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Quadrupedal Mechanics - Anatomy & Physiology (view source)
Revision as of 03:41, 29 November 2013
, 03:41, 29 November 2013→Using the head to change the centre of gravity
==='''Using the head to change the centre of gravity'''===
==='''Using the head to change the centre of gravity'''===
[[File:QMFig 10.3.png|thumb|'''Fig 10.3 Use of the head and neck to alter the centre of gravity''']]
The function of the limbs as struts in supporting the trunk, and the function of the trunk as a supporting beam, have already been discussed. The remaining major bulk of the body, the head and neck, is also important in the standing quadruped because of its influence on the centre of gravity. Raising the head will bring it nearer to the trunk in the dorsal plane, and lowering it to bring the neck parallel to the trunk axis will increase this distance. Thus raising the head moves the centre of gravity caudally, removing weight from the forelimbs, and lowering it moves the centre of gravity cranially, increasing weight on the forelimbs (Fig. 10.3). Thus when a lame forelimb takes weight, the head is raised to relieve it. When one wishes to lift a forefoot of a horse or ox, its head should be raised and move laterally away from the foot to be lifted. On the other hand, it should be lowered with a hindfoot is to be lifted. An animal can be prevented from kicking with its hindlimb by holding its head high.
The function of the limbs as struts in supporting the trunk, and the function of the trunk as a supporting beam, have already been discussed. The remaining major bulk of the body, the head and neck, is also important in the standing quadruped because of its influence on the centre of gravity. Raising the head will bring it nearer to the trunk in the dorsal plane, and lowering it to bring the neck parallel to the trunk axis will increase this distance. Thus raising the head moves the centre of gravity caudally, removing weight from the forelimbs, and lowering it moves the centre of gravity cranially, increasing weight on the forelimbs (Fig. 10.3). Thus when a lame forelimb takes weight, the head is raised to relieve it. When one wishes to lift a forefoot of a horse or ox, its head should be raised and move laterally away from the foot to be lifted. On the other hand, it should be lowered with a hindfoot is to be lifted. An animal can be prevented from kicking with its hindlimb by holding its head high.
[[File:QMFig 10.4.png|thumb|'''Fig 10.4 Curvature of the vertebral column in the sitting cat''']]
:::::'''Fig 10.3 Use of the head and neck to alter the centre of gravity'''
:::::'''Fig 10.3 Use of the head and neck to alter the centre of gravity'''
:::::'''Fig 10.4 Curvature of the vertebral column in the sitting cat'''
:::::'''Fig 10.4 Curvature of the vertebral column in the sitting cat'''
:::::The shape of the thoracic cage (doted outline) is maintained by bending the vertebral column predominantly near the thoracolumbar junction.
:::::The shape of the thoracic cage (doted outline) is maintained by bending the vertebral column predominantly near the thoracolumbar junction.
==='''Motion without change of location'''===
==='''Motion without change of location'''===