SALIVARY GLANDS ANATOMICAL ILLUSTRATIONS

salivary glands

1. SALIVARY GLANDS

2. 2 Gland - Group of cells in an animal's body that synthesizes substances for release into the bloodstream ( endocrine gland ) or into cavities inside the body or its outer surface ( exocrine gland ).

3. Types of gland

4. SALIVARY GLAND Introduction Classification Boundaries Blood and nerve supply Development Clinical Anatomy 4

5. introduction There are three pairs of large salivary glands-the parotid, submandibular and sublingual. In addition, there are numerous small glands in the tongue, the palate, the cheeks and the lips. Why this salivary glands are important? They produces Saliva which is a complex fluid which keeps oral cavity moist and forms a film that coats the teeth and mucosa. Also contains enzymes which helps in digestion of food Definition: Salivary glands are compound , tubuloacinar , merocrine, exocrine glands, ducts of whoich opens into the oral cavity

6. Classification of salivary glands 6 Based on the size & location, they are classified as : Minor salivary glands – located in various parts of the oral cavity Lingual, Labial, Palatal, Buccal, Glossopalatine , Retromolar Major salivary glands - 3 pairs Parotid gland Submandibular gland Sublingual gland

7. Classification of salivary glands 7 Based on the type of secretion, they are classified as : Serous secreting glands Eg – Parotid glands, von Ebner’s gland. Mucus secreting glands Eg - glands of blandin & nuh , glosso palatine glands. Mixed glands Eg – submandibular gland, sublingual gland.

8. Parotid gland FEATURES (para=around, otic =ear) Largest major salivary gland It is purely serous gland. It weighs about 25 gms . It is situated below the external acoustic meatus, between the ramus of the mandible and the sternocleidomastoid. Parotid gland contains vertically disposed blood vessels and horizontally situated facial nerve and its various branches

9. CAPSULE OF PAROTID GLAND The investing layer of the deep cervical fascia forms a capsule for the gland and it is supplied by great auricular nerve. The fascia splits (between the angle of the mandible and the mastoid process) to enclose the gland. It has superficial lamina/ parotidomassetric fascia & the deep lamina.A portion of the deep lamina, extending between the styloid process and the mandible, is thickened to form the stylomandibular ligament which separates the parotid gland from the submandibular salivary gland. The ligament is pierced by the external carotid artery.

10. EXTERNAL FEATURES The gland resembles a three-sided pyramid. The apex of the pyramid is directed downwards. T he gland has four surfaces: a. Superior (base of the pyramid) b. Superficial c. Anteromedial d. Posteromedial The surfaces are separated by three borders: a. Anterior b. Posterior c. Medial/pharyngeal

11. SUBMANDIBULAR SALIVARY GLAND Features This is a large salivary gland, situated in the anterior part of the digastric triangle. The gland is about the size of a walnut weighing about 15 to 20 g. It is roughly J-shaped, being indented by the posterior border of the mylohyoid which divides it into a larger part superficial to the muscle, and a small part lying deep to the muscle

12. Coverings : The gland is partially enclosed between two layers of deep cervical fascia. The superficial layer of fascia covers the inferior surface of the gland and is attached to the base of the mandible. The deep layer covers the medial surface of the gland and is superiorly to the mylohyoid line of the mandible .

13. DISSECTION Submandibular gland is seen in the digastric triangle. On pushing the superficial part of the gland posteriorly, the entire mylohyoid muscle is exposed. The deep part of the gland lies on the superior surface of the muscle. Separate the facial artery from the deep surface of gland and identify its branches in neck. The hyoglossus muscle is recognised as a quadrilateral muscle lying on deeper plane than mylohyoid muscle. Identify lingual nerve with submandibular ganglion, and hypoglossal nerve running on the hyoglossus muscle from lateral to the medial side. Deep part of gland and its duct are also visible on this surface of hyoglossus muscle. Carefully release the hyoglossus muscle from the hyoid bone and reflect it towards the tongue. Note the structures deep to the muscle, e.g. genioglossus muscle, lingual artery, vein and middle constrictor of the pharynx.

14. Superficial Part This part of the gland fills the digastric triangle. It extends superiorly deep to the mandible up to the mylohyoid line. Inferiorly: It overlaps stylohyoid and the posterior belly of digastric . It has three surfaces: a.Inferior b. Lateral c. Medial.

15. Relations The inferior surface is covered by: a. Skin b. Platysma c. Cervical branch of the facial nerve d. Deep fascia e. Facial vein f. Submandibular lymph nodes.

16. 20 The lateral surface is related to: a. The submandibular fossa on the mandible b. Insertion of the medial pterygoid c. The facial artery. The medial surface is related to: Anterior part: Mylohyoid, submental branch of facial artery, mylohyoid nerve and vessels Middle part: Hyoglossus, styloglossus, lingual artery, XII nerve • Posterior part: Stylohyoid, styloglossus, IX nerve.

