SUBMANDIBULAR REGION I Dr. Ahmed Fathalla Ibrahim

SUPRAHYOID MUSCLES DIGASTRIC MUSCLE: Origin: by 2 bellies: Anterior belly: from digastric fossa of mandible Posterior belly: from mastoid notch Insertion: both bellies unite in an intermediate tendon held by a fibrous loop into the hyoid bone Nerve supply: Anterior belly: nerve to myelohyoid Posterior belly: facial nerve

SUPRAHYOID MUSCLES STYLOHYOID MUSCLE: Origin: styloid process Insertion: hyoid bone Nerve supply: facial nerve

SUPRAHYOID MUSCLES MYELOHYOID MUSCLE: Origin: myelohyoid line of mandible Insertion: the muscles on both sides meet in a median raphe extending from symphysis menti to hyoid bone Nerve supply: nerve to myelohyoid

SUPRAHYOID MUSCLES GENIOHYOID MUSCLE: Origin: inferior genial tubercle Insertion: hyoid bone Nerve supply: ventral ramus of C1

ACTIONS OF SUPRAHYOID MUSCLES Fixation of hyoid bone (acting with infrahyoid muscles) during movement of tongue. Depression of mandible to assist lateral pterygoid in opening of the mouth Elevation of hyoid bone to elevate the floor of mouth & to improve tongue grip

EXTRINSIC MUSCLES OF TONGUE STYLOGLOSSUS MUSCLE (MOST SUPERFICIAL): Origin: styloid process Insertion: whole length of side of tongue Action: the muscles on both sides draw the tongue upwards & backwards

EXTRINSIC MUSCLES OF TONGUE HYOGLOSSUS MUSCLE: Origin: hyoid bone Insertion: posterior half of side of tongue Action: the muscles on both sides depress the tongue

EXTRINSIC MUSCLES OF TONGUE GENIOGLOSSUS (DEEPEST MUSCLE): Origin: superior genial tubercle Insertion: whole length of side of tongue Action: the muscles on both sides protrude the tongue

EXTRINSIC MUSCLES OF TONGUE PALATOGLOSSUS: Origin: soft palate Insertion: back of side of tongue Action: the muscles on both sides draw the tongue towards soft palate

NERVE SUPPLY OF EXTRINSIC MUSCLES OF TONGUE ALL MUSCLES ARE SUPPLIED BY HYPOGLOSSAL (12TH CRANIAL) NERVE EXCEPT: PALATOGLOSSUS (BY CRANIAL PART OF ACCESSORY NERVE)

SUBMANDIBULAR REGION (Ramus of mandible is removed) P. Styloglossus Hyoglossus Sublingual gland Myelohyoid Stylohoid M A N D I B L E Submandibular Gland (Superficial part) Digastric Posterior belly Hyoid bone Digastric Anterior belly

SUBMANDIBULAR REGION (Superficial part of submandibular gland is removed) Styloglossus Sublingual gland Hyoglossus Myeolohyoid M A N D I B L E Deep part of submandibular gland Digastric Posterior Belly Hyoid bone Digastric Anterior belly

RELATIONS OF HYOGLOSSUS (Myelohyoid & digastric muscles are removed) Styloglossus Stylopharyngeus Lingual nerve Sublingual gland Deep part of submandibular gland Submandibular ganglion Submandibular duct Stylohyoid ligament Glossopharyngeal nerve Hyoglossus Genioglossus Hypoglossal nerve External carotid artery Lingual artery Geniohyoid

SUBMANDIBULAR REGION 1 3 2

LINGUAL ARTERY BEGINNING: from anterior aspect of external carotid artery, in the carotid triangle, opposite the tip of greater cornu of hyoid bone COURSE: has a tortuous course, divided into 3 parts: FIRST PART: forms a loop crossed by hypoglossal nerve SECOND PART: runs along upper border of greater cornu of hyoid bone, deep to hyoglossus THIRD PART: ascends along anterior border of hyoglossus & runs along the under surface of tongue to reach its tip & anastomoses with artery of opposite side

BRANCHES OF LINGUAL ARTERY FROM FIRST PART: Suprahyoid artery: runs along upper border of greater cornu of hyoid bone, superficial to hyoglossus, supplying adjacent muscles FROM SECOND PART: Two dorsal lingual arteries: supply dorsum of tongue FROM THIRD PART: Sublingual artery: supplies sublingual gland & mucous membrane of floor of mouth N.B.: VEINS CORRESPONDING TO BRANCHES OF LINGUAL ARTERY UNITE TO FORM A SINGLE LINGUAL VEIN THAT DRAINS INTO INTERNAL JUGULAR VEIN

SUBMANDIBULAR GANGLION It is a small parasympathetic ganglion lying superficial to hyoglossus & is connected to lingual nerve by 2 roots (anterior & posterior) Origin of fibers: superior salivary nucleus in pons Preganglionic fibers: Runs along chorda tympani branch of facial nerve Chorda tympani transmits fibers to lingual nerve branch of mandibular nerve Lingual nerve transmits fibers to ganglion through posterior root

SUBMANDIBULAR GANGLION Postganglionic fibers: To submandibular gland: fibers are distributed directly to the gland To sublingual gland: Fibers pass along anterior root to lingual nerve again Lingual nerve transmits fibers to sublingual gland

RELATIONS OF HYOGLOSSUS SUPERFICIAL (LATERAL): 2 MUSCLES: myelohyoid, styloglossus 2 NERVES: lingual, hypoglossal 2 GLANDS: superficial & deep parts of submandibular glands 2 SUBMANDIBULAR: duct & ganglion

RELATIONS OF HYOGLOSSUS DEEP (MEDIAL): 1 MUSCLE: genioglossus 1 NERVE: glossopharyngeal 1 VESSEL: Lingual 1 LIGAMENT: stylohyoid