[0:39]Good morning. This is Dr. Adel Bonduk, Professor of Anatomy and Neuroscience, Mansour University, Egypt. Today I will talk about the anatomy of the parotid gland.
[0:57]Okay, I will talk about the position of the parotid gland, the capsule, the relations, the borders and the surfaces, structures inside the gland, arterial supply, nerve supply, and then I will talk about the parotid duct. Okay, start by the position and the capsule. This is the parotid gland. The parotid gland is located between the angle of the mandible and the sternomastoid muscle below the external auditory meatus. This parotid gland has a capsule. This capsule is derived from the investing layer of the deep cervical fascia and the parotid gland is separated from the submandibular gland by this ligament, stylomandibular ligament.
[2:05]Then we'll talk about the ends. It has upper end and lower end. The upper end of the parotid gland, it surrounds the external auditory meatus. And from the upper end comes out four structures, artery, vein and two nerves. The artery is the superficial temporal artery, the vein is the superficial temporal vein, going inside the parotid gland, and the two nerves auricotemporal nerve from the mandibular nerve and temporal branch of the facial nerve. Regarding the lower end, it overlaps the posterior belly of the digastric, and from the lower end comes out three structures, nerve, vein and artery. The nerve is the cervical branch of the facial nerve, the vein is the retromandibular vein or its two branches, and the artery entering the gland is the external carotid artery. Okay, then we have an anterior border and posterior border. But first reminding you of the upper end and lower end. The upper end surrounds the external auditory meatus. From the upper end comes out four structures, artery, superficial temporal artery, vein, superficial temporal vein, two nerves, auricular temporal nerve and temporal branch of the facial nerve. The lower end overlaps the posterior belly of the digastric, and from the lower end comes out three structures, nerve, vein and artery. The nerve is the cervical branch of the facial nerve, the vein is the retromandibular vein or its two branches, and the artery is the external carotid artery. Then we have an anterior border and posterior border. The anterior border overlaps the masseter muscle. And from the anterior border comes out duct, artery and three nerves. The duct is the parotid duct. This is the parotid duct. The artery is the transverse facial artery from the superficial temporal artery and the three nerves, three branches from the facial nerve: zygomatic, buccal and mandibular branches. The posterior border overlaps the sternomastoid muscle. So we talked about the upper end, lower end, anterior border and posterior border. Let us talk about the surfaces. Okay, before talking about the surfaces, this is the upper end of the parotid gland. Superficial temporal artery, superficial temporal vein, auriculotemporal nerve, temporal branch of the facial nerve. Lower end. Cervical branch of the facial nerve. Retromandibular vein and or its two branches, and external carotid artery entering the gland. The anterior border, parotid duct, transverse facial artery, zygomatic branch, buccal branch, and mandibular branch of the facial nerve. The posterior border overlaps the sternomastoid. This is a section of the parotid gland. It has lateral surface and medial surface. This is the lateral surface and this is the medial surface. And actually the medial surface is divided into anteromedial and posteromedial surface. The lateral surface is related to the skin. And superficial fascia containing branches of the great auricular nerve, and parotid lymph nodes; preauricular L nodes. The medial surface is divided into anteromedial surface, and posteromedial surface.
[6:38]Okay, so let us talk about the medial surface of the parotid gland. Anteromedial surface and posteromedial surface. And the posteromedial surface is called is related to structures forming parotid bed. Anteromedial surface, it surrounds the angle of the mandible or the remus of the mandible. Okay, and it is related to three structures. 3M. Masseter attached to the outer surface of the remus.
[7:17]Then the remus of the mandible. Then the medial pterygoid muscle attached to the inner surface of the angle of the mandible. So the anteromedial surface related to 3M, masseter, mandible, medial pterygoid. The posteromedial surface which is related to the parotid bed is related to three main structures. Mastoid process and structures attached to it. Styloid process and structures attached to it. And in between carotid sheath and its contents.
