THE CERVICAL PLEXUS:
Netter Plate Number: 27B

Anterior Primary Rami
Cutaneous senory branches:
Arising from posterior border of SCM, just above the midpoint (from anterior primary rami)
1. Great Auricular- C2 and C3
To skin over lower half of pinna and over angle of mandible
2. Lesser Occipital- C2 and C3
To scalp posterior to ear
3. Transverse Cervical- C2 and C3
Cutaneous sensation to the anterior triangle of the neck.
4. Supraclavicular- C3 and C4
To skin over clavicle and cape area of the shoulder. This nerve reaches out to the point of the shoulder. (note: pain from the diaphragm refers to this area)

Muscular branches
1. Superior root of ansa cervicalis: C1 and C2
2. Inferior root of ansa cervicalis: C2 and C3
3. Phrenic: C3, C4, and C5 (Major contribution is C4).
4. Nerve to levator scapulae: off of C3 & C4

Sensory branches:
6. Nerve to trapezius: off of C3 & C4
7. Nerve to SCM: off of C2 & C3

Posterior primary rami
C1 Suboccipital- motor to deep neck muscles
C2 Greater Occipital- sensory to posterior scalp
C3 Occipitalis tertious (least occipital)- sensory to posterior neck

*Of note, C1 has NO cutaneous distribution in the body (no C1 dermatome).