Reasons for performing study: Based upon human data, it is probable that many conditions associated with neck pain in horses may benefit from performing mobilisation exercises as part of the rehabilitation protocol.
Objectives: To compare sagittal plane intervertebral angulations in a neutral standing position with the angulations at end range of motion in 3 dynamic mobility exercises performed in cervical flexion.
Methods: Sagittal plane motion of the head, neck and back were measured in 8 sound horses standing in a neutral position and in 3 end-of-range neck flexion positions: chin-to-chest, chin-between-carpi, and chin-between-fore fetlocks. Skin markers on the head, transverse processes of C1–C6, and dorsal spinous processes of T6, T8, T10, T16, L2, L6, S2 and S4 were tracked and adjacent markers connected to form rigid segments. Intersegmental angles, measured between segments on the ventral surface, in the 4 positions were compared using repeated measures ANOVA with Bonferroni post hoc tests (P<0.05).
Results: The largest angular differences involved the cranial and caudal cervical joints with smaller angular differences (<10°) in the mid-neck. The angle at C1 was significantly more extended for chin-between-carpi (98 ± 11°) and chin-between-fetlocks (132 ± 11°) than for the neutral position (86 ± 8°) or chin-to-chest (92 ± 8°) positions. The intersegmental angle at C6 indicated progressive lowering of the neck from neutral through chin-to-chest and chin-between-carpi to chin-between-fetlocks. The intersegmental angles from T6–L1 were more flexed by 3–7° in the cervical flexions compared with the neutral position with the differences being significant for at least one of the dynamic mobilisations at each vertebral level.
Conclusions: The articulations at the extremities of the cervical vertebral column are primarily responsible for sagittal plane position and orientation of the head and neck. Dynamic cervical flexion also flexes the thoracic intervertebral joints.
Potential relevance: The results indicate that dynamic mobilisation exercises performed in cervical flexion have applications in mobilising the cervical and thoracic intervertebral joints, which may have some clinical applications in rehabilitation.