Human Anatomy Lecture 10: Salivary Gland - Almaaqal University 2022-2023 PDF

Academic year 2022-2023 ‫فرع جراحة الفم والوجه والفكين‬ ‫كلية طب االسنان‬ 2ed year Human Anatomy Lecture 10...

Academic year 2022-2023 ‫فرع جراحة الفم والوجه والفكين‬ ‫كلية طب االسنان‬ 2ed year Human Anatomy Lecture 10 Anatomy of the salivary gland By:Dr.Nada hashim AL JASSIM Snell R.S. Clinical Anatomy by regions, 9th Edition, Lippincott Williams & Wilkins, [2012 For more detailed instructions, any question, cases need help please post to the telegram group of the session Parotid region Regions of Head To allow clear communications regarding the location of structures, injuries, or pathologies, the head is divided into regions Parotid Region The parotid region is the posterolateral part of the facial region bounded by the: 1-Zygomatic arch superiorly. 2-Angle and inferior border of the mandible inferiorly. 3-Ramus of the mandible medially. 4-Anterior border of the masseter muscle anteriorly. 5-External ear and anterior border of the sternocleidomastoid muscle posteriorly The parotid region includes the parotid gland and duct, the parotid plexus of the facial nerve (CN VII), the retromandibular vein, the external carotid artery, and the masseter muscle. On the parotid sheath and within the gland are parotid lymph nodes. The five terminal branches of the facial nerve leave through the anterior border of the gland in a radiating manner that resembles the foot of a goose. Hence, this pattern is known as “pes anserinus Parotid Duct The parotid (Stensen’s) duct passes horizontally from the anterior edge of the gland. and passes forward over the lateral surface of the masseter muscle about one fingerbreadth below the zygomatic arch. It then turns medially, dives deeply into the buccal fat-pad, piercing the buccinator muscle and enters the vestibule of oral cavity through a small orifice (papilla) opposite the second maxillary molar tooth.The oblique passage of the duct in the buccinator muscle acts as a valve-like mechanism & prevents inflation of the duct during blowing. The duct is about 2 in. (5 cm) long. It is represented by the middle 1/3rd of a line extending from the tragus of the auricle to a point midway between the ala of nose & upper lip. The Buccal Pad of Fat Superficial to the buccinators (on either side of the face) are encapsulated collections of fat; these buccal fat-pads are much larger in infants, to reinforce the cheeks and keep them from collapsing during sucking. The blood supply to the buccal fat-pad originates from the buccal and deep temporal branches of the maxillary artery, the transverse facial branch of the superficial temporal artery, and branches of the facial artery. This rich vascularity allows a reliable long axial flap and explains the rapid surface re-epithelialization. The cheeks are innervated by buccal branches of the mandibular nerve. The buccal fat-pad’s primary function is thought to be related to chewing and suckling, especially in infants. Another proposed function is as gliding pads that facilitate the action of the muscles of mastication. The buccal fat pad may also function as a cushion to protect sensitive facial muscles from injury due to muscle action or exterior force. Clinical Notes Parotid Duct Injury The parotid duct may be damaged in injuries to the face or may be inadvertently cut during surgical operations on the face. Parotid Salivary Gland and Lesions of the Facial Nerve The parotid salivary gland consists essentially of superficial and deep parts, and the important facial nerve lies in the interval between these parts. A benign parotid neoplasm rarely, if ever, causes facial palsy. A malignant tumor of the parotid is usually highly invasive and quickly involves the facial nerve, causing unilateral facial paralysis.. Parotid Gland Infections The parotid gland may become acutely inflamed as a result of retrograde bacterial infection from the mouth via the parotid duct. The gland may also become infected via the bloodstream, as in mumps. In both cases, the gland is swollen; it is painful because the fascial capsule derived from the investing layer of deep cervical fascia is strong and limits the swelling of the gland. Frey’s Syndrome Frey’s syndrome is an interesting complication that sometimes develops after penetrating wounds of the parotid gland. When the patient eats, beads of perspiration appear on the skin covering the parotid. This condition is caused by damage to the auriculotemporal and great auricular nerves. During the process of healing, the parasympathetic secretomotor fibers in the auriculotemporal nerve grow out and join the distal end of the great auricular nerve. Eventually, these fibers reach the cutaneous sympathetic nerves that supply the sweat glands in the facial skin. By this means, a stimulus intended for saliva production produces sweat secretion instead THANK YOU