[8:00]So let us talk about the posteromedial surface in more details. This is the anteromedial surface and this is the posteromedial surface. This posteromedial surface is related to mastoid process and structures attached to it. Actually two muscles: sternomastoid and posterior belly of the digastric. So the posteromedial surface so far is related to three structures: mastoid process, sternomastoid, and posterior belly of the digastric. Then styloid process and structures attached to it. Actually five structures. These five structures: three muscles and two ligaments. The three muscles: stylohyoid, stylopharyngeus, and styloglossus muscles. The two ligaments: stylohyoid ligament and stylomandibular ligament. Then carotid sheath and its contents: internal jugular vein most lateral, internal carotid artery most medial, and in between the four, the last four cranial nerves. And the facial nerve enters the parotid gland from the posteromedial surface. So actually the posteromedial surface, we can count the structures forming the parotid bed. Number one sternomastoid. Number one, mastoid process. Two sternomastoid, three posterior belly of the digastric. Number four stylid process and five structures.
[9:57]Three muscles: stylohyoid muscle, styloglossus muscle, stylopharyngeus muscle. Two ligaments: stylomandibular ligament, stylohyoid ligament. Then carotid sheath and its contents: internal jugular vein, internal carotid artery and last four cranial nerves. And the facial nerve enters the parotid gland from the posteromedial surface. Then we'll talk about the structures inside the parotid gland. Three main structures inside the parotid gland. The most superficial structure is the facial nerve. And then the middle one is the retromandibular vein, and the deepest structure is the external carotid artery. And also inside the parotid gland is the auriculotemporal nerve. According to the blood supply of the parotid gland, of course, the artery is the external carotid artery, and the venous drainage is the retromandibular vein. This just to remind you of the parotid bed. This is the parotid gland. And deep to the parotid gland is the parotid bed. Mastoid process and structures attached to it. Sternomastoid and posterior belly of the digastric. Styloid process and structures attached to it: three muscles and two ligaments. Stylohyoid muscle, stylopharyngeus muscle and styloglossus muscle, two ligaments, stylohyoid ligament and stylomandibular ligament. Then carotid sheath and its contents: internal jugular vein, internal carotid artery and the last four cranial nerves. This is the vagus, this is the accessory, this is the hypoglossal nerve and this is the glossopharyngeal nerve. This is the anteromedial surface and this anteromedial surface is related to 3M: masseter, mandible, medial pterygoid. And this is the posteromedial surface: mastoid process, styloid process, carotid sheath and facial nerve entering the gland from the posteromedial surface. Structures inside the parotid gland: facial nerve is the most superficial structure, retromandibular vein in the middle, external carotid artery is the deepest structure. Then we'll talk about the nerve supply of the parotid gland. The parotid gland supplied by three different nerves: sensory, parasympathetic and sympathetic. Sensory nerve supply, two nerves. The capsule is supplied by the great auricular nerve, and the parenchyma is supplied by the auriculotemporal nerve. So the two sensory nerves: great auricular nerve supplying the capsule, auriculotemporal nerve supplying the parenchyma. Then parasympathetic or secretory motor fibers, parasympathetic or secretory motor fibers, it is the glossopharyngeal nerve. The nucleus is the inferior salivatory nucleus, fibers enter the glossopharyngeal nerve, tympanic branch, tympanic plexus, lesser petrosal nerve. This lesser petrosal nerve synapses in the otic ganglion, and from the otic ganglion postganglionic fibers reach the parotid gland with the auriculotemporal nerve. Then sympathetic fibers from the plexus around the external carotid artery. Then finally we'll talk about the parotid duct. Parotid duct is about 5 centimeters long. It begins at the anterior border. It crosses the masseter muscle and then pierces four structures. So the course of the parotid duct, number one, it passes on the masseter. Number two, it pierces buccal pad of fat, buccopharyngeal fascia, then buccinator, then the mucous membrane to open in the vestibule of the mouth opposite the upper second molar tooth. Then we'll talk about the surface anatomy of the parotid duct. This is the trigas of the ear and this is the ala of the nose, this is the red margin of the upper lip. So we draw a line from the trigas to the midway between the ala of the nose and the red margin. The parotid duct represents the middle third of this line. And thank you very much. Best wishes and good luck, and don't forget to subscribe to my channel. And share the video. And thank you again, and good luck.
