The neck contains important organs from the respiratory, endocrine and gastrointestinal systems.
The pharynx connects the nasal and oral cavities to the oesophagus and larynx. It is a tube of circular and longitudinal muscle innervated by its own pharyngeal plexus. Arterial supply is from branches of the external carotid while venous drainage is into the internal jugular vein. The pharynx is divided into the nasopharynx, oropharynx and laryngopharynx.
The larynx is a proximal component of the respiratory tract. Structurally, it is based on a cartilaginous scaffold bound by membranes, ligaments and intrinsic muscles. Extrinsic muscles move the larynx as a unit via their attachments to the hyoid bone. The vocal folds inside the larynx are mobile and give the organ its functions: to protect the more distal respiratory tract, to control phonation and to allow coughing.
The oesophagus is a muscular tube which conducts ingested food from the laryngopharynx to the stomach. It is lined internally by non-keratinized stratified squamous epithelium. The overlying muscle is layered in three different orientations to permit peristaltic contractions. The cricopharyngeus muscle forms an upper oesophageal sphincter which together with a functional lower oesophageal sphincter reduces air entry and gastric reflux.
The thyroid gland is found in the visceral compartment of the neck between the levels of C5 and T1, deep to the infrahyoid muscles. It has two broad lobes laterally which are joined medially by a narrower isthmus. Arterial supply to the thyroid is from bilateral superior and inferior thyroid arteries. The latter also supply the parathyroid glands: four small oval glands which sit in pairs immediately posterior to the lobes of the thyroid within its sheath.
In this section, learn more about the anatomy of the organs of the neck.
