Ch.8 Joints Flashcards
Joint
- site where 2 or more bones articulate, bone and cartilage, bone and teeth
- Rigid and strong enough to hold the skeleton together
- Soft and flexible enough to allow mobility
Joint Classification
by Function or structure
Joint Classfication by Function
Based on amount of movement
1. Synarthroses= immovable
2. Amphiarthroses= slightly moveable
3. Diarthroses = freely moving
Joint Classification by Structure
- Based on the type of connective
- Tissue binding and cavity presence
1. Fibrous joints
2. Cartilaginous joints
3. Synovial joints
Fibrous joints
Joint Classification by Structure
- connected by fibrous connective tissue
- no cavity present
- generally synarthroses
Types of fibrous joints
- Sutures: short fibers usually ossifies (synostosis)
- Syndesmoses: short ligaments
- Gomphoses: peg-in-socket
Cartilaginous joints
Joint Classification by Structure
-connected by cartilage
- no cavity present
- generally synarthroses to amphiarthroses
Types of Cartilaginous joints
Two types:
1. synchondrosis: bones connected by hyaline cartilage
2. symphysis: midline of the body
articular cartilage and a fibrocartilage pad
Synovial joints
Joint Classification by Structure
- fluid filled cavity present
- most common
- generally diarthroses
- Bones act as levers against which skeletal muscles pull
- Muscles are attached to at least 2 bones & contract across the joint
- Origin: attachment to the bone that
does not move when muscle contracts - Insertion: attachment to the bone that moves during contraction
Synovial joint structure
- Articular cartilage
- Synovial cavity filled with synovial fluid
- Articular capsule:
– outer fibrous capsule
– inner synovial membrane - may have associated fatty pads, menisci (fibrocartilage pad), bursa, tendon sheaths
Factors that stabilize synovial joints
- Shape of the articulating surfaces
- Reinforcing ligaments
- Tone in muscles crossing the joint
Types of movement
- Gliding = one flat surface slips smoothly across another
- Ex: carpals and tarsals - Rotation = moving around an axis
- Ex: head - Angular = causes increase or decrease in angle between 2 bones
- Extension: moving leg foward/ moving shoulder or head backward
- Flexion: moving leg backward/ moving shoulder or head foward
Classification of synovial joints
- Plane joint
- Hinge joint
- Pivot joint
- Condyloid joint
- Saddle joint
- Ball and Socket joint
Plane joint
Classification of synovial joints
- Flat articulating surfaces
- Gliding motion
Hinge joint
Classification of synovial joints
- Cylindrical projection on one bone fits in a trough on another bone
- Allows uniaxial angular motions: flexion and extension
