The cervical plexus is a

nerve plexus A nerve plexus is a plexus (branching network) of intersecting nerves. A nerve plexus is composed of afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels. There are five spinal nerve ple ...

of the

anterior rami The ventral ramus (: rami) (Latin for 'branch') is the anterior division of a spinal nerve. The ventral rami supply the antero-lateral parts of the trunk and the limbs. They are mainly larger than the dorsal rami. Shortly after a spinal nerve e ...

of the first (i.e. upper-most) four cervical spinal nerves C1-C4. The cervical plexus provides motor innervation to some muscles of the neck, and the diaphragm; it provides sensory innervation to parts of the head, neck, and chest.

Anatomy

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 The accessory nerve, also known as the eleventh cranial nerve, cranial nerve XI, or simply CN XI, is a cranial nerve that supplies the sternocleidomastoid and trapezius muscles. It is classified as the eleventh of twelve pairs of cranial nerv ...

hypoglossal nerve The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated b ...

and sympathetic trunk. It is located in the

neck The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body. Addition ...

, deep to the

sternocleidomastoid The sternocleidomastoid muscle is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. The sternocleidomastoid is innervated by the acces ...

muscle. 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.

Relations

The cervical plexus is situated deep to the

sternocleidomastoid muscle The sternocleidomastoid muscle is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and Anatomical terms of motion#Flexion and extension, flexion of the neck. ...

internal jugular vein The internal jugular vein is a paired jugular vein that collects blood from the brain and the superficial parts of the face and neck. This vein runs in the carotid sheath with the common carotid artery and vagus nerve. It begins in the posteri ...

, and

deep cervical fascia The deep cervical fascia (or fascia colli in older texts) lies under cover of the platysma, and invests the muscles of the neck; it also forms sheaths for the carotid vessels, and for the structures situated in front of the vertebral column. Its ...

. It is situated anterior to the middle scalene muscle, and

levator scapulae muscle The levator scapulae is a slender skeletal muscle Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous s ...

Branches

The cervical plexus has two types of branches:

cutaneous Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different d ...

and muscular. *Cutaneous (4 branches): ** Lesser occipital nerve - innervates the skin and the scalp posterosuperior to the auricle (C2) **

Great auricular nerve The great auricular nerve is a Cutaneous nerve, cutaneous (sensory) nerve of the head. It originates from the second and third spinal nerve, cervical (spinal) nerves (C2-C3) of the cervical plexus. It provides sensory innervation to the skin over ...

- innervates skin near concha auricle ( outer ear) and external acoustic meatus (

ear canal The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the auricle to the eardrum and is about in length and in diameter. S ...

) (C2-C3) ** Transverse cervical nerve - innervates anterior region of neck (C2 and C3) ** Supraclavicular nerves - innervate the skin above and below the clavicle (C3-C4)Clinically Oriented Anatomy by Moore and Dally's *Muscular ** Ansa cervicalis - a loop formed by C1-C3 that supplies most infrahyoid (a.k.a. "strap") muscles ( sternothyroid, sternohyoid, omohyoid muscles) etc. ** Nerve to thyrohyoid - fibres from C1 that run with the hypoglossal nerve (cranial nerve XII) and do not participate in the formation of the superior root of ansa cervicalis, instead continuing for some further distance to reach and innervate the

thyrohyoid muscle The thyrohyoid muscle is a small skeletal muscle of the neck. Above, it attaches onto the greater cornu of the hyoid bone; below, it attaches onto the oblique line of the thyroid cartilage. It is innervated by fibres derived from the cervical spin ...

and the geniohyoid muscle. ** Phrenic (C3-C5, but mostly C4) - innervates

thoracic diaphragm The thoracic diaphragm, or simply the diaphragm (; ), is a sheet of internal Skeletal striated muscle, skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm is the most important Muscles ...

and the

pericardium The pericardium (: pericardia), also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong inelastic connective tissue (fibrous pericardium), ...

. **Segmental branches (C1-C4) - innervate anterior and middle scalene muscles **

Levator scapulae muscle The levator scapulae is a slender skeletal muscle Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous s ...

(C3-C4) (also innervated by

dorsal scapular nerve The dorsal scapular nerve is a branch of the brachial plexus, usually derived from the ventral ramus of cervical nerve C5. It provides motor innervation to the rhomboid major muscle, rhomboid minor muscle, and levator scapulae muscle. Dorsal ...

(C5) of the

brachial plexus The brachial plexus is a network of nerves (nerve plexus) formed by the anterior rami of the lower four Spinal nerve#Cervical nerves, cervical nerves and first Spinal nerve#Thoracic nerves, thoracic nerve (cervical spinal nerve 5, C5, Cervical spi ...

)

Diagram

Additional images

Image:Gray804.png, Plan of the cervical plexus. Image:Gray805.png, The nerves of the scalp, face, and side of neck. Image:Gray838.png, The right sympathetic chain and its connections with the thoracic, abdominal, and pelvic plexuses. Image:Gray1210.png, Side of neck, showing chief surface markings.

References

External links

* - "Diagram of the cervical plexus" *
Diagram at msu.edu
{{Authority control Nerve plexus Spinal nerves Nerves of the head and neck Thoracic nerves