Altered spinal biomechanics (stiffness) is often accompanied by altered sensory function. Instead of sensing light touch when gentle touched, one might experience a more severe painful sensation. In these cases this appears to occur because the receptors in the skin are hypersensitised. 'Cold back' in horses is an example of altered sensation. Both touch receptors and deeper pressure receptors over react when stimulated leading to exaggerated responses from the horse. These exaggerated responses are referred to as hyperaesthesia (exaggerated response to touch) and mechano allodynia (exaggerated response to pressure).
These exaggerated responses are also not uncommon in the skin and muscles about the pole (behind the ears) and about the girth. These altered sensations may occur over any area of the horses body but most often are apparent in the neck, thorax, hindquarter and digits (hoof).
Altered behaviour such as; bucking, dropping in the back when saddled, girth shyness, reluctance to enter confined spaces (vans, float, starting gates) rushing through doorways, head shyness, tense when approached, uneasy to violent when groomed, one out in the field, and aggression towards other horses and handlers (mistrust) can often be attributed to altered neural responses with physical contact.
These altered sensations often regress following spinal therapy and with them permanent alterations in behaviour occur.
Further reading.
Ahern T J: Pain of spinal origin (PSO). Centaur (INDIA) 1992 ;IX: 6-17.
Ahern T J: Spinal mobilisation therapy: with particular reference to cervical vertebral mobilisation under anaesthetic (CVMUA). In: Pain Management of Dogs and Horses: Some alternative Therapies. CVE Murdoch University,Western Australia 1996; 43-49.
