2 The neurological examination
Examination of nervous system function is achieved by observation, palpation and inducing reflexes and responses. The following section will explain the significance of the tests and how to perform them.
MENTAL STATE
Examination
Notice if, and how, the animal responds to its name, noise and visual stimuli. Does it walk about the room without taking note of distractions? Does it bump into objects, get stuck in narrow places and have problems reversing out, or turn a particular way when changing direction? Does it stop and appear to stare into space, at a wall or into a corner? None of these behaviours are normal (Fig. 2.3).
POSTURE
Examination
When sitting, the weak or paralysed hindlimbs may extend straight out between or amongst the forelimbs. The paretic animal is often slow to rise from a sitting position and the hindlimbs may not be fully extended when standing, or could be further apart than normal (abducted) (Fig. 2.5).

Figure 2.5 Husky dog with paraparesis secondary to a chronic T3-L3 spinal cord lesion. Note the muscle atrophy.
GAIT
Significance
Movement is initiated by the upper motor neuron (UMN), a collective name for the nerve cell bodies within the cerebrum and brainstem and their axons which form the descending motor tracts (fasciculi) of the brainstem and spinal cord. The UMN initiates and maintains normal movement and influences extensor muscle tone to support the body against gravity (Fig. 2.8).
Descending tracts
Table 2.1 Characteristics of the motor supply
UMN lesions | LMN lesions | |
---|---|---|
Paresis or paralysis | Yes | Yes |
Spinal reflexes | Normal to increased | Decreased or absent |
Muscle tone | Normal to increased | Decreased or absent |
Atrophy | Gradual (disuse) | Rapid (denervation) |
Proprioception is the perception of the body in space. Position and movement of the head is chiefly detected by the vestibular apparatus in both inner ears (special proprioception). Receptors in muscles, tendons and joints project sensory information into the CNS (general proprioception). This is then transmitted to the cerebrum (conscious proprioception) and to the cerebellum (unconscious proprioception) by ascending pathways. Projections to the cerebellum enable it to regulate the gait. Cerebellar lesions do not cause weakness. Reduced or absent proprioception causes ataxia. Associated deficits found on examination help localize the lesion to the vestibular system, the cerebellum, the spinal cord, or the cerebrum. (Lesions of the special proprioception receptors are common. Lesions of the general proprioception receptors are rare.) Ataxia is a sensory phenomenon.
Examination
Neurological deficits are noticeable when the animal is walking. Lameness shows up at faster gaits. Observe the gait from the side, front and from the rear. Squat down to observe the footfall of smaller dogs and cats (Figs 2.10, 2.11).
Allow cats to walk around the examination room. If they refuse to move, place them on the opposite side of the room to their owners or basket, which may encourage them to walk.
POSTURAL REACTIONS
Examination
Hindlimbs
A similar technique is used. The body weight is supported by a hand under the animal’s sternum; while the examiner’s other hand holds one hindlimb in a flexed position. This is easier to perform with the animal’s head facing the clinician. The point of supporting some or all of the animal’s weight is to ensure that the limb being hopped is weight-bearing. It is very important, whether testing the fore- or hindlimbs, that the animal remains in as normal an anatomical position as possible, with the spine as parallel to the ground as possible (Fig. 2.14).
Assessment
Strength is subjectively graded as
Wheelbarrowing
assesses the forelimb gait. It is physically more difficult to perform than hopping. The clinician supports all the weight of the hindquarters by placing a hand under the animal’s abdomen. The animal is then pushed forward. Cats almost uniformly refuse to cooperate and lie down which may be misinterpreted as forelimb weakness. It can be difficult to observe the movement of the forelimbs from one’s position at the rear of the animal. It can be difficult controlling the direction the dog walks, and they may struggle when manipulated in this fashion. One way around this is for the clinician to place the other hand under the dog’s head and dorsiflex the neck; this also removes visual clues and may highlight a proprioceptive deficit. It places an enormous strain on the clinician’s back and the information obtained can be more reliably gained by hopping and proprioceptive testing.
The paper slide test
is harder to perform and less consistent results are obtained. The animal’s paw is placed on a sheet of paper, which is then pulled to the side. The animal should return the displaced limb to a normal position. The problem is that a lot of normal dogs do not seem stimulated enough to return the limb to a normal position, and thus allow the limb to remain on the paper sheet. There is some thought that the paper slide test assesses the proximal limb proprioceptors and the ‘knuckling’ tests the distal limb proprioceptors. This is irrelevant in the clinical setting. Proprioceptive deficits occur because of lesions in the sensory nerves, the ascending proprioceptive pathways, the sensory relay nuclei of the thalamus or the sensory cortex of the cerebrum.
PALPATION
Significance
Pain and joint abnormalities affect the gait and posture. Atrophy occurs with disuse, denervation, secondary fibrosis of muscle, generalized weight loss, and in some myopathies. Muscle enlargement may follow ischaemia, local inflammation, trauma, neoplasia, myotonia, and muscular dystrophy. The distal or proximal limb may be selectively involved.
Warmth of the extremities and pulse quality assesses limb perfusion.