The Canine Spine
30 Nov 2016
The Canine Spine
By Sue Van Evra, BScPT, MSc, BHScPT, Dipl Canine Rehab
Did you know that the Canine Spine is very similar to the human spine?
There are obvious differences – the most obvious being that the canine spine is horizontal!
If you look closely, both the human and canine spines have 7 vertebrae in the neck (cervical), humans have 12 (vs 13 in dogs) vertebrae in the mid back (thoracic spine), and 5 (vs 7 in the canine spine) in the lower back (lumbar spine). At the end of the spine, both humans and their furry friends have a bone called the sacrum which is part of the pelvis. Then humans have a tailbone, whereas dogs have extra vertebrae that form the tail.
In the spine, the vertebrae are bones stacked one behind (or below in the case of humans!) the other. As with the human spine, in between the vertebrae are ‘discs’ that cushion between the bones. Also between the vertebrae are joints (facet joints) that allow movement between the vertebrae. These joints are held together by ligaments, and surrounded by muscles. The spinal cord runs in a canal in the centre of the vertebrae, so is very protected. The spinal cord is a bundle of nerves and these nerves branch out between the vertebrae to different areas of the body…
Nerves are responsible for making muscles contract, and for sensation – so when you pet your dog along her spine, there are signals that run along the nerves to her brain so she can feel your hand. Nerves also are responsible for regular bodily functions – i.e. they signal your dog when it is time to go out to potty!
Because the spines are so similar between humans and dogs, almost any injury that can happen to the human spine, can also occur in a dog! For example, a dog can sprain a joint in its back, strain a muscle, herniate (prolapse) a ‘disc’, develop degeneration in the spine, etc., etc. It is possible with back injuries for the spinal cord or the nerves that branch from the spinal cord, to be affected. For example, a ‘slipped’ disc can put pressure on the spinal cord (see below). Also, with degeneration of the discs and joints in the spine with age, the dog can end up with pressure on the nerves that control its limbs.
A very big difference between humans and dogs with respect to the spine, is that when there is an injury to the spine, and the dog is in pain it is not always immediately easy to recognize. Dogs are very stoic and will try to hide pain. Also, if the nerves to one or both hind limbs are affected, it might look like a knee or hip injury …with limping or weakness, but the problem can be actually coming from the spine.
Some ways to recognize that your dog may have back pain:
- Walking with a ‘roached’ spine ( arched up like a cat)
- Tries to avoid certain activities that usually are not a problem – i.e. jumping onto a couch, or into a car, or standing on hind legs with front paws on a windowsill
- Hind end (or front end!) is weak
- Can’t walk as far as normal
- Has started licking or chewing paws (sometimes pressure on a nerve will make it feel like there is numbness or tingling in a limb – because it feels ‘funny’ dogs sometimes bite at their paw or lick)
- Trouble getting up from lying
- Flinching when you run your hand lightly down the spine
- Change in mood – can be more aggressive if in pain or not want to play with other dogs
It is important to have a thorough rehab assessment of the entire spine if you see any of these signs or even if it looks like your dog is favouring one of its limbs. If the problem is originating in the spine, but only the limb is treated, your dog won’t improve as much as is possible!
For more information, or to book your dog for a full spinal assessment, please contact The Canine Fitness Centre (403-204-0823)!