Cervical Plexus

CERVICAL PLEX

Formed by the ventral branches of the four upper cervical nerves, it innervates some neck muscles, the diaphragm, and skin areas on the head, neck, and chest.

Each ventral branch anastomizes with the subsequent one forming three lateral convexity loops (C1 with C2, C2 with C3 and C3 with C4). From these three loops derive branches that constitute the two parts of the cervical plexus (superficial and deep).

The superficial part consists of essentially sensitive fibers, which form a bundle that appears at the middle of the posterior edge of the sternocleidomastoid muscle, at which point the strands fan out to the skin in the surrounding region, to the ear pavilion, to the skin. of the neck and the region near the collarbone.

The deep part of the plexus is made up of motor fibers, intended for the anterolateral neck muscles and the diaphragm. For this, in addition to branches that come out separately from the three loops, we find two important formations that are the cervical loop and the phrenic nerve.

The cervical loop consists of two roots, one upper and one lower. The upper root of the cervical loop reaches the hypoglossal nerve as it descends into the neck. The inferior root descends a few centimeters laterally to the internal jugular vein, then bends forward, anastomosing with the superior root.

The cervical loop emits branches that innervate all infrahyoid muscles.

The phrenic nerve, formed by motor fibers that derive from C3, C4 and C5, descends in front of the anterior scalene muscle, passes close to the pericardium, to distribute in the diaphragm.

Each branch, except the first, is divided into ascending and descending parts that unite into communicating loops. From the first loop (C2 and C3), superficial branches originate that innervate the head and neck; from the second loop (C3 and C4) the cutaneous nerves of the shoulder and thorax originate. The branches are shallow or deep; the superficial ones pierce the cervical fascia to innervate the skin, while the deep branches innervate the muscles.

The superficial branches form ascending and descending groups and the deep medial and lateral series.

Rising Surfaces:

 Minor Occipital Nerve (C2) & #8211; innervates the skin posterior to the ear pavilion;

OCCIPITAL NERVE MINOR
 
OCCIPITAL NERVE MINOR
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

 Great Auricular Nerve (C2 and C3) & #8211; its anterior branch innervates the skin of the face over the parotid gland communicating with the facial nerve; the posterior branch innervates the skin over the mastoid process and the back of the ear pavilion;

 Transverse Neck Nerve (C2 and C3) & #8211; its ascending branches rise to the submandibular region forming a plexus with the cervical branch of the facial nerve below the platysma; The descending branches pierce the platysma and are distributed anterolaterally to the skin of the neck to the lower part of the sternum.

Descending Surface:

 Medial Supraclavicular Nerves (C3 and C4) & #8211; innervate the skin to the midline, lower second rib, and sternoclavicular joint;

 Intermediate Supraclavicular Nerves & #8211; innervate the skin over the pectoralis major and deltoid muscles along the level of the second rib;

 Lateral Supraclavicular Nerves & #8211; innervate the skin of the upper and posterior parts of the shoulder.

Deep Branches & #8211; Medial Series:

Branches communicating with the halibut, vague and sympathetic; muscle branches innervate the muscles lateral rectus of the head (C1), rectus anterior of the head (C1 and C2), long of the head (C1, C2 and C3), long of the neck (C2-C4), lower root of the cervical loop ( C2-C3), infra-hyoid muscles (except the thyroid-hyoid) and phrenic nerve (C3-C5), which innervates the diaphragm.

Phrenic Nerve
 
Phrenic Nerve
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

Deep Branches & #8211; Side Series:

The lateral deep branches of the cervical plexus communicate with the spinal roots of the accessory nerve (C2, C3, C4) in the sternocleidomastoid muscle, posterior neck triangle, and posterior trapezius; the muscular branches are distributed to the sternocleidomastoid muscle (C2, C3, C4) and to the trapezius (C2, C3), scapular lifter (C3, C4) and middle scalene (C3, C4) muscles.

CERVICAL PLEX
 CERVICAL PLEXO - SCHEME
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

CERVICAL PLEX
 CERVICAL PLEX
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

CERVICAL PLEX
CERVICAL PLEX
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.