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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.
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.
The 126 bones of the appendicular skeleton and the 80 bones of the axial skeleton together form the complete skeleton of 206 bones in the human body. Unlike the axial skeleton, the appendicular skeleton is made up of significantly more long bones and predominantly articulated via synovial joints, which allow for a much greater range of motion.
Most bones of the limbs, including those of the fingers and toes, are long bones. The exceptions are the eight carpal bones of the wrist, the seven articulating tarsal bones of the ankle and the sesamoid bone of the kneecap. Long bones such as the clavicle, that have a differently shaped shaft or ends are also called modified long bones.
The number of bones varies according to the method used to derive the count. While some consider certain structures to be a single bone with multiple parts, others may see it as a single part with multiple bones. [5] There are five general classifications of bones. These are long bones, short bones, flat bones, irregular bones, and sesamoid bones.
The tarsus articulates with the bones of the metatarsus, which in turn articulate with the proximal phalanges of the toes. The joint between the tibia and fibula above and the tarsus below is referred to as the ankle joint proper. In humans the largest bone in the tarsus is the calcaneus, which is the weight-bearing bone within the heel of the ...
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 ...