Anatomy of Bones and Bone Markings Quiz

Bone Markings and Attachments

• Bone markings are surface features of bones, which are not smooth but scarred with bumps, holes, and ridges.
• Sites of attachments for muscles, tendons, and ligaments are part of bone markings.
• Passages for nerves and blood vessels are also categories of bone markings.
• Projections and processes grow out from the bone surface.
• Depressions or cavities are indentations in the bones.

Microscopic Anatomy of Bone

• Osteocytes are mature bone cells.
• Lacunae are tiny cavities arranged in concentric circles, containing osteocytes.
• Osteon (Haversian System) is a unit of bone, consisting of a central (Haversian) canal, lacunae, and lamellae.
• The central canal carries blood vessels and nerves.
• Perforating (Volkman's) canals are perpendicular to the central canal and carry blood vessels and nerves.
• Canaliculi are tiny canals that radiate from the central canal to lacunae, forming a transport system that connects all bone cells to the nutrient supply through the hard bone matrix.

Types of Bone Cells

• Osteocytes are mature bone cells.
• Osteoblasts are bone-forming cells.
• Osteoclasts are bone-destroying cells that break down bone matrix for remodeling and release of calcium.

Bone Development and Growth

• In embryos, the skeleton is primarily hyaline cartilage.
• During development, much of this cartilage is replaced by bone.
• Cartilage remains in isolated areas, such as the bridge of the nose, parts of ribs, and joints.
• Epiphyseal plates allow for growth of long bone during childhood.
• Bone growth involves the formation of new cartilage, osteogenesis, and bone remodeling.

Bone Formation

• Ossification (osteogenesis) is the process of bone formation, which occurs in four situations:
  • During embryological and fetal development
  • When bones grow before adulthood
  • When bones remodel
  • When fractures heal
• Bones thicken due to the action of osteoblasts and osteoclasts.

Classification of Bones

• Flat bones are thin and flattened, usually curved, with thin layers of compact bone around a layer of spongy bone.
• Examples of flat bones include the skull, ribs, and sternum.
• Irregular bones have an irregular shape and do not fit into other bone classification categories.
• Examples of irregular bones include vertebrae and hip bones.

Gross Anatomy of a Long Bone

• The diaphysis (shaft) makes up the bone's length and is composed of compact bone.
• The epiphysis (end of the bone) articulates with other bones and is composed mostly of thin layers of spongy bone.
• The periosteum is the outside covering of the diaphysis, protected by a fibrous connective tissue membrane.
• Sharpey's fibers are connective tissue fibers that secure the periosteum to the underlying bone.
• Arteries supply bone cells with nutrients.

Test your knowledge of bone anatomy, including sites of attachments for muscles, tendons, and ligaments, as well as categories of bone markings. Identify structures such as projections, processes, depressions, and cavities found in bones. Explore the microscopic anatomy of bone, including osteocytes, lacunae, and the Haversian system.