Osteology of the Maxilla and Facial Bones PDF

Osteology of the Maxilla (and Facial Bones) Dr. Vehid Salih Programme Lead Year 1 Learning Objectives To identify location, shape and articulations To identify the alveolar and other maxillary processes and their significan...

Osteology of the Maxilla (and Facial Bones) Dr. Vehid Salih Programme Lead Year 1 Learning Objectives To identify location, shape and articulations To identify the alveolar and other maxillary processes and their significance To recognise landmarks and facets and their significance To identify foramina present within the maxilla and the structures which pass Facial Bone Recap Some Maxillae facts... The maxilla bones (or maxillary bones) are fused (paired) bones that provide lower part of the bony structure of the eye sockets, lateral walls of the nasal passage, the hard palate, the left and right maxillary sinuses, and the upper tooth sockets. It is the second-largest facial bone. Without the maxilla, we can neither eat properly nor speak clearly. Each maxilla articulates with 9 cranial & facial bones Opposite maxilla; nasal; lacrimal; ethmoid; palatine; frontal; vomer; zygomatic and inferior concha. The maxilla bone is composed of a main body with four projections = 4 processes. The Maxillary Surfaces May be thought of as a hollow, pyramidal body presenting 4 sides and having 4 attached ‘processes’ The facial (anterior) surface – forms the upper face The infratemporal (posterior) surface forms the anterior wall of the infratemporal region The orbital surface is the superior aspect i.e. forms the floor of the orbit The nasal (medial) surface is the base of the pyramid; forms the bulk of the lateral wall of the nasal cavity.  The Maxillary Processes Alveolar Process – forms the sockets/supporting bone for the maxillary teeth (and both maxillae form the upper dental arch) Zygomatic Process on the lateral aspect is the apex (top) of the pyramid Frontal Process is the vertical piece extending upwards to the anterosuperior aspect of the frontal bone Palatal (Palatine) Process is the horizontal shelf which extends from the medial aspect of the maxilla towards the midline and joins it’s other half i.e. the roof of the oral cavity Processes & Surfaces in context... Key Features Facial Surface: Infraorbital foramen (infraorbital nerves and blood vessels) Incisive fossa – overlies the roots of the incisor teeth (site of injection for LA of the maxillary incisors) Canine fossa – overlies the maxillary premolar roots (site of injection for LA of premolar maxillary teeth) Posterior Surface: Represents a gently rounded convex contour (maxillary tuberosity) Orbital Surface: Immediately deep to this is the maxillary sinus; the infraorbital groove then angles slightly and deeply as the infraorbital canal before opening via the infraorbital foramen. Nasal Surface: Occasionally the roots of maxillary teeth may meet or even protrude through he sinus floor. The incisive foramen transmits the nasopalatine nerve and sphenopalatine artery Route of Maxillary Nerve (Foramina) Maxillary Nerve – Branches Directly off Nerve Trunk rotundum foramen maxillary infraorbital groove/ nerve infraorbital nerve canal infraorbital foramen Maxillary Nerve – Branches Directly off Nerve Trunk rotundum foramen maxillary infraorbital groove/ nerve infraorbital nerve canal infraorbital foramen Maxillary Nerve – Branches Directly off Nerve Trunk zygomaticotemporal nerve i c rotundum zygomaticofacial at foramen nerve g ome z y er v maxillary n palpeb infraorbital groove/ nerve infraorbital nerve ral canal nasal infraorbital foramen superi anterio or middle r labial superio superio r r posteri alveola alveola or r r superio r alveola r Maxillary Nerve – Branches from Pterygopalatine Ganglion rotundum _ _ _ _ _ _ _ _ _ nerve foramen (carrying parasympathetic pharyngeal branches secretomotor fibres from (to mucosa of VII to lacrimal gland) nasopharynx) greater petrosal nerve (parasympathetic posterior superior fibres from CN VII) lateral nasal (to nerve of mucous membrane _____ of lateral wall of canal