PAROTID GLAND
>The parotid gland is the largest of the three pairs salivary gland.
>It is composed almost entirely of serous alveoli cells.
>It is lobulated, yellowish brown, and weighs about 25g.
#Location;parotid gland lies in the pyramidal fossa, posterior to the ramus of the
mandible called retromandibular Fossa.
# boundaries of parotid bed
Anterior Posterior border of ramus of mandible
Medial Styloid process
Posterior Mastoid process
Superior External acoustic meatus and posterior of TMJ
• Parotid bed is lined by muscles to make it soften
Area Muscle
Styloid process Styloglossus,stylohyoid, Stylopharyngeus
Mastoid process Medially -posterior belly of digastric muscle.
Laterally-sternocleidomastoid
Ramus of mandible Laterally-masseter, medially-medial pterygoid
• Parotid gland is soft so it is not confined to parotid bed it extends
beyond it
Above Extents from external auditory meatus
Below Upper part of carotid 📐
Medially Styloid process-and wraps around the neck of mandible
Posterior Sternocleidomastoid
Anterior Masseter
• Parotid gland is enclosed by fibrous capsule called parotid capsule
• It has two layers;
1. Thick superficial lamina
2. Thin deep lamina
• Thick superficial lamina is attached to zygomatic arch
• Thin deep lamina is attached to styloid process of temporal bone and
tympanic plate
1. Thickens to form stylomandibular ligament
2. It separates the parotid and sub Mandibular gland
• Parotid gland resembles three sided pyramid with
1. With apex directed towards upward
2. Four borders
3. Three boundaries
• It projects downwards overlapping the posterior belly of digastric
muscle and adjoining part of the carotid triangle.
• The structures emerging through the apex include
1. Cervical branch of the facial nerve.
2. Anterior and posterior divisions of retromandibular vein.
• Superior Surface or Base
1. It is concave
2. related to the external acoustic meatus and posterior aspect of
temporomandibular joint.
⁃ structures emerge
1. Superficial temporal vessels.
2. Auriculotemporal nerve.
Superficial surface
• Largest of all surface
• It is covered from superficial to deep by :
1. Skin.
2. Superficial fascia containing anterior branches of greater auricular
nerve, superficial parotid (preauricular) lymphnodes, and platysma.
3. Parotid fascia.
4. Deep parotid lymph nodes embedded in the gland.
• Anteromedial Surface
⁃ deeply grooved by the posterior border of the ramus of the mandible.
⁃ It is related to
1. Masseter.
2. Medial pterygoid.
3. Posterior border of the ramus of the mandible.
4. Lateral aspect of the temporomandibular joint.
The branches of facial nerve emerge on face from underneath the anterior margin of
this surface
Posterior medial surface
• moulded onto the mastoid and styloid processes and their covering
muscles.
• It is related to
1. Mastoid process, sternocleidomastoid, and posterior belly of digastric.
2. Styloid process and styloid group of muscles.
3. The styloid process and its muscles separate the gland from internal
carotid artery, internal jugular vein, and last four cranial nerves.
4. The following structures enter the gland through this surface
⁃ Facial nerve trunk in its upper part.
⁃ External carotid artery in its lower part
Anterior Border:
• separates the superficial surface from the anteromedial surface.
• It is related to
⁃ Above the parotid duct
1. Temporal branch of the facial nerve.
2. Zygomatic branch of the facial nerve.
3. Transverse facial vessels.
4. Upper buccal branch of the facial nerve.
5. Parotid duct.
⁃ Below the parotid duct
1. Lower buccal branch of the facial nerve.
2. Marginal mandibular branch of the facial nerve.
• Posterior Border
⁃ It separates the superficial surface from the posteromedial surface.
⁃ The following structures emerge underneath this border
1. Posterior auricular vessels.
2. Posterior auricular branch of the facial nerve.
• Medial Border
⁃ It separates the anteromedial surface from the posteromedial surface.
⁃ It is related to the lateral wall of the pharynx.
Structure present within the parotid gland
• Three main structures present within the parotid gland
• From superficial to deep
1. Facial nerve.
2. Retromandibular vein.
3. External carotid artery.
Facial nerve:
⁃ most superficial.
⁃ Enters the gland through the upper part of posteromedial surface
⁃ Divide into terminal branches within gland
⁃ It leaves the gland horizontally through anteromedial surfaces
⁃ Appears on the face by passing underneath the anterior border
⁃ The five terminal branches of the facial nerve radiate like a goose-
foot through the anterior border of the gland and such branching pattern of the
facial nerve is termed pes anserinus.
⁃ Supply for muscles of facial expressions
Retromandibular vein :
⁃ occupies the intermediate zone of the gland
⁃ formed by the union of the superficial temporal and maxillary veins.
⁃ ends below by dividing into anterior and posterior divisions.
⁃ anterior division joins the facial vein to form the common facial vein
⁃ posterior division joins the posterior auricular vein to form the
external jugular vein
External carotid artery :
⁃ pierces the lower part of the posteromedial surface to enter the gland
⁃ it occupies the deep zone of the gland.
⁃ it divides into superficial temporal and maxillary arteries
⁃ The transverse facial artery, branch of superficial temporal artery
emerges through the anterior border of the gland.
