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shift their mass more to the pelvic limbs by bringing the feet of the pelvic limbs cranially. If you look at them stand from the side you will see that their feet are cranial to a line drawn perpendicularly from the hip to the ground.
When dogs have a bilateral hindlimb lameness they often shift their mass more to the thoracic limbs by bringing their elbows caudally so they are positioned more caudally underneath their thorax than normal. If you look at them stand from the side you will often see that the feet of the thoracic limbs are caudal to a line drawn perpendicularly from the shoulder to the ground. They will often also lower their head to further shift their weight from the hindlimbs.
Not that too many dogs do “handstands” but if you think of the action they would need to make if they were going to perform a handstand this will explain the way they change their stance in bilateral hindlimb lameness.
Observation of gait: what sort of gait abnormalities could you observe? This depends whether the cause of the lameness is unilateral or bilateral.
If lameness is unilateral, or if one leg is significantly worse than the other, then these gait changes are typically observed:
· the classic “head-bobbing” lameness. Remember the head drops on the good limb not on the lame limb. “Down on the sound” is the phrase that is often used. This not infrequently is misinterpreted by owners and they may wrongly advise you that they think the dog is lame on what is actually the sound limb. The classic head-bobbing lameness is most obvious in unilater-
al forelimb lameness. Landing more heavily on the sound limb is also seen in the hind limbs though is less obvious than in the forelimbs.
· shortened contact length and duration in the affect- ed limb and increased contact length and duration on the sound limb. The animal wants to spend as little time with the sore leg bearing weight as possi- ble. The contact phase is shorter in the lame leg and longer in the sound leg. The swing phase is quicker in the sound leg as the dog is “rushing” the good
leg through to take weight to minimise the time that the sore leg needs to bear weight. This faster swing phase in the sound leg is often misinterpreted as indi- cating this is the lame leg.
· circumduction – the animal with a painful joint or a decreased range of motion in a joint will often circum- duct the limb in preference to flexing the joint.
Bilateral lameness, particularly when it is symmetric, is particularly hard to detect. Beware the bilaterally lame animal as these commonly go undetected as the gait abnormalities are more subtle. In these cases, the dog has “lost the luxury of limping” as the limb on one side
is just as sore as the other. Their main compensation in these cases is to walk with their centre of mass set in the
position described above under changes in stance.
Typically dogs with bilateral joint-related lameness will walk with a “stiff” or “stilted” gait as they limit the range of motion of their painful joint.
What about grading the severity of the lameness?
This is subjective and varies with the individual doing the grading. There are a number of “systems” for grading lameness, including a descriptive scale, a scale of 1 to 10, a scale of 1 to 5 etc but none is widely accepted. None have been validated for repeatability. The key is to be consistent with whatever system you choose and ideally use the one simple system throughout all clinicians in your hospital.
3. Standing symmetrical examination followed by recumbent examination
Standing symmetric examination
The aim of this part of the exam is to compare each side simultaneously for evidence of difference in size, either muscle wasting or joint / segment / limb enlargement. Also, to palpate the musculature of the spine. This is most easily done standing behind and over the dog.
The forelimbs are easier to detect relative muscle wasting than the hindlimbs by comparing the prominence of the spine of the scapula. In the hindlimbs muscle wasting is identified by symmetric palpation of the main muscle masses and is more affected by the amount of load the dog is taking on the limb at the time.
Relative hindlimb muscle mass is most reliably compared visually when the dog is anesthetised in dorsal recumbency during the subsequent diagnostic investigation. Relative joint enlargement, which can be from a variety of causes most commonly effusion and periarticular fibrosis, can be palpated in the elbow and stifle and joints distal to these. It is uncommon to be able to palpate joint enlargement in the shoulder or hip joints.
Conscious proprioception should be assessed as part of the standing symmetry exam. The spine should be assessed by gentle palpation of the epaxial muscles and vertebrae for pain and assessment of free range of motion of the cervical and lumbosacral spine.
Recumbent examination
This obviously relies on having a cooperative dog. Most dogs will allow a calm recumbent exam. Owners are most often not useful in helping quietly restrain the dog.
Start at the foot pads and work proximally. Palpate every structure progressively as you move up. Think of the underlying anatomy as you do so.
Palpate each joint and assess whether it is enlarged, either through effusion or periarticular fibrosis, has normal stability and a normal range of motion, whether there is crepitus or palpable osteophytes present and in particular whether there is consistent localisation of pain.
Localising a focus of pain is of course challenging. It
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