JAW RELATIONSHIPS and Mandibular Movements

Vocabulary-style flashcards covering the basics of jaw relationships, determinants of mandibular movement, and types of motion including rotational and translatory movements as described by Dr. Salman Ahmad.

Human masticatory apparatus

A complex system composed of the teeth, periodontal ligaments, bone of the jaws, neurovascular bundles, muscles of mastication, TMJ and its ligaments, tongue, cheeks, and lips.

Maxilla

The stationary or fixed bone of the jaws.

Mandible

The movable bone of the jaws that maintains dynamic relationships with the maxilla.

Functional movements

Mandibular movements that occur during mastication, speech, swallowing, respiration, and facial expression.

Parafunctional movements

Mandibular movements that include clenching and bruxism or night grinding.

Posterior determinants

Fixed structures consisting of the left and right TMJs and their associated structures.

Anterior determinants

Adjustable factors of mandibular movement consisting of the teeth and cuspal inclines.

Neuromuscular determinants

Partially adjustable factors involving the muscles of mastication and their innervation.

Hinge/rotational movement

A movement where all points within a body move around a common axis, which can occur around the transverse, sagittal, and frontal or vertical axes.

Translatory movement

A movement where all points within a body move at the same velocity and in the same direction to the same extent.

Bennet movement

The lateral side shift observed during translatory movement of the mandible.

Lower compartment of TMJ

The anatomical section of the temporary mandibular joint where all rotational movements occur.

Upper compartment of TMJ

The anatomical section of the temporary mandibular joint where all translational movements occur.

Working side

The side towards which the mandible moves during a lateral excursion.

Nonworking side (Balancing side)

The side of the mandible which moves towards the median line during a lateral excursion.

Rotating condyle

The condyle on the working side during a lateral movement of the mandible.

Balancing condyle

The nonworking condyle on the side of the mandible moving towards the median line.

Envelope of motion

The maximum extent to which the mandible can move in any direction or plane, such as the sagittal or frontal plane.

Terminal hinge movement

The specific mandibular movement occurring from Centric relation (B) to point C in the sagittal plane envelope of motion.

Orientation relation

One of the three recorded jaw relationships, alongside vertical and horizontal relations.