Parotid Region - khaleelya.files.wordpress.com
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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