Parotid salivary gland

PAROTID SALIVARY GLAND
(Ox, Sheep & Goat, Horse,Pig, Dog, Rabbit)

Ox (View image)

  • The parotid gland is situated below the ear in the space between the ramus of the mandible and the wing of atlas, overlapping the caudal part of the masseter muscle
  • It has the form of a very narrow triangle with its base upwards. It is light red brown in colour and weighs about 115 gm
  • It presents for description two surfaces, two borders, a base and an apex. The lateral surface is covered by the parotid fascia and the parotido-auricularis muscle
  • It is crossed obliquely by the external jugular vein at its lower part. The medial surface is uneven and has many important relations -the great cornu of the hyoid bone, masseter, digastric and occipito-hyoideus muscles, tendons of brachio-cephalicus and sterno-cephalicus muscles, external carotid artery and its branches, facial nerve and its branch, pharyngeal lymph gland and the sub-maxillary salivary gland.
  • The cranial border is closely attached to the masseter muscle and partly covers the parotid lymph gland
  • The caudal border is concave and is loosely attached to the surrounding structures
  • The base is superior and embraces the base of ear. The apex is bent forwards and fits in to the angle of union of the external jugular and external maxillary veins
  • The parotid duct or Stenson’s duct leaves the inferior part of the medial face of the gland and gains the medial face of the medial pterygoid muscle
  • It runs forwards in the mandibular space below the external maxillary vein, winds round the inferior border of the horizontal ramus of the mandible passes upwards in company with the facial vessels situated behind them and in front of the cranial border of the masseter muscle and covered by the inferior buccal nerve or its communicating branch to the superior buccal
  • It crosses the facial vessels and penetrates the cheek opposite to the upper fifth cheek tooth and opens on the summit of the papilla salivalis

Species difference

Sheep and Goat

  • The gland is darker in colour and more compact in texture than the mandibular
  • It is rounded in outline, but has a rounded cervical angle
  • The duct leaves the lower part of the cranial border of the gland and runs forward over the masseter muscle about an inch and a half above the ventral border of the ramus
  • It opens the third or fourth cheek tooth

Horse

  • The parotid is the largest salivary gland and weighs about 200 to 225 gm
  • It has a long quadrilateral outline
  • It is yellowish-grey in colour
  • Its medical face is related to the guttural pouch in addition to other structures
  • The apex is above, embracing the base of the ear. The base is inferior and is related to the external maxillary vein
  • The duct leaves the gland at its inferior part near the cranial border about one inch above the external maxillary vein
  • It opens on the papilla salivalis about the level of the upper third cheek tooth

Pig

  • It is large and distinctly triangular: its upper angle does not reach the base of the ear
  • Pale in colour
  • Parotid duct perforates the cheek opposite to the fourth or fifth upper cheek tooth
  • Small accessory parotid glands may be found along the course of the duct

Dog (Click to see the salivary glands in dog)

  • It is very small and irregularly triangular with its base upwards
  • The apex overlaps the mandibular gland. The dorsal end (base) shows a deep notch
  • The duct leaves the gland at the lower part of the cranial border, crosses the masseter muscle and opens into the mouth cavity opposite to the upper third cheek tooth
  • Small accessory glands are sometimes present along the course of the duct

Rabbit

  • It has three pairs of salivary glands – parotid, sublingual and infraorbital
  • The parotid gland is large lying below the ear along the caudal border of the mandible
  • The parotid duct opens behind upper incisors
Last modified: Friday, 20 April 2012, 9:22 AM