Overview
This lecture covers the detailed anatomy of the viscerocranium (facial bones), focusing on the maxilla, its processes, relationships with other facial bones, and related anatomical features and foramina.
Maxilla: Structure & Processes
- The maxilla consists of two bones joined at the intermaxillary suture at the midline.
- The maxilla has a body and four processes: frontal (superior), zygomatic (lateral), alveolar (inferior), and palatine (posterior).
- The body of the maxilla houses the maxillary sinuses, forming parts of the nasal cavity walls, orbital floor, and infraorbital margin.
- The infraorbital nerve (branch of maxillary division of trigeminal nerve) travels through the infraorbital groove, canal, and foramen.
Processes & Related Features
- Frontal process: Projects superiorly towards the nasal bones and forms part of the lateral nose.
- Zygomatic process: Articulates with the zygoma, forming part of the zygomatic arch and orbit.
- Alveolar process: Houses the upper teeth and borders the maxillary sinus (alveolar recess).
- Palatine process: Extends posteriorly, forming most of the hard palate, separated by the median and transverse palatine sutures.
Openings & Nasal Anatomy
- The anterior nasal spine and pear-shaped piriform aperture are formed by the maxilla and nasal bones.
- Inferior nasal concha: A separate shell-shaped bone forming the lower lateral wall of the nasal cavity.
- Maxillary sinus drains into the middle nasal meatus via the maxillary ostium and osteomeatal complex.
Additional Facial Bones & Structures
- Vomer: Unpaired bone forming the posterior and inferior part of the bony nasal septum.
- Ethmoid bone: Contributes to the roof and lateral walls of the nasal cavity, including the perpendicular plate.
- Nasal septum: Formed by the vomer, perpendicular plate of ethmoid, and maxillary crest.
Lacrimal & Palatine Bones
- Lacrimal bone: Small bone forming part of the medial orbit; contains the lacrimal fossa and canal for the nasolacrimal duct.
- Palatine bone: Has horizontal and vertical parts; forms the posterior hard palate and part of the orbit and nasal cavity; vertical part interacts with pterygoid processes of sphenoid.
Sphenoid Bone & Fossa
- Sphenoid bone: Contains pterygoid processes (lateral and medial plates) for muscle attachment.
- Openings include sphenopalatine foramen, vidian (pterygoid) canal, and greater/lesser palatine foramina.
Mandible Anatomy
- Mandible: Lower jaw, not always included in viscerocranium but essential; houses lower teeth.
- Divided into the body (contains alveolar and basal parts), angle, and rami.
- Rami contain condylar (articulates with temporal bone) and coronoid (temporalis muscle attachment) processes.
- Contains mental foramen (anterior), mandibular foramen (medial), and mandibular canal (inferior alveolar nerve).
Key Terms & Definitions
- Viscerocranium â The facial skeleton excluding the braincase.
- Maxilla â Upper jaw bone, forms part of orbit, nose, and palate.
- Intermaxillary Suture â Midline joint uniting the two maxillae.
- Infraorbital Foramen â Exit of infraorbital nerve onto face.
- Piriform Aperture â Pear-shaped anterior nasal opening.
- Inferior Nasal Concha â Separate bone forming lower lateral nasal wall.
- Vomer â Bone forming part of the nasal septum.
- Lacrimal Bone â Small medial orbital bone with nasolacrimal canal.
- Palatine Bone â Forms part of hard palate, orbit, and nasal cavity.
- Mandible â Lower jaw bone.
Action Items / Next Steps
- Review scans to identify the maxilla, its processes, and associated foramina.
- Study the question bank linked in the lecture for exam preparation.
- Prepare for the next lecture on the pterygopalatine fossa.