SURGICAL AND APPLIED ANATOMY OF MAXILLA.

Anatomy of maxilla and various fractures associated to maxilla

1. MAXILLA : THE UPPER JAW PRESENTED BY : ANIKET CHOUDHARY ( PG 1 ST YEAR) DEPARTMENT OF OMFS

2. MAXILLA : THE UPPER JAW PRESENTED BY : ANIKET CHOUDHARY ( PG 1 ST YEAR) DEPARTMENT OF OMFS

3. CONTENT INTRODUCTION OSTEOLOGY OF MAXILLA DEVELOPMENT OF MAXILLA AGE CHANGES OF MAXILLA MUSCLE ATTATCHMENT BLOOD SUPPLY NERVE SUPPLY MAXILLARY SINUS APPLIED ANATOMY OF MAXILLA SURGICAL ANATOMY OF MAXILLA

4. INTRODUCTION : 2 nd Largest bone of the face 2 Maxillae forms whole of upper jaw Each maxilla contributes in formation of – Face Nose Mouth Orbit Infratemporal fossa Pterygopalatine fossa

5. FEATURES OF MAXILLA : Each maxilla has a body and 4 Processes – 1. Frontal 2. Zygomatic 3. Alveolar 4. Palatine

6. BODY OF MAXILLA : Shape – pyramidal It has- Base - Directed at medially at nasal surface Apex - Directed at laterally at zygomatic process 4 Surfaces - Anterior / Facial Posterior / Infra Temporal Superior / Orbital Medial / Nasal

7. ANTERIOR / FACIAL SURFACE : Directed – laterally Incisive fossa – Depressor septi Canine fossa – Levator anguli oris Alveloar margin - orbicularis oris attachment below the incisive fossa Transverse part of nasalis/compressor nares – along with nasal notch Alar part of nasalis/dilator nares - superolateral to incisive fossa Infraorbital foramen – below the infra orbital margin ,allows passage of infraorbital vessels and nerve Levator lebii superioris – above the infra orbital foraman close to infraorbital margin Medially – nasal notch, Anterior nasal spine

8. POSTERIOR / INFRATEMPORAL SURFACE : Directed – backward & laterally Forms- anterior wall of infratemporal fossa & pterygopalatine fossa 2 - 3 number of canals behind 3 rd molar – provide passage of posterior superior alveolar nerve and vessels Buccinator – attach just above the area of 1 st and 2 nd molar teeth and extend posteriorly Posteroinferiorly – maxillary tuberosity & superficial head of medial pterygoid muscle

9. SUPERIOR / ORBITAL SURFACE Smooth , triangular, slightly concave Forms – Greater part of floor of orbit. Posterior medial border –relation with the orbital plate of palatine bone and superior orbital fissure. Medial portion – anterior part of border forms lacrimal notch which is converted in to nasolacrimal canal. Behind the notch , the border articulate with orbital plate of ethmoid and thin layer of sphenoid bone. Just lateral to lacrimal notch provide origin to inferior oblique muscle.

10. MEDIAL / NASAL SURFACE : Forms a part of lateral wall of nose. Large irregular opening of maxillary sinus called maxillary hiatus. Above the hiatus, articulation of labyrinth of ethmoid and lacrimal bones. Below the hiatus ,smooth concave surface forms inferior meatus of nose. Behind the hiatus, articulation of perpendicular plate of palatine bone, enclosing the greater palatine canal which runs downwards and forwards , and transmits greater palatine vessels and ant, middle , post palatine nerve. In front of hiatus, an oblique ridge called conchal crest, it is articulate with inferior nasal concha and descending process of lacrimal bone articulate, it is form nasolacrimal canal ,which transmits nasolacrimal duct to the inferior meatus of nose. Above the conchal crest, shallow depression forms a part of atrium of middle meatus of nose.

11. FRONTAL PROCESS Projects upwards and backwards. Above , articulate with nasal margin of frontal bone. Below , articulate with nasal bone. Behind, articulate with lacrimal bone. 2 surfaces- Lateral surface- Divided by lacrimal crest, smooth anterior part and grooved posterior part. Lacrimal crest gives attachment to lacrimal facia and medial palpebral ligament. Anterior part provides attachment of orbicularis oculi (above and below to ligament) and levator labii superioris alaeque nasi (in front of orbicularis occuli ). Posterior grooved area forms anterior half of lacrimal groove, which lodege lacrimal sac.

