anatomy of submandibular region presentation

anatomy of submandibular region

1. SUBMANDIBULAR REGION By DR. MALA. M DEPT OF ORAL AND MAXILLOFACIAL SURGERY

2. INTRODUCTION The submandibular region contains the suprahyoid muscles, submandibular and sublingual salivary glands and submandibular ganglion.

3. SUPRAHYOID MUSCLES DIGASTRIC STYLOHYOID MYLOHYOID GENIOHYOID HYOGLOSSUS

4. SUPRAHYOID MUSCLES

5. Relations of Hyoglossus Superficial: Styloglossus, lingual nerve, submandibular ganglion, deep part of the submandibular gland, submandibular duct, hypoglossal nerve Deep: (a) Inferior longitudinal muscle of the tongue; (b) genioglossus (c) middle constrictor of the pharynx; (d) glossopharyngeal nerve; (e) stylohyoid ligament; and (f) lingual artery. Structures passing deep to posterior border of hyoglossus, from the above downwards: (a) Glossopharyngeal nerve; (b) stylohyoid ligament; and (c) lingual artery.

6. SUBMANDIBULAR SALIVARY GLAND Introduction : This is a large salivary gland, situated in the anterior part, of the digastric triangle. The gland is about the size of a walnut. It is roughly Jshaped , 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

7. Superficial Part This part of the gland fills the digastric triangle. It extends upwards deep to the mandible up to the mylohyoid line. It has (a) inferior; (b) lateral; and (c) medial surfaces. 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 attached to the mylohyoid line of the mandible

8. Relations The inferior surface is covered by: (a) Skin; (b) platysma; (c) cervical branch of the facial nerve; (d) deep fascia; (e) facial vein; and (f) submandibular lymph nodes The lateral surface is related to: (a) The submandibular fossa on the mandible; (b) insertion of the medial pterygoid; and (c) the facial artery The medial surface may be divided into three parts; ( i ) The anterior part is related to the mylohyoid muscle, nerve and vessels. (ii) The middle part is related to the hyoglossus, the styloglossus, the lingual nerve the submandibular ganglion and the hypoglossal nerve (iii) The posterior part is related to the styloglossus, the stylohyoid ligament, the ninth nerve, and the wall of the pharynx. Inferiorly, it overlaps the stylohyoid and the posterior belly of the digastric

9. 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 round the posterior border of the mylohyoid. Anteriorly, it extends up to the posterior end of the sublingual gland

10. Submandibular 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 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

11. Blood Supply and Lymphatic Drainage It is supplied by the facial artery. The veins drain into the common facial or lingual vein. Lymph passes to submandibular lymph nodes. Nerve Supply It is supplied by branches from the submandibular ganglion. These branches convey: (a) Secretomotor fibres ; (b) sensory fibres from the lingual nerve, and (c) vasomotor sympathetic fibres from the plexus on the facial artery.

12. Secretomotor pathway

13. SUBMANDIBULAR GANGLION This is a parasympathetic peripheral ganglion. It is a relay station for secretomotor fibres to the submandibular and sublingual salivary glands. Topographically, it is related to the lingual nerve, but functionally, it is connected to the chorda tympani branch of the facial nerve (chorda tympani) The fusiform ganglion lies on the hyoglossus muscle just above the deep part of the submandibular salivary gland, suspended from the lingual nerve by two roots

14. Sublingual salivary gland This is smallest of the three salivary glands. It is almond-shaped and weighs about 3 to 4 g. It lies above the mylohyoid, below the mucosa of the floor of the mouth, medial to the sublingual fossa of the mandible and lateral to the genioglossus. About 15 ducts emerge from the gland. Most of them open directly into the floor of the mouth on the summit of the sublingual fold. A few of them join the submandibular duct. The gland receives its blood supply from the lingual and submental arteries. The nerve supply is similar to that of the submandibular gland.