Saddle joint
Encyclopedia
In a saddle joint the opposing surfaces are reciprocally concave-convex.
; that is to say, flexion
, extension
, adduction
, abduction
, and circumduction
are allowed; but no axial rotation
. Saddle joints are said to be biaxial, allowing movement in the sagittal and frontal planes.
of the thumb
as well as the sternoclavicular joint.
Movements
The movements are as same as in the condyloid jointCondyloid joint
In a condyloid joint an ovoid articular surface, or condyle, is received into an elliptical cavity. This permits movement in two planes, allowing flexion, extension, adduction, abduction, and circumduction.-Examples:Examples include:* the wrist-joint* metacarpophalangeal joints*...
; that is to say, flexion
Flexion
In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
, extension
Extension (kinesiology)
In kinesiology, extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of...
, adduction
Adduction
Adduction is a movement which brings a part of the anatomy closer to the middle sagittal plane of the body. It is opposed to abduction.-Upper limb:* of arm at shoulder ** Subscapularis** Teres major** Pectoralis major** Infraspinatus...
, abduction
Abduction (kinesiology)
Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...
, and circumduction
Circumduction (anatomy)
In anatomy, circumduction means to move a limb in a circular manner.Circumduction is defined as the movement pattern which is a combination of flexion, extension, adduction and abduction. It occurs at synovial joints where a circle can be described by the body part...
are allowed; but no axial rotation
Axis (anatomy)
In anatomy, the second cervical vertebra of the spine is named the axis or epistropheus.It forms the pivot upon which the first cervical vertebra , which carries the head, rotates....
. Saddle joints are said to be biaxial, allowing movement in the sagittal and frontal planes.
Examples
The best example of this form is the carpometacarpal jointCarpometacarpal joint
The carpometacarpal joints are five joints in the wrist that articulates the distal row of carpal bones and the proximal bases of the five metacarpal bones....
of the thumb
Thumb
The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...
as well as the sternoclavicular joint.