大方廣佛華嚴經疏 48.19

48.19

第十七腨有三相，第三膊毛通於二腨。若準晉經，直云毛端，則通身一切毛也，義應如昔，則處成十九。

Seventeenth, the calves have three marks; the third, the hair on the arms, extends across both calves. If following the Jin translation of the sūtra, it simply says "the tips of the hairs," meaning all the hairs over the entire body; the meaning should be as in the past, and thus the locations make nineteen.