Rod Lakes
University of Wisconsin-Madison
Tissue Mechanics: Bone and Ligament Biomechanics

Tissue biomechanics BME 615
Outline
  Bone composition and structure
  Bone properties: elasticity, strength, and toughness
  Bone properties: effect of age and species
  Bone properties: anisotropy
  Bone properties: viscoelasticity
  Bone nonlinearity compared with other tissues
  Bone as a natural composite
  Bone remodeling and adaptation

Bone structure and properties
The left image shows structure of a cross section of bovine plexiform bone; the center image, of a cross section of human Haversian bone under polarized light.
The far right image shows a stained section of bone, showing the osteocytes (bone cells). The image, after Professor Peter Muir of Veterinary Medicine, is a composite image, obtained with a confocal microscope in bright light, of a decalcified transverse section of the mid-diaphysis of a dog humerus, stained with silver to highlight the canaliculi.
bovine bone human bone bone slice
The small dark circles in the human bone at center are cross sections of Haversian canals. The crossed polarizers give rise to the dark color in the empty canals. The large circles are cross sections of osteons, which are large fibers about 200 microns across. Bovine plexiform bone has a laminated structure. Colors in the polarized light images arise from the fibrous structure of bone; the anisotropy gives rise to a wavelength dependent rotation of the polarization of the light.

The images below show schematic diagrams of hierarchical structure of bone and of tendon.

bone structure
larger image
Hierarchical structure of compact bone. Reference: Lakes, R. S., "Materials with structural hierarchy", Nature, 361, 511-515 (1993). link

tendon structure

Hierarchical structure of tendon.
Reference: J. Kastelic, A. Galeski, and E. Baer, The Multicomposite Structure of Tendon, Connective Tissue Research, 1978, Vol 6, pp. 11-23.