BASICS of HUMAN ANATOMY
The Submandibular region It lies under cover of the body of the mandible, between the mandible and the hyoid bone. The superficial part includes the submental and digastric triangles, while the deep part includes the floor of mouth and the root of the tongue.The submandibular region contains the following structures:
Digastric muscle:Mylohyoid muscle
GeniohyoidOrigin: slender muscle that arises from the lower mental spine Insertion: it passes backwards and downwards to insert into the body of the hyoid bone. Nerve supply: ventral ramus of C1 via the hypoglossal nerve. Action: it pulls the hyoid bone forwards and upwards; also it depresses the mandible when the hyoid bone is fixed.
Genioglossus
Origin: it is a fan shape muscle that forms the main bulk of the tongue. It arises from upper mental spine Insertion: its fibers spread out into the tongue in vertical plane so: The upper fibers are inserted into the tip of tongue. The middle fibers are inserted into the dorsum of the tongue. The lower fibers are inserted into the body of the hyoid bone. Nerve supply: hypoglossal nerve Action: The upper fibers are retract the tip of the tongue The middle fibers are depress the central part of the tongue The lower fibers are protrude the tongue from the mouthThe submandibular gland
It is one of the major salivary glands, lies in the anterior part of digastric triangle, under cover of the body of mandible. It is about half the size of the parotid gland, and has two parts: Superficial part: is large and lies superficial to the mylohyoid. Deep part: is small and lies deep to mylohyoid. The two parts are continuous with each other around the posterior border of the mylohyoid.
The superficial part of the gland
Relation of the superficial part:The Submandibular Region
The deep part of the glandSubmandibular duct
Thin wall tube [5 cm in long], emerges from anterior end of the medial surface of the deep part of the gland, and runs forwards and upwards along the side of the tongue, beneath the mucus membrane of the floor of mouth[in angle between the mylohyoid and the side of the tongue].It opens into the floor of mouth, at the side of the frenulum of the tongue, on the summit of sublingual papilla [an elevation at the anterior end of sublingual fold].
Submandibular duct
Course and relation of the duct: At first; the duct lies on hyoglossus muscle, between lingual nerve and hypoglossal nerve, and is separated from mylohyoid by deep part of the gland. Next; at the anterior border of the hyoglssus, the lingual nerve crosses the lateral surface of the duct, hooks round the inferior surface and then runs upwards and forwards [medial to the duct] into the tongue. At last; it lies on the genioglossus muscle, medial to the sublingual gland.
Submandibular duct
Submandibular ganglionIt is a small parasympathetic ganglion, lies on the lateral surface of the hyoglossus muscle between the lingual nerve and the deep part of submandibular gland and the submandibular duct. It is suspended from the lingual nerve by two short ganglionic branches [anterior and posterior branches].Posterior branch carries preganglionic parasympathetic fibers and sensory fibers to the ganglion. Anterior branch carries postganglionic parasympathetic fibers to the lingual nerve which transmit these fibers to the sublingual gland and to the glands in the anterior 2/3 of the tongue. Connections:Sensory root: from lingual nerve [through the posterior ganglionic branch]. preganglionic parasympathetic root: from the facial nerve as fellow: Facial nerve→→chorda tympani→lingual nerve→submandibular ganglion [through posterior ganglionic branch]. Postganglionic sympathetic root: by facial artery and lingual artery plexus [supply both glands]. 2-6 branches arises from the inferior border of the ganglion to supply the submandibular gland [both sensory, postganglionic parasympathetic and sympathetic].
Lingual artery
Lingual arteryThe distal parts of the lingual n.,IIX n.,&lingual a.
Facial arteryIs the chief artery of the face, arises from the anterior surface of the external carotid artery above the tip of the greater horn of hyoid bone [in the carotid triangle].it runs in tortuous course to accommodate the mobility of the structures through which it passes. It has two parts: Cervical part [in the neck]:It ascends vertically on the middle and superior constrictor muscles of the pharynx close to palatine tonsil, lying under cover of the angle of the mandible, posterior belly of digastric, and stylohyoid muscles. Then it turns forwards above these muscles [to enter the submandibular region].it runs in tortuous course to allow free movement of the pharynx. In the submandibular region, the artery makes an S –bend [two loops]. First, it hooks round the posterosuperior part of the submandibular gland and runs anteroinferior between the gland and the medial pterygoid to reach the lower border of the body of the mandible. Then it hooks round the lower border of the body of the mandible to appear in the face at the anterior margin of the masseter.
Branches in the neck: Ascending palatine artery: it ascends along the pharynx, crosses over the upper border of the superior constrictor to reach the soft palate. Tonsillar artery: it pierces the superior constrictor muscle to supply the palatine tonsil. Glandular branches: to submandibular gland. 4.Submental artery: [is accompanied the mylohyoid nerve] to submandibular and sublingual glands, adjacent muscles and skin of the lower lip and chin
The parotid bed
The Submandibular RegionSuperficial dissection of the submandibular region
E C ASubmandibular gland
Facial artery
Sternocleidomastoid
sternohyoid
Omohyoid
Jugulodigastric lymph nodes
External jugular vein
Facial vein
The carotid and submandib-ular triangles
Veins in the parotid and submandibular regions
Superficial relation of the sub-mandibular glandSubmandibular & other cervical lymph nodes
Extrinsic muscles of the tongueNerves & Muscles of the submandibular region
Arrangement of the nerves and vessels of the submandibular region around HyoglossusI J V
E C AOmohyoid
Digastric,post.belly
XII nerve
Lingual nerve
stylohyoid
styloglossus
Sublingual gland
sternohyoid
XII nerve
Deep dissection of the submandibular region
To show the Lingual and Facial Arteries{part of hyoglossus has been cut to expose the lingual artery}
The Ligual & Facial arteries
The Lingual arteryExt. C.A.
Superficial temporal A.Sup. Thyroid A.
Lingual A.
Facial A.
Occipital A.
Maxillary A.
Occipital A.
Angiogram of the external carotid artery and its branches
The IX nerve
The XII nerve