Ohalot, Chapter One, Mishnah Eight
Today’s mishnah defines “limbs.” Obviously, the modern use of the word limb is not the same as the rabbinic use of the term. The word “limb” mostly seems to refer to bones, as we shall see.
1) There are two hundred and forty-eight limbs in a human body:
a) Thirty in the foot, six for every toe,
b) Ten in the ankle,
c) Two in the shin,
d) Five in the knee,
e) One in the thigh,
f) Three in the hip,
g) Eleven ribs,
h) Thirty in the hand, [that is] six to every finger,
i) Two in the fore-arm,
j) Two in the elbow,
k) One in the upper arm and
l) Four in the shoulder,
m) [For a total of] one hundred and one on the one side [of the body] and one hundred and one on the other.
n) Eighteen vertebrae in the spine,
o) Nine in the head,
p) Eight in the neck,
q) Six in the key of the heart,
r) And five around the genitals.
2) Each one [of these] can defile by contact, carriage or overshadowing.
3) When is this so? When they have upon them the appropriate amount of flesh,
a) But if they do not have the appropriate amount flesh upon them, they can defile by contact and carriage but cannot defile by overshadowing.
Section one: The count of 248 likely refers to bones and perhaps a few sinews and ligaments as well, and not what we would call limbs. It does not include the teeth. When I googled how many bones are in the human body, most answers seemed to be 206. The rabbinic answer seems to include some parts that modern anatomists do not consider bones. In any case, the count is not that far off.
Section two: Each of these “limbs” can cause defilement in any of the three ways that a dead body causes defilement: by contact, by being carried (even without contact) and by overshadowing (ohel). However, for it to defile as a “limb” it must have enough flesh such that if it was attached to the body it could heal.
If it does not have this amount of flesh, it still defiles by contact and carriage, but it doesn’t defile through overhanging. We shall see more concerning this is 2:3.