יורה דעה ל״בYoreh De'ah 32

Se’if 1א׳

חוּט הַשִּׁדְרָה שֶׁנִּפְסַק רֹב הֶקֵּף עוֹר הַחוֹפֶה אֶת הַמֹּחַ, טְרֵפָה, אַף עַל פִּי שֶׁכָּל הַמֹּחַ קַיָּם; וְאִם לֹא נִפְסַק רֹב הָעוֹר, אַף עַל פִּי שֶׁנִּפְסַק כָּל הַמֹּחַ שֶּׁבִּפְנִים, כָּשֵׁר.

If most of the skin that surrounds the marrow of the spinal cord was severed, the animal is invalid, even though all of the marrow is intact. And if most of the skin was not severed, even if all of the marrow inside was severed, it is valid.

Se’if 2ב׳

נִסְדַּק הָעוֹר לְאָרְכּוֹ, כְּשֵׁרָה; וְכֵן אִם נִשְׁבְּרָה הַשִּׁדְרָה וְלֹא נִפְסַק הַחוּט, אוֹ שֶׁנִּתְמַעֵךְ הַמֹּחַ שֶׁבְּתוֹךְ הַחוּט וְנִתְנַדְנֵד, הוֹאִיל וְעוֹרוֹ קַיָּם הֲרֵי זוֹ מֻתֶּרֶת.

If the skin split lengthwise, it is valid. And so too, if the spine broke but the [spinal] cord was not severed, or if the marrow that is inside the [spinal] cord was crushed and it wobbles, since the skin is still intact it is permitted.

Se’if 3ג׳

הֻמְרַךְ הַמֹּחַ וְנִשְׁפַּךְ כַּמַּיִם אוֹ כַּדוֹנַג שֶׁנָּמֵס, עַד שֶׁיִּמָּצֵא הַחוּט כְּשֶׁמַּעֲמִידוֹ בְּיָדוֹ הָיָה הַמְּעַט שֶׁחוּץ לְיָדוֹ שׁוֹחֶה, וְלֹא הָיָה יָכוֹל לַעֲמֹד, טְרֵפָה; (ל' הַטוּר) וְכֵן אַף עַל פִּי שֶׁלֹּא נִתְרַכֵּךְ מִבִּפְנִים, אֶלָּא שֶׁהוּא עָב וְכָבֵד, וְאִם מַעֲמִידִין אוֹתוֹ אֵינוֹ יָכוֹל לַעֲמֹד מִפְּנֵי כָּבְדוֹ, טְרֵפָה.

If the marrow decomposed and it can be poured like water or melted wax to the extent that the [spinal] cord, when one holds it in his hand, the part that extends out from his hand bends over and is not able to stand by itself, the animal is invalid. And so too, even though the inside didn't soften, but rather it became thick and heavy, if when one stands it up it is not able to stand because of its heaviness, it is an invalid animal.