17. 21 Deep Part This part is small in size. It lies deep to the mylohyoid, and superficial to the hyoglossus and the styloglossus. Posteriorly, it is continuous with the superficial part around the posterior border of the mylohyoid. Anteriorly, it extends up to the posterior end of the sublingual gland. Relations Present in between mylohyoid and hyoglossus. Laterally – Mylohyoid Medially – Hyoglossus Above – Lingual nerve with submandibular ganglion Below – Hypoglossal nerve

18. Blood Supply and Lymphatic Drainage The submandibular gland is supplied by the facial artery. The facial artery arises from the external carotid just above the tip of the greater cornua of the hyoid bone. The cervical part of the facial artery runs upwards on the superior constrictor of pharynx deep to the posterior belly of the digastric, and stylohyoid to the ramus of the mandible. It grooves the posterior end of the submandibular salivary gland. Next the artery makes an S-bend (two loops) first winding down over the submandibular gland, and then up over the base of the mandible .Facial artery is palpable on the base of mandible at the anteroinferior angle of masseter muscle. The veins drain into the common facial or lingual vein. Lymph passes to submandibular lymph nodes.

19. 23 Nerve Supply It is supplied by branches from the submandibular ganglion. These branches convey: 1 Secretomotor fibres. 2 Sensory fibres from the lingual nerve 3 Vasomotor sympathetic fibres from the plexus on the facial artery. SUBMANDIBULAR DUCT/WHARTON’S DUCT It is thin walled, and is about 5 cm long. It emerges at the anterior end of the deep part of the gland and runs upwards and forwards on the hyoglossus, between the lingual and hypoglossal nerves. At the anterior border of the hyoglossus, the duct is crossed by the lingual nerve . It opens on the floor of the mouth, on the summit of the sublingual papilla, at the side of the frenulum of the tongue.

20. SUBMANDIBULAR SALIVARY GLAND Features This is a large salivary gland, situated in the anterior part of the digastric triangle. The gland is about the size of a walnut weighing about 15 to 20 g. It is roughly J-shaped, being indented by the posterior border of the mylohyoid which divides it into a larger part superficial to the muscle, and a small part lying deep to the muscle

21. Coverings : The gland is partially enclosed between two layers of deep cervical fascia. The superficial layer of fascia covers the inferior surface of the gland and is attached to the base of the mandible. The deep layer covers the medial surface of the gland and is superiorly to the mylohyoid line of the mandible .

22. DISSECTION Submandibular gland is seen in the digastric triangle. On pushing the superficial part of the gland posteriorly, the entire mylohyoid muscle is exposed. The deep part of the gland lies on the superior surface of the muscle. Separate the facial artery from the deep surface of gland and identify its branches in neck. The hyoglossus muscle is recognised as a quadrilateral muscle lying on deeper plane than mylohyoid muscle. Identify lingual nerve with submandibular ganglion, and hypoglossal nerve running on the hyoglossus muscle from lateral to the medial side. Deep part of gland and its duct are also visible on this surface of hyoglossus muscle. Carefully release the hyoglossus muscle from the hyoid bone and reflect it towards the tongue. Note the structures deep to the muscle, e.g. genioglossus muscle, lingual artery, vein and middle constrictor of the pharynx.

23. Superficial Part This part of the gland fills the digastric triangle. It extends superiorly deep to the mandible up to the mylohyoid line. Inferiorly: It overlaps stylohyoid and the posterior belly of digastric . It has three surfaces: a.Inferior b. Lateral c. Medial.

24. Relations The inferior surface is covered by: a. Skin b. Platysma c. Cervical branch of the facial nerve d. Deep fascia e. Facial vein f. Submandibular lymph nodes.

25. 29 The lateral surface is related to: a. The submandibular fossa on the mandible b. Insertion of the medial pterygoid c. The facial artery. The medial surface is related to: Anterior part: Mylohyoid, submental branch of facial artery, mylohyoid nerve and vessels Middle part: Hyoglossus, styloglossus, lingual artery, XII nerve • Posterior part: Stylohyoid, styloglossus, IX nerve.

26. 30 Deep Part This part is small in size. It lies deep to the mylohyoid, and superficial to the hyoglossus and the styloglossus. Posteriorly, it is continuous with the superficial part around the posterior border of the mylohyoid. Anteriorly, it extends up to the posterior end of the sublingual gland. Relations Present in between mylohyoid and hyoglossus. Laterally – Mylohyoid Medially – Hyoglossus Above – Lingual nerve with submandibular ganglion Below – Hypoglossal nerve

27. Blood Supply and Lymphatic Drainage The submandibular gland is supplied by the facial artery. The facial artery arises from the external carotid just above the tip of the greater cornua of the hyoid bone. The cervical part of the facial artery runs upwards on the superior constrictor of pharynx deep to the posterior belly of the digastric, and stylohyoid to the ramus of the mandible. It grooves the posterior end of the submandibular salivary gland. Next the artery makes an S-bend (two loops) first winding down over the submandibular gland, and then up over the base of the mandible .Facial artery is palpable on the base of mandible at the anteroinferior angle of masseter muscle. The veins drain into the common facial or lingual vein. Lymph passes to submandibular lymph nodes.

28. 32 Nerve Supply It is supplied by branches from the submandibular ganglion. These branches convey: 1 Secretomotor fibres. 2 Sensory fibres from the lingual nerve 3 Vasomotor sympathetic fibres from the plexus on the facial artery. SUBMANDIBULAR DUCT/WHARTON’S DUCT It is thin walled, and is about 5 cm long. It emerges at the anterior end of the deep part of the gland and runs upwards and forwards on the hyoglossus, between the lingual and hypoglossal nerves. At the anterior border of the hyoglossus, the duct is crossed by the lingual nerve . It opens on the floor of the mouth, on the summit of the sublingual papilla, at the side of the frenulum of the tongue.

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