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The long bones of the human leg comprise nearly half of adult height. The other primary skeletal component of height are the vertebrae and skull. The outside of the bone consists of a layer of connective tissue called the periosteum. Additionally, the outer shell of the long bone is compact bone, then a deeper layer of cancellous bone (spongy ...
The long, relatively straight main body of a long bone; region of primary ossification. Also known as the shaft. dia-+ physis, "between the growth parts" epiphysis: The end regions of a long bone; regions of secondary ossification. epi-+ physis, "on top of the growth part" physis (epiphyseal plate) Also known as the growth plate.
Located in the main shaft of a long bone (consisting mostly of compact bone), the medullary cavity has walls composed of spongy bone (cancellous bone) and is lined with a thin, vascular membrane . [1] [2] This area is involved in the formation of red blood cells and white blood cells, and the calcium supply for bird eggshells. The area has been ...
Diagram of a typical long bone showing both cortical (compact) and cancellous (spongy) bone. Haversian canals [i] (sometimes canals of Havers, osteonic canals or central canals) are a series of microscopic tubes in the outermost region of bone called cortical bone. They allow blood vessels and nerves to travel through them to supply the osteocytes.
It is composed of 270 bones at the time of birth, [2] but later decreases to 206: 80 bones in the axial skeleton and 126 bones in the appendicular skeleton. 172 of 206 bones are part of a pair and the remaining 34 are unpaired. [3] Many small accessory bones, such as sesamoid bones, are not included in this.
Diagram of a typical long bone showing both compact (cortical) and cancellous (spongy) bone. Osteons on cross-section of a bone. In osteology, the osteon or haversian system (/ h ə ˈ v ɜːr. ʒ ən /; named for Clopton Havers) is the fundamental functional unit of much compact bone.
The axial skeleton (80 bones) is formed by the vertebral column (32–34 bones; the number of the vertebrae differs from human to human as the lower 2 parts, sacral and coccygeal bone may vary in length), a part of the rib cage (12 pairs of ribs and the sternum), and the skull (22 bones and 7 associated bones).
Diagram showing stages of endochondral ossification. Endochondral ossification is the formation of long bones and other bones. This requires a hyaline cartilage precursor. There are two centers of ossification for endochondral ossification. The primary center. In long bones, bone tissue first appears in the diaphysis (middle of shaft).