VISCERA OF THE NECK

The cervical viscera are disposed in three layers, named for their primary function. Superficial to deep, they are the:

Endocrine layer: the thyroid and parathyroid glands.

Respiratory layer: the larynx and trachea.

Alimentary layer: the pharynx and esophagus

Endocrine Layer of Cervical Viscera

1. Thyroid Gland

lies deep to the sternothyroid and sternohyoid muscles, located anteriorly in the neck at the level of the C5-T1 vertebrae

It consists primarily of right and left lobes, anterolateral to the larynx and trachea.

The thyroid gland is the body's largest endocrine gland. It produces thyroid hormone, which controls the rate of metabolism, and calcitonin, a hormone controlling calcium metabolism. The thyroid gland affects all areas of the body except itself and the spleen, testes, and uterus.

Arteries of Thyroid Gland : the superior and inferior thyroid arteries.

Veins of Thyroid Gland : Superior, middle and inferior thyroid veins .

The lymphatic vessels of the thyroid gland run in the interlobular connective tissue (near the arteries), they communicate with a capsular network of lymphatic vessels. From here, the vessels pass initially to prelaryngeal, pretracheal, and paratracheal lymph nodes.

The prelaryngeal nodes the superior cervical lymph nodes,

The pretracheal and para-tracheal lymph nodes the inferior deep cervical nodes.

Laterally, lymphatic vessels located along the superior thyroid veins the inferior deep cervical lymph nodes. Some lymphatic vessels may drain into the brachiocephalic lymph nodes or the thoracic duct.

Nerves of Thyroid Gland: superior, middle, and inferior cervical (sympathetic) ganglia .

2. Parathyroid Gland

The small flattened, oval parathyroid glands usually lie external to the thyroid capsule on the medial half of the posterior surface of each lobe of the thyroid gland, inside its sheath. Most people have four parathyroid glands.

The hormone produced by the parathyroid glands, parathormone (PTH), controls the metabolism of phosphorus and calcium in the blood.

Arteries of Parathyroid Gland : inferior thyroid arteries, the superior thyroid arteries; the thyroid ima artery; or the laryngeal, tracheal, and esophageal arteries.

Veins of Thyroid Gland : thyroid plexus of veins

The lymphatic vessels : deep cervical lymph nodes and paratracheal lymph nodes

Respiratory Layer of Cervical Viscera

The viscera of the respiratory layer, the larynx and trachea, contribute to the respiratory functions of the body. The main functions of the cervical respiratory viscera are as follows:

Routing air and food into the respiratory tract and esophagus, respectively.

Providing a patent airway and a means of sealing it off temporarily.

Producing voice.

3. Larynx

The larynx is located in the anterior neck at the level of the bodies of C3-C6 vertebrae. It connects the inferior part of the pharynx (oropharynx) with the trachea.

The larynx is the complex organ of voice production (the voice box) composed of nine cartilages connected by membranes and ligaments and containing the vocal folds.

Arteries of Larynx: The laryngeal arteries (branches of the superior and inferior thyroid arteries). The superior laryngeal artery (supply the internal surface of the larynx). The cricothyroid artery (supplies the cricothyroid muscle). The inferior laryngeal artery (supplies the mucous membrane and muscles in the inferior part of the larynx)

Veins of Larynx: The laryngeal, The superior laryngeal vein usually joins the superior thyroid vein and through it drains into the IJV .The inferior laryngeal vein joins the inferior thyroid vein or the venous plexus of veins on the anterior aspect of the trachea, which empties into the left brachiocephalic vein.

Lymphatics of Larynx: The laryngeal lymphatic vessels superior to the vocal folds accompany the superior laryngeal artery through the thyrohyoid membrane and drain into the superior deep cervical lymph nodes. The lymphatic vessels inferior to the vocal folds drain into the pretracheal or paratracheal lymph nodes, which drain into the inferior deep cervical lymph nodes .

Nerves of Larynx: The nerves of the larynx are the superior and inferior laryngeal branches of the vagus nerves (CN X).

SUPERFICIAL STRUCTURES OF NECK: CERVICAL REGIONS

Terdapat empar regions dalam Neck

1. Sternocledomastoid Region

Dibentuk oleh SCM muscle, SCM muscle membagi setiap sisi leher ke dalam anterior dan lateral cervical Regions (anterior and posterior triangles).

SCM merupakan strap-like muscle yang punya two head tendon:

Rounded tendon of the sternal head yang attach ke manubrium

Clavicular head yang attach ke permukaan 1/3 superior clavicle.

Kedua head tendon SCM dipisahkan oleh small triangular depression, yaitu the lesser supraclavicular fossa.

Kedua tendon tersebut menyatu ke superior dengan arah oblique ke cranium.

Superior SCM melekat di the mastoid process dari the temporal bone dan the superior nuchal line of the occipital bone.

2. Lateral Cervical Region

- The lateral cervical region (posterior triangle) di batasi oleh :

Anteriorly by the posterior border of the SCM.

Posteriorly by the anterior border of the trapezius.

Inferiorly by the middle third of the clavicle between the trapezius and the SCM.

By an apex, where the SCM and trapezius meet on the superior nuchal line of the occipital bone.

By a roof, formed by the investing layer of deep cervical fascia.

By a floor, formed by muscles covered by the prevertebral layer of deep cervical fascia.

The lateral cervical region dibagi menjadi dua segitiga oleh the inferior belly of the omohyoid.: large occipital triangle superiorly ( terdapat occipital artery dan nerve penting yaitu spinal accessory (CN XI) dan a small omoclavicular triangle inferiorly (The inferior part of the EJV lewat pada segitiga ini, terdapat the subclavian artery).

ARTERIES IN LATERAL CERVICAL REGION: lateral branches of the thyrocervical trunk, the third part of the subclavian artery, and part of the occipital artery.

VEINS IN LATERAL CERVICAL REGION: The external jugular vein (EJV) begins near the angle of the mandible (just inferior to the auricle) by the union of the posterior division of the retromandibular vein with the posterior auricular vein .

NERVES OF LATERAL CERVICAL REGION: The spinal accessory nerve (CN XI)

LYMPH NODES IN LATERAL CERVICAL REGION:

Lymph from superficial tissues in the lateral cervical region enters the superficial cervical lymph nodes that lie along the EJV superficial to the SCM. Efferent vessels from these nodes drain into the deep cervical lymph nodes, which form a chain along the course of the IJV that is embedded in the fascia of the carotid sheath.