Neurological conditions can vary from severe, permanent, life-threatening problems such as “Wobbler Syndrome” to much more minor injuries that involve “nerve bruising” (e.g. radial paralysis caused by blunt trauma) or merely gait abnormalities (e.g. stringhalt) that don’t affect athletic performance in some disciplines.
It is vital to distinguish between a true (orthopaedic) lameness and an abnormal gait or “way of moving” that is caused by a neurological injury. Sometimes this can be very difficult to be sure about and it may take many nerve blocks and imaging techniques to diagnose the problem.
It is important to realise that gait variations such as “dishing”, “plaiting” or “brushing” may be normal for a particular horse and are not regarded as abnormalities. They may be altered or helped by trimming and/or shoeing (sometimes using special shoes).
There are gait abnormalities such as stringhalt and “shivering” that are caused by neuromuscular problems and are not merely problems with the nerves. These are very difficult to treat although may be associated with underlying orthopaedic injuries.
There are also orthopaedic conditions that can lead to gait abnormalities but may not be particularly painful; we often describe these as “mechanical lameness” where there is a physical restriction or limitation that produces the lameness. Examples of these are Ruptured Peroneus Tertius (damage to a muscle/tendon in the gaskin region allowing the hock to be extended as the stifle is flexed (see picture)) and Fibrotic Myopathy (scar tissue in the “hamstring” muscles limiting forward movement of the hindlimb). This can be compared with a “true” or painful lameness caused by pain in one or more structures that cause the lameness.
Sometimes damage to a nerve can lead to temporary paralysis (e.g. radial nerve paralysis) although there are situations where the damage may lead to permanent problems (suprascapular nerve damage in the shoulder that can lead to muscle wastage “Sweeny” (see picture)).