Oral Cavity Anatomy PDF - GIT 2025

GIT 2025 Anatomy Lecture(4):ANATOMY OF ORAL CAVITY, PHARYNX, ESOPHAGUS AND STOMACH Boundaries of the mouth - Lips (labia): protect the anterior opening - Cheeks: form the lateral walls - Hard pal...

GIT 2025 Anatomy Lecture(4):ANATOMY OF ORAL CAVITY, PHARYNX, ESOPHAGUS AND STOMACH Boundaries of the mouth - Lips (labia): protect the anterior opening - Cheeks: form the lateral walls - Hard palate: forms the anterior roof - Soft palate: forms the posterior roof - Uvula: fleshy projection of the soft palate Parts of oral cavity and teeth internally 1- Vestibule: space between lips externally and gums 2- Oral cavity proper: area contained by the teeth Salivary glands - Parotid gland: In the parotid fossa, three main structures transverse this gland – facial nerve, external carotid artery, and retromandibular vein. The parotid duct opens opposite to the upper 2nd molar tooth. The gland is completely serous - Submandibular gland: Sitting most posteriorly in the submandibular triangle, it is supplied by the facial artery and vein Submandibular ducts, which cross the lingual nerves, open on both sides of the tongue frenulum. It is mostly serous but partially mucus, - Sublingual gland: The smallest salivary gland sits beneath the oral mucosa in the floor of the mouth. It has multiple small openings. It is almost completely mucus- secreting. Pharynx Parts - Nasopharynx : not part of the digestive system - Oropharynx : posterior to oral cavity 19 GIT 2025 Anatomy - Laryngopharynx : below the oropharynx and connected to the esophagus It: Oropharynx is the middle part of the pharynx situated behind the oral cavity Boundaries of oropharynx - Above: communicates with nasopharynx through nasopharyngeal isthmus Below: opens into laryngopharynx- Anterior wall- - upper part, deficient, oropharynx communicates with oral cavity through oropharyngeal isthmus/ isthmus of fauces - lower part, related to - base of tongue - lingual tonsils - valleculae - Posterior wall: 3rd cervical vertebrae - Lateral wall: ♦ Palatine/faucial tonsil ♦ Anterior pillar (Palatoglossus muscle) ♦ Posterior pillar (Palatopharyngeus muscle) ESOPHAGUS - It is a tubular structure about 25 cm long. Beginning: it begins as the continuation of the pharynx at the level of the 6th cervical vertebra. End: it pierces the diaphragm at the level of the 10 th thoracic vertebra to join the stomach. It is divided into 3 parts: 1- Cervical. 2- Thoracic. 20  GIT 2025 Anatomy 3- Abdominal. - In the thorax, it passes downward and to the left through superior then to posterior mediastinum - At level of sternal angle, aortic arch pushes esophagus again to midline. Esophageal constrictions The esophagus has 4 anatomic constrictions. 1- at the junction with the pharynx(pharyngeoesophageal junction). 2- where it crossed by aortic arch at superior mediastinum 3- where it crossed by left main bronchus at posterior mediastinum. 3- at the junction with the stomach where it piercing the diaphragm. They have a considerable clinical importance. 1- They may cause difficulties in passing an esophagoscope. 2- In case of swallowing of caustic liquids strictures develop in these sites. 3- The esophageal strictures are a common sites of the development of esophageal carcinoma. Arterial supply: from; - thoracic part: from descending aorta, bronchial arteries, and right intercostal arteries. - abdominal part: by left gastric artery, short gastric arteries Venous drainage - The upper third drains in into the inferior thyroid veins. - The middle third into the azygos veins. - The lower third into the left gastric vein, which is a tributary of the portal vein. Lymphatic drainage - The upper third is drained into the deep cervical nodes. - The middle third is drained into the superior and inferior mediastinal nodes. - The lower third is drained in the celiac lymph nodes in the abdomen. 