Bone


Read here about biological bones and their role in tensegrity-based explanations of structural anatomy.

The Conventional View of Bones


From wikipedia: Bones are rigid organs that form part of the endoskeleton of vertebrates (people and animals). They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue. Because bones come in a variety of shapes and have a complex internal and externalstructure they are lightweight, yet strong and hard, in addition to fulfilling their many other functions. One of the types of tissue that makes up bone is the mineralized osseous tissue, also called bone tissue, that gives it rigidity and a honeycomb-like three-dimensional internal structure. Other types of tissue found in bones includemarrow, endosteum and periosteum, nerves, blood vessels and cartilage. There are 206 bones in the adult human body and 270 in an infant.

The hard outer layer of bones is composed of compact bone tissue, so-called due to its minimal gaps and spaces. Its porosity is 5-30%. This tissue gives bones their smooth, white, and solid appearance, and accounts for 80% of the total bone mass of an adult skeleton. Compact bone may also be referred to as dense bone. Filling the interior of the bone is the trabecular bone tissue (an open cell porous network also called cancellous or spongy bone), which is composed of a network of rod- and plate-like elements that make the overall organ lighter and allow room for blood vessels and marrow. Trabecular bone accounts for the remaining 20% of total bone mass but has nearly ten times the surface area of compact bone. Its porosity is 30-90%. If for any reason there is an alteration in the strain to which the cancellous is subjected, there is a rearrangement of the trabeculae. The microscopic difference between compact and cancellous bone is that compact bone consists of haversian sites and osteons, while cancellous bones do not. Also, bone surrounds blood in the compact bone, while blood surrounds bone in the cancellous bone.

The Tensegrity View of Bone


Bone as Tensegrity Strut


In tensegrity models of structural anatomy, bone is the component that is optimized to bear compressive load.

Levin wrote, "The hard outer layer of bones is composed of compact bone tissue, so-called due to its minimal gaps and spaces. Its porosity is 5-30%. This tissue gives bones their smooth, white, and solid appearance, and accounts for 80% of the total bone mass of an adult skeleton. Compact bone may also be referred to as dense bone. Filling the interior of the bone is the trabecular bone tissue (an open cell porous network also called cancellous or spongy bone), which is composed of a network of rod- and plate-like elements that make the overall organ lighter and allow room for blood vessels and marrow. Trabecular bone accounts for the remaining 20% of total bone mass but has nearly ten times the surface area of compact bone. Its porosity is 30-90%. If for any reason there is an alteration in the strain to which the cancellous is subjected, there is a rearrangement of the trabeculae. The microscopic difference between compact and cancellous bone is that compact bone consists of haversian sites and osteons, while cancellous bones do not. Also, bone surrounds blood in the compact bone, while blood surrounds bone in the cancellous bone." [1]

Scarr replied, "Interesting, Littlejohn mechanics (Paolo BIG 1) describe the lower border of the 3rd lumbar as horizontal (with respect to gravity), which means that it cannot slip out of the way because it is the 'keystone' of the lumbar curve, and a jump on both feet causes it to takes the full weight of the body above on the posterior aspect, which abnormally acts like a lever and causes the fracture at that point."

Bone as Tensegrity Mast


Any given bone, being composed mostly of empty space, is itself a tensegrity of cellular compressional struts and tensional tendons.

Links and References


[1] Levin reply to de jong, Geodesic list, 11 August 2010


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