12. ZYGOMATIC PROCESS Pyramidal lateral projection. Situated at the junction of ant, post and superior surfaces. In front and behind, it is continuous with corresponding surface of the body. Superiorly, it is rough for articulation with zygomatic bone.

13. ALVEOLAR PROCESS Forms half of the alveolar arch and bears socket for the roots of upper teeth. Eight sockets - canine socket is deepest, molar socket is widest and divided into three minor socket by septa. Incisor and 2 nd premolar sockets are single and 1 st premolar socket is sometimes divided in to two. Buccinator arises from the posterior part of its outer surface up to the first molar tooth.

14. PALATINE PROCESS Horizontal plate projecting medially forms a large part of the roof of mouth and floor of nasal cavity. Inferior surface is concave,2 palatine process form anterior ¾ of hard palate and it presents vascular foramina and pits for palatine glands. Posterolaterally , 2-3 grooves for greater palatine vessels and anterior palatine nerves. Posterior border articulate with horizontal plate of palatine bone. Lateral border continuous with the alveolar process. Anterior ridge is high called incisor crest, which terminate anteriorly as anterior nasal spine. Incisive foramen located in midline of the palate posterior to central incisors, which transmits the greater palatine artery and vein from oral to nasal cavity and nasopalatine nerve from nasal to oral cavity.

15. MAXILLA PROPER Develops in the mesenchyme of the maxillary process of the 1 st branchial arch. Intramembranous ossification The ossified tissue appears as a thin strip of bone.

16. Ossification spreads as follow: Backward : below the orbit toward the developing zygomatic bone. Forward : toward the future incisor region. Upward : to form the frontal process of the maxilla. Bony trough is formed infra orbital groove The inner and outer edges of the groove grow up, meet and fuse forming a canal that encloses the nerve & open anteriorly at the infra orbital foramen. Downward : to form the outer alveolar plate for the maxillary tooth germs Toward the midline : ossification spreads with the development of the palatal process in the substance of the united palatal folds to form the hard palate.

17. DEVELOPMENT OF MAXILLARY SINUS At 4 months of IU as a small depression of the mucosa of the lateral wall of the nasal cavity In its gradual extension the sinus comes into relation with the maxilla above the level of the palatal process &hallow out the interior of the bone, so separating its upper or orbital surface from its lower or dental region.

18. PREMAXILLA Two centers of ossification for the premaxilla: The palato- ficial center: Appear at the end of 6 WIU . It starts close to the external surface of the nasal capsule, in front of the anterior superior dental nerve and above the germ of the lateral deciduous incisor. From this center bone formation spreads: To form the inner wall of their alveolar & palatal part of the premaxilla. b) The prevomerine center: It begins at about 8-9WIU along the outer alveolar wall it is situated beneath the anterior part of the vomer bone and it forms that part of the bone lies mesial to the nasal paraseptal cartilage.

19. ACCESORY CARTILAGE Accessory cartilaginous center appears in the region of the future zygomatic or malar process and this undergoes rapid ossification &adds considerable thickness to the bulk of the part. Small area of secondary cartilaginous center appears along the growing margin of the alveolar plate. In the middle line of the developing hard palate between the two palatine processes.

20. AGE CHANGES AT BIRTH The transverse and anteroposterior diameters are each more than the vertical diameter Frontal process is well marked Body consist of a little more than the alveolar process the tooth sockets close to the floor of orbit Maxillary sinus is a mere furrow on the lateral wall of the nose INADULT Vertical diameter is greatest due to development of the alveolar process and increase in the size of the sinus. IN OLD The bone reverts to infantile condition its height is reduced as a result of absorption of the alveolar process.

21. Maxillary sinus It is the largest bilateral air containing cavity ,occupying the body of maxilla, open into the nasal cavity by a single or multiple opening. It is described as 4 sided pyramid wall : Anterior wall: to facial surface of maxilla (region to canine, premolars) Posterior wall : to infra temporal surface of maxilla. Inferior floor : to alveolar process, 1mm below the level of the floor of the nose Superior roof : floor of orbit.

22. Relation with maxillary teeth The apices of the roots ( specially of palatal roots) of 1 st ,2 nd molars are usually near to the floor of sinus followed by 2 nd and 1 st premolar , canine and 3 rd molar respectively. Formed convexity toward floor of the sinus. Fractured root tip push in to the floor of the sinus due to close relation between root tip and sinus , this lead to infection of sinus and oroantral communication.

