DSF Anatomy of Joints

Question 1

How are joints classified?

Answer 1

Joints (articulations) classified based on the material joining or attaching the bones:
Fibrous
Cartilaginous
Synovial

Question 2

Fibrous Joints

Answer 2

United by fibrous tissue such as a ligament or fibrous membrane
Very stable, little movement
Ex: fontanelles and sutures of skull, intraosseous membrane of forearm, ligamentum flavum, interspinous ligament, supraspinous ligament

Question 3

Cartilaginous Joints

Answer 3

United by fibrocartilage
Ex: intervertebral discs
*Degenerative changes in fibrocartilage of intervertebral disks can lead to herniation, which can impinge on spinal nerves

Question 4

Growth Plates (Physes)

Answer 4

Temporary cartilaginous joints

Question 5

Synovial Joints

Answer 5

Articular surfaces of bones covered by specialized articular cartilage
2+ bones forming the joint united by joint capsule
Synovial membrane of inner capsule secretes synovial fluid into joint cavity
Normal synovial fluid is similar in appearance and consistency to an uncooked egg white
Exhibit different degrees of mobility (and stability - intrinsic and extrinsic ligaments) depending on the shape of the articular surfaces
Capsule richly innervated by sensory nerves

Question 6

Intra-articular structures of synovial joints

Answer 6

Aid in mobility, adjust joint contours, absorb compressive forces
Menisci
Glenoid labrum
Intra-articular ligaments
Fat pads
Tendons

Question 7

How are synovial joints classified?

Answer 7

Based on shape of articular surfaces, and the movements they permit
6 types based on shape:
Pivot: cervical vertebrae
Ball and socket: shoulder, hip
Planar (flat): acromial-clavicular joint
Hinge: elbow, knee
Saddle:
Condyloid (ellipsoid):

Question 8

Bursae

Answer 8

Closed sacs of serous membrane that reduce friction by enabling one structure to move freely over another

Question 9

Synovial tendon sheaths

Answer 9

Facilitate gliding and reduce “wear and tear” of tendons

Question 10

Injuries to joints

Answer 10

Dislocation - Joint completely out of place
Subluxation - Joint partially out of place
Arthritis - Breakdown of bearing surface of joint