noun
nape of the neck; back of the neck; scruff of the neck
Refers to the back of the neck, often in contexts of tension, touch, or grabbing someone by the scruff.
首筋がこっている。
My neck is stiff.
彼は猫の首筋をつかんだ。
He grabbed the cat by the scruff of the neck.
Rarely used kanji form; 頚 is a variant of 頸.
Compound of 首 (kubi, 'neck') + 筋 (suji, 'line, muscle, sinew'). The reading くびすじ is a straightforward combination of the kun'yomi readings of the two kanji.