Another case of an animal rendered a tereifa – that it has a terminal condition that will not allow it to survive – is discussed in the Mishna on today’s daf. The Mishna teaches that if the hind legs of an animal were cut off “from the joint and below”, it is permitted, but if they were cut off “from the joint and above”, it is considered a tereifa. This is also the case if the tzomet ha-gidim – the convergence of sinews – was removed.
Which joint is the one that serves as the “cut-off point” for this law?
The Gemara brings a difference of opinion with regard to this question. Rav Yehuda said in the name of Rav who reported it in the name of Rabbi Ḥiyya, “below” means below the joint, and “above” means above the joint, and the joint referred to is the joint which is sold together with the head. Ulla said in the name of Rabbi Oshaya: It is that joint which is clearly distinguishable in the camel.
An animal’s leg is made up of three main bones (aside from the smaller bones around the hoof that are comparable to a human foot). They are:
The lower leg, or metatarsus, which traditionally was sold by butchers together with the animal’s head. This bone is referred to by many rishonim as the regel.
The middle bone (the tibia or shank bone) called the shok.
The upper bone, which would be the thigh bone or femur, called the yerekh or kulit.
Between each of these bones there is a joint called an arkuba; the upper arkuba can be seen clearly in a camel, although in a cow it is difficult to discern since it is close to the cow’s belly and it is covered with muscle and skin. The discussion in the Gemara is which arkuba is referred to in the Mishna when it teaches that an animal becomes a tereifa if the hind legs of an animal were cut off “above the joint.”