(A-D) Micrographs of suprascapular nerve cross-sections were stained with 2% osmium tetroxide (original magnification, x 1000). Arrows indicate normal axon, and arrowheads indicate degenerating axons. (E-L) Neuromuscular junction staining of supraspinatus and infraspinatus is shown (original magnification, x 1000); acetylcholine receptors are red, axons green; arrows indicate normal or reinnervated neuromuscular junction and arrowheads indicate denervated neuromuscular junction. (M) Ratio of degenerating axon in suprascapular nerve (%) = degenerating axons/entire axons. (N-O) Ratio of the denervated neuromuscular junction in both supraspinatus and infraspinatus (%) = number of denervated neuromuscular junction/number of entire neuromuscular junction; solid lines indicate p < 0.05, and dashed lines indicate p < 0.01. Error bars indicate SD. DN = denervation; NC = nerve compression; NCR = nerve compression and release; NMJ = neuromuscular junction; SS = supraspinatus; IS = infraspinatus.