nasal cavity) deep petrosal nerve (sympathetic fibres from ____________ carotid plexus) _ _ (to hard palate) lesser palatine nasopalatine nerve nerve (to soft (to nasal septum; palate) to hard palate through _ _ _ _ _ _ _ _ _ _ _ _ _) Another way to ‘follow’ nerves via Foramina Maxillary Nerve S P A I note: posterior Liebgott superior alveolar nerve Maxillary Nerve Maxillary Nerve S A P I posterosuperi or lateral nasal posteroinferi or lateral nasal _______ _ nasopalatin e (cut) Liebgott _____ lesser _ palatine palatine Maxillary Nerve lacrimal nerve of pterygoid canal pharyngeal nerve nasopalatine and posterior lateral nasal zygomaticotempor nerves al and pterygopalatine zygomaticofacial ganglion greater and lesser nerves palatine nerves _________ nerves infraorbital nerve Grant’s Palatine Bone The palatine bones contribute to the posterior part of the roof of the mouth and floor and lateral walls of the nose, the medial wall of the maxillary sinuses and the orbital floors. (A) medial view (B) posterior view. Sort of shaped like an ‘L’ Helps form the nasal cavity, oral cavity, and the orbit. Zygomatic Bone The zygomatic bone is an irregularly, almost diamond- shaped bone of the skull. It is often referred to as the cheekbone; forms skeletal framework of orbit and cheeks. Lacrimal Bone The lacrimal bone is a paired facial bone that makes up the most anterior part of the medial wall of the orbit. It’s shaped like a fingernail and thus the smallest bone of the skull. The lateral surface houses the lacrimal sac and nasolacrimal duct. Nasal Bone The nasal bones are thin, flat, rectangular bones with two surfaces (lateral/facial) and (nasal/medial). Their superior borders and main bodies form the bridge of the nose while the inferior borders connect with the nasal cartilage to form the superior margin of the nasal aperture. Inferior Concha A separate bone which helps form the lateral wall of the nasal cavity; it’s sort of half- shell shaped. (A) medial view (B) lateral view Vomer Bone Provides a major contribution to the bony nasal septum; a thin flat bone that appears trapezoidal in outline Paranasal Sinuses The sinuses are named for the facial bones that they are located behind. 4 groups; the maxillary, frontal, ethmoid, and sphenoid. The biological role of the sinuses is debated, but a number of possible functions have been proposed: decreasing weight of the face; increasing resonance of voice; buffer against blows; insulating sensitive structures from rapid temperature fluctuations; and humidifying and heating of inhaled air. Summary paranasal sinuses: A group of four, paired, air- filled spaces that surround the nasal cavity (maxillary sinuses), above the eyes (frontal sinuses), between the eyes (ethmoid sinuses), ‘Functions’ of the Paranasal Sinuses The biological role of the sinuses is debated, but a number of possible functions have been proposed. These include: Decreasing the relative weight of the front of the skull, and especially the bones of the face. Increasing resonance of the voice. Providing a buffer against blows to the face. Insulating sensitive structures like dental roots and eyes from rapid temperature fluctuations in the nasal cavity. Humidifying and heating of inhaled air because of slow air turnover in this region. Regulation of intranasal and serum gas pressures. Immunological defence... Paranasal Sinuses Drake et al.  Frontal Sinus separated by septum usually asymmetrical drainage _ _ _ _ _ _ _ meatus (hiatus semilunaris) Liebgot t Sphenoidal Sinus within _ _ _ _ of sphenoid relations? drainage into sphenoethmoidal recess Drake et al. Ethmoidal Sinuses drainage ____________ __________ superior meatus anterior and middle ethmoidal air cells ____________ Liebgot t  Maxillary Sinus largest pyramidal walls innervation posterior, middle and anterior superior alveolar nerves Liebgot t  Maxillary Sinus arterial supply superior alveolar arteries from maxillary venous drainage _ _ _ _ _ _ _ plexus drainage middle meatus _______________ Liebgot t Maxillary Sinus - Clinical Grant’s Atlas  SDL Resources 3D Anatomy App