Dr.Ban I.S. head & neck anatomy 2 nd y. جامعة تكريت كلية طب االسنان املرحلة الثانية

Transcription

1 جامعة تكريت كلية طب االسنان التشريح مادة املرحلة الثانية أ.م.د. بان امساعيل صديق

2 The Palate The palate forms the roof of the mouth and the floor of the nasal cavity. It is divided into two parts: the hard palate in front and the soft palate behind. Hard Palate The hard palate is formed by the palatine processes of the maxillae and the horizontal plates of the palatine bones. It is continuous posteriorly with the soft palate. Soft Palate The soft palate is a mobile fold attached to the posterior border of the hard palate. It is free posteriorly and is continuous at the sides with the lateral wall of the pharynx. The soft palate is composed of mucous membrane, palatine aponeurosis, and muscles. Mucous Membrane The mucous membrane covers the upper and lower surfaces of the soft palate. Palatine Aponeurosis The palatine aponeurosis is a fibrous sheet attached to the posterior border of the hard palate. It is the expanded tendon of the tensor veli palatini muscle. Muscles of the Soft Palate The muscles of the soft palate are the tensor veli palatini, the levator veli palatini, the palatoglossus, the palatopharyngeus, and the uvula. 2

3 1/Tensor palati This muscle arises from, the scaphoid زورق fossa at the upper end of the medial pterygoid plate, the lateral side of the cartilaginous part of the auditory tube, and the spine of the sphenoid And from this origin the triangular muscle passes down between the medial and lateral pterygoid plates converging to a tendon that turns medially around the pterygoid hamulus شص. The tendon, together with the tendon of the opposite side, expands to form the palatine aponeurosis. When the muscles of the two sides contract, the soft palate is tightened so that the soft palate may be moved upward or downward as a tense sheet. The aponeurosis is attached anteriorly to the hard palate. The aponeurosis is not flat, but concave towards the mouth; when tensed by contraction of the tensor muscle it is flattened and therefore depressed somewhat. The main action of the tensor palati is to tense the palatine aponeurosis so that other muscles may elevate and depress it without altering its shape. 3

4 2/ Levator palatini This muscle arises from the apex of petrous part of temporal bone,and from the adjacent medial side of the cartilaginous part of the auditory tube, it forms a rounded belly that is inserted into the nasal surface [superior] of the palatine aponeurosis between the two heads of palatopharyngeus. The two levator muscles in passing down to the palate are directed forwards and medially, together forming a V-shaped sling.رافعة Their contraction pulls the palate upwards and backwards. 3/Palatoglossus The muscle arises from the undersurface of the palatine aponeurosis and passes downwards to interdigitate with styloglossus [inserted to the side of the tongue]. The muscle raises the palatoglossal fold of mucous membrane in front of the tonsil (the anterior pillar عمود ), it pulls the root of the tongue upward and.منطقة ضيقة backward and narrows oropharyngeal isthmus 4

5 Uvula 5

6 4/Palatopharyngeus The muscle arises from two heads. The anterior head arises from the posterior border of the hard palate. The posterior head arises from the upper surface of the aponeurosis. The two heads arch downwards and passes beneath the mucous membrane of the lateral wall of the pharynx just behind the tonsil. The upper part of the muscle raises the palatopharyngeal fold of mucous membrane that constitutes the posterior pillar. It is inserted to the posterior border of thyroid cartilage. It elevates wall of pharynx, pulls palatopharyngeal arch upward and medially. The muscle is an elevator of the larynx and pharynx. 5/Uvula consists of two strips شريطين of muscle on the upper surface of the aponeurosis on either side of the midline, running from the posterior nasal spine of the palatine bone to the mucosa of the uvula. They aid palatopharyngeal closure. Blood supply: The greater palatine artery was the main vessel to supply the hard palate, runs anteromedially towards the incisive foramen, it ascends through the incisive foramen and anastamoses with branches of the sphenopalatine artery. The blood supply of soft palate include the following arteries: 1-Lesser palatine branches of the maxillary artery. 2-Ascending palatine branch of the facial artery. 3-Palatine branches of the ascending pharyngeal artery The venous drainage passes through the pharyngeal wall into the pharyngeal venous plexus and the pterygoid plexus. Lymph drainage: Lymphatic vessels from hard palate empty into submandibular and superior deep cervical nodes. Lymphatics from the soft palate empty into retropharyngeal and superior deep cervical lymph nodes. 6

7 Nerve supply: The hard palate is innervated by branches of the maxillary nerve, both of which initially pass through the pterygopalatine ganglion. The greater palatine nerve descends through the greater palatine foramen with its companion artery, and runs anteromedially to supply the mucosa of the posterior 2/3 of hard palate. The nasopalatine nerve descends through the incisive foramen to supply the most anterior parts of the hard palate. Secretomotor fibers to the salivary glands on the posterior hard palate have their cell bodies in the pterygopalatine ganglion and travel to the hard palate with the greater palatine nerve. 7

8 All the muscles of the soft palate are supplied by the pharyngeal plexus except for tensor palati, which is supplied by a branch from the nerve to the medial pterygoid (from the mandibular branch of the trigeminal nerve). The plexus fibers to the palate are from the cranial part of the accessory nerve and the pharyngeal branch of the vagus. Postganglionic secretomotor fibers to the palatal glands from the pterygopalatine ganglion run with the lesser palatine nerves, these nerves also carry taste fibers (cell bodies in geniculate ganglion) from the few taste buds on the oral surface of the soft palate. Common sensation from the mucous membrane of the soft palate is transmitted by the lesser palatine nerves also. On the oral surface there is slight overlap of glossopharyngeal sensory fibers from the lateral wall of the pharynx. 8