HEAD AND NECK
INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
Salivary Glands 1. The Major Salivary Glands 1. Parotid 2. Submandibular 3. Sublingual
2. The Minor Salivary Glands
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Salivary Glands
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Salivary Glands Functions 1. Cleanses the mouth due to the bactericidal action of lysozyme and IgA (immunoglobulin A [one of the immune system's antibodies] )plus the constant backward flow towards the esophagus. 2. Creates a feeling of oral comfort by it's lubricating action 3. Dissolve food chemicals so that they can stimulate the tongue's taste buds. 4. Help to form a bolus (ball of food) by the action of mucins thus facilitating swallowing. www.indiandentalacademy.com
Salivary Glands 5.
Contain a digestive enzyme called salivary amylase (ptyalin) which starts the process of breaking down complex starchy sugars.
6.
Buffering (phosphate ions and bicarbonate) –
bacteria require specific pH conditions
–
plaque microorganisms produce acids from sugars
7.
Maintenance of tooth integrity –
8.
calcium and phosphate ions (ionic exchange with tooth surface) Tissue repair
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bleeding time of oral tissues shorter than other tissues
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resulting clot less solid than normal
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Re-mineralization www.indiandentalacademy.com
Salivary Glands Major glands 1. Parotid 2. Submandibular 3. Sublingual
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Salivary Glands 1. Parotid Gland The parotid salivary glands secrete a serous product only. They are situated on either side of the head in front of the ears. They have long ducts (Stensen’s duct) which open into the mouth opposite the second molar tooth on either side.
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Salivary Glands 2. Submandibular Gland The submandibular salivary gland secretes a mixed product containing both serous and mucous secretions although the serous component is the larger. They are roughly ovoid in shape and are situated below the mandible (jaw bone) to the left and right. Their ducts (Wharton’s duct) open into the floor of the mouth on either side of the tongue's
frenum.
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Salivary Glands 3. Sublingual Glands The sublingual glands produce a mainly mucous product. They are situated just under the back of the tongue again in a left and right pair. Their ducts (Bartholin’s duct) open close to those of the submandibular glands.
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Salivary Glands Minor glands In addition there are numerous smaller groups of salivary gland tissue scattered diffusely in the submucosa. The most important are: 1. lingual glands in the submucosa and muscle layers of the dorsal surface of the tongue 2. minor sublingual glands close to the larger major sublingual glands (other tongue glands are found on the inferior surface of the tip of the tongue and on its lateral borders) 3. labial glands on the inner surface of the lips 4. palatine glands in the submucosa of the soft and hard palates www.indiandentalacademy.com
Salivary Glands 5. tonsillar glands in the mucosa associated with the palatine and pharyngeal tonsils 6. buccal glands in the submucosa lining the cheeks. 7. The labial, sublingual, minor lingual and buccal glands are composed predominantly of mucous cells, but some serous cells may be present. 8. The palatine and lateral lingual glands are entirely mucous secreting
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Salivary Glands Autonomic Innervation •
Parasympathetic – Abundant, watery saliva – Amylase down
•
Sympathetic – Scant, viscous saliva – Amylase up
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Head & Neck
Blood Supply: Major arteries
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Blood supply- Arteries • The arterial supply of the head and neck is derived from the common carotid, vertebral and subclavian arteries. • The right common carotid arises from the brachiocephalic trunk. • The left common carotid arises from the aortic arch directly.
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Blood supply- Arteries • The common carotid runs upwards in the neck to the upper border of the thyroid cartilage. • Then it divides into external an internal carotid arteries.
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Blood supply- Arteries I The external carotid artery provides the major blood supply for the face and mouth. • The two major terminal branches of the external the maxillary and the facial arteries.
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carotid artery are
Blood supply- Arteries
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Blood supply- Arteries i. The maxillary artery is the large of the two terminal branches of the external carotid artery. • It arises behind the angle of the mandible and supplies the deep structures of the face.
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Blood supply- Arteries Major branches of the maxillary artery: 1. Infraorbital artery 2. Posterior superior alveolar artery 3. Inferior alveolar artery
1
2
3
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Blood supply- Arteries 1. Infraorbital artery gives branches to anterior and middle superior alveolar arteries. Their distribution to the maxillary incisors and cuspid teeth and to the maxillary sinuses. 2. Posterior superior alveolar artery. Its distribution is to the maxillary molar and premolar teeth and gingiva. 3. Inferior alveolar artery. It descends close to the medial surface of the mandibular ramus to the mandibular foramen. Before entering the foramen, it gives off the mylohyoid branch which supplies tissues in the floor of the mouth.
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Blood supply- Arteries ii. The facial artery is the other major branch of the external carotid artery. • It enters the face at the inferior border of the mandible. It passes forward and upward across the cheek towards the angle of the mouth. • It continues upward along the side of the nose and ends at the medial canthus (inner corner) of the eye.
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Blood supply- Arteries iii. The lingual artery also is a branch of the external carotid artery. • Its distribution is along the surface of the tongue.
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Blood supply- Arteries II The internal carotid artery has a dilation at its root, the carotid sinus. • The internal carotid artery has no branches outside the skull and enters the skull through the carotid canal. • Inside the skull the internal carotid artery gives off the ophthalmic artery which supplies the optic nerve, eye, orbit and scalp.
