flat bones

Examples of flat bones in the following topics:

• Gross Anatomy

  • All the bones in the body can be described as long bones or flat bones.
  • Cortical bone is compact bone, while cancellous bone is trabecular and spongy bone.
  • Flat bones are broad bones that provide protection or muscle attachment.
  • These bones are expanded into broad, flat plates, as in the cranium (skull), ilium (pelvis), sternum, rib cage, sacrum, and scapula.
  • The flat bones are as follows:

• Scapula

  • The scapula, or shoulder bone, is a flat, triangular bone that connects to the humerus and the clavicle.
  • The scapula, or shoulder blade, is a flat, triangular bone located to the posterior of the shoulder.
  • Due to its flat nature, the scapula presents two surfaces and three borders; the front-facing costal surface and the rear-facing dorsal surface, as well as the superior, lateral, and medial borders.

• Stages of Bone Development

  • Intramembranous ossification mainly occurs during the formation of the flat bones of the skull, but also the mandible, maxilla, and clavicles; the bone is formed from connective tissue such as mesenchyme tissue rather than from cartilage.
  • They are responsible for the formation of the diaphyses of long bones, short bones, and certain parts of irregular bones.
  • Secondary ossification occurs after birth, and forms the epiphyses of long bones and the extremities of irregular and flat bones.
  • The bone remodeling period refers to the average total duration of a single cycle of bone remodeling at any point on a bone surface.
  • Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts.

• Divisions of the Skeletal System: Axial and Appendicular

  • Humans are born with between 300 and 350 bones.
  • However, many bones fuse together between birth and maturity.
  • While some consider certain structures to be a single bone with multiple parts, others may see it as a single part with multiple bones.
  • There are five general classifications of bones.
  • These are long bones, short bones, flat bones, irregular bones, and sesamoid bones.

• Pubis

  • The pubis is the lowest and most anterior portion of the hip bones of the pelvis.
  • The pubic bone articulates with the ilium and the ischium on each hip.
  • The body of the pubis is a wide, strong, medial, and flat portion of the pubic bone that unites with the pubic symphisis.
  • The superior pubic ramus is one third of the pubic bone.
  • The inferior pubic ramus is a thin and flat bone that makes up one third of the pubis.

• Postnatal Bone Growth

  • It forms the epiphyses of long bones and the extremities of irregular and flat bones.
  • 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.
  • The growth in the diameter of bones around the diaphysis occurs through the deposition of bone beneath the periosteum.
  • The epiphysis is the rounded end of a long bone located at its joint with adjacent bone(s).
  • Newly formed bonee.

• Development of the Skeleton

  • It is synonymous with bone tissue formation.
  • This is how the flat bones of the skull and the clavicles are formed.
  • This serves as support for the new bone.
  • This creates cavities within the bone.
  • Osteoclasts, formed from macrophages, break down spongy bone to form the medullary (bone marrow) cavity.

• Thoracic Cage: Sternum

  • The sternum or breastbone is a long, flat, bony plate connected to the rib bones via cartilage that forms the anterior section of the rib cage.
  • The sternum, or breastbone, is a long, flat, bony plate that forms the most anterior section of the ribcage.
  • The sternum is highly vascular in nature and covered with a thin layer of compact bone providing a degree of flexibility.

• Cranial Bones

  • The neurocranium is comprised of eight bones: occipital, two temporal bones, two parietal bones, sphenoid, ethmoid, and the frontal bone.
  • The neurocranium consists of the occipital bone, two temporal bones, two parietal bones, the sphenoid, ethmoid, and frontal bones—all are joined together with sutures.
  • The squamosal suture separates the parietal bone and squama portion of temporal bone.
  • Squamous: This part is large and flat and forms the main region of the forehead.
  • The frontal bone borders two other neurocranial bones—the parietal bones through the coronal sutures and the sphenoid bone through the sphenofrontal suture.

• Bone Marrow Examination

  • In patients with suspected peripheral blood or bone marrow diseases, a bone marrow biopsy can isolate bone marrow for an examination.
  • Bone marrow examination is the pathologic analysis of samples of bone marrow obtained by bone marrow biopsy and bone marrow aspiration.
  • This is the purpose of bone marrow aspiration and biopsy.
  • After the procedure is complete, the patient is typically asked to lie flat for five to ten minutes to provide pressure over the procedure site.
  • A bone marrow biopsy procedure consists of inserting a large-gauge syringe into an area of the hip and extracting the bone marrow.