Lecture 6: Joint classifications

Question 1

What types of joints are in the human body and how do they differ on a basic level?

Answer 1

Synovial, Cartilaginous and Fibrous. These are ordered in level of most movement to least movement, and least stability to most stability.

Question 2

Describe the basic structure of synovial joints.

Answer 2

Bone articulations are covered in a thin layer of hyaline cartilage - called articular cartilage. To the side of this is the joint cavity which suspends synovial fluid. Lining the joint cavity is the synovial membrane which secretes the synovial fluid. Superficial to this is the joint capsule, then the ligaments.

Question 3

What is the purpose of synovial fluid?

Answer 3

Synovial fluid lubricates the joint adding to frictionless properties.

Question 4

How does the properties of the joint capsule ligament change depending on support?

Answer 4

Where more support is needed it is tight and thick. Where movement is allowed it is loose. E.g. medial collateral ligament and lateral collateral ligament.

Question 5

What is the purpose of intracapsular ligaments?

Answer 5

Restricts movement of bones. E.g. Anterior cruciate ligament restricts posterior displacement of femur in the knee joint. Posterior cruciate ligament prevent anterior displacement of femur over knee joint.

Question 6

What is the role of fibrocartilaginous menisci?

Answer 6

Example - found between tibia and femur. Hugs distal end of femur and deepens the articulation to add stability. Due to cartilaginous structure also provides some cushioning.

Question 7

What factors determine the ROM of a joint.

Answer 7

Body surface contact, Bone end shape and Ligament location / length.

Question 8

List the types of synovial joints.

Answer 8

Ball and Socket, Condylar, Ellipsoid, Plane, Hinge, Saddle and Pivot.

Question 9

Ball and Socket.

Answer 9

Multiaxial, Flexion Extension, Abduction Adduction, Circumduction, Rotation
E.g. Shoulder and Hip

Question 10

Hinge.

Answer 10

Uniaxial, flexion extension. E.g. Elbow.

Question 11

Plane.

Answer 11

Multiaxial, sliding and gliding. E.g. Intercarpal joints.

Question 12

Pivot.

Answer 12

Uniaxial, rotation. E.g. radioulnar joint.

Question 13

Condylar.

Answer 13

Biaxial. Flexion Extension, Rotation when flexed e.g. Knee

Question 14

Ellipsoid.

Answer 14

Biaxial. Flexion Extension, Abduction Adduction, Circumduction. E.g. Wrist Joint

Question 15

Saddle.

Answer 15

Biaxial (+), Flexion, Extension, Adduction, Abduction, Circumduction and Obligatory Rotation (opposition) e.g. carpometacarpal joint.