GlossarySee Full Entry

Bone: Bone, or osseous tissue, is a form of dense connective tissue in which the intercellular substance, or matrix, is infiltrated with calcium salts. It is a vascular tissue permeated with canaliculi, which are tiny canals that connect the lacunae with each other and serve as a transport system (Haversian system) between the blood capillaries and the bone cells. There are multiple types of bones 1. Long bones-found in arms and legs. 2. Short bones-short and cuboid or irregular shape. Found in wrist and ankle bones (carpal and tarsal). 3. Flat bones-protection for the soft body parts. Found in ribs, sternum, scapulae and bones of pelvis and skull. 4. Irregular bones-similar in structure to flat bones, but because of a peculiar shape, are included in own classification. Found in vertebrae, sacrum, ethmoid, sphenoid and ear bones of skull. 5. Round bones-small, flat round sesamoid bones. Function of the round bones is to eliminate or reduce friction. Patella or kneecap is the largest sesamoid bone. The outside of the bone is covered by a fibrous membrance, the periosteum. Blood vessels, lymphatic vessels, and nerves are present in the periosteum and enter the Haversian canals of the compact bone to become vessels of the Haversian system permeating the entire bone.

Abstractor Notes
Bone is derived from three cell lines of which can produce tumors: osteogenic, chondrogenic and collagenic. Bone also houses the marrow which contains hematopoietic precursors of myelogenic tumors. Common malignant tumors include: osteogenic sarcoma (osteosarcoma), periosteal sarcoma, giant cell tumor, chondrosarcoma, ewing's sarcoma. Note: bone is a common metastatic site for malignant cancer cells which are usually transported by way of the blood stream. The primary sites from which metastases to bone most often occur are breast, prostate, lung, colon, stomach, and urinary bladder.