Mandible is the dental word for your child's lower jaw, the only jaw that moves.

In kid words

Your mandible is your lower jaw, the part of your face that moves every time you talk, chew, or open wide and say ahh. Your upper jaw stays still and lets your mandible do all the work. Try it: rest a finger gently in front of your ear and open your mouth wide, that's your mandible swinging into motion.

The parent version

Mandible is the clinical name for the lower jawbone, the horseshoe-shaped bone that holds the lower teeth and forms the lower third of the face. It meets the skull on each side at the temporomandibular joint, a hinge-like joint just in front of each ear, and that joint is what lets it open, close, and slide side to side. The upper jaw, called the maxilla, is fixed directly to the skull and does not move on its own, which is why the mandible handles essentially all the motion involved in talking and chewing.

Like the rest of a child's skeleton, the mandible grows substantially between infancy and the teenage years, and it does not grow at a perfectly even pace. That growth is part of what eventually shapes how the upper and lower teeth fit together, so a wide range of jaw shapes and growth timelines is considered ordinary. If you are ever curious how your own child's jaw growth is tracking, ask your pediatric dentist.

Where you might hear it at our office

Growth is checked at every routine visit, and the mandible sits right at the center of that check, since how it grows and how it lines up against the upper jaw ends up shaping a child's whole bite over time. Most of the time, that quiet, ongoing watching is exactly what it should be, simply reassuring.

For some children, the mandible's own growth pattern is exactly why an early look through orthodontics gets suggested, well before any braces are anywhere in the picture. Whether that fits your child is worth asking your pediatric dentist, not something to guess at on your own. If another word from today's visit is still a mystery, the rest of the dictionary is right here.

Related words

Words that often come up alongside mandible: maxilla, jaw joint and bite.