23. Pneumatization of maxillary sinus It is process of growth by bone resorption on internal wall of sinus & bone deposition on outer surface of maxilla. Maxillary sinus extended to many processes : Outward to zygomatic process. Inward, upward to frontal process. Downward to alveolar process. When it extend downward into alveolar process; the apices of the roots may appears protruded into sinus.

24. MUSCLE ATTACHMENT GROUP OF THE MUSCLE WHICH ORIGINATE/ INSERT ON THE MAXILLARY BONE Levator labii superioris- Origin - Arises From The Maxilla Just Superior To The Infra Orbital Foramen. Insertion – Blend with the orbicularis oris and insert in to skin of the upper lip. Action - r aises upper lip; helps to form nasolabial furrow (smile line).

25. LEVATOR LABII SUPERIORIS ALAEQUE NASI It is medial to levator labii superioris, arises from the maxilla next to the nose, and insert into both the alar cartilage of nose and skin of the upper lip. LEVATOR ANGULI ORIS It is more deeply placed and covered by the other two levators and the zygomaticus muscle, arises from the maxilla, just inferior to the infra orbital foramen, and insert into the skin at the corner of the mouth.

26. ORBICULARIS ORIS It is the complex muscle that completely encircle the mouth. ORIGIN- some fibers originate near midline from the maxilla superiorly and the mandible inferiorly, other fibers are derived from both buccinator, in the cheek. INSERTATION- forms ellipse around mouth; insert into the skin and mucous membrane of lips. ACTION- contraction of the muscle narrows the mouth and close the lips.

27. ORBICULARIS OCULI Large Muscle That Encircle The Orbital Orifice and extend into each eyelids. 3 parts of the muscle: 1. Orbital part 2. Palpebral part 3. Lacrimal part ORBITAL PART ORIGIN – frontal process of maxilla; medial palpebral ligament. INSERTION- fibers forms uninterrupted ellipse around orbit. ACTION- closes the eye more forcefully and produce wrinkling on the forehead.

28. BUCCINATOR It occupying the interval between the maxilla and the mandible at the side of the face. Forms the muscular component of the cheek. ORIGIN- posterior part of maxilla and mandible; pterygomandibular raphe which separates it from the superior pharyngeal constrictor muscle. INSERTION- blend with orbicularis oris . ACTION- the buccinators compress the cheeks, so that , during the process of mastication , the food is kept under the immediate pressure of the teeth. It aids whistling and smiling and in neonates it is used to suckle.

29. NASALIS Consists of two parts: TRANSVERSE PART - ORIGIN- maxilla just lateral to nose. INSERTION –across dorsum of the nose with muscle fibers from the other side. ACTION- compresses nasal aperture. ALAR PART - ORIGIN- maxilla over lateral incisor. INSERTION- alar cartilage of nose. ACTION- draws cartilage downward and laterally opening nostril.

30. 31- ORBICULARIS OCCULI 34-NASALIS 35-LEVATOR LABI SUPERIORIS ALAEQUE NASI 36-LEVATOR LABI SUPERIORIS 37-ORBICULARIS ORIS

31. BLOOD SUPPLY At about the level of hyoid bone each common carotid artery divides into an external carotid artery and an internal carotid artery. Internal carotid artery supplies the tissues of the cranium and the eyes. External carotid artery, with its many branches, supplies the exterior of the head ,the face and much of the neck.

32. At about the level of the lower part of the ear, the external carotid divides into its two main terminal branches, the maxillary artery and the superficial temporal artery. Maxillary Artery Through Various Branches Supply The Bones Of The Jaws, The Teeth And Their Supporting Tissues.

33. Important branches of maxillary artery are: Branches of the maxillary artery Supplies blood to Inferior alveolar artery -Supplies mandible and mandibular teeth. -enters to mandible through mandibular foramen. Posterior superior artery -supplies the maxilla and the roots of the last maxillary molar tooth. -bone and teeth including the first bicuspid. Greater palatine and lesser palatine artery -supplies the soft tissue of the hard palate , gingival tissue on the palatine and maxillary teeth. -emerges into the roof of the mouth through the greater palatine foramen. Infra orbital artery -supplies incisors and cuspids of the maxilla.

