The parotid duct, or Stensen duct, is a salivary duct. It is the route that saliva takes from the major

salivary gland The salivary glands in mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands ( parotid, submandibular, and sublingual), as well as hundreds of minor salivary glands. Salivary ...

, the

parotid gland The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the ma ...

, into the mouth.

Structure

The parotid duct is formed when several interlobular ducts, the largest ducts inside the

, join. It emerges from the parotid gland. It runs forward along the

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction * Lateral cricoarytenoid muscle * Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral co ...

side of the

masseter muscle In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it ...

for around 7 cm. In this course, the duct is surrounded by the buccal fat pad. It takes a steep turn at the border of the masseter and passes through the

buccinator muscle The buccinator () is a thin quadrilateral muscle occupying the interval between the maxilla and the mandible at the side of the face. It forms the anterior part of the cheek or the lateral wall of the oral cavity.Illustrated Anatomy of the Head ...

, opening into the vestibule of the mouth, the region of the mouth between the

cheek The cheeks ( la, buccae) constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the insi ...

and the gums, at the parotid papilla, which lies across the second Maxillary (upper)

molar tooth The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...

. The buccinator acts as a valve that prevents air forcing into the duct, which would cause pneumoparotitis. Running along with the duct superiorly is the transverse facial artery and upper

buccal nerve The buccal nerve (long buccal nerve) is a nerve in the face. It is a branch of the mandibular nerve (which is itself a branch of the trigeminal nerve) and transmits sensory information from skin over the buccal membrane (in general, the cheek) an ...

; running along with the duct inferiorly is the lower buccal nerve. The exit of the parotid ducts can be felt as small bumps ( papillae) on both sides of the mouth, and are usually positioned next to the

maxillary second molar The maxillary second molar is the tooth located distally (away from the midline of the face) from both the maxillary first molars of the mouth but mesial (toward the midline of the face) from both maxillary third molars. This is true only in pe ...

Relations

The parotid duct lies close to the

buccal branch The buccal branches of the facial nerve (infraorbital branches), are of larger size than the rest of the branches, pass horizontally forward to be distributed below the orbit and around the mouth. Branches The ''superficial branches'' run beneath ...

of the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste ...

(VII). It is also close to the transverse facial artery.

Clinical significance

Blockage, whether caused by salivary duct stones or external compression, may cause pain and swelling of the

(

parotitis Parotitis is an inflammation of one or both parotid glands, the major salivary glands located on either side of the face, in humans. The parotid gland is the salivary gland most commonly affected by inflammation. Etymology From Greek παρωτῖ ...

Koplik's spots Koplik's spots (also Koplik's sign) are a prodromic viral enanthem of measles manifesting two to three days before the measles rash itself. They are characterized as clustered, white lesions on the buccal mucosa (opposite the lower 1st & 2nd ...

which are pathognomonic of measles are found near the opening of the parotid duct. The parotid duct may be cannulated by inserting a tube through the internal orifice in the mouth. Dye may be injected to allow for imaging of the parotid duct.

History

The parotid duct is named after

Nicolas Steno Niels Steensen ( da, Niels Steensen; Latinized to ''Nicolaus Steno'' or ''Nicolaus Stenonius''; 1 January 1638 – 25 November 1686Niels Stensen, a

Danish Danish may refer to: * Something of, from, or related to the country of Denmark People * A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark * Culture of Denmark * Danish people or Danes, people with a Danish a ...

anatomist Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...

(albeit best known as a

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althoug ...

) credited with its detailed description in 1660. This is where the alternative name "Stensen duct" originates from.

Additional images

File:Gray1200.png, Outline of side of face, showing chief surface markings. File:Parotid-interlobular duct.JPG, Microscopic slide of a human interlobular duct. File:Parotid-striated duct.JPG, Microscopic slide of a human striated duct. File:Parotid duct papillae.JPG, The left papilla (soft tissue protuberance at the exit) of the parotid duct is clearly visible on the cheek in the right of the photo. File:Slide6rrrr.JPG, Parotid duct File:Slide7yyyy.JPG, Parotid duct File:Slide3BBB.JPG, Parotid duct

References

External links

Diagram at MSU
* - Parotid duct injuries * {{Authority control Glands of mouth Saliva