Special features
In certain joints, additional structures within the joint (intra-articular structures) are also present. Menisci articulares are sickle-shaped structures with a wedge-shaped cross-section that are only found in the knee joint. They consist of firm collagenous connective tissue and fibrous cartilage.
They serve to compensate for the non-fitting joint partners and reduce the pressure load on the joint cartilage. Disci artikulares are disc-shaped and consist partly of connective tissue and partly of fibrocartilage.They divide a joint into two separate chambers and reduce the pressure load on the fibrous cartilage. They are found in the temporomandibular joint, the clavicle joint and the wrist close to the body.
Joint lips
Articular lips (labra articularia) of the joints are wedge-shaped supports on the edges of the bony acetabular and acetabular cups. They consist mainly of fibrous cartilage and are fused with a connective tissue portion outside the joint capsule. The joint lips enlarge the joint surfaces.
Intra-articular ligaments are also known as intracapsular ligaments, occur in the knee and hip joints and have different functions. While the cruciate ligaments (Ligg. cruciata) in the knee have a predominantly mechanical function, the femoral head ligament (Lig. capitis femoris) serves as a vascular ligament for feeding the femoral head. They consist of taut connective tissue well interspersed with vessels and are covered by parts of the synovial membrane.
Joint mobility
The movement behavior of the joints is described with the help of the theory of motion (kinematics). Every joint movement is attributed to two basic movements and is therefore always a composite complex movement. On the one hand there is a: In sliding or displacement motion, a body moves on a straight line or on a curve of any curvature in space.
Here the body does not rotate around itself. So all points of the body make the same movement. The movement can take place along three spatial axes.
One speaks here of three degrees of freedom of the displacement movement. If one or two main directions are blocked in a joint, the number of possible movement directions is reduced. During the rotational movement of joints, a joint body rotates around an axis or a center point.
The center of rotation can be inside or outside the joint. Three degrees of freedom are also possible here. During the rotational movement, the joint surfaces can slide or roll on each other, whereby a combination of rolling and sliding usually occurs.
If a joint body moves on its joint surface with a gain in displacement of the axis, this is called rolling. However, if a body rotates without gaining distance from its axis, but with gaining distance from its surface, it slides.
- Sliding or sliding movement of the joints (translational movement), on the other hand a
- Rotation of the joints (rotational movement).
Shoulder joint Elbow joint Wrist joint Finger joints Hip joint Knee joint Upper ankle joint Lower ankle joint Base toe joint Shoulder girdle
- Diffraction 170°
- Aspect ratio 40
- Approach 30°.
- Spreading 160
- Turning inward 70°
- Turning outward 60
- Diffraction 150°
- Aspect ratio 10
- Diffraction 60°
- Aspect ratio 40
- Approach 30° (radial induction)
- Spreading 40° (ulnar induction)
- Turning 90° inwards (pronation)
- Outward rotation 90° (supination)
- Diffraction 90°
- Aspect ratio 0
- Diffraction 140°
- Aspect ratio 10
- Approach 30°.
- Spreading 50
- Turning inwards 50°.
- Turning outwards 40
- Diffraction 150°
- Aspect ratio 10
- Turning inward 10°.
- Turning outwards 40
- Diffraction 50°
- Aspect ratio 30
- Turning inwards 20° (inversion)
- Outward rotation 10° (Eversion)
- Diffraction 45°
- Aspect ratio 70
- Raise 40°.
- Pulling down 10
- Pull forward 30°.
- Pull backwards 25°.
