ossification

(noun)

the normal process by which bone is formed

Related Terms

Examples of ossification in the following topics:

  • Embryonic and Fetal Bone Formation

    • During fetal development, bone tissue is created through intramembranous ossification and endochondral ossification.
    • Unlike endochondral ossification, which is the other process by which bone tissue is created, cartilage is not present during intramembranous ossification.
    • Unlike intramembranous ossification, cartilage is present during endochondral ossification .
    • The first site of ossification occurs in the primary center of ossification, which is in the middle of diaphysis (shaft).The perichondrium becomes the periosteum.
    • Chondrocytes in the primary center of ossification begin to grow (hypertrophy).

  • Bone Development

    • Intramembranous ossification stems from fibrous membranes in flat bones, while endochondral ossification stems from long bone cartilage.
    • The development of bone from fibrous membranes is called intramembranous ossification; development from hyaline cartilage is called endochondral ossification.
    • Intramembranous ossification is the process of bone development from fibrous membranes.
    • They then differentiate into osteoblasts at the ossification center.
    • Endochondral ossification is the process of bone development from hyaline cartilage.

  • Stages of Bone Development

    • Although bone initially forms during fetal development, it undergoes secondary ossification after birth and is remodeled throughout life.
    • The formation of bone during the fetal stage of development occurs by two processes: intramembranous ossification and endochondral ossification.
    • The steps in intramembranous ossification are:
    • Endochondral ossification begins with points in the cartilage called "primary ossification centers. " They mostly appear during fetal development, though a few short bones begin their primary ossification after birth.
    • Secondary ossification occurs after birth, and forms the epiphyses of long bones and the extremities of irregular and flat bones.

  • Development of the Skeleton

    • Early in gestation, a fetus has a cartilaginous skeleton that becomes skeletal bones in the gradual process of endochondral ossification.
    • Early in gestation, a fetus has a cartilaginous skeleton from which the long bones and most other bones gradually form throughout the remaining gestation period and for years after birth in a process called endochondral ossification.
    • Intramembranous ossification is the direct laying down of bone into the primitive connective tissue (mesenchyme).
    • Endochondral ossification involves cartilage as a precursor.
    • Chondrocytes in the primary center of ossification begin to grow (hypertrophy).

  • Postnatal Bone Growth

    • Secondary ossification occurs after birth at the epiphyses of long bones and continues until skeletal maturity.
    • Secondary ossification occurs after birth.
    • During postnatal bone formation, endochondral ossification initiates bone deposition by first generating a structural framework at the ends of long bones, within which the osteoblasts can synthesize new bone matrix.
    • 3) Zone of cell hypertrophy: Next, the chondrocytes cease to divide and begin to hypertrophy (enlarge), much like they do in the primary ossification center of the fetus.
    • Differentiate among the zones of development from cartilage to bone in postnatal ossification

  • Growth of Bone

    • It is a layer of hyaline cartilage where ossification occurs in immature bones.
    • The newly-deposited bone tissue at the top of the zone of ossification is called the primary spongiosa.
    • The older bone at the bottom of the zone of ossification is called the secondary spongiosa.
    • At the same time, osteoblasts via intramembranous ossification, produce new bone tissue beneath the periosteum.
    • The bottom-most row is the zone of ossification which is part of the metaphysis.

  • Fontanels

    • The ossification of the bones of the skull causes the fontanelles to close over a period of 18 to 24 months, eventually forming the sutures of the neurocranium.
    • This is called intramembranous ossification.

  • Sutures

    • As such the degree of ossification can be a useful tool in determining age during post-mortem.

  • Cartilaginous Joints: Synchodroses

    • Depletion of chondrocytes due to apoptosis leads to less ossification, and growth slows down and later stops when the entire cartilage have become replaced by bone, leaving only a thin epiphyseal scar, which later disappears.

  • Fibrous Joints

    • Except for the mandible, all of the bones of the skull are joined together by sutures, semi-rigid articulations formed by bony ossification, the presence of Sharpey's fibers permitting a little flexibility.