Joint Classifications: Structural, Functional, and Key Features in Anatomy

What are the two ways joints are classified?

Structurally (what binds them and if a cavity exists) and functionally (by amount of movement).

What are the three structural classifications of joints?

Fibrous, cartilaginous, synovial.

What are the three functional classifications of joints?

Synarthroses (immovable), amphiarthroses (slightly movable), diarthroses (freely movable).

What type of joints are mostly found in the axial skeleton?

Synarthroses and amphiarthroses.

What type of joints are mostly found in the appendicular skeleton?

Diarthroses.

What connects fibrous joints?

Dense, fibrous connective tissue.

What are the three types of fibrous joints?

Sutures, syndesmoses, gomphoses.

Where are sutures found and what movement do they allow?

In the skull; immovable (synarthrotic).

What are syndesmoses?

Joints connected by ligaments; may allow slight movement (amphiarthrotic).

What is a gomphosis?

A peg-in-socket joint found only where teeth fit into alveolar sockets.

What unites bones in cartilaginous joints?

Cartilage.

What are the two types of cartilaginous joints?

Synchondroses and symphyses.

Give an example of a synchondrosis joint.

Epiphyseal plate between bone shaft and ends.

What kind of cartilage is found in symphyses?

Fibrocartilage.

Give examples of symphyses joints.

Intervertebral discs, pubic symphysis.

What are the six features of synovial joints?

Articular cartilage, joint cavity, articular capsule, synovial fluid, reinforcing ligaments, nerves and blood vessels.

What are bursae?

Synovial fluid-filled sacs that reduce friction around joints.

What are articular discs (menisci/labra)?

Fibrocartilage that improves fit, stabilizes, and absorbs shock.

What three factors influence joint stability?

Shape of articular surface, ligaments, and muscle tone (most important).

Define flexion.

Bending movement that decreases joint angle.

Define extension.

Straightening movement that increases joint angle.

Define abduction.

Movement away from the body's midline.

Define adduction.

Movement toward the body's midline.

What is circumduction?

Circular motion combining flexion, abduction, extension, and adduction.

What is rotation?

Movement of a bone around its own axis.

What is supination vs pronation?

Supination = palms up; Pronation = palms down.

What are the five major synovial joints studied?

TMJ, shoulder (glenohumeral), elbow (humeroulnar), hip (coxal), knee (tibiofemoral).

Describe the temporomandibular joint (TMJ).

Modified hinge joint allowing elevation, depression, glide, protraction, and retraction.

What stabilizes the shoulder joint?

Coracohumeral & glenohumeral ligaments, biceps & deltoid tendons, rotator cuff muscles.

What movements occur at the elbow joint?

Flexion and extension.

What ligament is repaired in Tommy John surgery?

Ulnar Collateral Ligament (UCL).

What ligaments stabilize the hip joint?

Iliofemoral, pubofemoral, ischiofemoral, and ligament of the head of femur.

What deepens the hip socket?

Acetabular labrum.

What two joints form the knee?

Femoropatellar and tibiofemoral.

What ligaments prevent medial/lateral collapse of the knee?

Medial and lateral collateral ligaments (MCL, LCL).

What ligaments prevent hyperextension and hyperflexion of the knee?

Anterior and posterior cruciate ligaments (ACL, PCL).

What is the "Unhappy Triad"?

Injury to MCL, ACL, and medial meniscus.

What are the three common types of joint injury?

Sprains, dislocations, cartilage tears.

What is tendonitis?

Inflammation of a tendon, often from overuse.

What is bursitis?

Inflammation of a bursa, caused by friction or direct blow.

What is Osgood-Schlatter's disease?

Avulsion of the patellar tendon at the tibial tuberosity in adolescents.

What is arthritis?

Inflammation or degeneration of joints causing pain and stiffness.

What are the four chronic forms of arthritis?

Osteoarthritis, rheumatoid arthritis, gouty arthritis, Lyme disease.

Describe osteoarthritis.

Wear-and-tear arthritis causing cartilage breakdown and bone spurs.

Describe rheumatoid arthritis.

Autoimmune disorder causing chronic inflammation of joints.

Describe gouty arthritis.

Uric acid crystal buildup in joints, especially the big toe.

Describe Lyme disease arthritis

Autoimmune reaction from tick-borne bacteria causing joint inflammation.