Our Gemara on Amud Beis discusses how a severed spinal cord renders the animal a tereifah. The Baal Hatanya (Likkutei Torah Balak 3) observes that the spinal cord is not counted as one of the 248 limbs in the body according to Talmudic medical tradition. Yet, despite it not being a specific limb, it serves a vital purpose as a conduit of the life force from the brain to the rest of the parts of the body. Therefore, even though it is not a limb, if it is severed, the animal is rendered tereifah.

Likkutei Torah considers this as an allegorical message regarding prayer and spiritual intentions. We have many mitzvos which could be considered like the limbs of the body of Torah. Just as limbs help us accomplish our intentions, so too the mitzvos allow us to accomplish God’s intention. Yet, even though the spinal cord is not one of those limbs, if it is severed the animal is a tereifah; the mitzvos will not be effectively alive without the unifying force of our intentions. He goes on to explain how prayer is a way of materializing those intentions. Notably, the 18 blessings in the Anudah correspond to the rabbinical anatomical 18 joints in the spine. Though it is a debate between Rambam and Ramban (Sefer Hamitzvos 5 and Hasagos Haramban) if prayer itself is a Torah obligation, it transcends obligation as an implicit necessity. Just as a spinal cord is not a limb, but it is vital to the life of the animal, so too intention — and prayer that helps create that intention — is vital to every single limb, that is every single mitzvah within the Torah.