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Elevation and depression are movements above and below the horizontal. The words derive from the Latin terms with similar meanings. [c] Elevation is movement in a superior direction. [19] For example, shrugging is an example of elevation of the scapula. [20] Depression is movement in an inferior direction, the opposite of elevation. [21]
In humans, the mandible, or lower jaw, is connected to the temporal bone of the skull via the temporomandibular joint. This is an extremely complex joint which permits movement in all planes. The muscles of mastication originate on the skull and insert into the mandible, thereby allowing for jaw movements during contraction.
When measuring the vertical range of motion, the measurement must be adjusted for the overbite. For example, if the measurement from the edge of the lower front teeth to the edge of the upper front teeth is 40 millimeters and the overbite is 3 millimeters, then the jaw opening is 43 millimeters. During jaw movements, only the mandible moves.
The anterior and posterior belly of the digastric are also involved in the depression of the mandible and elevation of the hyoid bone and are therefore relevant to the masticatory system. [2] Ligaments. There are various ligaments associated with the TMJ and these limit and restrict border movements by acting as passive restraining devices.
Jaw pain Stress and grinding your teeth at night are both generally benign reasons behind why your jaw may be aching. But persistent jaw pain may also be a sign of an underlying health condition.
Depression: Depressor labii inferioris: Mandible: Underneath skin of lower lip Opening mouth and sliding lower jaw left and right: Lower jaw: Depression, lateral: Depressor angulus oris: Mandible: Underneath skin at corners of mouth Smiling: Corners of mouth: Lateral elevation: Zygomaticus major: Zygomatic bone
Emotional stress (anxiety, depression, anger) may increase pain by causing autonomic, visceral and skeletal activity and by reduced inhibition via the descending pathways of the limbic system. The interactions of these biological systems have been described as a vicious "anxiety-pain-tension" cycle which is thought to be frequently involved in TMD.
In jawed vertebrates, the mandible (from the Latin mandibula, 'for chewing'), lower jaw, or jawbone is a bone that makes up the lower – and typically more mobile – component of the mouth (the upper jaw being known as the maxilla). The jawbone is the skull's only movable, posable bone, sharing joints with the cranium's temporal bones.