34. VENOUS DRAINAGE The maxilla is mainly drained by the maxillary vein. The two maxillary veins are the outlet of the large and dense pterygoid venous plexus which surrounds the maxillary artery in the infratemporal fossa. The pterygoid plexus of veins, into which the veins of the deep structures of the face open, is situated between temporal and lateral pterygoid.

35. The pterygoid plexus drains into the maxillary vein. Maxillary vein drains into the retromandibular vein which in turn drains into internal jugular vein. Internal jugular vein finally drains into the subclavian vein.

36. NERVE SUPPLY Nasopalatine nerve - It enters the nasal cavity through the sphenopalatine foramen, passes across the roof of the nasal cavity below the orifice of the sphenoidal sinus to reach the septum. It runs obliquely downward and forward between the periosteum and mucous membrane of the lower part of the septum. It descends to the roof of the mouth through the incisive canal and it supplies palatal structure around maxillary teeth.

37. Greater palatine nerve - It descends through the greater palatine canal, emerges upon the hard palate through the greater palatine foramen.

38. Posterior superior alveolar nerve - The posterior superior alveolar nerves enter the bone surface through two or three fine openings, the posterior superior alveolar foramina. They lead into narrow canals which run downward and forward in the thin wall of the maxillary sinus and supply the posterior teeth in the maxilla. Inferior orbital fissure carries infraorbital nerve. it supplies the soft tissue after exiting the infraorbital canal anteriorly. The infraorbital fissure and canal it gives out a branches called the middle and anterior superior alveolar nerve which supply the teeth of the maxilla anastomosing with the posterior superior alveolar nerve.

39. APPLIED AND FUNCTIONAL ANATOMY OF MAXILLA

40. SUPPORTIVE PILLARS : Canine pillar : It starts in the region of the alveolar process of the canine, forms the lateral boundary of the anterior nasal aperture and continues as the frontal process of the maxilla to the frontal bone. Zygomatic pillar : It starts in the region of the first molar, bends upward and outward as the zygomaticoalveolar crest and the zygomatic process of the maxilla to continue toward the frontal process of the zygoma to end at the zygomatic process of the frontal bone. Pterygoid pillar : It is the pterygoid process of the sphenoid bone to which the pyramidal process of the palatine bone is anchored. These vertical pillars are braced against each other by the superior and inferior orbital rims and the zygomatic arch.

41. VERTICAL AND HORIZONTAL BUTTRESSES According to Bennignhoff – Vertical trajectories Frontonasal buttress Malarzgomatic buttress Pterygoid buttress Horizontal trajectories Hard palate Orbital margin Zygomatic arches Palatal bone Lesser wing of sphenoid

42. Pathologic condition of maxillary sinus Maxillary sinusitis Odontogenic cystic lesion of maxillary sinus Tumors of maxillary sinus

43. Maxillary sinusitis of dental origin Dental abscess (periodontal and periapical infection) Infected dental cyst Oro-antral communication

44. OROANTRAL COMMUNICATION AND OROANTRAL FISTULA Maxillary sinus perforation occurs occasionally during the extraction of a maxillary tooth, and it may be a cause of maxillary sinusitis or oro -antral fistula. Less chances in patient below the age of 15 year due to incomplete development of sinus. Root which is most close to the sinus is “palatal root of maxillary 2 nd molar”.

45. Symptoms Of Fresh Oroantral Communication Escape Of Fluids Epistaxis Escape Of Air Excruciating Pain

46. Symptoms Of Established Oroantral Fistula. Pain. Persistent purulent unilateral nasal discharge. Popping out of antral polyp.

47. Cystic lesion of maxillary sinus Radicular cyst - appear at apical portion of root. Dentigerous cyst - usually appear on the impacted 3rd molar. Mucous retention cyst - very common, expansile, destructive.

48. TUMORS OF MAXILLARY SINUS Benign tumor- Ameloblastoma – most common tumor affecting to maxillary sinus.

49. Malignant tumor Squamous cell carcinoma - - most common malignant tumor. - invasive and destructive lesion.

50. MAXILLARY FRACTURE The middle third of the facial skeleton consists of a series of bone struts (buttresses) passing upwards from the upper teeth to the bones of the skull . Midface acts as a cushion for the trauma directed toward the cranium from the anterior or anterolateral direction analogous to a “matchbox” sitting below and in front of a hard shell containing the brain. Violent forces to this region are dissipated or absorbed by fractures of the maxilla and other facial bones, and thus offer protection to the brain and spinal cord .

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