Posterior belly of digastric Submandibular Region Boundaries: Ant: anterior belly of digastric ms Post: posterior belly of digastric and stylohyoid ms Base of the mandible M a n d i b l e Posterior belly of digastric Stylohyoid Mylohyoid Hyoglossus Anterior belly of digastric Hyoid bone

Main contents of the submandibular region Salivary glands Submandibular Sublingual Nerves Lingual nerve (sensory) Hypoglossal nerve (motor) Submandibular parasympathetic ganglion Muscles Digastric & Stylohyoid Mylohoid & Geniohyoid Hyoglossus, Genioglossus & Styloglossus Vessels -Facial artery and vein -Lingual vessels Sublingual gland Anterior belly of digastric Mylohoid Submandibular Hypoglossal n ganglion Lingual n. Stylohyoid Post. belly Hard palate Palato-glossus Post. belly of digastric Stylopharyngeus Stylohyoid Styloglossus Pharynx Geniohyoid Genioglossus Soft palate Hyoid bone

sternomastoid Post. belly of digastric Tonsillar a. Ascending palatine a. Hypoglossal n. Lingual a. Ant. belly of digastric ECA Submental a. mylohyoid ICA Facial a.

Digastric muscle O: arises by two bellies: -anterior belly: digastric fossa of mandible -posterior belly: mastoid notch of temporal bone I : Intermediate tendon is attached by a fibrous loop to the hyoid bone N: -anterior belly: mylohyoid nerve (madibular division of trigeminal N) -posterior belly: facial nerve A: -elevation of hyoid bone during swallowing -depression of mandible

Important relations of digastric muscle Superficial relations: Skin & fasciae and platysma muscle Posterior belly overlapped by parotid gland and sternomastoid muscle Anterior belly overlapped by submandibular gland Crossed by facial v. Parotid Sternomastoid Post belly of digastric Facial v. Submandibular gland Mylohyoid Ant belly

Deep relations: Ant. Belly: mylohoid m. Post. Belly, Crosses the following: IJV, ICA, ECA Branches of ECA (occipital, facial & lingual a.) X, XI & XII cranial n. Hyoglossus m. Mylohyoid Sternomastoid S t y l o h y o i d I J V E C A Post belly of digastric X, XI, XII cranial n. ICA Facial & lingual a Hyoglossus m Anterior belly of digastric Occipital a

Stylohyoid muscle O: styloid process I: hyoid bone. Its tendon is perforated by the intermediate tendon of digastric m. N facial nerve A elevation and retraction of hyoid bone Posterior belly of digastric Mylohyoid Stylohyoid Anterior belly of digastric Hyoglossus Hyoid bone

Superficial & deep parts Submandibular Gland Position: Lies in the digastric triangle of the neck, lodged in the submandibular fossa of the mandible Formed of a large superficial part and a small deep part (the 2 parts are continuous at the posterior border of mylohyoid) Mylohyoid Mylohyoid nerve & vessels Surfaces & Relations: Superficial (inferior): covered by skin, fasciae & platysma submandibular LN. crossed by facial vein and cervical branch of facial n. Lateral: submandibular fossa of the mandible & facial a. Medial: mylohyoid anteriorly and hyoglossus posteriorly separated from mylohyoid by mylohyoid nerve & vessels separated from hyoglossus by: Styloglossus muscle Lingual nerve Submandibular ganglion Deep part of submandibular gland Hypoglossal nerve Suprahyoid vessels. Superficial & deep parts of submandibular G. Hyoglossus Mylohyoid nerve & vessels Hyoglossus Facial a Mylohyoid Submandibular LN Facial v. Submandibular G

Styloglossus Palatoglossus Lingual n. Hyoglossus Suprahyoid vessels Hyoid bone Hypoglossal n. Submandibular ganglion Lingual a. Genioglossus

Submandibular duct: About 5cm long. Arises from the medial surface of the superficial part Passes forwards through the deep part on the lateral surface of hyoglossus (between lingual & hypoglossal n) Runs between genioglossus and sublingual gland Opens in the floor of mouth on the summit of the sublingual papilla at the anterior end of the sublingual fold Submandibular duct Sublingual G Lingual n. Palatoglossus Hyoglossus Styloglossus Genioglossus Submandibular ganglion Suprahyoid vessels Hypoglossal n. Lingual a. Hyoid bone

