Maxilla and mandible: applied anatomy for dentistry
- Anatomy and histology
The upper teeth sit in the maxilla, next to the maxillary sinus; the lower teeth sit in the mandible, which carries the nerve to the lower lip.
See it in 3D: Maxillae · Mandible · Mental foramen · Maxillary sinus · Palatine bones · Hyoid bone
What it is
The paired maxillae form the upper jaw, most of the hard palate and the floor of the orbit, and contain the maxillary sinus. Their alveolar process holds the upper teeth, and the roots of the upper premolars and molars often lie just under the sinus floor. The mandible is the only movable bone of the skull: a horseshoe-shaped body carrying the lower teeth and two rami that end in the condyle (at the temporomandibular joint) and the coronoid process. The inferior alveolar nerve runs in the mandibular canal from the mandibular foramen to the mental foramen, below the premolars.
Clinical anatomy
- Maxillary sinus: its floor is close to the roots of the upper molars and premolars.
- Hard palate: palatine processes of the maxillae in front and palatine bones behind; the incisive and greater palatine foramina carry nerves for palatal anaesthesia.
- Mandibular foramen: on the inner surface of the ramus, the target of the inferior alveolar nerve block.
- Mandibular canal: runs below the molar roots, close to the third molars.
- Mental foramen: below the premolars; the mental nerve exits to supply the lower lip and chin.
Clinical correlation
- Infection of an upper molar can cause maxillary sinusitis, and extraction of an upper molar can open the sinus (oro-antral communication).
- Sinusitis can be felt as pain in several upper back teeth at once, which can be mistaken for toothache.
- Numbness of the lower lip and chin (mental nerve) after third-molar surgery, a fracture or with no cause is a warning sign; without a cause it can mean a tumour in the mandible.
- Mandible fractures are often double (for example body on one side and condyle on the other) because the bone is a ring.
Next step / Initial management
- Pain in several upper back teeth with nasal congestion: consider sinusitis before a dental cause.
- Unexplained numbness of the lower lip or chin («numb chin»): image the mandible and refer urgently to rule out malignancy.
- Jaw trauma with malocclusion, pain on opening or lip numbness: obtain a panoramic radiograph or CT and refer to maxillofacial surgery.
Test yourself
Think of the answer, then tap the question to see it.
Why can an upper molar infection cause sinusitis?
Because the roots of the upper molars and premolars often lie just under the floor of the maxillary sinus.
Which nerve supplies the lower lip and chin, and where does it exit?
The mental nerve, a branch of the inferior alveolar nerve, exiting through the mental foramen below the premolars.
Why should a second mandible fracture be sought?
The mandible behaves like a ring, so a blow often breaks it in two places, commonly body and opposite condyle.
Elsewhere in DurgiPedia
Connections
See it in 3D6
The structures of Durgical's 3D anatomy where it is found.
Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.
Sources: Anatomy, Head and Neck, Mandible (StatPearls Publishing (NCBI Bookshelf), 2023); Anatomy, Head and Neck, Maxilla (StatPearls Publishing (NCBI Bookshelf), 2025); Mandible Fracture (StatPearls Publishing (NCBI Bookshelf), 2023).
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Representative model, for educational purposes only.