The effect of ex vivo flexion and extension on intervertebral foramina dimensions in the equine cervical spine.
Abstract: In dressage, the head and neck position has become an issue of concern as certain extreme positions may imply a welfare risk for the horse. In man, extension and flexion of the cervical spine cause a decrease and increase in intervertebral foramina dimensions, respectively. However, in horses, the influence of flexion and extension on foramina dimensions and its possible interference with peripheral nerve functioning remains unknown. Objective: To determine the effect of ex vivo flexion and extension on intervertebral foramina dimensions in the equine cervical spine. Methods: Computed tomography was performed on 6 cadaver cervical spines from adult Warmblood horses subjected to euthanasia for reasons unrelated to cervical spine abnormalities, in a neutral position, in 20 and 40° extension, and in 20 and 40° flexion. Multiplanar reconstructions were made to obtain transverse images perpendicular to the long axis of each pair of intervertebral foramina from C2-T1. Intervertebral foramina dimensions were measured in the 5 positions. Results: Compared to the neutral position, 40° extension caused a decrease in foramina dimensions at segments C4-C5, C5-C6, C6-C7 (P < 0.001) and C7-T1 (P < 0.002); 20° extension caused a decrease in foramina dimensions at segments C5-C6 (P < 0.02), C6-C7 (P < 0.001) and C7-T1 (P < 0.01); 20° flexion caused an increase in foramen length at segment C6-C7 (P < 0.01). Conclusions: Ex vivo extension of the cervical spine causes a decrease in intervertebral foramina dimensions at segments C4-T1, similar to that found in man. Conclusions: In vivo extension of the cervical spine could possibly interfere with peripheral nerve functioning at segments C4-T1. This effect may be even more profound in patients with a reduced intervertebral foramina space, for example in the presence of facet joint arthrosis.
© 2010 EVJ Ltd.
Publication Date: 2011-05-27 PubMed ID: 21059040DOI: 10.1111/j.2042-3306.2010.00226.xGoogle Scholar: Lookup
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Summary
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The research investigates how the flexion and extension movements in horses’ cervical spine affect the dimensions of the space between vertebrae (intervertebral foramina). The study reveals that the extension of the cervical spine reduces the intervertebral foramina dimensions, which could potentially interfere with the functioning of peripheral nerves.
Research Objective and Method
- The objective of this research was to understand the effects of extension (backward bending) and flexion (forward bending) movements on the intervertebral foramina dimensions found in a horse’s cervical spine.
- The researchers used computed tomography to analyze six cadaver cervical spines from adult Warmblood horses. These horses were euthanized for reasons not related to cervical spine abnormalities.
- The necks of these horses were positioned in five different ways: a neutral position, a 20° and a 40° extension, and a 20° and a 40° flexion.
- The researchers obtained transverse images perpendicular to the long axis of each pair of intervertebral foramina from C2-T1. The dimensions of the foramina were measured for each of the positions.
Results of the Research
- When the cervical spine was extended to 40°, there was a significant decrease in the foramina dimensions for all vertebra segments from C4 to T1.
- A 20° extension also resulted in a notable decrease in the foramina dimensions, particularly for segments C5 to T1.
- An increase in the length of the foramen was observed in the C6-C7 segment when the cervical spine was flexed to 20°.
Conclusions of the Study
- The research concluded that extension of the cervical spine results in a decrease in intervertebral foramina dimensions—similar to what is observed in humans.
- Such a decrease could potentially pose problems for the functioning of peripheral nerves located in segments C4-T1.
- This effect has potential welfare implications, especially in horses with pre-existing narrower intervertebral foramina space, such as those suffering from facet joint arthrosis.
Cite This Article
APA
Sleutjens J, Voorhout G, Van Der Kolk JH, Wijnberg ID, Back W.
(2011).
The effect of ex vivo flexion and extension on intervertebral foramina dimensions in the equine cervical spine.
Equine Vet J Suppl(38), 425-430.
https://doi.org/10.1111/j.2042-3306.2010.00226.x Publication
Researcher Affiliations
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
MeSH Terms
- Animals
- Biomechanical Phenomena
- Cadaver
- Female
- Horses / anatomy & histology
- Horses / physiology
- Male
- Neck / anatomy & histology
- Neck / physiology
- Spine / anatomy & histology
- Spine / physiology
Citations
This article has been cited 8 times.- Bergmann W, de Lest CV, Plomp S, Vernooij JCM, Wijnberg ID, Back W, Gröne A, Delany MW, Caliskan N, Tryfonidou MA, Grinwis GCM. Intervertebral disc degeneration in warmblood horses: Histological and biochemical characterization. Vet Pathol 2022 Mar;59(2):284-298.
- Story MR, Haussler KK, Nout-Lomas YS, Aboellail TA, Kawcak CE, Barrett MF, Frisbie DD, McIlwraith CW. Equine Cervical Pain and Dysfunction: Pathology, Diagnosis and Treatment. Animals (Basel) 2021 Feb 6;11(2).
- Gough SL, Anderson JDC, Dixon JJ. Computed tomographic cervical myelography in horses: Technique and findings in 51 clinical cases. J Vet Intern Med 2020 Sep;34(5):2142-2151.
- Haussler KK, Pool RR, Clayton HM. Characterization of bony changes localized to the cervical articular processes in a mixed population of horses. PLoS One 2019;14(9):e0222989.
- Boado A, Pollard D, Lopez-Sanroman FJ, Dyson S. Orthopaedic Injuries in 272 Dressage Horses: A Retrospective Study. Animals (Basel) 2025 Oct 14;15(20).
- Hellige M, Schröder C, Seehusen F, Cavalleri JM, Rohn K, Stadler P, Geburek F. Computed tomographic myelography of the cranial cervical spine in Warmblood horses with no spinal pathology-Inter- and intravertebral ratios and distribution of contrast columns in neutral and flexed cervical spine. Equine Vet J 2025 Sep;57(5):1375-1386.
- Dyson S, Phillips K, Zheng S, Aleman M. Congenital variants of the ventral laminae of the sixth and seventh cervical vertebrae are not associated with clinical signs or other radiological abnormalities of the cervicothoracic region in Warmblood horses. Equine Vet J 2025 Mar;57(2):419-430.
- Dyson S, Zheng S, Aleman M. Primary phenotypic features associated with caudal neck pathology in warmblood horses. J Vet Intern Med 2024 Jul-Aug;38(4):2380-2390.
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