Assessment of the Equine Spine
Introduction[edit | edit source]
Back pain and dysfunction can lead to poor performance and cause changes in a horse’s spinal kinematics.[1] However, it is often difficult to distinguish whether the spine or limb is the primary cause of lameness in a horse as spinal problems are often related to limb lameness.[2]
A comprehensive assessment is, therefore, essential to determine the cause of lameness in a horse. As with any assessment, it is important to first obtain a subjective history of the equine patient, including background information, training / discipline history, history of presenting condition, past medical history and special questions / red flags. The subjective assessment is discussed in detail here.
The objective assessment will be guided by your findings in the subjective interview. A discussion of the overall objective assessment of horses is found here, including conformation, gait and lameness assessments, range of motion, muscle strength, palpation and the neurological assessment. This page will discuss assessments specific to the equine spine that are not discussed in detail in the general assessment page.
Range of Motion[edit | edit source]
It is difficult to ask a horse to perform specific active movements of either the front or hind limbs, so active movement is best assessed during different gait activities.
The horse’s stay mechanism (i.e. the tendinous structures that support the limbs during standing[3]) makes localisation of passive testing to a specific joint difficult. Thus, careful observations of the horse’s responses to manipulations of its joints are very important.[4]
Abnormal responses to range of motion (ROM) tests include:[4]
- Resistance to being moved
- Excessive movement at proximal (more common) or distal motion segments
- Excessive stance adjustments with the other limbs
These movements can be used as stretching exercises to increase range of motion.[2]
Cervical Spine[edit | edit source]
Active ROM[edit | edit source]
Horses who have normal cervical mobility will be able to move their heads and necks from side to side and bring their chin to near their girth, hip, or tarsus without difficulty.[5]
Poll Flexion:[4]
Use a treat to encourage the horse to bring its chin to its chest. If the horse deviates to one side, repeat the test standing on the other side of the horse to see if there is internal consistency of this deviation.
Poll Extension:[4]
Use a treat to encourage the horse to move its nose forward and up. Any deviations should be carefully assessed for consistency.
Poll Rotation:
Place one hand on C1 and use it to stabilise the upper cervical area - this will localise the movement to the poll. Use a treat to encourage the horse to bring its nose laterally towards you and up. It is important to observe both the horse’s willingness to move and the actual range obtained.
Differentiating between C0/C1 and C1/C2
The C0/C1 joint is responsible for flexion and extension of the head (THESIS) (i.e. dorsoventral glide of the occiput on C1). A unilateral restriction of C0/C1 means that there is only a dorsoventral glide on the unrestricted side. Thus, the horse’s head will move towards the side of restriction in flexion and away from the side of restriction in extension. VAN DER WALT
C1/C2 is largely responsible for rotation of the head (THESIS), which is seen as a lateral deviation of the horse’s nose when viewed from the front. A localised, unilateral restriction of C1/2 will cause lateral deviation away from the side of restriction regardless of whether the poll is flexed or extended. VAN DER WALT
Global Lateral Flexion
Use a treat to encourage the horse to bring its nose around to the caudal border of the triceps. The examiner observes both the horse’s willingness to bend its head and the quality of the movement (i.e. does it bend in a smooth curve through the cervical spine or does the horse hinge at a specific level?).
Lower Cervical Flexion
Use a treat to encourage the horse to bring its nose towards the ground, keeping the poll as neutral as possible. The examiner will look for any deviations or rotations in the cervical spine.
NB: It is possible to do this movement using a theraband to apply unilateral resistance as a strengthening exercise.
Activation of the Deep Neck Flexors
Grasp the base of the brachiocephalicus muscle in a lumbrical grip. Gently apply pressure with your whole hand. The horse should respond by arching and lengthening its neck forwards and downwards. This should be performed on both sides.
NB: You should not perform this test on horses who have significant trigger points in their brachiocephalicus muscle.
References[edit | edit source]
- ↑ Hardeman AM, Byström A, Roepstorff L, Swagemakers JH, van Weeren PR, Serra Bragança FM. Range of motion and between-measurement variation of spinal kinematics in sound horses at trot on the straight line and on the lunge. PLoS One. 2020;15(2):e0222822.
- ↑ 2.0 2.1 Haussler KK. Review of the examination and treatment of back and pelvic disorders. AAEP Focus Meeting - Lameness and Imaging. 2007.
- ↑ Gussekloo SW, Lankester J, Kersten W, Back W. Effect of differences in tendon properties on functionality of the passive stay apparatus in horses. Am J Vet Res. 2011 Apr;72(4):474-83.
- ↑ 4.0 4.1 4.2 4.3 Van der Walt A. Assessment and Management of the Equine Spine Presentation. Physioplus, 2021.
- ↑ Story MR, Haussler KK, Nout-Lomas YS, Aboellail TA, Kawcak CE, Barrett MF et al. Equine cervical pain and dysfunction: pathology, diagnosis and treatment. Animals (Basel). 2021;11(2):422.
- ↑ LMU CVM. 9 Equine Head & neck flexion and extension. Available from: https://www.youtube.com/watch?v=xxmGnfgy9rQ [last accessed 28/4/2021]
- ↑ LMU CVM. 8 Equine Head & neck flexion side to side. Available from: https://www.youtube.com/watch?v=HN30vJ6_FWQ [last accessed 28/4/2021]
