The cervical plexus is formed from the anterior rami of cervical nerves C1-C4. It has cutaneous branches that innervate the skin of the head and neck, and muscular branches that innervate muscles in the neck. The most important deep branch is the phrenic nerve, which arises from C3-C5 and exclusively innervates the diaphragm, the main muscle of respiration. Other branches include the ansa cervicalis and communicating branches with nearby cranial nerves.

1. The Spinal Nerves

2. 31 pairs:
Cervical 8
Thoracic 12
Lumbar 5
Sacral 5
Coccygeal 1

3. The Cervical Plexus

4. The cervical plexus is a network of nerves formed by
communications between the anterior rami of the
upper 4 cervical nerves.

5. It lies posterior to the internal jugular vein and
the SCM muscles.

6. -supplies the back and
sides of the head, and
front of the neck;
phrenic nerve –
supplies the
diaphragm.

9. Branches of the
Cervical Plexus

10. Branches of the
Cervical Plexus
• A. Superficial or Cutaneous Branches
• Deep branches or muscular and
communicating branches

11. A. Superficial or
Cutaneous Branches

12. 1. Ascending branches
a. Lesser occipital nerve
b. Great auricular nerve
c. Nervus cutaneous colli
2. Descending branches
a. Medial supraclavicular
b. Intermediate supraclavicular
c. Lateral supraclavicular

13. 1. ASCENDING BRANCHES

14. a. Lesser occipital
nerve
b. Great auricular
nerve
c. Transverse
cervical nerve

15. A. LESSER OCCIPITAL NERVE

16. - Comes from the second cervical ventral ramus
and sometimes also from the third

17. - curves around the accessory nerve and ascends along
the posterior border of the sternocleidomastoid.

18. - supplies the skin on the upper third of the
medial auricular aspect

19. -connects with the posterior branch of the great
auricular nerve.

20. B. THE GREAT AURICULAR
NERVE

21. This is the largest ascending branch.

22. It arises from the second and third cervical rami,
encircles the posterior border of the
sternocleidomastoid.

23. supplies the skin over the mastoid process and on
the back of the auricle, the lobule and concha. .

24. communicates with the lesser occipital, the auricular
branch of the vagus and the posterior auricular branch
of the facial nerve.

25. C. TRANSVERSE CUTANEOUS NERVE

26. This arises from the second and third cervical
rami, curves round the posterior border of the
sternocleidomastoid

27. It perforates the deep cervical fascia, dividing under the
platysma into ascending and descending branches distributed to
the anterolateral areas of the neck.

28. distributed to the skin of the upper anterior areas of
the neck and anterolaterally to the skin of the neck, as
low as the sternum.

29. 2. DESCENDING BRANCHES

30. Supra Clavicular Nerves
• These arise by a common trunk from the third and fourth cervical ventral
rami and emerge from the posterior border of the sternocleidomastoid, to
descend under the platysma and the deep cervical fascia;

31. 3 Branches:
1. The medial
supraclavicular nerves
- supply the skin as
far as the midline and
as low as the second
rib. They supply the
sternoclavicular joint.

32. 2. The intermediate
supraclavicular nerves
-cross the clavicle
to supply the skin over
the pectoralis major
and deltoid down to
the level of the
second rib

33. 3. The lateral
supraclavicular nerves
- supply the skin of
the upper and
posterior parts of the
shoulder.

34. Deep branches or Muscular and
Communicating Branches

35. 1. Lateral Branches:
a. Muscular branches going to the following:
i. SCM
ii. Trapezius
iii. Levator scapula
iv. Scalenius medius
v. Scalenius posterior
b. Communicating branches to spinal accessory nerves

36. Deep Branches—Lateral Series
Muscular branches
Sternocleidomastoid
C2, 3, 4
Trapezius
C2, (3)
Levator scapulae
C3, 4
Scalenus medius
C3, 4
Communicating branches
Accessory Nerve
C2, 3, 4

37. 2. Medial branches:
a. Muscular branches going to the following muscles:
i. Prevertebral muscles
ii.Infrahyoid muscles thru the ansa
hypoglossi
iii. Diaphragm thru the phrenic nerve
b. Communicating branches to the vagus, hypoglossal
and sympathetic nerves
c. Phrenic nerve is the most important branch because it
supplies the diaphragm which is the chief muscle for
respiration. It is derived from cervical nerves 3, 4, and 5.

38. Communicating and Muscular Branches
(Medial Series)
Communicating branches with
Hypoglossal
C1, 2
Vagus
C1–2
Sympathetic
C1, 2

39. Muscular branches to
Rectus capitis lateralis C1
Rectus capitis anterior
Longus capitis C1–4
Longus colli
C1, 2
C2–4
Inferior root of ansa cervicalis
C2, 3
Phrenic nerve C3–5

40. THE ANSA HYPOGLOSSI

41. Formed by spinal nerves C1, C2, and
C3.
• 3 parts:
1. Superior root C1
- innervates the superior
belly of omohyoid
2. Inferior root C2, C3
3. Loop of ansa cervicalis
-innervates the
sternothyroid, sternohyoid,
inferior belly of omohyoid

42. THE PHRENIC NERVE

43. • Arises from the
converging APR of spinal
nerves C3, C4, and C5.
• This is the sole motor
supply to the diaphragm,
and also contains
widespread sensory
fibres.