Lecture 5 - PAROTID AND SUBMANDIBULAR REGIONS.pdf

PAROTID REGION AND PAROTID GLAND Nicholas Lutfi, MD, MS, DPM INTRODUCTION § The parotid region is made out of: the parotid glands, ramus of the mandible (anteriorly), the styloid process (medially). § It lies below the zygomatic arch. § It is a space between the mastoid process, the neck and the...

PAROTID REGION AND PAROTID GLAND Nicholas Lutfi, MD, MS, DPM INTRODUCTION § The parotid region is made out of: the parotid glands, ramus of the mandible (anteriorly), the styloid process (medially). § It lies below the zygomatic arch. § It is a space between the mastoid process, the neck and the ramus of the mandible. THE PAROTID GLAND § The parotid gland is the largest salivary gland. § It is wrapped in a fibrous capsule: parotid fascia. § It occupies the side of the face anterior and inferior to the auricle. § The parotid gland is irregular and lobulated in shape. § It overlaps the posterior aspect of the masseter muscle. § The parotid duct (Stensen’s duct) measures approximately 5 cm in length, runs along the masseter muscle, and it turns sharply to pierce the buccinator muscle. § It enters the the oral cavity opposite the crown of the 2nd maxillary molar tooth. Structures Within the Parotid Gland § From lateral to medial: ú Facial Nerve, which gives off two branches before it enters the gland: Muscular branches to the posterior belly of the digastric, and stylohyoid muscles Posterior Auricular nerve ú Retromandibular Vein: formed within the parotid gland by the union of the maxillary and superficial temporal veins ú ECA ú Parotid LN Blood and Nerve Supply of the Parotid Gland § The parotid gland is supplied by the EXTERNAL CAROTID ARTERY § NERVE SUPPLY: ú The innervation to this gland is derived from the auriculotemporal nerve (V3) and from the sympathetic and parasympathetic systems. ú PARASYMPATHETIC supply is derived from the glossopharyngeal nerve (CN IX). Stimulation of these fibers will produce a thin, watery salivary flow. ú SYMPATHETIC innervation is derived from the cervical ganglia. Stimulation will cause a thick, mucous salivary discharge. SUBMANDIBULAR REGION SUBMANDIBULAR REGION § It is the area located between the mandible and the hyoid bone. § It is a triangular shaped region bounded by the inferior border of the mandible superiorly, and the two bellies of the digastric muscle. Contents of the Submandibular Region § MUSCLES: ú ú ú ú ú ú Digastric Mylohyoid Hyoglossus Genioglossus Geniohyoid Styloglossus § SALIVARY GLANDS: ú Submandibular ú Sublingual § NERVES: ú Lingual nerve ú Glossopharyngeal nerve (CN IX) ú Hypoglossal nerve (CN XII) § BLOOD VESSELS: ú ú ú ú Facial artery Facial vein Lingual artery Lingual vein § LN Muscles of the Submandibular Region § DIGASTRIC MUSCLE: O-mastoid process (post. belly); digastric fossa of mandible (anterior belly) I-hyoid bone (intermediate tendon) N-posterior belly=CN VII; anterior belly=CN V F-depress the mandible, elevate hyoid bone § MYLOHYOID MUSCLE: O- mylohyoid line of the mandible I-hyoid bone N-nerve to the mylohyoid (CNV3) F-elevate the floor of the mouth, support the tongue § HYOGLOSSUS MUSCLE: O-hyoid bone I-side of the tongue N-CN XII F-depress the tongue § GENIOHYOID MUSCLE: O-inferior mental spine I-hyoid bone N-C1 via the hypoglossal nerve (CN XII) F-elevate the hyoid bone, depress the mandible Muscles of the Submandibular Region § GENIOGLOSSUS MUSCLE: ú O-superior mental spine ú I-tip and middle of the tongue ú N-CN XII ú F-protrude the tongue § STYLOGLOSSUS MUSCLE: ú O-tip of styloid process ú I-side of the tongue ú N-CN XII ú F-draw the tongue up and back Submandibular Gland § It is a salivary gland that lies in the digastric triangle of the neck. § The submandibular duct (Wharton’s duct) opens in the oral cavity in the sublingual papillae at the sides of the frenulum of the tongue. § NERVE SUPPLY: ú Parasympathetic: pre-ganglionic fibers from CN VII via the chorda tympani to submandibular ganglion and then postganglionic to the gland ú Sympathetic: post-ganglionic fibers from the superior cervical ganglion SUBLINGUAL GLANDS § Supplied by the autonomic nervous system via the lingual nerve (V3). § They lie in the floor of the mouth between the mandible and the genioglossus muscle. § Numerous small sublingual ducts open into the floor of the mouth along the sublingual folds. SUBLINGUAL GLANDS § Sympathetic and parasympathetic fibers through the lingual nerve. These fibers hitch a ride on the lingual nerve to reach the sublingual glands. § Parasympathetic supply = CN VII (chorda tympany) § Sympathetic supply = superior cervical ganglion Lingual Nerve § It carries general sensation from the anterior 2/3 of the tongue. § It is a branch off the mandibular division of the trigeminal nerve (V3). § It is found on the lateral surface of the hyoglossus muscle. § It crosses the submandibular duct twice.