Joints Flashcards
Bone-to-bone connections
- Articulations
- Some permit free movement, others firmly unite bones
3 major categories
1) Fibrous joints
- Joined by connective tissue
- ex between bones of the skull or teeth in socket
- Dense connective tissue unites bones generally immovable
- Skull develops as continuous membrane with separate ossification centres.
- sutures grows via growth of bones at their margin
3 major categories
2) Cartilaginous joints
- few are permanent (ex; juvenile long bones)
- mandibular symphysis pelvic symphysis and intervertebral discs have cartilaginous + fibrous
- Cartilage covers bone, fibrous tissue between the cartilage-covered surfaces
3 major categories
Synovial Joints
-Articulating bones separated by fluid-filled space; greatest range of motion
Components
- Joint cavity- a potential space filled with a small amount of lubricating synovial fluid
- Joint capsule- membrane enclosing the cavity; outer layer is fibrous, inner layer is glandular and secretes synovial fluid
- articular cartilage- covers the articular surface of the bone; very smooth; avascular and insensitive.
Motion at Joints
Flexion
-Movement in which the angle of the joint is decreased (flexion)
Motion of joints
Extension
Movement in which the angle of the joint is increased
Motion of Joints
Protraction
Movement of the limb cranially
Motion of joints
Retraction
Movement of the limb caudally
Motion at joints
Adduction
Movement towards the body
Motion at joints
Abduction
Movement away from the midline
Motion at joints
Rotation
- Movement of the limb around its long axis; inward (medical rotation) or outward (lateral rotation)
Motion at joints
Pronation
- rotation of the forearm such that the palm faces caudally (face down)
- species covered in this course have pronated forearms with limited (if anu) ability to supinate
Motion at the joints
Supination
A result of the radius crossing over the ulna
