Nervous System IV

Question 1

What are the nerve plexuses?

Answer 1

Nerve plexuses
-network of nerve axons from anterior rami

Principal spinal nerve plexuses
1. Cervical
C1-C5

2. Brachial
   C5-T1
3. Lumbar
   L1-L4
4. Sacral
   L4-L5 & S1-S4
5. Coccygeal
   S4-S5+ coccygeal nerves

Question 2

Describe the cervical plexus

Answer 2

Anterior rami of C1-C4 with contribution from C5

Supplies skin & muscles of head, neck, superior shoulder and chest

Question 3

What are the superior (sensory ) branches of the cervical plexuses?

Answer 3

Lesser occipital-C2- skin of scalp posterior and superior to ear

Great auricular(aw-RIK-u-lar)- C2-C3- skin anterior, inferior and over ear and over parotid glands

Transverse cervical- C2-C3- Skin over anterior aspect of neck

Supreclavicular- C3-C4- Skin over superior portion of chest and shoulder

Question 4

What are the deep(largely motor) branches of the cervical plexuses?

Answer 4

Ansa cervicalis - this nerve divides into superior and inferior roots

Superior root-C1-Infrahyoid and geniohyoid muscles of neck

Inferior root-C2-C3-infrahyoid muscles of the neck

Phrenic nerve-C3-C5- Diaphragm

Segmental branches- C1-C5- PREVERTEBRAL (deep) muscles of neck, legation scapulae and middle scalene muscles