Degenerative changes in the cervical spine and their relationship to its mobility

Relationship between spinal biomechanics and pathological changes in the equine thoracolumbar spine

“…1975b(Jeffcott , 1977(Jeffcott , 1978(Jeffcott , 1979(Jeffcott , 1980 has been used to describe vertebral body osteophytes in horses, but the morphological appearance of these lesions is the same as that described in the dog (Morgan 1967; Morgan et a1 1967), cat (Read and Smith 1%8), bull (Thomson 1969;Almquist and Thomson 1973), cetaceans (Lagier 1977) and man (Nathan 1%2) as 'spondylosis deformans'. The exact pathogenesis of these lesions is not fully understood but biomechanical factors are thought to be involved (Morgan 1967;Morgan et al 1967;Badoux 1968;Read and Smith 1968;Thomson 1969;Nathan 1971, 1973;Almquist and Thomson 1973;Jeffcott 1975b;Ten Have and Eulderink 1980). Thomson (1969) summarises the pathogenesis of spondylosis deformans in the bull as degeneration of the annulus fibrosis leading to impairment of the function of the disc, probably abnormal movements between vertebral bodies; stimulation of bone formation at the vertebral corners and in the annulus fibrosis; and stimulation of periosteal bone formation on the ventral surface of the vertebral body.…”

“…The condition has been reported previously in the equine lumbosacral disc (Rooney 1970). Its pathogenesis is unknown, but may be associated with ageing, the relatively wide range of dorsoventral movement in these joints and the relatively greater thickness of the discs at these locations (Ten Have and Eulderink 1980;Townsend and Leach 1984). In the case of the lumbosacral disc, increased mechanical strain on this joint caused by the fusion of joint complexes cranial to it may also be of importance (Kirkaldy-Willis, Wedge, Yong-Hing and Reilly 1978).…”

Kinematics of the equine thoracolumbar spine

“…In using isolated thoracolumbar spines from cadavers in this study of equine spinal kinematics, a number of important assumptions were made: (1) that, based upon the fact that none of the spines were obtained from animals reported to be suffering from back pain and upon the results of examination of the vertebrae at necropsy, the spines used in this study were considered functionally normal; (2) that the relative mobility of each individual joint complex, as compared to the entire mobility of the spine, in horses three years of age and older was not influenced by age, breed, sex or size of the animal from which it was obtained (Evans and Lissner 1959;White 1969;Braund, Taylor, Gosh and Sherwood 1977;Ten Have and Eulderink 1980); (3) that the relative mobility of each joint complex of the spine did not substantially change post mortem and, therefore, any changes that did occur in the strength and elasticity of the intervertebral discs and ligaments affected all the joints equally (Evans and Lissner 1959); (4) that the method of manipulation of the spine approximated the full range of motion of each joint complex (Ten Have and Eulderink 1980); (5) that at the limits of the full range of motion of the specimen, a torque applied to T1 was distributed to all the joint complexes of the spine; and (6) that this model can be used to make useful predictions regarding in vivo spinal kinematics, even though the effects of isolation of the spine upon the characteristics of mobility are not known (Andriacchi, Shultz, Belytschko and Galante 1974;Panjabi et 01 1976;White and Panjabi 1978).…”

“…Biomechanics is the application of mechanical laws to living structures (Dorland's 1967) and spinal kinematics, a subdiscipline of biomechanics, is the study of the kind and amount of motion the spine undergoes during its normal movements (White and Panjabi 1978). The various methods of measuring movement in mammalian spines have been reviewed (White 1969;Ten Have and Eulderink 1980) and sophisticated radiographic techniques have been developed for the study of spinal motion ( O h , Olson, Selwick and Willner 1976; White and Panjabi 1978;Frymoyer, Frymoyer, Wilder and Pope 1979). However, because of the size of the equine vertebral column, radiographic techniques are of limited use in the study of its movement and the development of other techniques for this purpose is required.…”

Normal neck motion

“…Answers have been sought to questions in anatomy, pathology, motion of the entire neck as a region, and motion of individual joints, both in cadaveric studies and in live subjects. Answers gleaned thereby have included data on the relative strength of structural components of the neck 87,88,89,90 and neck motion in both the normal state 91,92,93 and with degenerative joint disease 94,95 , to investigate surgical instability after trauma in both human 96,97,98 and animal models 99 .…”