Ahmed Haidar. In the end of his competetive career lost his lats and inner calves. Just like Iain And Wolf.
I think we can now put a nail in this coffin and point out that it's the
Thoracic nerve.
Ahmed:

Dennis:

Now, it would be interesting to know what causes this nerve to stop "working". Impingment(likely from disc herniation), blunt force damage, or some kind of disease.
The thoracic nerves has roots in/originates from the C5, C6 and C7 in the neck.
:watermark(/images/watermark_only.png,0,0,0):watermark(/images/logo_url.png,-10,-10,0):format(jpeg)/images/anatomy_term/long-thoracic-nerve-3/WB7kDc1l3QVrugwP9iIkOQ_Long_thoracic_nerve.png)