Nerve supply: Sensory: lingual n. Sympathetic: plexus around facial a. Parasympathetic: postganglionic fibres from the submandibular ganglion (the preganglionic fibres originate from the superior salivary nucleus and run with the facial n., then run into the chorda tympani which joins the lingual n, then leave the lingual nerve to the submandibular ganglion where they relay) Superior salivary nucles Facial n. Chorda tympani Facial a. Submandibular & sublingual Gl. Submandibular ganglion Lingual n. Arterial supply: Facial & lingual a. Venous drainage: Facial & lingual v. Lymphatic drainage: Submandibular LN.

Mylohyoid muscle Mylohyoid O: mylohoid line of the mandible I : mylohyoid raphe. The posterior parts of both muscles are inserted into the hyoid bone. N: mylohyoid n. (from the inferior alveolar branch of the mandibular n.) A: -elevation of hyoid bone and floor of the mouth -depression of the mandible Anterior belly of digastric Mylohyoid raphe Stylohyoid Mylohyoid Posterior belly of digastric Hyoglossus Hyoid bone

Relations of mylohyoid muscle Superficial relations: Skin, faciae & platysma Anterior belly of digastric Submandibular gland (superficial part) Mylohyoid n and vessels Submental vessels Submental LN. Mylohyoid Anterior belly of digastric Mylohyoid nerve & vessels Submandibular Gl.

Deep relations: Genioglossus & geniohyoid m. Sublingual gland Lingual a. Sublingual vessels Hyoglossus m. Structures on the lateral surface of hyoglossus: Styloglossus m. Lingual n. Submandibular ganglion Deep part of submandibular gl. Submandibular duct Hypoglossal n. Suprahyoid a. Genioglossus Styloglossus Hyoglossus Geniohyoid Mylohyoid Hyoglossus Lingual n. Submandibular ganglion Sublingual vessels Genioglossus Submandibular duct Geniohyoid Lingual a. Hypoglossal n. Suprahyoid vessels

Superficial (lateral) relations: Hyoglossus Muscle O: hyoid bone (greater horn) I : side of the tongue N: hypoglossal n. A: depression of the tongue Genioglossus Styloglossus Superficial (lateral) relations: Styloglossus m. Lingual n. Submandibular ganglion Deep part of submandibular gl. Submandibular duct Hypoglossal n. Suprahyoid a. Covered by: Mylohyoid muscle Submandibular gland Hyoglossus Mylohyoid Hyoglossus Lingual n. Submandibular ganglion Sublingual vessels Genioglossus Submandibular duct Geniohyoid Lingual a. Hypoglossal n. Suprahyoid vessels

Deep (medial) relations: Glossopharyngeal nerve Stylohyoid ligament Middle constrictor of the pharynx Genioglossus Lingual artery (2nd part) Stylohyoid ligament Middle pharyngeal constrictor Hyoglossus Stylohyoid ligament Middle pharyngeal constrictor Genioglossus Submandibular duct Lingual a.

Sublingual salivary gland Lies in the sublingual fossa of the mandible, beneath the mucosa of the floor of the mouth Raises the floor of the mouth forming the sublingual fold Relations Med: genioglossus, submandibular duct, lingual n. Lat: sublingual fossa Sup: mucosa of the floor of the mouth Inf: mylohyoid m. Sublingual ducts 8-20 small ducts Open separately on the summit of the sublingual papilla Arterial supply Sublingual artery Venous drainage Lingual & facial v. Lymphatic drainage Submental and submandibular LN Nerve supply Sensory: lingual n. Sympathetic: plexus around facial a. Parasympathetic: submandibular ganglion

