Articulations and Body Movements Flashcards
Articulations
Joints that hold bones together and allow the rigid skeletal system some flexibility so that gross body movements can occur
Structural classifications of joints
Fibrous, cartilaginous and synovial joints
Functional classifications of joints
Synarthroses, amphiarthroses, diarthroses
Synarthroses
Immovable joints
Amphiarthroses
Slightly movable joints
Diarthroses
Freely movable joints
Where do diarthroses joints predominate?
In the limbs
Where do synarthroses and amphiarthroses joints predominate?
Restricted to the axial skeleton, where firm bony attachments and protection of enclosed organs are priorities
General rule about fibrous and synovial joints
Fibrous joints are immovable and synovial joints are feely movable
General rule about cartilaginous joints
Offers both rigid and slightly movable examples
Fibrous joints
Bones joined by fibrous tissue, no joint cavity is present. Amount of movement depends on length of fibers uniting bones. Some are slightly movable, most are synarthrotic and permit virtually no movement.
2 major types of fibrous joints
Sutures and syndesmoses
Sutures
Irregular edges of the bones interlock and are united by very short connective tissue fibers
Syndesmoses
Articulating bones are connected by short ligaments of dense fibrous tissue; bones do not interlock.
Cartilaginous joints
The articulating bone ends are connected by a plate or pad of cartilage. No joint cavity is present. Most are slightly movable (amphiarthrotic)
2 major types of cartilaginous joints
Synchondroses and symphyses
Symphyses
Bones are connected by a broad, flat disc of fibrocartilage. i.e. intervertebral joints and pubic symphysis
Synchondroses
Bony portions are united by hyaline cartilage. i.e. articulation of costal cartilage of the ribs to the sternum
Synovial joints
Articulating bone ends are separated by a joint cavity containing synovial fluid. All are diarthroses (freely movable)
Movement of Synovial joints
All are freely movable joints (diarthroses) but mobility varies: some synovial joints permit only small gliding movements, and others can move in several planes.
Structural characteristics of synovial joints
- Enclosed by a 2-layered articular capsule, creating a joint cavity.
- Inner layer is smooth CT membrane (synovial membrane) producing lubricating fluid to reduce friction. Outer layer dense irregular CT
- Articular (hyaline) cartilage covers surfaces of the bones forming a joint
- Articular capsule typically reinforced with ligaments and may contain bursae
- Fibrocartilage pads (articular discs) may be present within capsule