====== PAROTID GLAND ====== {{ :maps:parotid_region_.svg |}} {{:anatomy:parotid_gland_-development.png}} {{:anatomy:parotid_gland_surface.png}} {{:anatomy:parotid_gland.png}} {{:anatomy:parotid-region.png}} parotid region * features * largest of salivary gland * situated below external acoustic meatus * between the ramus of mandible and sternocleidomastoid * skin over gland supplied by greater auricular nerve * structures within parotid gland * arteries * external carotid artery enters gland through posteromedial surface * maxillary artery leaves the gland through its anteromedial surface * superficial temporal artery gives transverse facial artery and emerges at the * anterior part of superior surface * veins * retromandibular vein is formed within the gland * union of * superficial tempora and maxillary veins * in lower part of gland vein divides in t * these emerge close the apex (lower pole * anterior division * posterior division * nerve * facial nerve is the nerve of second branchial arch * leaves the skull by passing through stylomastoid foramen * extracranial course * 1. crosses the lateral side of base of styloid process * then enters the posteromedial surface of partodi gland * branches at its exit from stylomastoid foramen * communicating branches with adjacent cranial and spinal nerves * posterior auricular nerve arises just below the stylomastoid foramen * ascends between mastoid process and external acoustic meatus * supplies * auricularis posterior * occipitalis * intrinisic muscles on back of auricle * digastric branch arises close to previous nerve * short and supplies posterior belly of digastric * stylohyoid branch arises with digastric branch * long and supplies stylohyoid muscle * terminal branches * temporal branches cross zygomatic arch and supply * auricularis anterior * auricularis superior * intrinsic muscles on the lateral side of ear * frontalis * orbicularis oculi * corrugator supercili * zygomatic branches * run across zygomatic bone * supply orbicularis oculi * buccal branches are two in number * marginal mandibular branch * runs below the angle of mandible * deep to platysma * crosses body of mandible supplies * muscles of lower lip and chin * cervical branch * emerges from apex of parotid gland * runs downwards and forwards in the neck to supply platysma * bells palsy * sudden paralysis of facial nerve at stylomastoid foramen * results in asymmetry of corner of mouth * inability to close eye * dissapearance of nasolabial fold * loss of wrinkling of skin of forehead on same side * nerve supply * parasympathetic nerves are secretomotor * reach the gland through auriculotemporal nerve * preganglionic fibres begin in inferior salivatory nucleus * pass through glossopharyngeal nerve * tympanic branch * relay in otic ganglion * sympathetic nerves * postganglionic * vasomotor * derived from plexus around middle meningeal artery * travel along branches of maxillary,external carotid artery and their branches * sensory nerves * to the gland come from * auriculotemporal nerve * parotid fascia innervated by sensory fibres of great auricular nerve * parotid duct or stensons duct * superiorly * accessory parotid gland * transverse facial vessels * upper buccal branch of facial nerve * inferiorly * lower buccal branch of facial nerve * anterior border of masseter * parotid duct turns medially and pierces * buccal pad of fat * buccopharyngeal fascia * buccinator * contains * largest salivary gland * histology * it is a serous acini * external features * surfaces * superior (base of pyramid) * forms the upper end of the gland * small and concave * related to cartilaginous part of external acoustic meatus * posterior surface of temporomandibular joint * superficial temporal vessels * auriculotemporal nerve * superficial * largest surface * covered by * skin * superficial fascia * containing anterior branches of great auricular nerve * preauricular or superficial parotid lymph nodes * posterior fibres of platysma * risorius * parotid fascia which is thick and adherent * anteromedial * grooved by posterior border of ramus of mandible * related to * masseter * lateral surface of temporomandibular joint * posterior border of the ramus of mandible * medial pterygoid * emerging branches of facial nerve * posteromedial * moulded to mastoid * moulded to styloid processs * structures attached to them * related to * mastoid process * sternocleidomastoid * posterior belly of digastric * styloid process with structures attached to it * external carotid artery and facial nerve * enter the gland through this surface * internal carotid artery lies deep to styloid process * relations * borders * anterior * separates superficial surface from anteromedial surface * extends from anterior part of the superior surface to the apex * following structures emerge at this border * parotid duct * terminal braches of facial nerve * transverse facial vessels * posterior * separates superficial surface from posteromedial surface * overlaps sternocleidomastoid * medial / pharyngeal edge * separates anteromedial surface from posteromedial surface * related to lateral wall of pharynx * blood supply * parotid lymph nodes * CLINICAL ANATOMY * parotid abscess * caused by spread of infection from opening of parotid duct * drained by making holes (hiltons method) * mixed parotid tumour is slow growing tumour * parotid calculi may be formed in the parotid duct