Innervation of muscle in leprosy with special reference to the muscle spindle.

The pattern of extrafusal and intrafusal innervation was studied in muscle biopsies from the flexor carpi ulnaris and biceps brachii muscles, which were clinically unimpaired. Smudginess and enlargement of the motor end plates were the most definitely abnormal feature of the extrafusal innervation pattern; the intrafusal fibers, on the other hand, were either unremarkable or showed increased tortuosity, beading and in more extreme cases of grossly complicated intertwining pattern. Bacilli were frequently found in the spindles, no component being spared. The study emphasizes the significant involvement of striated muscle in leprosy, a fact not revealed by clinical examination alone.