The parotid gland is the largest of the salivary glands. It is found wrapped around the mandibular ramus, and it secretes saliva through Stensen's duct into the oral cavity, to facilitate mastication and swallowing.
The facial nerve and its branches pass through the parotid gland, as does the external carotid artery, which gives off its two terminal branches, the maxillary artery and the superficial temporal artery, inside the gland.
The parotid gland resembles a three sided pyramid. The apex of the pyramid is directed downwards. the gland has four surfaces: (1) superior (2) superficial (3) anteromedial & (4) posteromedial. The surfaces are separated by three borders: (1) anterior (2) posterior & (3) medial.
Serous fluid (as opposed to mucous fluid) is produced by the parotid gland.
Secretion of saliva by the parotid gland is controlled by postsynaptic parasympathetic fibres originating in the inferior salivatory nucleus; these leave the brain via the typanic nerve (branch of glossopharyngeal nerve (CN IX), travel through the tympanic plexus (located in the middle ear), and then form the lesser petrosal nerve until reaching the otic ganglion. After synapsing in the Otic ganglion, the postganglionic (postsynaptic) fibers travel as part of the auriculotemporal nerve (a branch of the mandibular nerve (V3)) to reach the parotid gland.
Parasympathetic stimulation produces a water rich, serous saliva. Sympathetic stimulation leads to the production of a low volume, enzyme-rich saliva. This is done by vasoconstricting to blood supply to the parotid gland reducing the potential for water collection. There is no inhibitory nerve supply to the gland.
The maxillary vein and superficial temporal vein meet to form the retromandibular vein within the parotid gland, but are not responsible for draining it.
Lymphatics mainly comprise pre-auricular lymph nodes.
The most common of tumors in the parotid gland are benign and only affect the superficial gland. These include pleomorphic adenoma and adenolymphoma. Their importance is in relation to their anatomical position. The tumorous growth can also change the consistency of the gland and cause facial pain on the involved side since the facial nerve travels through the gland (Illustrated Head and Neck Anatomy, Fehrenbach and Herring, Elsevier, 2007, p. 172). Critically, the relationship of the tumor to the branches of the facial nerve (CN VII) must be defined because resection may damage the nerves, resulting in paralysis of the muscles of facial expression. If the tumor is deep within the gland, the patient should give consent for potential damage of the facial nerve.
Atrial Natriuretic Peptide Presence in Parotid Gland of Human Fetus at 13th Week of Development and in Adult Man
Mar 01, 2013; Abstract: Our immunohistochemical study shows that atrial natriuretic peptide (ANP) is present in both human fetal and adult...