Bones and Joints

Question 0

Describe a sesamoid bone and give an example.

Answer 0

Sit within a tendon. Stops rubbing on the bone.

Patella/pisiform

Question 1

What are the functions of bone?

Answer 1

Support
Protection
Shape
Movement (muscle attachment, lever)
Metabolism (haemopoiesis in red marrow, mineral storage, lipid storage in yellow marrow)

Question 2

Describe fibrous joints with examples.

Answer 2

Fixed or immoveable
Joined by fibrous connective tissue

E.g. Sutures in the skull, gomphosis, syndesmosis (interosseus membrane)

Question 3

Describe cartilagenous joints with examples.

Answer 3

Primary - synchondrosis. Hyaline cartilage, most replaced by bone during growth e.g. Epiphyseal plate

Secondary - symphysis. Fibrocartilage e.g. Intervertebral disc, pubic symphysis

Question 4

Describe a synovial joint.

Answer 4

Articular capsule that secretes synovial fluid, synovial fluid and articular (hyaline) cartilage. Can have a fibrous capsule.
Additional structures include menisci for cushioning and ligaments inside or out.

Plane e.g. Acromioclavicular joint
Hinge e.g. Elbow/knee
Saddle e.g. Wrist/1st carpometacarpal joint
Ball and socket e.g. Shoulder/ head of femur to acetabulum
Condyloid e.g. Metacarpalpharyngeal joint
Pivot e.g. Atlantoaxial joint

Question 6

What does joint stability depend on?

Answer 6

Articular surface (depth/ratio)
Ligaments
Muscle/muscle tone

Question 7

Describe the difference between synarthrosis, amphiarthrosis and diarthrosis.

Answer 7

Synarthrosis - joint which permits little or no movement. Mostly fibrous.

Amphiarthrosis - continuous, slightly moveable joint

Diarthrosis - synovial joint. Lots of movement.

Question 8

Describe and give an example of a first class lever.

Answer 8

Force is on the opposite side of the load. Most efficient lever.
e.g. skull

Question 9

What class of lever is the majority of muscles?

Answer 9

Third class.