Trouble understanding the meaning of 怒った肩 here


The man is about to commit harakiri:

刀を前へ廻し、腰を持ち上げ、上半身が刃先へのしかかるようにして、体に全力をこめているのが、軍服の **怒った肩** からわかった。

What is understood here by "pointy shoulders" (if I'm understanding 怒った肩
correctly)? How can pointy shoulders (which I assume to be part of his
uniform) show that he was gathering his strength?




肩を[怒]{いか}らせる = [square one's
shoulders](http://ejje.weblio.jp/content/%E8%82%A9%E3%82%92%E6%80%92%E3%82%89%E3%81%9B%E3%82%8B)

He squared his shoulders under the uniform. You could see that he was
gathering his strength from the shape of his squared, raised shoulders.

> [軍服]{ぐんぷく}の[怒]{いか}った[肩]{かた}

≒ 軍服の[下]{した}の怒った肩 or 軍服を着た、怒った肩  
= his squared shoulders under the uniform




肩を[怒]{いか}らせる = [square one's
shoulders](http://ejje.weblio.jp/content/%E8%82%A9%E3%82%92%E6%80%92%E3%82%89%E3%81%9B%E3%82%8B)

He squared his shoulders under the uniform. You could see that he was
gathering his strength from the shape of his squared, raised shoulders.

> [軍服]{ぐんぷく}の[怒]{いか}った[肩]{かた}

≒ 軍服の[下]{した}の怒った肩 or 軍服を着た、怒った肩  
= his squared shoulders under the uniform

