament increase the diameter of the carpal tunnel

23. Lumbar Plexus T12 – L4 Arises from the last thoracic (Sub-costal nerve) and the first 4 lumbar nerves Gives rise to nerves which innervate the flexors and the adductors of the leg Lumbar Plexus

24. Lumbar Plexus

25. Nerves from the Lumbar Plexus Obturator innervates the adductors of the thigh Femoral Innervates the quadriceps Obturator Nerve Femoral Nerve

26. Sacral Plexus L4 – S5 Comprised of the last two lumbar and all the sacral nerves Innervates the buttocks and the lower limbs Sacral Plexus

27. Sacral Plexus

28. Nerves from the Sacral Plexus Sciatic Nerve The largest branch of the sacral plexus Innervates the hamstrings Appears from under the piriformis muscle Piriformis Muscle Sciatic Nerve

29. Nerves from the Sacral Plexus Tibial Nerve Innervates the gastrocnemius and the soleus Peroneal Nerve Innervates the tibialis anterior and other dorsiflexors Tibial Nerve Peroneal Nerve

30. Nervous Injuries Below are the names of some injuries to specific nerves. The name of the injured nerve is beside them. Whiplash  C4 / C5 or C5 / C6 Crutch Paralysis  Radial Nerve Wrist drop  Radial Nerve Carpal Tunnel Syndrome  Median Nerve Sciatica  Sciatic Nerve

31. Dermatomes DEFN – the area of skin innervated by the cutaneous branch of a spinal nerve. Occurs in every spinal nerve except C1 Dermatomes help physicians determine which nerves are damaged and localize the injured region of the spinal cord

32. Deramtomes