筋肉

きんにく

muscle

背筋

せすじ

spine, back muscles

筋

すじ

muscle, line, reason

首筋

くびすじ

nape of neck, back of neck

一筋

ひとすじ

single-minded, devoted

背筋を伸ばす

せすじをのばす

to straighten one's back, sit up straight

血筋

ちすじ

lineage, blood relation, family line

筋力

きんりょく

muscle strength, physical strength

筋合い

すじあい

reason, right, proper way

道筋

みちすじ

path, course, route, reasoning