יורה דעה ס״אYoreh De'ah 61

Se’if 1א׳

חַיָּב לִתֵּן לַכֹּהֵן הַזְּרוֹעַ וְהַלְּחָיַיִם וְהַקֵּבָה שֶׁל שׁוֹר וָשֶׂה.

One is obligated to give the priest the foreleg, the cheeks and the maw of an ox and of a sheep.

Se’if 2ב׳

הַזְּרוֹעַ, דַּוְקָא שֶׁל יָמִין, וְהוּא מִפֶּרֶק אַרְכֻּבָּה הַנִּמְכֶּרֶת עִם הָרֹאשׁ עַד כַּף הַיָּד שֶׁקּוֹרִין אישפאלד"ה, וְהֵם שְׁנֵי פְּרָקִים.

The foreleg — specifically the right one; and it is from the joint of the knee that is sold along with the head up to the socket of the shoulder, which they call espalda; and they are two joints.

Se’if 3ג׳

הַלְּחָיַיִם הֵם מִפֶּרֶק שֶׁל לֶחִי עַד פִּיקָא שֶׁל גַּרְגֶּרֶת שֶׁהִיא טַבַּעַת הַגְּדוֹלָה עִם הַלָּשׁוֹן שֶׁבֵּינֵיהֶם, וְצָרִיךְ לִתְּנוֹ עִם הָעוֹר וְעִם הַצֶּמֶר שֶׁבְּרָאשֵׁי כְּבָשִׂים וְהַשֵּׂעָר שֶׁבְּרָאשֵׁי תְּיָשִׁים שֶׁאֵינוֹ רַשַּׁאי לְמָלְגָם (פי' לְהַרְתִּיחָם בְּחַמִּים לְהַעֲבִיר הַשֵּׂעָר) וְלֹא לְהַפְשִׁיט הָעוֹר קֹדֶם שֶׁיִּתְּנֶנּוּ לַכֹּהֵן.

The cheeks are from the joint of the jaw up to the knob of the windpipe, which is the large ring, together with the tongue that is between them. And he must give it with the hide and with the wool that is on the heads of sheep and the hair that is on the heads of he-goats, for he is not permitted to scald them (that is, to boil them in hot water to remove the hair), nor to flay the hide, before he gives it to the priest.