Skeletal System

Question 1

How many joints in the human body?

Answer 1

187

Question 2

Types of joints

Answer 2

1) Fibrous- bones are held tightly together, permitting limited movement eg sutures in the skull
2) cartilaginous - bones tightly connected by cartilage eg ephiphyseal growth plate,intervertebrae
3) Synovial- permit the most movement eg ball and socket (shoulder and hip) and hinge (elbow and knee)

Question 3

Explain the process of fracture repair?

Answer 3

1. Haematoma (and inflammation):
   Blood vessels at fracture line are broken and blood
   leaks into site. Causes death of local cells and swelling.
2. Fibrocartilaginous callus formation:
   Phagocytes clean up the debris. Fibroblasts invade and
   lay down collagen forming a soft callus (two–three weeks).
3. Bony callus formation:
   Osteoblasts replace soft callus with new bone (< three months).
4. Bone remodelling:
   The callus is mineralised and compact bone laid down.
   Then osteoclasts reshape the new bone. Remodelling
   occurs over months to years.

Question 4

How is osteoporosis diagnosed?

Answer 4

Diagnosed conventionally by dual
x-ray absorptiometry (a DXA scan).
On this test, a T-Score lower than
-2.5 indicates osteoporosis