Synovial Joints

Synovial Joints

Bones that are separated by a joint cavity in which the cavity contains synovial fluid

Describe the flexibility of this joint.

freely moveable (diarthroses) (most appendicular)

What planes can synovial joints move?

Some only move in one plane (uni-axial) while others move in multiple planes (multi-axial)

What four main things are these joints composed of?

1. Articular Capsule

2. Articular Hyaline Cartilage

3. Ligaments

4. Joint Cavity

Articular Capsule

2-layered connective tissue sleeve covering joint

1. Synovial membrane: inner layer, produces synovial fluid which reduces friction

2. Fibrous Capsule: thicker, outer layer -

   dense irregular connective tissue

Articular Hyaline Cartilage

covers articulating surfaces of bones

Ligaments

present to reinforce articular capsule

Joint Cavity

contains synovial fluid

Uni-axial (function)

a. Joint only allows movement in one plane or direction

b. Example: elbow - Flexion/Extension (One plane of movement) One-plane

Bi-axial

a. Joint allows for movement in 2 planes

b. Example: Joints involving the fingers such as Carpals/Metacarpals - Flexion/Extension, Adduction/Adbuction (2 planes of movement)

Multi-axial

a. Joint allows movement in all 3 planes

b. Example: shoulder — ball-and-socket -

Rotation (all planes) multi-planes

Hinge + Pivot Joint

(uni-axial)

1. rounded portion on one bone fits into concave depression of another bone (elbow, knee)

2. rounded portion of one bone articulates with shallow depression of another bone (C1 & C2)

Condyloid + Gliding + Saddle

(bi-axial)

1. Condyle of one bone fits into ellipoidal depression. mostly seen as a shallow bone region (wrist)

2. flat surface (wrist)

3. bone bone is concave (bends inward) and the other is convex (bends outward) (thumb)

Ball-and-Socket

(multi-axial)

head fits into rounded socket (hip, shoulder)