Osteology of the Maxilla and Facial Bones

Osteology of the Maxilla (and Facial Bones)

• The maxillae (maxillary bones) are paired bones forming the lower part of the eye sockets, lateral nasal walls, hard palate, and the upper tooth sockets.
• The maxilla is the second largest facial bone.
• Without the maxilla, proper eating and speech are impossible.
• Each maxilla articulates with 9 cranial and facial bones: nasal, lacrimal, ethmoid, palatine, frontal, vomer, zygomatic, and inferior concha.
• The maxilla has a main body with four projections (processes).

Learning Objectives

• Identify the location, shape, and articulations of the maxilla.
• Identify the alveolar and other maxillary processes and their significance.
• Recognize landmarks and facets, and understand their significance.
• Identify foramina present within the maxilla and the structures that pass through them.

Facial Bone Recap (14 bones in total):

• Nasal (2)
• Lacrimal (2)
• Palatine (2)
• Inferior nasal concha (2)
• Maxilla (2)
• Mandible (1)
• Zygomatic (2)
• Vomer (1)

Maxillary Surfaces

• Facial (anterior) surface: Forms the upper face.
• Infratemporal (posterior) surface: Forms the anterior wall of the infratemporal region.
• Orbital surface: The superior aspect; forms the floor of the orbit.
• Nasal (medial) surface: Forms the bulk of the lateral wall of the nasal cavity.

Maxillary Processes

• Alveolar process: The sockets/supporting bone for maxillary teeth.
• Zygomatic process: Located on the lateral aspect, forming the apex (top) of the pyramid.
• Frontal process: A vertical piece extending to the anterosuperior aspect of the frontal bone.
• Palatal (palatine) process: A horizontal shelf extending from the medial aspect to the midline, forming the roof of the oral cavity.

Key Features

• Facial surface: Contains the infraorbital foramen (infraorbital nerves and blood vessels), incisive fossa (overlying incisor roots), and canine fossa (overlying premolar roots).
• Posterior surface: Exhibits a gently rounded convex contour (maxillary tuberosity).
• Orbital surface: Contains the infraorbital groove/canal that angles from the infraorbital foramen.
• Nasal surface: May have maxillary tooth roots extending through the sinus floor.

Route of Maxillary Nerve (Foramina)

• Details the pathway and branches of the nerve through various foramina in the skull.

Maxillary Nerve - Branches Directly off Nerve Trunk

• Explains the nerve connections and where they originate.

Maxillary Nerve - Branches from Pterygopalatine Ganglion

• Shows the branches emanating from the ganglion.

Another way to 'follow' nerves via Foramina

• Demonstrates another anatomical pathway to follow the nerves via foramina present in the cranium.

Paranasal Sinuses

• These are air-filled spaces within facial bones surrounding the nasal cavity.
  • Maxillary sinuses
  • Frontal sinuses
  • Ethmoid sinuses
  • Sphenoid sinuses
• Their possible biological functions include decreasing skull weight, voice resonance, buffering against facial blows, insulating sensitive structures, regulating temperature and humidity, and regulating pressure.

Functions of the Paranasal Sinuses

• Decrease the weight of the skull and face.
• Enhance voice resonance.
• Protect against facial blows.
• Insulate against rapid temperature fluctuations.
• Humidify and heat inhaled air.
• Regulate intranasal and serum gas pressures.

Frontal Sinus

• Separated by a septum.
• Usually asymmetrical.
• Drains into the meatus (hiatus semilunaris, or the medial wall of the nasal cavity).

Sphenoidal Sinus

• Located within the sphenoid bone.
• Contains connections and drainage to the sphenoid-ethmoidal recess.

Ethmoidal Sinuses

• Drain into the superior meatus.
• Contain anterior and middle ethmoidal air cells.

Maxillary Sinus

• Largest, pyramidal shape.
• Has walls and innervation.
• Innervated by the posterior, middle, and anterior superior alveolar nerves.

Maxillary Sinus (Clinical Features)

• Relevant information about clinical aspects.

Palatine Bone

• Contributes to the posterior portion of the roof of the mouth.
• Forms part of the floor and lateral walls of the nose.
• Forms part of the medial wall of the maxillary sinuses and the orbital floors.

Zygomatic Bone

• Irregularly diamond-shaped, often referred to as the cheekbone.
• Forms part of the skeletal framework of the orbit and cheeks.

Lacrimal Bone

• One of the smallest facial bones.
• Located in the anterior region of the medial wall of the orbit.
• The lateral surface contains the nasolacrimal duct.

Nasal Bone

• Thin, flat, and rectangular bones forming part of the bridge of the nose.

Inferior Concha

• A separate bone forming part of the lateral wall of the nasal cavity.
• Its shape is roughly half-shell-shaped.

Vomer Bone

• A major contributor to the nasal septum.
• Exhibits a trapezoid shape.

This quiz covers the detailed anatomy of the maxilla and its articulations with other facial bones. You'll learn to identify key features, processes, and foramina of the maxilla, as well as recognize the importance of these structures for functions like eating and speech. Test your knowledge of the 14 facial bones and their respective roles.