Cervical plexus

Cervical plexus
	Dermatome distribution of the trigeminal nerve (Superficial cervical plexus visible in purple, at center bottom.)
Details
From	C1-C4
Identifiers
Latin	plexus cervicalis
MeSH	D002572
TA	A14.2.02.012
FMA	5904
	Anatomical terms of neuroanatomy

The cervical plexus is a plexus of the anterior rami of the first four cervical spinal nerves which arise from C1 to C4 cervical segment in the neck. They are located laterally to the transverse processes between prevertebral muscles from the medial side and vertebral (m. scalenus, m. levator scapulae, m. splenius cervicis) from lateral side. There is anastomosis with accessory nerve, hypoglossal nerve and sympathetic trunk.

It is located in the neck, deep to the sternocleidomastoid muscle. Nerves formed from the cervical plexus innervate the back of the head, as well as some neck muscles. The branches of the cervical plexus emerge from the posterior triangle at the nerve point, a point which lies midway on the posterior border of the sternocleidomastoid. Also from the posterior ramus of C2 greater occipital nerve arises

Branches

The cervical plexus has two types of branches: cutaneous and muscular.

Cutaneous (4 branches):
- Lesser occipital - innervates the skin and the scalp posterosuperior to the auricle (C2)
- Great auricular nerve - innervates skin near concha auricle (outer ear) and external acoustic meatus (ear canal) (C2&C3)
- Transverse cervical nerve - innervates anterior region of neck (C2 and C3)
- Supraclavicular nerves - innervate the skin above and below the clavicle (C3 and C4) [1]
Muscular
- Ansa cervicalis (This is a loop formed from C1-C3 which supplies the four infrahyoid aka strap muscles), etc. (thyrohyoid (C1 only), sternothyroid, sternohyoid, omohyoid)
- Phrenic (C3-C5 (primarily C4))-innervates diaphragm and the pericardium
- Segmental branches (C1-C4)- innervates anterior and middle scalenes

Additionally there are two branches formed by the posterior roots of spinal nerves:

Preauricular nerve (from the posterior roots of C2–C3)[2][3]
Postauricular nerve (from the posterior roots of C3–C4)[3]

Diagram

Additional images

Plan of the cervical plexus.
The nerves of the scalp, face, and side of neck.
The right sympathetic chain and its connections with the thoracic, abdominal, and pelvic plexuses.
Side of neck, showing chief surface markings.

References

Clinically Oriented Anatomy by Moore and Dally's
Robert Schwartzman (15 April 2008). Neurologic Examination. John Wiley & Sons. p. 58. ISBN 978-1-4051-7283-7.
R.J. Schwartzman (31 July 2006). Differential Diagnosis in Neurology. IOS Press. pp. 326–. ISBN 978-1-60750-179-4.

External links

Anatomy figure: 25:03-02 at Human Anatomy Online, SUNY Downstate Medical Center - "Diagram of the cervical plexus"
MedicalMnemonics.com: 268
Diagram at msu.edu

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[1] Clinically Oriented Anatomy by Moore and Dally's

[Schwartzman2008-2] Robert Schwartzman (15 April 2008). Neurologic Examination. John Wiley & Sons. p. 58. ISBN 978-1-4051-7283-7.

[Schwartzman2006-3] R.J. Schwartzman (31 July 2006). Differential Diagnosis in Neurology. IOS Press. pp. 326–. ISBN 978-1-60750-179-4.

Spinal nerves
Cervical	C1 C2 C3 C4 C5 C6 C7 C8 anterior Cervical plexus Brachial plexus posterior Posterior branches of cervical nerves Suboccipital – C1 Greater occipital – C2 Third occipital – C3
Thoracic	T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 anterior Intercostal Intercostobrachial – T2 Thoraco-abdominal nerves – T7–T11 Subcostal – T12 posterior Posterior branches of thoracic nerves
Lumbar	L1 L2 L3 L4 L5 anterior Lumbar plexus Lumbosacral trunk posterior Posterior branches of the lumbar nerves Superior cluneal L1–L3
Sacral	S1 S2 S3 S4 S5 anterior Sacral plexus posterior Posterior branches of sacral nerves Medial cluneal nerves
Coccygeal	anterior Coccygeal plexus posterior Posterior branch of coccygeal nerve

Nerves of the cervical plexus
Superficial	C2 Lesser occipital C2–C3 Greater auricular Transverse cervical C3–C4 Supraclavicular
Deep	C1–C3 Ansa cervicalis superior root inferior root C3–C5 Phrenic