lamellar bone

Examples of lamellar bone in the following topics:

• Microscopic Anatomy of Bone

  • The basic microscopic unit of bone is an osteon, which can be arranged into woven bone or lamellar bone.
  • Osteons can be arranged into woven bone or lamellar bone.
  • Woven bone is replaced by lamellar bone during development.
  • Lamellar bone makes up the compact or cortical bone in the skeleton, such as the long bones of the legs and arms.
  • When the same lamellar bone is loosely arranged, it is referred to as trabecular bone.

• Bone Repair

  • The next phase is the replacement of the hyaline cartilage and woven bone with lamellar bone.
  • Substitution of the woven bone with lamellar bone precedes the substitution of the hyaline cartilage with lamellar bone.
  • The lamellar bone begins forming soon after the collagen matrix of either tissue becomes mineralized.
  • The osteoblasts form new lamellar bone upon the recently exposed surface of the mineralized matrix.
  • This new lamellar bone is in the form of trabecular bone.

• Capacity of Different Tissues for Repair

  • The next phase is the replacement of the hyaline cartilage and woven bone with lamellar bone.
  • Substitution of the woven bone with lamellar bone precedes the substitution of the hyaline cartilage with lamellar bone.
  • The lamellar bone begins forming soon after the collagen matrix of either tissue becomes mineralized.
  • The osteoblasts form new lamellar bone upon the recently exposed surface of the mineralized matrix.
  • This new lamellar bone is in the form of trabecular bone.

• Paget's Disease

  • Paget's disease is a chronic bone disorder that causes affected bones to become large and misshapen.
  • Paget's disease of bone is a chronic disorder that can result in enlarged and misshapen bones .
  • The excessive breakdown and formation of bone tissue causes affected bone to weaken, resulting in pain, misshapen bones, fractures, and arthritis in the joints near the affected bones.
  • This is associated with accelerated deposition of lamellar bone in a disorganized fashion.
  • This intense cellular activity produces a chaotic picture of trabecular bone ("mosaic" pattern), rather than the normal linear lamellar pattern.

• Embryonic and Fetal Bone Formation

  • It is the process by which bone tissue is created.
  • Eventually, woven bone is replaced by lamellar bone.
  • The primary center of ossification is the area where bone growth occurs between the periosteum and the bone.
  • It is also an essential process during the rudimentary formation of long bones, the growth of the length of long bones, and the natural healing of bone fractures.
  • This serves as support for the new bone.

• Gross Anatomy

  • All the bones in the body can be described as long bones or flat bones.
  • Bone is made of bone tissue, a type of dense connective tissue.
  • Cortical bone is compact bone, while cancellous bone is trabecular and spongy bone.
  • The outer shell of the long bone is compact bone, below which lies a deeper layer of cancellous bone (spongy bone), as shown in the following figure.
  • These are flat bone, sutural bone, short bone, irregular, sesamoid bone, and long bone.

• Bone Grafting

  • Bone grafting is a surgical procedure that replaces missing bone in order to repair bone fractures.
  • Bone grafting is a surgical procedure that replaces missing bone in order to repair bone fractures that are extremely complex, pose a significant health risk to the patient, or fail to heal properly .
  • Bone grafts may be autologous (bone harvested from the patient's own body, often from the iliac crest), allograft (cadaveric bone usually obtained from a bone bank), or synthetic (often made of hydroxyapatite or other naturally-occurring and biocompatible substances) with similar mechanical properties to bone.
  • Most bone grafts are expected to be reabsorbed and replaced as the natural bone heals over a few months' time.
  • Bone grafting is also used to fuse joints to prevent movement, repair broken bones that have bone loss, and repair broken bone that has not yet healed.

• Bone Scans

  • Bone scans are a special type of nuclear scanning test that is often used to find bone cancer or bone inflammation.
  • A bone scan is a nuclear scanning test to find certain abnormalities in bone that are triggering the bone's attempts to heal.
  • A nuclear bone scan is a functional test, which means it measures an aspect of bone metabolism or bone remodeling .
  • Nuclear bone scans are not to be confused with the completely different test often termed a "bone density scan," DEXA or DXA, which is a low exposure X-ray test measuring bone density to look for osteoporosis and other diseases where bones lose mass, without any bone re-building (osteoblastic) activity.
  • The technique, therefore, is sensitive to fractures and bone reaction to infections and bone tumors, including tumor metastases to bones, because all these pathologies trigger bone osteoblast activity.

• Bone Remodeling

  • Bone remodeling or bone turnover is the process of resorption followed by replacement of bone and occurs throughout a person's life.
  • Bone volume is determined by the rates of bone formation and bone resorption.
  • Numerous bone-derived growth factors have been isolated and classified via bone cultures.
  • Essentially, bone growth factors may act as potential determinants of local bone formation.
  • Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts.

• 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 occipital bone borders the parietal bones through the heavily serrated lambdoidal suture, and also the temporal bones through occipitomastoid suture.
  • The squamosal suture separates the parietal bone and squama portion of temporal bone.
  • The frontal bone borders two other neurocranial bones—the parietal bones through the coronal sutures and the sphenoid bone through the sphenofrontal suture.