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Quadrupedal Mechanics - Anatomy & Physiology (view source)
Revision as of 00:37, 20 June 2013
, 00:37, 20 June 2013→Kinds of fractures
==='''Kinds of fractures'''===
==='''Kinds of fractures'''===
[[File:QMFig 3.4.png|thumb|'''Fig. 3.4 Ways in which a long bone may fracture''']]
Bone, we have noted, is stronger under compression than under tension, while shear is intermediate. Appropriate combinations of forces cause tensile fractures (Fig. 3.4 A) in bone mainly at the sites of attachment of tendons and ligaments. Common sites of fracture are, in the horse, the proximal ulna, the patella, the proximal sesamoids, the calcaneus and the accessory carpal bone. Such fractures are usually transverse.
Bone, we have noted, is stronger under compression than under tension, while shear is intermediate. Appropriate combinations of forces cause tensile fractures (Fig. 3.4 A) in bone mainly at the sites of attachment of tendons and ligaments. Common sites of fracture are, in the horse, the proximal ulna, the patella, the proximal sesamoids, the calcaneus and the accessory carpal bone. Such fractures are usually transverse.
Compression fractures, (Fig. 3.4 B) by contrast, are usually oblique, at an angle of 45° that corresponds to the plane of maximal shear stress due to the compressive load.
Compression fractures, (Fig. 3.4 B) by contrast, are usually oblique, at an angle of 45° that corresponds to the plane of maximal shear stress due to the compressive load.
::::::B Compression
::::::B Compression
::::::C Bending (tension and compression)
::::::C Bending (tension and compression)
::::::D Torsion (shear).
::::::D Torsion (shear).
==='''The role of tendons'''===
==='''The role of tendons'''===