Anatomy Sheet: Oral cavity Done by: rasha Rakan edited by: khansaa Mahmoud

Anatomy Sheet: Oral cavity Done by: rasha Rakan edited by: khansaa Mahmoud

The oral cavity has 2 parts: 1. Oral vestibule: outer part that consists of outside the teeth, between the teeth, the cheeks and lips 2. Oral cavity proper: the part enclosed the teeth When we close our mouth, oral vestibule and cavity proper is in continuity through the openings between the teeth or behind the molar teeth )الضروس( (retro moral area) Lower jaw is called mandible, and upper jaw is called maxilla, they contain alveolar processes where the which is bone that contains the alveolar sockets.

The mouth is covered by mucous membrane that is composed of stratified squamous epithelium, some of it is keratinized (non-movable parts like the hard palate and dorsum of the tongue) and some non-keratinized (the remaining parts like the soft palate, floor of the mouth and lateral surface of the tongue). In the floor of the mouth there s a movable organ, the tounge which is partly sitting in the cavity proper and partly sitting into the oropharynx. Superiorly there s the hard palate. The oral cavity proper is separated from the oropharynx by sphincter that closes during swallowing to prevent the food from coming back into the mouth until the bolus of food is passing down into the esophagus. The sphincter is composed of: 1. Palatopharyngeal arch (posterior pillar of fauces 2.Palatoglossal arch (anterior pillar of fauces) Between them there s the palatine tonsil.

The teeth of children, the eruption of them beings at 6 month. The first to appear is the lower incisor tooth. By the 24 th month all the teeth are complete. The replacement begins at the 6 th year, the first to be replaced are the molars, and permanent teeth begins to appear. The permanent teeth complete by the age of 25, when the wisdom teeth (third and last molar teeth) أسنان العقل appear (it starts from the age of 17 to 25) Permanent teeth

Milk teeth are 20 teeth Permanent teeth are 32 (including 3 rd molar) Incisors have sharp ends,القواطع canine tooth األنياب conical in shape الشكل,أسطوانية premolar teeth are bicuspid (tow tubercles), molar teeth have many tubercles that may reach to 5, they are used for granting tooth The tooth is composed of the following: 1. Crown 2. Neck 3. Root can be 1-3 roots Periodontal membrane Incisors, canine and premolars have only one root, while the molars have 2-3 roots (upper molars have 3 roots, and the lower ones have 2 roots) Inside the tooth there s cavity, inside it there s pulp that is composed of artery, vein and nerve.

The cavity is covered by a white material that s called Dentine Outside the dentine there s a socket تجويف the roots are sitting in, this alveolar socket is in the alveolar processes (maxillary) that are lower (mandibular) and upper,العظم Around the dentin there s a material called cementum or cement that s calcified bony area. The crown is covered by inorganic hard material that s called Enamel The teeth are covered by a red vascular mucous membrane inside it there s tough collagenous tissue called the Gum, but it s loose around the neck so it doesn t play any role in fixing the teeth, and you can enter a tooth pick between the gum and the tooth. The fixing role is done by periodontal membrane, it is like the membrane that covers the bones of our body (periosteum membrane). The upper teeth are supplied by the anterior and posterior superior alveolar nerves, that are branches of the maxillary nerve.

Trigeminal (cranial nerve #5) nerve branches into 3 nerves : Infraorbital Nerve 1. Ophthalmic nerve 2. Maxillary nerve, passes through infraorbital canal and exits through infraorbital foramen and branches into posterior and anterior superior alveolar nerves The upper gum is supplied by infraorbital nerve( another branch of maxillary nerve) and posterior superior alveolar nerve 3. Mandibular nerve branches into: A. inferior alveolar nerve that supplies the lower teeth, that enters the mandibular foramen and passes through the mandible and exits through mantel foramen to give mantel nerve B. Mylohyoid nerve C. Lingual nerve that supplies the tongue

The lower gum is supplied by anteriorly by the mental nerve and posteriorly by the buccal nerve (branch of the mandibular nerve and works as a sensory nerve of the mouth area) Pterygoid Fossa Hard palate We are looking at the base of the skull. We are going to study the roof of the mouth, the hard palate 1. It is composed of: A. Palatine processes of the maxilla: (one on the right and the other on the left and they meet in the middle) B. Palatine bone that takes the shape of L and it has a vertical and horizontal planes, the later completes the hard palate.

