Neuro case study: 6 years old Staffi male entire suddenly 'off it's legs'!

Hi Aidan,

Great, that's all correct, well done; answer A is correct and the dog will have deep pain indeed. We presume that this is due to the fact that the motor pathways are more superficial than those for nociception; therefore if there is still 'some' voluntary movement, one would expect 'some' motor pathways to remain intact and therefore the deeper pathways to be preserved too! That's assuming the problem is compressive (from periphery of the cord to the middle) and this is most of the spinal conditions we see. It would be very rare / unusual to have a lesion that takes out 'just' the pain pathways.

I will post a few more things now, starting with some useful definitions.

Thanks Aidan.

Bw

Nicolas

Hi,

So here are some answers tonight to the few questions I posted yesterday.

Video 2 shows the conscious proprioception testing. Here are some comments:

Postural reactions are tested first, before spinal reflexes.

These include testing conscious proprioception first (paw placement as seen in the video), and then unconscious proprioception. Dogs have ‘some’ voluntary control over paw placement (this involves the somatosensory cortex), whereas unconscious proprioception is tested with ‘hopping’ tests where the correction of the posture is a reflex to prevent the fall.

Postural reactions are not reflexes, but ways to challenge the ‘whole’ nervous system (ascending and descending pathways) to demonstrate presence / absence of a deficit. If a deficit is detected, the spinal reflexes are then performed as a second step, in order to further localise the origin of the deficit(s) to one nervous system segment.

In video 3, the patellar reflex and tibial cranial reflex are tested.

Here are some comments:

The patellar reflex is done by tapping the patellar tendon leading to an extension of the stifle. This allows to test the femoral nerve.

The tibial cranial reflex is done by tapping the tibial cranial muscle, below the stifle and cranial to the tibia, leading to a flexion of the foot. This allows to test the peroneal nerve, a branch of the sciatic nerve.

The gastrocnemius reflex is done by tapping the gastrocnemius tendon just above it’s insertion on the calcaneus leading to an extension of the foot. This allows to test the tibial nerve, however it is not a reliable reflex in dogs and is not usually performed.