By: Dr. Saeed Vohra

Region between the body of the mandible& the hyoid bone

The contents of the region are

Salivary Glands Submandibular & Sublingual

Muscles Digastric, Mylohyoid,

Hyoglossus Geniohyoid, Genioglossus, & Styloglossus

Nerves Lingual, Glossopharyngeal, &Hypoglossal

Parasympathetic Ganglion Submandibular

Blood Vessels Facial/Lingual artery & Vein

Lymph NodesSubmandibular group

Submandibular gland

Sublingual gland

Muscles

Nerves & vessels

Submandibular ganglion

Lymph nodes

Part I

Part II

• The submandibular gland consists of a mixture of serous and mucous acini

• It lies beneath the lower border of the body of the mandible

• Is divided into superficial and deep parts by the mylohyoid muscle.

• The deep part of the gland lies beneath the mucous membrane of the mouth on the side of the tongue.

• The submandibular duct emerges from the anterior end of the deep part of the gland and runs forward beneath the mucous membrane of the mouth.

• The duct opens into the mouth on a small papilla, which is situated at the side of the frenulum of the tongue

Submandibular Gland

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NERVE SUPPLY

Postganglionic sympathetic fibers reach the gland as a plexus of nerves around the facial and lingual arteries.

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NERVE SUPPLY

Parasympathetic secretomotor supply is provided from the superior salivary nucleus of the facial (VIIth) cranial nerve. › The nerve fibers pass

to the submandibular ganglion and other small ganglia close to the duct via the chorda tympani nerve and the lingual nerve.

› Postganglionic parasympathetic fibers reach the gland either directly or along the duct.

• The sublingual gland lies beneath the mucous membrane (sublingual fold) of the floor of the mouth, close to the frenulum of the tongue

• It has both serous and mucous acini, with mucous predominating

• The sublingual duct (8 to 20 in number) open into the mouth on the summit of the sublingual fold

Nerve SupplyParasympathetic secretomotor supply is from the facial nerve via the chorda tympani, and the submandibular ganglion.

Postganglionic fibers pass directly to the gland.

Sublingual Gland

Clinical Notes

Submandibular Salivary Gland: Calculus FormationThe submandibular salivary gland is a common site of calculus formation. This condition is rare in the other salivary glands. The presence of a tense swelling below the body of the mandible, which is greatest before or during a meal and is reduced in size or absent between meals, is diagnostic of the condition. Examination of the floor of the mouth will reveal absence of ejection of saliva from the orifice of the duct of the affected gland. Frequently, the stone can be palpated in the duct, which lies below the mucous membrane of the floor of the mouth.

Enlargement of the Submandibular Lymph Nodes and Swelling of the Submandibular Salivary GlandThe submandibular lymph nodes are commonly enlarged as a result of a pathologic condition of the scalp, face, maxillary sinus, or mouth cavity. One of the most common causes of painful enlargement of these nodes is acute infection of the teeth. Enlargement of these nodes should not be confused with pathologic swelling of the submandibular salivary gland.

Sublingual Salivary Gland and Cyst FormationThe sublingual salivary gland, which lies beneath the sublingual fold of the floor of the mouth, opens into the mouth by numerous small ducts. Blockage of one of these ducts is believed to be the cause of cysts under the tongue.0

Muscle of the Submandibular Region

Digastric, Mylohyoid, Hyoglossus, Geniohyoid,

Genioglossus, & Styloglossus

Hyoid Bone

Muscles of the Submandibular Region

Mylohyoid Triangular sheet

Origin Whole length of mylohyoid line Insertion posterior fibers — hyoid bone

anterior fibers — fibrous raphe

Mylohyoid Nerve a br alveolar nerve

ActionSupport tongue. Fixed mandible elevate the floor of mouth & hyoid bone during the 1st stage of swallowing. Fixed hyoid open the mouth

Hyoglossus Origin Body & greater cornu of hyoid bone Insertion Deep to the mylohyoid mix with other

muscles of the tongue

Hypoglossal nerve Depress the tongue

GeniohyoidOrigin inferior mental spine Insertion body of hyoid bone (deep to mylohyoid)

C1 throughHypoglossalnerve

Elevates HyoidDepress Mandible

Genioglossus Origin superior mental spine Insertion Fan shaped

superior fibers — tip of the tonguemiddle fibers — dorsum of the tongue inferior fibers — hyoid bone

Hypoglossalnerve

Action of the Genioglossus

Draws the tongue forward & protrudes the tip so that it points to

the opposite side

Both side of the muscles protrudes the tongue in midline

Styloglossus Origin tip of the styloid process Insertion side of the tongue

Hypoglossal nerve

Action of the styloglossus

Draws the tongue upward and backward

Genioglossus, Hyoglossus, Styloglossus & Palatoglossus are considered as extrinsic

muscles of the tongueoriginate outside the tongue

& attach to it They can move the tongue but can not alter its shape