Topics

Topic

design image
Maxilla

The maxilla is a paired irregular bone forming the central portion of the midface. It contributes to the upper jaw, the floor of the orbit, the lateral walls and floor of the nasal cavity, and the anterior portion of the hard palate. Each maxilla contains a large maxillary sinus and supports the upper teeth via the alveolar processes. The maxilla articulates with nine bones: frontal, nasal, zygomatic, lacrimal, palatine, inferior nasal concha, vomer, and the contralateral maxilla. It is triangular in shape, with a broad superior base forming the orbital floor and a narrow inferior apex forming the alveolar ridge. The maxilla plays a key structural, functional, and aesthetic role in facial form, mastication, and nasal cavity architecture.

Synonyms

  • Upper jaw

  • Maxillary bone

  • Os maxillare

Function

  • Forms the upper jaw and dental arch, housing the upper teeth

  • Supports the floor of the orbit and lateral nasal walls

  • Contributes to the hard palate, separating oral and nasal cavities

  • Provides structural support to midfacial skeleton

  • Contains maxillary sinuses, important for sinus drainage and resonance

MRI Appearance
T1-weighted images:

  • The cortical bone of the maxilla appears hypointense (black)

  • Marrow spaces within the maxilla appear intermediate signal intensity, slightly darker than surrounding soft tissue

  • Adjacent fat is hyperintense, providing contrast for anatomical delineation

  • Fractures, bone lesions, or marrow infiltration may disrupt the normal low-signal continuity or show abnormal intermediate signal

T2-weighted images:

  • Cortical bone remains hypointense, while marrow shows variable hyperintensity depending on fatty content or edema

  • Pathologies such as osteomyelitis or neoplasms appear hyperintense relative to normal marrow

  • Maxillary sinus contents are hyperintense if fluid is present, while air remains signal void (black)

STIR (Short Tau Inversion Recovery):

  • Fat suppression removes signal from marrow fat, highlighting bone marrow edema, infection, or tumor

  • Normal cortical bone remains hypointense; abnormal lesions appear bright

  • Useful for detecting subtle inflammatory or neoplastic changes in the maxilla

CT Appearance

  • The maxilla is hyperdense due to cortical bone, with clear visualization of alveolar processes, orbital floor, palatal plate, and maxillary sinus walls

  • Maxillary sinus air appears hypodense (black), providing natural contrast with surrounding bone

  • CT clearly delineates fractures, congenital anomalies, sinus pathology, and tumor invasion

  • Thin cortical bone, alveolar ridge height, and sinus anatomy can be precisely measured for surgical planning, dental implants, or trauma evaluation

MRI images

Maxilla mri axial image -img-00000-00000