Though all the fibrous organs have precisely the same nature, and
though the same fibre enters into the composition of all, yet the
forms which they assume are extremely various; it is this variety of
form, joined to that of their position and their functions, which has
given them a different denomination, and made us designate them by the
name of tendons, aponeuroses, ligaments, &c.; for there is no general
denomination for the whole system, no word which answers for example
to that of muscle, nerve, &c. which in the muscular, nervous systems,
&c. gives an idea of the organization, whatever may be the form of the
organ. I shall not create a word, I shall be easily understood without
it.
All the fibrous forms can be referred to two general ones; one of these
is membranous, the other in fasciæ. The organ is broad and thin in the
first; it is longer and thicker in the second. Thus the muscles, the
nerves, the bones themselves exhibit alternately this arrangement in
their conformation, as we see in the retina compared with the round
nerves, in the muscular layers of the stomach and the intestines,
compared with the muscles of locomotion, and in the bones of the
cranium compared with those of the extremities.