Advertisement Upgrade to remove ads

Joints (articulations)

where two or more bones meet

Function of Joints

give skeleton mobility and hold skeleton together

Three Classifications of Joints

synarthrotic, amphiarthrotic, diathrotic

Synarthroses

immovable joints

Amphiarthroses

slightly movable joints

Diarthroses

freely movable joints

Suture

an immovable joint (especially between the bones of the skull) that ossify during middle age

Structural Classification of Joints

focuses on the material binding the bones together and whether or not a joint cavity is present. There are fibrous, cartilaginous, and synovial joints

Fibrous Joints

synarthrotic joints connect bone to bone with dense fibrous connective tissue. There are sutures, gomphoses, and sydesmoses

Gomphoses

fibrous joints consisting of pegs, sockets they fit into and the ligaments that hold them; is an amphiarthrosis

Syndemoses

structural classification; fibrous joint; bones connected by ligaments; synarthrotic (tibia/fibula) to amphiarthrotic (ulna/radius)

Cartilaginous Joints

Have no joint cavity, connects bones to bone by cartilage.

Examples of Cartilaginous Joints

growth plates, disks between vertebrae and the pelvic symphysis

Types of Cartilaginous Joints

synchondroses, symphyses

Synchondroses

bones joined by hyaline cartilage; synarthrotic

Symphyses

bones are connected by a broad, flat disc of fibrocartilage; amphiarthrotic

Synovial Joints

the most movable joints of the body; diarthrotic each contains a fluid-filled joint cavity

Distinguishing Factors of Synovial Joints

articular cartilage, joint (synovial) cavity, and articular (joint) capsule

Articular cartilage

hyaline cartilage that covers ends of long bones; decreases friction

Joint cavity

filled with synovial fluid and provides constant lubrication during movement

Articular capsule

external fibrous capsule (dense irregular connective tissue) and internal synovial membrane (loose connective tissue)

Synovial fluid

plasma and hyaluronic acid lubricates, nourishes, and keeps the joint moveable

Distinguishing Features of Synovial Joints

three types of reinforcement ligaments; capsular, extracapsular, intracapsular

Capsular

part of fibrous capsule

Extracapsular

outside the capsule

Intracapsular

deep to capsule; covered by synovial membrane

Bursae

flattened fibrous sacs lined with synovial membranes, common where ligaments, muscles, skin, and tendons rub together

Function of Bursae

act as a "ball-bearing"

Tendon sheath

Elongated bursae; urrounds a tendon and found along long tendons in bone

Stabilizing Factors in Synovial Joints

shapes of articular surface, ligament number and location, and muscle tone

Shape of Articular Surface

plays a minor role in mobility but play major role in stabilizing synovial joints

Ligament Number and Location

plays a limited role in synovial joint stabilization, but the more ligaments there are, the stronger the joint

Stretching Ligaments

Once you stretch a ligament, it stays stretched. After stretched more than 6% of its original length, ligaments snap

Muscle Tone

plays a major role in stabilizing synovial joints and keeping tendons that cross the joint taut. Especially key in the knee, shoulder, and arches of foot)

Movement of Synovial Joints

muscle attachments across a joint

Origin of Synovial Joints

attachment to the immoveable (or less moveable) bone

Insertion of Synovial Joints

attachment to the moveable bone

Where Synovial Joint Movements Occur

transverse, frontal, or sagittal planes

Muscle Contraction

causes the insertion to move toward the origin

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set