Cervical plexus

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 sternocleidomastoid m. 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

Cervical plexus
Gray784
Dermatome distribution of the trigeminal nerve (Superficial cervical plexus visible in purple, at center bottom.)
Details
FromC1-C4
Identifiers
Latinplexus cervicalis
MeSHD002572
TAA14.2.02.012
FMA5904
Anatomical terms of neuroanatomy

Branches

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

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

Cervical plexus

Additional images

Gray804

Plan of the cervical plexus.

Gray805

The nerves of the scalp, face, and side of neck.

Gray838

The right sympathetic chain and its connections with the thoracic, abdominal, and pelvic plexuses.

Gray1210

Side of neck, showing chief surface markings.

See also

  • Cervical plexus block

References

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

External links

Ansa cervicalis

The ansa cervicalis (or ansa hypoglossi in older literature) is a loop of nerves that are part of the cervical plexus. It lies superficial to the internal jugular vein in the carotid triangle. Its name means "handle of the neck" in Latin.

Branches from the ansa cervicalis innervate most of the infrahyoid muscles, including the sternothyroid muscle, sternohyoid muscle, and the omohyoid muscle. Note that the thyrohyoid muscle, which is also an infrahyoid muscle, is innervated by cervical spinal nerve 1 via the hypoglossal nerve.

Auricular nerve

Auricular nerve may refer to:

Lesser auricular nerve, originates from the cervical plexus, composed of branches of spinal nerves C2 and C3

Posterior auricular nerve, arises from the facial nerve close to the stylomastoid foramen and runs upward in front of the mastoid process

Great auricular nerve, originates from the cervical plexus, composed of branches of spinal nerves C2 and C3.

Or any of the auricular branches

Cervical branch of the facial nerve

The cervical branch of the facial nerve runs forward beneath the platysma, and forms a series of arches across the side of the neck over the suprahyoid region. This nerve innervates the posterior belly of the Digastric muscle and the Stylohyoid muscle.

One branch descends to join the cervical cutaneous nerve from the cervical plexus. Also supplies the platysma muscle.

Cervical lymph nodes

Cervical lymph nodes are lymph nodes found in the neck. Of the 800 lymph nodes in the human body, 300 are in the neck. Cervical lymph nodes are subject to a number of different pathological conditions including tumours, infection and inflammation.

Great auricular nerve

The great auricular nerve (or greater auricular nerve) originates from the cervical plexus, composed of branches of spinal nerves C2 and C3. It provides sensory innervation for the skin over parotid gland and mastoid process, and both surfaces of the outer ear.

Lesser occipital nerve

The lesser occipital nerve or small occipital nerve is a cutaneous spinal nerve arising between the second and third cervical vertebrae, along with the greater occipital nerve. It innervates the scalp in the lateral area of the head posterior to the ear.

Longus capitis muscle

The longus capitis muscle (Latin for long muscle of the head, alternatively rectus capitis anticus major), is broad and thick above, narrow below, and arises by four tendinous slips, from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebræ, and ascends, converging toward its fellow of the opposite side, to be inserted into the inferior surface of the basilar part of the occipital bone.

It is innervated by a branch of cervical plexus.

Longus capitis has several actions:

acting unilaterally, to:

flex the head and neck laterally

rotate the head ipsilaterallyacting bilaterally:

flex the head and neck

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 plexuses, except in the thoracic region, as well as other forms of autonomic plexuses, many of which are a part of the enteric nervous system. The nerves that arise from the plexuses have both sensory and motor functions. These functions include muscle contraction, the maintenance of body coordination and control, and the reaction to sensations such as heat, cold, pain, and pressure. There are several plexuses in the body, including:

Spinal Plexuses

Cervical plexus - serves the head, neck and shoulders

Brachial plexus - serves the chest, shoulders, arms and hands

Lumbar plexus - serves the back, abdomen, groin, thighs, knees, and calves

Sacral plexus - serves the pelvis, buttocks, genitals, thighs, calves, and feet

Coccygeal plexus - serves a small region over the coccyx

Autonomic Plexuses

Celiac plexus (solar plexus) - serves internal organs

Auerbach's plexus (myenteric plexus) - serves the gastrointestinal tract

Meissner's plexus (submucosal plexus) - serves the gastrointestinal tract

Pharyngeal plexus of vagus nerve - serves the palate and pharynx

Cardiac plexus - serves the heart

Nerve point of neck

The nerve point of the neck, also known as Erb's point is a site at the upper trunk of the brachial plexus located 2–3 cm above the clavicle.

It is named for Wilhelm Heinrich Erb. Taken together, there are six types of nerves that meet at this point.

"Erb's point" is also a term used in head and neck surgery to describe the point on the posterior border of the sternocleidomastoid muscle where the four superficial branches of the cervical plexus—the greater auricular, lesser occipital, transverse cervical, and supraclavicular nerves—emerge from behind the muscle. This point is located approximately at the junction of the upper and middle thirds of this muscle. From here, the accessory nerve courses through the posterior triangle of the neck to enter the anterior border of the trapezius muscle at a point located approximately at the junction of the middle and lower thirds of the anterior border of this muscle. The spinal accessory nerve can often be found 1 cm above Erb's point.

Occipital triangle

The occipital triangle, the larger division of the posterior triangle, is bounded, in front, by the Sternocleidomastoideus; behind, by the Trapezius; below, by the Omohyoideus.

