By: Prof. Saeed Makarem

1. The Submandibular Region-II By: Prof. Saeed Makarem

2. Objectives By the end of this session the students should know: Salivary Glands Submandibular & Sublingual Parasympathetic Ganglion Submandibular Lymph Nodes Submandibular group

4. Submandibular Gland • It consists of a mixture of serous and mucous acini. • It lies beneath the lower border of the body of the mandible. • It is divided into superficial and deep parts by the mylohyoid muscle. • The deep part of the gland lies beneath the mucous membrane of the floor of the mouth. • The submandibular duct emerges from the anterior end of the deep part of the gland & runs forward beneath the mucous membrane of the mouth. • The duct opens into the floor of the mouth on a small papilla, which is situated at the side of the frenulum of the tongue.

5. RELATIONS OF THE SUPERFICIAL PART OF THE GLAND • Anteriorly: • anterior belly of digastric. • Posteriorly: • posterior belly of digastric , • stylohyoid & • parotid gland. • Medially: • mylohyoid, • hyoglossus, • lingual nerve, • submandibular ganglion • hypoglossal nerve. • Laterally: • submandibular fossa of the mandible. • NB. Inferolaterally, it is covered by the investing layer of deep cervical fascia, platysma & skin.

6. Anteriorly: • sublingual gland. • Posteriorly: • posterior belly of digastric & • stylohyoid, • parotid gland. • Medially: • hyoglossus & • styloglossus. • Laterally: • mylohyoid muscle & • superficial part of the gland. • Superiorly: • lingual nerve & • submandibular ganglion. • It is covered by the mucous membrane of floor of the mouth. • Inferiorly: • hypoglossal nerve. RELATIONSOFTHEDEEPPARTOFTHEGLAND

7. HYOGLOSSUS MUSCLE The hyoglossus is a flat, quadrilateral muscle. • Origin:from the upper border of the body and greater cornu of the hyoid bone. • Insertion: to the side of the tongue. • Action: depression of tongue. • Nerve supply:hypoglossal nerve. Prof. Makarem

8. SUBMANDIBULARDUCT • It emerges from the anterior end of the deep part of the gland. • It passes forward along the side of the tongue, beneath the mucous membrane of the floor of the mouth. • It is crossed laterally by the lingual nerve. • It then lies between the sublingual gland and the genioglossus muscle. • It opens at the summit of a small papilla, situated at the side of the frenulum of the tongue. • The duct and the deep part of the gland could be palpated through the mucous membrane of the floor of the mouth.

9. Sublingual Gland • The sublingual gland lies beneath the mucous membrane (sublingual fold) of the floor of the mouth, close to thefrenulumof the tongue • It has both serous and mucous acini. • The sublingual ducts (8 to 20 in number) open into the mouth on the summit of the sublingual fold. • Nerve Supply • Parasympathetic secretomotor supply is from the facial nerve via the chorda tympani, and the submandibular ganglion. • Postganglionic fibers pass directly to the gland.

10. Relations: • Anteriorly : the gland of the opposite side • Posteriorly: • deep part of the submandibular gland • Medially: • genioglossus muscle, • lingual nerve & • submandibular duct • Laterally: • sublingual fossa of the mandible • Superiorly: • mucous membrane of the floor of the mouth. The gland forms the sublingual fold. • inferiorly: • mylohyoid muscle. SUBLINGUALGLAND

11. SUBLINGUAL GLAND • Blood supply: • facial and lingual arteries. • Venous drainage: • into the facial and lingual veins. • Lymph drainage: • submandibular & deep cervical lymph nodes. • .

12. SUBMANDIBULAR GANGLION • Small parasympathetic ganglion • Location: • on the lateral surface of the hyoglossus muscle. • Suspended from the lingual nerve by several branches; • Preganglionic parasympathetic fibers reach the ganglion from the superior salivary nucleus of the facial nerve via the chorda tympani & lingual nerves. • The pre-ganglionic fibers synapse within the ganglion, and the post­ganglionic fibers pass to the submandibular & sublingual salivary glands.

13. SUBMANDIBULAR GANGLION 2/3

14. NERVE SUPPLY • Parasympathetic secretomotor supply from the superior salivary nucleus of the seventh cranial nerve. • The nerve fibers pass • to the submandibular ganglion via • the chorda tympani nerve and • the lingual nerve. • Postganglionic parasympathetic fibers pass to the gland via the lingual nerve. Prof. Makarem

15. NERVE SUPPLY Postganglionic sympathetic fibers reach the gland as a plexus of nerves around the facial and lingual arteries. Prof. Makarem

16. LYMPH NODES OF THE SUBMANDIBULAR REGION • The submandibular lymph nodes are situated on the superficial surface of the submandibular salivary gland. • They can be palpated just below the lower border of the body of the mandible. • They receive lymph from a wide area, including the anterior two thirds of the tongue (except the tip); the floor of the mouth & vestibule; and the gums. • The efferent lymph vessels drain into the deep cervical lymph nodes. • The submental lymph nodes are situated in the submental triangles. • They receive lymph from • tip of the tongue, • floor of the mouth beneath the tip of the tongue, • incisor teeth and the associated gums, • center part of the lower lip, • skin over the chin. • The efferent lymph vessels drain into the submandibular and deep cervical lymph nodes.

17. The deep cervical lymph nodes form a chain along the course of the internal jugular vein, from the skull to the root of the neck. They are embedded in the fascia of the carotid sheath and the tunica adventitia of the internal jugular vein; Most lie on the anterolateral aspect of the internal jugular vein. Two of the nodes are often referred to clinically and are called the jugulodigastric node and the jugulo-omohyoid node.

18. The jugulodigastric node lies just below the posterior belly of the digastric muscle and is located just below and behind the angle of the mandible. It is chiefly concerned with the lymph drainage of the tonsil and the tongue. • The jugulo-omohyoid node is related to the intermediate tendon of the omohyoid muscle and is associated mainly with the lymph drainage of the tongue.

19. CYSTS OF THE SUBLINGUAL SALIVARY GLAND • The sublingual salivary gland, opens into the mouth by numerous small ducts. • Blockage of one of these ducts is believed to be the cause of cyst (Ranula)under the tongue.

20. Thank you