2. Incisive foramen: a central orifice. Nasopalatine nerve (a branch of the maxillary nerve) and greater palatine artery pass through it, to supply the hard palate. 3. Greater palatine foramen Great palatine nerve passes through it Lesser palatine foramen Lesser palatine nerve passes through it 4. The lingual side of the gum الداخلية للثة باتجاه اللسان) (الجهة is supplied anteriorly by the nasopalatine nerve, and posteriorly by the greater and lesser palatine nerves. 5. The Pterygoid bone has median and lateral plates and between them there s the pterygoid fossa. The median pterygoid plate has a project called Hamulus. Inferiorly is covered by stratified keratinized squamous epithelium

Hard and soft palate 6. Mucous membrane (stratified squamous epithelium), underneath it mucoperiosteum (mucosa), and there s a lot of salivary glands (mucus and serous glands) and taste buds. We conclude that the hard palate is bone covered by mucosa (mucoperiosteum) and modified mucous membrane. It continues posteriorly as soft palate. Soft palate اللهاة is the movable part, and it moves while swallowing the food. It ends with a project called uvula. When we swallow food the soft palate closes the oropharynx and prevents the food from going up into the nasopharynx. Thus the soft palate separates the oropharynx and the

nasopharynx. We are sitting inside the oropharynx and looking to the front and we can see the soft palate and the uvula. Muscles of soft palate posterior view Soft palate is composed of stratified non-keratinized squamous epithelium, and muscles. The muscles: 1. Tensor veli palatine originates from Eustachian (auditory) tube (a canal that connects between the pharynx and the middle ear) and base of the skull (between the spine of the sphenoid and pterygoid fossa). The muscle becomes tendon and wraps on the Hamulus and then fanning كالمروحة( and )تنفرد continues medially to connect with the tensor veli from the (غشاء عريض) other side in the middle to form aponeurosis 2. Levator veli palatine palatine originates from Eustachian (auditory) tube and the medial side of the petrous temporal bone and does insertion in the edge of the soft palate. Levator means elevation so it elevates the soft palate.

Below the soft palate we have 2 muscles and both of them are covered by mucous membrane: 1. Palatoglossus muscle originates from the soft palate coming down into the tongue. 2. Palatopharyngeus muscle originates from the soft palate coming down into the pharynx. Anterior and posterior pillar arches and the palatine tonsil in between are located here. All the muscles of soft palate is supplied by vagus nerve through pharyngeal plexus except Tensor veli palatine supplied by the medial pterygoid nerve, a branch of mandibular nerve. Oral Mucosa All of the oral mucosa is made up of a thick stratified squamous epithelium, supported by a lamina propria (loose CT under stratified squamous). The epithelium is thick because the epithelial lining of the oral cavity is التمسق والجروح وخشونة الطعام tear. subject to a lot of wear and In mobile areas, such as the soft palate, underside of the tongue, floor of the mouth, and mucosal surfaces of the cheeks and lips, the epithelium is not keratinised. In other areas, such as the gums (gingivae), hard palate, and most of the upper surface of the tongue, the epithelium is keratinised.

Underneath the oral mucosa, there is a tough collagenous submucosal layer to attach the mucous membrane with the mandible and the maxilla bone, with Histology of the Hard palate accessory salivary glands, except where the oral mucosa lies over bone, where the submucosa is thin.

Histology of the lip Oral surface mucosa S. Q.NON-k = Stratified squamous non keratinised epith.

Outside the lip there s skin, and the skin has hair follicles. دهن أو زيتsebum that secrets غدد دهنية and Sebaceous gland Vermillion border is the red area in the lip, and it s red because it is rich in blood supply. It is red skin, and contains stratum lucidum which is transparent, so it reflexes the red color of the vessels. Then we oral surface and under it lamina propria, and then labial salivary glands. Gums = Gingivae They consist of mucosal tissue that covers the alveolar processes of the maxilla and mandible and finish at the neck of each tooth. The gingivae functions to cover the alveolar bone and surround the teeth. the gingiva is the only clinically visible component of the periodontium inside the mouth. Healthy gingiva will appear pink in colour The gingival margin follows a scalloped-like course across the dentition due to the interdental papillae, which fill the interdental spaces beneath the tooth contacts.

There are two types of gingiva, Two portions of the gingiva can be identified: Free gingiva and attached gingiva The free gingiva surrounds the tooth and creates a cuff or collar of gingiva measured from the margin of the attached gingiva extending coronally about 1.5mm. The inner surface of the free gingiva (next to the tooth) forms the gingival wall of the sulcus. The healthy patient will present with a sulcus measuring approximately 1-3mm in depth Histology the tissue on the outer surface of the free gingiva, the papillae and the attached gingiva is stratified squamous keratinized epithelium. The inner surface of the free gingival margin (sulcus) is stratified squamous non keratinized epithelium.

The gingival connective tissue consists of a dense network of collagen fibers. Collagen fibers function to provide firmness to the gingiva and to attach the gingiva to the underlying cementum and alveolar bone. The connective tissue of the gingiva is also rich in blood, lymphatic vessels, nerves وال تقنع بما دون النجوم