Manasara 65.27

65.27

dvāviṃśāṃśakaṃ cordhve catvāriṃśārdhamātrakam
bāhuparyantavistāraṃ bāhumūlaviśālakam

Above, [the chest] is twenty-two parts; the width across the arms / is twenty units; [such is] the width at the arm-roots.