Responsa for Bava Metzia 210:4

ה"ד אדם שכוחו רע אמר ר"ל כל שרוכבו וארכבותיו נוקשות ה"ד בהמה שכוחה רע אמרי דבי ר' ינאי כל שרוכבה מטילה גללים

We learnt elsewhere: If a man travels through grave area<span class="x" onmousemove="('comment',' [H] Lit., 'a field of a Peras square.' Peras = half (the length of a furrow of 100 cubits), and it is a term applied to a field declared unclean on account of a grave that was ploughed therein. Maim. and Asheri on Oh. XVII, 1 translate [H] as derived from [H] to extend, i.e., the area over which the bones may extend. Others derive it from [H] to break, i.e., an area of splintered bones; v. Jast. ');">⁴</span>

Teshuvot Maharam