21  GIT 2025 Anatomy The stomach Definition: it is the widest part of the alimentary tract and lies between the esophagus and the duodenum. Site: located in the hypochondriac, epigastric and umbilical areas. Shape: J-shaped has 2 surfaces, 2 borders, 2 ends and 3 parts: Gastric surfaces: Anterior (superior) Posterior (inferior) surface surface The entire anterior The posterior surface is covered by peritoneum of (superior) surface is the lesser sac, which separate stomach from the covered by peritoneum of stomach bedstructures (4 horizontal, 4 vertical). the greater sac. - Transverse colon. -mesocolon. - Related to ant. Abd. Wall, - Body of pancreas. -splenic artery. diaphragm and Lt lobe of - Spleen. - LT crus of the liver. diaphragm. - LT suprarenal gland. - LT kidney. Gastric borders: Lesser curvature (RT border) Greater curvature (LT border) - It shows a notch, the angular notch, whose - It is four or five times longer than the lesser. position and appearance vary with gastric -it gives attachment to: distension. - gastrophrenic ligament. - The lesser omentum is attached to the - gastrosplenic ligament. lesser curvature and contains the right and - greateromentum, which contains the left gastric vessels and LT gastric LN. gastroepiploic vessels and gastroepiploic LN. 22 GIT 2025 Anatomy Parts of the stomach: Fundus Body pylorus It is dome shaped, Extends from fundus to the Include the following: projects above and to the angular notch, A line a-pyloricantrum: left of cardiac orifice, It drawn from the angular dilated part below the lies above a line drawn notch to an indentation on body. horizontally from the greater curvature defines b- pyloric canal: distal cardiac notch to the lower boundary of body. narrow 2.5 cm of greater curvature. stomach. c- pyloric sphincter: distal end of stomach. Gastric orifices (surface anatomy): Cardiac orifice Pyloric orifice - The opening of oesophagus into the stomach. -It is the opening of stomach - It is situated to LT of the midline behind 7th into duodenum. costal cartilage at the level of T11 vertebra. It - It lies 1–2 cm to the right is10 cm from anterior abdominal wall and 40 of the midline in the cm from incisor teeth. transpyloric plane L1. Relations -anteriory: LT lobe of liver & anterior gastric - Quadrate lobe the liver. nerve. - Neck of pancreas. - posteriory: Diaphragm and posterior gastric nerve. - There is specific Sphincter: anatomical pyloric sphincter - There is no specific anatomical cardiac - It is often marked by: sphincter related to this orifice but - A prepyloric vein which physiological sphincter depends on: crosses the anterior surface 23 GIT 2025 Anatomy - acute angle between stomach and esophagus. vertically downwards. - Lower end of esophagus is surrounded by RT - feeling thickness of pyloric crus of diaphragm (has sphincteric action). sphincter. - Lower end of esophagus has thick mucosal - circular groove(pyloric folds. constriction). Vascular supply and lymphatics: Arteries Veins Lymphatic drainage arteries of the stomach arise - has the same - Lymphatic drainage of mainly from the coeliac trunk names and stomach is of great 1- Left gastric artery: arises accompany importance during directly from celiac trunk. the resection of the 2- Right gastric artery: arise from corresponding stomach, particularly for gastroduodenal artery, from arteries. malignancy. hepatic art. - They end in - lymphatics of the 3- Right gastroepiploic artery: portal vein. stomach end on: arise from gastroduodenal artery, - They may 1- superior gastric L.N. from hepatic artery. end in splenic 2-Inferior gastric L.N. 4- leftgastroepiploic artery: : arise or superior 3- pancreatico-dudenal from splenic artery. mesenteric L.N. 5- Short gastric arteries: arise from veins. These lymphatics end splenic artery. finally in celiac L.N.→ preaortic L.N. 24 GIT 2025 Anatomy Peritoneal attachment of the stomach: - gastrophrenic ligament. - gastrosplenic ligament. - greater omentum. -lesser omentum. 25