Page 765 - Clinical Small Animal Internal Medicine

68 The Neurologic Examination 733

rapidly the paw is replaced. Most normal small animals walked on one side (hemiwalking). Hemiwalking is
VetBooks.ir immediately return the paw to its normal position. This performed by standing on one side of the patient. Grasp
each limb on that side and lift the limbs off the ground
response is known as the paw replacement reaction that
requires many peripheral and central components to be
will hop with both limbs on that side. Switch sides and
normal. This test is not just for conscious perception of and push the patient toward its opposite side. The patient
GP and should not be called the CP test. This term is a repeat the hemiwalking performance on the opposite
misnomer that we are well aware will be difficult to limbs. Be sure to compare one thoracic limb with the
eliminate from the clinical language of veterinarians, other and one pelvic limb with the opposite pelvic limb.
even boarded veterinary neurologists. In small animals in which the hopping responses are
Moving on, palpate the thoracolumbar epaxial muscles equivocal or difficult to interpret, testing the placing
and then the muscles of both pelvic limbs followed by responses may be useful. Pick up the patient and bring its
flexing and extending those limbs for tone and range of thoracic limbs to the edge of a shelf, table, or chair so that
motion and checking for paw replacement. Check for the the dorsal surface of the paw contacts the front surface of
degree of tail tone, and while extending the tail, evaluate the object. The normal patient will immediately place its
the anal tone. paws on the horizontal surface of the object. Test both
Hopping responses, in our opinion, are the most reliable thoracic limbs while holding the patient from both sides.
of the postural reactions that we test. While still strad- For some unknown reason, occasionally the normal
dling the patient, move back to the thoracic limbs and patient will not respond on the side on which it is being
elevate the abdomen with one hand so that the pelvic held. Blocking the vision of the patient while conducting
limbs are not bearing any weight. With your other hand, this test may also be useful. Do this by extending its head
pick up the thoracic limb on that side. With all the weight and neck so that it cannot see the protruding surface of
supported on that thoracic limb, hop the patient later- the shelf, table, or chair. Whether the lack of vision or the
ally. Go as far as you can without moving your pelvic position of the head and neck helps exacerbate the plac-
limbs. Then, switch hands and hop the patient back on ing deficits is unclear.
the other thoracic limb. Repeat this test many times until In cooperative patients in which you are not sure of the
you are sure the thoracic limbs are normal or abnormal. thoracic limb function, you can wheelbarrow the patient
Only evaluate hopping in the lateral direction. As you while holding its head and neck in extension. With one of
stand over your patient and look down the lateral aspect your forelimbs, elevate the abdomen of your patient, and
of the limb that is being hopped, the limb should move with the other hand, hold the head and neck in extension
as soon as you move the shoulder region laterally over and force the patient to walk forward. With this posture,
the paw. Any delay in this response is abnormal. The vision is compromised, and the need for GP is increased.
hopping movements should be smooth and fairly rapid Remember that patients with LMN disease that still
and not irregular or excessive. The paw should never have some voluntary movements will hop or circle rapidly
drag or land on its dorsal surface. Carefully compare one if their weight is supported because their GP is unaffected.
thoracic limb with the other. This observation may help distinguish between subtle
To test the hopping responses in the pelvic limbs, UMN and LMN paresis. When we are presented with a
stand beside the patient, and place your forelimb that is patient that we suspect has LMN paresis, we will hop the
closest to the patient’s head between its thoracic limbs patient with and without supporting all the weight on the
with your hand on its sternum. Lift up on the thorax just affected limb or limbs. As already stated, the patient with
enough to take the weight off the thoracic limbs. With LMN paresis should know exactly where the limb is
the other hand, pick up the pelvic limb on the side where located during these postural reactions.
you are standing and push the patient toward the pelvic When presented with a recumbent patient, you
limb that is bearing the weight. This action will force the should pick it up and hold it in a standing position. Get
patient to hop laterally on that pelvic limb in a direction help if the patient is too large for you to handle alone.
away from you. After a few hops, switch sides, and hop By holding it in this position and lifting it up and down,
the patient back on the other pelvic limb. Keep repeating you can readily determine the quality of the muscle
this test until you have determined that the response is tone, whether they are hypotonic‐flaccid from LMN
normal or abnormal. The responses should be brisk and disease, or hypertonic from spasticity of UMN disease.
smooth but will not be quite as rapid as in the thoracic You can determine whether any voluntary movements
limbs. While you are hopping the patient, you will also are present in the limbs, and while supporting the
be aware of the degree of tone in the limb that is bearing patient, you can determine the presence and quality of
all the weight. the hopping responses.
In large dogs that are too heavy to lift for this testing, One might conclude that these postural reactions
the same observations can be made while the patient is are relatively nonspecific. This conclusion is absolutely