Its floor is formed from above downward by the Splenius capitis, Levator scapulæ, and the Scalenus medius and posterior.

It is covered by the skin, the superficial and deep fasciæ, and by the Platysma below.

The accessory nerve is directed obliquely across the space from the Sternocleidomastoideus, which it pierces, to the under surface of the Trapezius; below, the supraclavicular nerves and the transverse cervical vessels and the upper part of the brachial plexus cross the space.

The roof of this triangle is formed by the cutaneous nerves of cervical plexus and the external jugular vein and platysma muscle.

A chain of lymph glands is also found running along the posterior border of the Sternocleidomastoideus, from the mastoid process to the root of the neck.

Phrenic nerve

The phrenic nerve is a nerve that originates in the neck (C3-C5) and passes down between the lung and heart to reach the diaphragm. It takes its name from the Ancient Greek phren, meaning diaphragm. It is important for breathing, as it passes motor information to the diaphragm and receives sensory information from it. There are two phrenic nerves, a left and a right one.

The phrenic nerve originates mainly from the 4th cervical nerve, but also receives contributions from the 5th and 3rd cervical nerves (C3-C5) in humans. Thus, the phrenic nerve receives innervation from parts of both the cervical plexus and the brachial plexus of nerves.

The phrenic nerves contain motor, sensory, and sympathetic nerve fibers. These nerves provide the only motor supply to the diaphragm as well as sensation to the central tendon. In the thorax, each phrenic nerve supplies the mediastinal pleura and pericardium.

Plexus

A plexus (from the Latin for "braid") is a branching network of the vessels or nerves. The vessels may be blood vessels (veins, capillaries) or lymphatic vessels. The nerves are typically axons outside the central nervous system.

Although many medical words ending in -us that came to English from Latin have the plural suffix -i (and the plural form plexi indeed does exist in Latin), English does not use the -us/-i pattern for this particular term; the standard plural form in English is plexuses.

Spinal nerve

A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. There are eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves. The spinal nerves are part of the peripheral nervous system.

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 flexion of the neck. The sternocleidomastoid is innervated by the accessory nerve.

It is given the name sternocleidomastoid because it originates at the manubrium of the sternum (sterno-) and the clavicle (cleido-), and has an insertion at the mastoid process of the temporal bone of the skull.

Sternothyroid muscle

The Sternothyroideus (or sternothyroid muscle) is a muscle in the neck. It is shorter and wider than the sternohyoideus, beneath which it is situated.

It arises from the posterior surface of the manubrium sterni, below the origin of the sternohyoideus, and from the edge of the cartilage of the first rib, and sometimes that of the second rib, it is inserted into the oblique line on the lamina of the thyroid cartilage.

This muscle is in close contact with its fellow at the lower part of the neck, but diverges somewhat as it ascends; it is occasionally traversed by a transverse or oblique tendinous inscription.

Supraclavicular nerves

The supraclavicular nerves (descending branches) arise from the third and fourth cervical nerves; they emerge beneath the posterior border of the sternocleidomastoideus (sternocleidomastoid muscle), and descend in the posterior triangle of the neck beneath the platysma and deep cervical fascia.

Transverse cervical nerve

The transverse cervical nerve (superficial cervical or cutaneous cervical) arises from the second and third spinal nerves, turns around the posterior border of the sternocleidomastoideus about its middle, and, passing obliquely forward beneath the external jugular vein to the anterior border of the muscle, it perforates the deep cervical fascia, and divides beneath the Platysma into ascending and descending branches, which are distributed to the antero-lateral parts of the neck. It provides cutaneous innervation to this area.

During dissection, the sternocleidomastoid (SCM) is the landmark. The transverse cervical nerves will pass horizontally directly over the SCM from Erb's point.

Ventral ramus of spinal nerve

The ventral ramus (pl. 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 exits the intervertebral foramen, it branches into the dorsal ramus, ventral ramus, and ramus communicans. Each of these three structures carries both sensory and motor information. Because each spinal nerve carries both sensory and motor information, spinal nerves are referred to as “mixed nerves.”

In the thoracic region they remain distinct from each other and each innervates a narrow

strip of muscle and skin along the sides, chest, ribs, and abdominal wall. These rami are called the

intercostal nerves. In regions other than the thoracic, ventral rami converge with each other to form networks of nerves

called nerve plexuses. Within each plexus, fibers from the various ventral rami branch and

become redistributed so that each nerve exiting the plexus has fibers from several different spinal

nerves. One advantage to having plexuses is that damage to a single spinal nerve will not completely

paralyze a limb.

There are four main plexuses formed by the ventral rami:

the cervical plexus contains ventral rami from spinal nerves C1-C4. Branches of the

cervical plexus, which include the phrenic nerve, innervate muscles of the neck, the diaphragm, and the

skin of the neck and upper chest.

The brachial plexus contains ventral rami from spinal nerves C5-T1. This plexus innervates

the pectoral girdle and upper limb.

The lumbar plexus contains ventral rami from spinal nerves L1-L4. The sacral plexus contains ventral

rami from spinal nerves L4-S4. The lumbar and sacral plexuses innervate the pelvic girdle and lower

limbs.

Ventral rami, including the sinuvertebral nerve branches, also supply structures anterior to the facet joint, including the vertebral bodies, the discs and their ligaments, and joins other spinal nerves to form the lumbo-sacral plexus.

Cervical
Thoracic
Lumbar
Sacral
Coccygeal
Nerves of the cervical plexus
Superficial
Deep

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