Maxilla: anatomy and difference from the mandible
- Highlighted area
Quick facts
- Type
- Paired bone: two maxillae joined at the midline form the upper jaw, fixed to the skull.
- Parts
- Body, with the maxillary sinus, and four processes: frontal, zygomatic, alveolar and palatine.
- Takes part in
- Floor of the orbit, lateral wall of the nose, hard palate and the arch of the upper teeth.
- Key foramen
- Infraorbital foramen, below the rim of the orbit, where the infraorbital nerve exits.
- Relevance in HOF
- Bony foundation of the midface; its resorption with age deepens folds and reduces projection.
The maxilla is the central bone of the midface. In fact there are two maxillae, one on each side, joined at the midline, which together form the upper jaw. It holds the upper teeth and takes part in the floor of the orbit, the lateral wall of the nose and the hard palate. Unlike the mandible, which is movable, the maxilla is fixed to the skull. In HOF, it is the bony base on which the cheek, the nasolabial fold and the upper lip rest.
What are the parts of the maxilla?
The body of the maxilla is hollow: it houses the maxillary sinus, the largest paranasal cavity. Four processes extend from it:
| Part | Where it goes | What it forms |
|---|---|---|
| Body | Center of the bone | Anterior wall of the cheek; contains the maxillary sinus |
| Frontal process | Upward, beside the nose | Part of the lateral wall of the nose and the medial rim of the orbit |
| Zygomatic process | Sideways | Articulates with the zygomatic bone, the base of the cheekbone |
| Alveolar process | Downward | Sockets of the upper teeth |
| Palatine process | Inward, horizontal | Most of the hard palate (roof of the mouth) |
On the anterior surface, the maxilla has important landmarks: the edge of the piriform aperture, which surrounds the entrance of the nose; the anterior nasal spine, at the base of the columella; the canine fossa, a depression above the canine; and the area of the premaxilla, at the front, under the upper lip.
What passes through the maxilla?
The infraorbital foramen sits on the anterior surface, slightly below the lower rim of the orbit. Through it exit the infraorbital nerve, which gives sensation to the lower eyelid, the side of the nose, the cheek and the upper lip, and the infraorbital vessels. The facial artery and vein and the angular artery run over the maxilla, beside the nose.
Mandible, maxilla and jaw: what is the difference?
| Maxilla | Mandible | |
|---|---|---|
| Position | Midface, top | Lower third, bottom |
| Number | Paired (two, joined) | Unpaired (single) |
| Mobility | Fixed to the skull | Movable, through the TMJ |
| Teeth | Upper | Lower |
| Reference foramen in HOF | Infraorbital | Mental |
"Jaw" is the popular term. "Upper jaw" is the maxilla, and "lower jaw" is an old name for the mandible.
Why does the maxilla matter in HOF?
With aging, the maxilla undergoes resorption, especially at the edge of the piriform aperture and in the area below the orbit. The skeleton loses projection, the tissues have less support and this contributes to the deepening of smile lines and the tear trough and to the loss of midface projection. A maxilla with little projection from a young age also changes the nasolabial angle and the facial profile. For that reason, the midface assessment considers the bone before thinking only about folds, as in the cheekbone area. The context is in layered facial aging.
Also called: upper jaw, maxillary bone, maxilla.
Frequently asked questions
What is the difference between the mandible and the maxilla?
The maxilla, or upper jaw, is the upper bone: paired, fixed to the skull, it holds the upper teeth. The mandible is the lower bone: single and movable, it holds the lower teeth and connects to the skull through the TMJ. In everyday Portuguese, the word for jaw sometimes refers to both.
Where is the maxilla located in the face?
In the center of the midface: it forms the lower part of the orbit, the sides of the nasal opening, the roof of the mouth and the base of the upper teeth. Laterally, it joins the zygomatic bone, which forms the cheekbone.