articulations - westmont college...classification of joints (cont.) structural classification...

Articulations

Articulations = JointsAn area where two or more bones

join together (conjoin)

Arthrology: study of joints

Classification of Joints Functional Classification

Based on the degree of motion at eachjoint. Synarthrosis (immovable joint) Amphiarthrosis (slightly moveable) Diarthrosis (freely moveable)

Classification of Joints (cont.)

Structural Classification According to major connective tissue type Whether there is a fluid-filled joint capsule

Fibrous jointsCartilaginous jointsSynovial joints

Fibrous Joints Held together by Dense

regular CT (fibrous CT)

Immovable

No joint capsule

Example: sutures of theskull

Cartilaginous Joint Partially (slightly) movable

joint Held together by hyaline or

fibrocartilage Has no joint capsule Fairly strong

Examples: intervertebraldisks, epiphyseal plates,cartilage between ribs andsternum

Synovial Joints

Freely movable Most abundant Joint capsule (sleeve

around the joint)

Details of Synovial Joint

Movable Synovial Joint

Types of Synovial Joints Pivot Joint

uniaxial One bone rotates on a

horizontal axis

Ball and Socket Joint multiaxial

Condyloid Joint Biaxial Oval convex surface

articulates with concave

Types of Synovial Joints Gliding

Two opposing flatsurfaces slide over eachother

Saddle Consists of two saddle-

shaped articulatingsurfaces at right angles

Hinge Unaxial Convex-concave

Joint is protected by Synovial capsule Synovial membrane Synovial fluid

Types of Synovial JointsFunctional classification :

ExamplesMovementJoint

Ankle; Elbow (humeroulna);Interphalangeal.

1 axisHinge

Carpal bones within thewrist, intervertebral.

TranslationGliding

Hip; glenohumeral3 axesBall & socket

Thumb: carpometacarpal3 axesSaddle

Wrist (radius & carpals);Metacarpophalangeal

2 axesCondyloid

Atlanto-axial1 axisPivot

Joint Related Structures - Ligaments

Ligaments – Very strong bands of fibrous connective tissue, that hold the bones of a joint together.

Ligaments can be inside (intracapsular) and outside (extracapsular) the synovial joint capsule.

Knee Bursae

Bursa – small fluid filled sacks, help to reduce friction in some major joints.

Joint Related Structures

Joint Related Structures

Tendons – tough bands ofconnective tissue joiningmuscles to bones.

Typically attach to bones nearthe joints.

Immovable jointsJoints - Fixed

Slightly movable jointsJoints –Slightly movable