| Axial skeleton | The axial skeleton consists of the bones of the cranium (i.e. skull and mandible), the vertebrae, ribs and sternum |
| Intramembranous ossification | Involves the differentiation of mesoderm directly into bones.This is most common in flat bones like those of the skull. |
| Ossification | Form into bone |
| Endochondral ossification | -Involves formation of a hyaline cartilage model of the bone being formed, which is gradually replaced by bony tissue during development.
-Most common in long bones of the limbs
-Also occurs in some regions of the skull |
| Osteoblasts | The mesenchymal stem cell that form an osteoprogenitor cell differentiate to an osteoblast that form the cellular component of bone and produce the bone matrix. Osteoblast mature to form osteocytes. |
| Primary ossification center | This is the area during the process of intramembranous ossification where central mesenchymal cells cluster and differentiate directly into bone |
| Osteocyte | The mature bone-forming cell, which are the cellular component of bone and produce bone matrix. |
| Trabeculae | Is spongy-woven bone formed when osteoid accumulates b/n embryonic blood vessels. It later serves to resist strain on the bone in many different directions. |
| Periosteum | the outermost layer of the bone that is formed when mesenchyme condenses on the edges of the trabeculae during intramembranous ossification |
| Ossification center | The area in a tissue where ossification begins |
| Neurocranium | -Consists of the domed part of the skull surrounding the brain itself.
-The neurocranium can further be divided into two developmental units – the membranous portion which consist of the flat bones (frontal, parietal, squamous
occipital, squamous temporal), and a cartilaginous part called the chondrocranium which forms the base of the skull (region of the foramen magnum and occipital condyles). |
| Viscerocranium | Consists of bones of the face |
| Pharyngeal arches | clusters of mesoderm that form in the neck region of the developing embryo |
| Vertebral arch | Formed by the pedicles, transverse and spinous processes and the laminae |
| Lamellar bone | Multilayered bone that replaces trabeculae when they thicken |
| Compact bone | Layer of bone b/n the outer periosteal and inner trabeculae portions of the bone |
| Diploe | Of flat bones, is the trabeculae on the inside of the bones that remains the same |
| Chondrocyte | Cartilage cells that produce and maintain cartilage matrix |
| Diaphysis | Shaft of a long bone |
| Epiphysis | End part of a long bone initially growing separately from the shaft |
| Chondrocranium | Part of the neurocranium comprising of the foramen magnum and occipital condyles |
| Kyphosis | Curvature that causes the SC to bend forward, and is found in the thoracic and sacral regions |
| Lordosis | Curvatures in the cervical and lumbar regions that cause the SC to bend backwards |