Submandibular ganglion Lingual Nerve A branch of the posterior division of the madibular nerve Course Takes origin in the infratemporal fossa Joined by the chorda tympani at the lower border of lateral pterygoid Runs between the ramus of the mandible and medial pterygoid muscle Enters the floor of the mouth by passing medial to the root of the 3rd molar tooth Runs on the lateral surface of hyoglossus Hooks below the submandibular duct Forms communication with the hypoglossal nerve Fiber types carried by the lingual nerve: General sensations from the anterior 2/3 of the tongue Taste sensation from the anterior 2/3 of the tongue (fibers belong to chorda tympani) Preganglionic secretomotor fibers to the submandibular ganglion (fibers belong to chorda tympani) Medial pterygoid Lingual nerve Submandibular ganglion

Submandibular Ganglion A small parasympathetic ganglion on the lateral surface of the hyoglossus It lies between the lingual nerve above and the deep part of the submandibular gland below Anatomically connected to the lingual nerve Functionally associated with the chorda tympani (facial nerve) Roots: Sensory: lingual n. Sympathetic: plexus around facial a. Parasympathetic: fibers from the chorda tympani (carried by the lingual nerve) The preganglionic parasympathetic fibers originate from the superior salivary nucleus through the facial nerve, the chorda tympani and the lingual nerve Branches: Sensory: carry sensations from the submandibular and sublingual glands Sympathetic: to the vessels of the submandibular and sublingual glands Parasympathetic: secretomotor to both submandibular and sublingual glands

Genioglossus Muscle Styloglossus Muscle Geniohyoid Muscle Genioglossus O: superior genial tubercle of the mandible I : side of the tongue, medial to hyoglossus N: hypoglossal n. A: protrusion of the tongue Styloglossus Palatoglossus Styloglossus Muscle O: styloid process I : side of the tongue, lateral to hyoglossus N: hypoglossal n. A: draws the tongue upwards and backwards Hyoglossus Genioglossus Geniohyoid Geniohyoid Muscle O: inferior genial tubercle of the mandible I : hyoid bone N: nerve to geniohyoid (fibers from C1 carried by hypoglossal nerve) A: elevates and draws the hyoid bone forwards

Facial artery Origin, From the front of ECA in the carotid triangle, slightly above the lingual a. Course and relations Ascends deep to the posterior belly of digastric and stlyohyoid ms. to reach the digastric triangle Continues deep to the ramus of the mandible and grooves the posterior end of submandibular gland Curves downwards between the gland and the mandible Pierces the deep fascia at the base of the mandible and curves upwards, crossing the anterior inferior angle of the masseter to reach the face Branches in the neck Ascending palatine artery Tonsillar artery Glandular branches to the submandibular G. Submental artery Branches in the face Inferior labial artery Superiror labial artery Lateral nasal artery Lateral nasal a Superior labial a Ascending palatine Tonsillar artery Inferior labial a Submental artery Facial artery ECA ICA CCA

Lingual artery Origin: from the front of ECA in the carotid triangle, opposite the tip of the greater horn of hyoid bone Course and relations, Its course is divided into 3 parts First part, forms a loop over the tip of the greater horn of hyoid bone Second part, runs deep to the hyoglossus Third part (profunda linguae artery) Ascends on the anterior border of hyoglossus Runs forwards under cover of the mucosa of the undersurface of the tongue Reaches the tip of the tongue and ends by anastomosing with the lingual artery of the opposite side Branches From the first part -Suprahyoid artery From the second part -Dorsalis linguae arteries From the third part -Sublingual artery -Lingual branches 2nd part of lingual a. 3rd part of lingual a. Dorsalis linguae 1st part of lingual a. Sublingual a. Suprahyoid a. Hypoglossal n. Hyoglossus ECA

Lingual artery (2nd part) Lingual veins: Profunda linguae vein: receives the sublingual v. and continues backwards (superficial to hyoglossus) as the vena comitans of hypoglossal nerve Lingual veins: venae comitantes of the 2nd part of lingual artery (deep to hyoglossus), they receive the dorsalis linguae veins. Lingual vein: is formed at the posterior border of hyoglossus by the union of lingual veins and vena comitans of hypoglossal nerve, and drains into IJV Dorsal lingual v. Profunda linguae v. Sublingual vessels IJV Lingual artery (2nd part) Hypoglossal n. Vena comitans of hypoglossal n.