Spinal lesions affect parts of the body below the point of the lesion. Have a look at a “map”:
Think of your spinal cord as like the M1 motorway, with the brain being up in Yorkshire.
If there’s a big smash (lesion!) on the motorway, traffic between The North (your brain!) and The South (lower extremities!) will be disrupted.
But the exact nature and extent of the disruption will depend where the accident happened. If it happened right up in Yorkshire (near your brain), then ALL points South will be affected - traffic will have trouble getting to and from any of them.
But if it happened, at, say, Watford, then traffic to and from most places might still be OK. Only traffic needing to travel the full length, down to London, will find its way blocked.
You have a lesion at C4, which is the equivalent of “up North” somewhere (nearer to the brain). I’ve got one at T12, which is pretty low (almost unusually low, for an MS lesion).
So mine is like the crash being over halfway down, at - I dunno - Northampton or somewhere. Southerly destinations are all b*ggered up.