What is "hinge joint"

Hinge \Hinge\, n. [OE. henge, heeng; akin to D. heng, LG. henge, Prov. E. hingle a small hinge; connected with hang, v., and Icel. hengja to hang. See Hang.]

1. The hook with its eye, or the joint, on which a door, gate, lid, etc., turns or swings; a flexible piece, as a strip of leather, which serves as a joint to turn on.

   The gate self-opened wide, On golden hinges turning.
   --Milton.

2. That on which anything turns or depends; a governing principle; a cardinal point or rule; as, this argument was the hinge on which the question turned.

3. One of the four cardinal points, east, west, north, or south. [R.] When the moon is in the hinge at East. --Creech. Nor slept the winds . . . but rushed abroad. --Milton. Hinge joint.

   1. (Anat.) See Ginglymus.

   2. (Mech.) Any joint resembling a hinge, by which two pieces are connected so as to permit relative turning in one plane.

      To be off the hinges, to be in a state of disorder or irregularity; to have lost proper adjustment.
      --Tillotson.

1. n. a freely moving joint in which the bones are so articulated as to allow extensive movement in one plane [syn: ginglymus, ginglymoid joint]

2. a joint allowing movement in one plane only [syn: knuckle joint]

A hinge joint (ginglymus) is a bone joint in which the articular surfaces are molded to each other in such a manner as to permit motion only in one plane. According to one classification system they are said to be uniaxial having one degree of freedom. The direction which the distal bone takes in this motion is seldom in the same plane as that of the axis of the proximal bone; there is usually a certain amount of deviation from the straight line during flexion.

The articular surfaces of the bones are connected by strong collateral ligaments.

The best examples of ginglymoid joints are the interphalangeal joints of the hand and those of the foot and the joint between the humerus and ulna. The knee joints and ankle joints are less typical, as they allow a slight degree of rotation or of side-to-side movement in certain positions of the limb. The knee is the largest hinge joint in the human body.

Hinge and pivot joints are both types of synovial joint. A hinge joint can be considered a modified sellar joint, with reduced movement.

Other objects that work like hinged joints are door hinges, closet doors, dog flaps etc.