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Head & Neck
Major veins
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Head and neck major veins drainage The venous drainage of the head and neck begins as drainage of the brain. • The superior and inferior sagittal sinuses drain to the transverse then sigmoid sinuses to form the internal jugular vein. • The ophthalmic veins from the orbit drain backwards to the cavernous sinus or forwards to the facial vein.
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Head and neck major veins •The cavernous sinus drains to the pterygoid plexus of veins, through the superior petrosal sinus to the transverse sinus and through the inferior petrosal sinus to the internal jugular vein.
1.
Facial vein
2.
Cavernous sinus
3.
Pituitary plexus
4.
Superior petrosal sinus
5.
Inferior petrosal sinus
6.
Internal jugular vein
7.
Transverse sinus
8.
Confluence of sinuses
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Head and neck major veins
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Head and neck major veins • The maxillary and superficial temporal veins form the retromandibular vein behind the angle of the mandible.
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Head and neck major veins • The retromandibular vein communicates with the external jugular vein and the internal jugular vein. • The facial vein drains into the internal jugular vein. • The internal jugular vein empties into the superior veina cava, which returns blood from the upper portion of the body to right atrium of the heart.
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Head & Neck
Cranial nerves
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Cranial nerves
• The cranial nerves are arranged in 12 pairs, so the two nerves on a pair are identical in function and structure. • These nerves serve both sensory and motor functions. • The cranial nerves are generally named after the area or function they serve, and are identified with Roman numerals: I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII
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Cranial nerves
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Cranial nerves
I.
Olfactory nerve: sensory for the sense of smell.
II. Optic nerve: sensory for the sense of sight. III. Oculomotor nerves: nerves controls muscle of the eye. IV. Trochleal nerves controls muscles of the eye.
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Cranial nerves v. Trigeminal nerves: each divide into 3 branches: 1. Ophthalmic branches go to the eyes & forehead. 2. Maxillary branches go to the upper jaw & innervate the teeth & surrounding tissues. 3. Mandibular branches go to the lower jaw & innervate the teeth & surrounding tissues.
VI. Abducens nerves control muscles of the eyes.
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Cranial nerves VII. Facial nerves innervate the muscles of facial expression, salivary glands, lacrimal glands & sense of taste on the anterior 2/3 rd of the tongue.
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Cranial nerves VIII. Acoustic nerves: each divide into two branches a. Cochlear branches, which are concerned with the sense of hearing. b. Vestibular branches, which are concerned with the sense of balance. IX. Glossopharyngeal nerves: innervate the parotid glands, sense of taste on the posterior third of the tongue, and part of the pharynx. X. Vagus nerves innervate part of the pharynx, larynx and vocal cords, part of the thoracic and abdominal viscera. XI. Spinal accessory nerves innervate the shoulder muscles. XII. Hypoglossal nerves: innervate the muscles concerned with movements of the tongue. www.indiandentalacademy.com
Trigeminal nerve •
The trigeminal nerve is the primary source of innervations for the oral cavity.
•
The trigeminal nerve subdivided into three main branches: 1. Ophthalmic 2. Maxillary 3. Mandibular
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Trigeminal nerve- Maxillary division The maxillary division subdivides to provide the following innervations: 1. The nasopalatine nerve, which passes through the incisive foramen, supplying the mucoperiosteum (periosteum covered with mucous membrane) palatal to the maxillary anterior teeth.
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Trigeminal nerve- Maxillary division 2. The anterior palatine nerve, which passes through the posterior palatine foramen and forward over the palate, supplying the mucoperiosteum intermingling with nasopalatine nerve. 3. The anterior superior alveolar nerve supplies the maxillary central lateral and cuspid teeth, plus their periodontal membrane and gingiva. This nerve also supplies the maxillary sinus.
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Trigeminal nerve- Maxillary division 4. The middle superior alveolar nerve supplies the maxillary first and second premolars, the mesiobuccal root of the maxillary first molar and maxillary sinus. 5. The posterior superior alveolar nerve supplies the other roots of the maxillary first molar and the maxillary second and third molars, it also branches forward to serve the lateral wall of the maxillary sinus.
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Trigeminal nerve- Mandibular division The mandibular division of the trigeminal nerve subdivides into: 1. Buccal nerve 2. Lingual nerve 3. Inferior alveolar nerve, which subdivides into: Mylohyoid nerve branch Small dental nerves branches Mental nerve branch Incisive nerve branch
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Trigeminal nerve- Mandibular division 1. The buccal nerve supplies branches to the buccal mucous membrane and the mucoperiosteum of the maxillary and mandibular molar teeth. 2. The lingual nerve supplies the anterior 2/3 rd of the tongue and gives off branches to supply the lingual mucous membrane and mucoperiosteum.
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Trigeminal nerve- Mandibular division 3. The inferior alveolar nerve subdivides into •
Mylohyoid nerve supplies the mylohyoid muscles and the anterior belly of the digastric's muscle.
•
Small dental nerves supply the molar and premolar teeth, alveolar process and periosteum.
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Trigeminal nerve- Mandibular division • Mental nerve, which moves outward and anteriorly through the mental foramen and supplies the chin and mucous membrane of the lower lip. • Incisive nerve, which continues anteriorly within the bone and gives off small branches to supply the cuspid, lateral and central incisors.
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Head & Neck
Lymphatic drainage
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