PAROTID REGIONKHALEEL ALYAHYA, PHD, MED

www.khaleelalyahya.net

RESOURCES

By Elaine Marieb and Suzanne Keller

Essential of Human Anatomy & Physiology

By Richard Drake, Wayne Vogl & Adam Mitchell

Gray’s Anatomy

By Frank Netter

Atlas of Human Anatomy

SALIVARY GLANDS

▪ They are exocrine glands that produce saliva.

▪ There are three large named pairs of salivary glands and

multiple unnamed glands in the submucosa of the oral cavity.

Parotid produces a serous watery secretion.

Submandibular produces a mixed serous & mucous secretion.

Sublingual secretes a saliva that is mostly mucous.

Khaleel Alyahya, PhD, MEd

PAROTID GLAND

▪ It is a bilateral and paired structure located on both side of theface.

▪ It is the largest of the serous salivary glands.

▪ Function

• It produces about 30% of the serous salivary secretion rich inenzymes in the oral cavity.

▪ Position

• It lies within a deep hollow, known as the parotid region, boundedas:

o Superiorly – Zygomatic arch.

o Inferiorly – Inferior border of the mandible.

o Anteriorly – Masseter muscle.

o Posteriorly – External ear and sternocleidomastoid.Khaleel Alyahya, PhD, MEd

LOCATION

▪ It lies anterior to the external acoustic meatus between the

sternomastoid and masseter.

▪ Each one extends to the angle of the mandible.

▪ Occasional islet of parotid tissue separate from the mass of the

gland, lying anteriorly just above the beginning of the parotid

duct.

Khaleel Alyahya, PhD, MEd

PAROTID DUCT

▪ It is 5 cm long.

▪ Runs forwards Superficially to masseter muscle.

▪ Pierces the buccal fat and buccinator muscle.

▪ Opens into the vestibule of the mouth opposite the upper

second molar tooth.

▪ It is related to accessory part of the gland.

Khaleel Alyahya, PhD, MEd

SECRETION

▪ The secretions of the parotid gland are transported to the oral

cavity by the Stensen duct.

• It is named after a Danish anatomist Nicolas Steno (1638–1686).

▪ It arises from the anterior surface of the gland and crossing

the masseter muscle.

▪ The duct then pierces the buccinator moving medially.

▪ It then opens into the oral cavity near the 2nd upper molar.

Khaleel Alyahya, PhD, MEd

SHAPE

▪ It is pyramidal in shape.

▪ The upper base is concave and the lower is apex.

▪ Two borders:

▪ anterior convex

▪ posterior straight

▪ Three surfaces:

▪ lateral (superficial) surface.

▪ anteromedial surface.

▪ posteromedial surface.

Khaleel Alyahya, PhD, MEd

STRUCTURES COURSING THE GLAND

▪ Facial nerve:

• It divides the gland into two parts; superficial & deep parts.

• It divides into five terminal branches, which leave the gland as

o Temporal

o Zygomatic

o Buccal

o Mandibular

o Cervical nerves

▪ Formation of the Retromandibular vein.

▪ External carotid artery and its two terminal branches:

• Superficial temporal.

• Maxillary arteries.

Khaleel Alyahya, PhD, MEd

BLOOD VESSELS

▪ Arterial supply

Posterior auricular and superficial temporal arteries.

Both branches of the external carotid artery which arise within theparotid gland itself.

▪ Venous drainage

Venous drainage is achieved via the retromandibular vein.

It is formed by unification of the superficial temporal and maxillaryveins.

Khaleel Alyahya, PhD, MEd

INNERVATION

▪ The parotid gland receives sensory and autonomic innervation.

▪ The autonomic innervation controls the rate of saliva production.

▪ Sensory innervation is supplied by the auriculotemporal nerve (gland) andthe great auricular nerve (fascia).

▪ The parasympathetic innervation to the parotid gland begins withthe glossopharyngeal nerve (cranial nerve IX).

▪ This nerve synapses with the otic ganglion (a collection of neuronal cell bodies).

▪ The auriculotemporal nerve then carries parasympathetic fibres from the oticganglion to the parotid gland.

▪ Parasympathetic stimulation causes an increase in saliva production.

▪ Sympathetic innervation originates from the superior cervical ganglion, part of theparavertebral chain.

▪ Fibres from this ganglion travel along the external carotid artery to reach theparotid gland.

▪ Increased activity of the sympathetic nervous system inhibits saliva secretion, viavasoconstriction.

Khaleel Alyahya, PhD, MEd

CLINICALS

▪ Mumps

• A common cause of parotid gland swelling

• 85% of cases occur in children younger than 15 years.

• The disease is highly contagious and spreads by airborne droplets from salivary, nasal, and urinary

secretions.

• Symptoms include oedema in the area, trismus as well as otalgia. The lesion tends to begin on one

side of the face and eventually becomes bilateral.

▪ Parotitis

• It is an inflammation of one or both parotid glands.

• The most common cause of parotitis is mumps.

• Widespread vaccination against mumps has markedly reduced the incidence of mumps parotitis.

• The pain of mumps is due to the swelling of the gland within its fibrous capsule.

• Apart from viral infection, other infections, such as bacterial, can cause parotitis.

▪ Tumours

• The parotid gland is the most common site of a salivary gland tumour.

• These tumours are usually benign, such as an adenolymphoma.

• In contrast, tumours of the submandibular and sublingual glands are less common, but more likely

to be malignant.Khaleel Alyahya, PhD, MEd

QUESTIONS

alkhaleel@ksu.edu.sa