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It also provides nourishment by providing the blood supply to the body from the marrow. [5] The periosteum is attached to the bone by strong collagen fibres called "Sharpey's fibres", which extend to the outer circumferential and interstitial lamellae. It also provides an attachment for muscles and tendons.
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.
They usually run at obtuse angles to the Haversian canals (which run the length of the bone) and contain anastomosing vessels between haversian capillaries. They were named after German physiologist Alfred Volkmann (1800–1878). The perforating canals, with the blood vessels, provide energy and nourishing elements for osteons.
The nutrient artery (arteria nutricia, or central artery), usually accompanied by one or two nutrient veins, enters the bone through the nutrient foramen, runs obliquely through the cortex, sends branches upward and downward to the bone marrow, which ramify in the endosteum–the vascular membrane lining the medullary cavity–and give twigs to the adjoining canals.
The nutrient canal (foramen) is directed away from the growing end of bone. The growing ends of bones in upper limb are upper end of humerus and lower ends of radius and ulna. In lower limb, the lower end of femur and upper end of tibia are the growing ends. [1] The nutrient arteries along with nutrient veins pass through this canal.
The long bone category includes the femora, tibiae, and fibulae of the legs; the humeri, radii, and ulnae of the arms; metacarpals and metatarsals of the hands and feet, the phalanges of the fingers and toes, and the clavicles or collar bones. The long bones of the human leg comprise nearly half of adult height.
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The outer surface of a bone is lined by a thin layer of connective tissue that is very similar in morphology and function to endosteum. It is called the periosteum, or the periosteal surface. During bone growth, the width of the bone increases as osteoblasts lay new bone tissue at the periosteum.