- 206 bones
- 80: axial skeleton
- 126: appendicular skeleton.
- Ossification (the formation of bone)
- intramembranous (without a cartilage model eg.skull)
- enchondral (with a cartilage model eg. most bones)
- Enchondral growth begins in the diaphyses of long bones at primary ossification centers
- most are present at birth
- Secondary ossification centers usually develop in the periphery of bones and are important for growth and
the treatment of childhood fractures.
- Enchondral growth begins in the diaphyses of long bones at primary ossification centers
| Bone | Ossification Centre | Age of Appearance | Age of Fusion |
| Scapula | Body (primaly) | 8 wk (fetal) | |
| Coracold (tlp) | 1yr | ||
| Coracoid | 15 yr | ||
| Acromion | 15 yr | ||
| Inferior angle | 16 yr | ||
| Medial border | 16 yr | ||
| Clavicle | Medial (primary) | 5 wk (fetal) | 25 |
| Lateral (primary) yr | 5 wk (fetal) | ||
| Sternal | 19 yr | ||
| Humerus | Body (primary) | 8 wk (fetal) | Blends at 6 yr and unites at 20 yr |
| Head | 1 yr | ||
| Greater tuberosity | 3 yr | ||
| Lesser tuberosiry | 5 yr | ||
| Capitulum | 2 yr | Blends and unites with body at 16-18 yr | |
| Medial epicondyles | 5yr | ||
| Trochlea | 9 yr | ||
| Lateral epicondyles | 13 yr | ||
| Ulna | Body (primary) | 8 wk (fetal) | |
| Dlstal ulna | 5 yr | 20 yr | |
| Olecranon | 10 yr | 16 yr | |
| Radius | Body (primary) | 8 wk (fetal) | |
| Distal radius | 2 yr | 17-20 yr | |
| Proximal radius | 5 yr | 15-18 yr | |
| Pelvis | Ili um (primary) | 2 mo | 15 yr |
| Ischium (plimary) | 4 mo | 15 yr | |
| Pubis (primaty) | 6 mo | 15 yr | |
| Acetabulum | 12 yr | 15 yr | |
| Tibia | Body (primaty) | 7 wk (feral) | |
| Proximal (secondary) | Birth | 20 yr | |
| Distal (secondary) | 2 yr | 18 yr | |
| Fibula | Body (primary) | 8 wk (feral) | |
| Proximal (secondary) | 3 yr | 25 yr | |
| Distal (secondary) | 2 yr | 20 yr |