Symphysis is the uniting of two Bones by the interposition of a Medium, which ties them very streight together, being also threefold: Such is the Connexion of the Knee-Pan or Whirl-Bone of the Knee, and the Omoplata or Shoulder-Blade.
Are not these three kinds of Articulations or Symphyses distinguish'd one from another?
Yes; for tho' they are all made by the means of a third Body intervening, which joins them together; nevertheless every one of these various Bodies gives a different Denomination to its respective Articulation: Thus the Articulation which is caus'd by a Glutinous and
Cartilaginous Substance, is properly call'd Synchondrosis; as that of the Nose, Chin, Os Pubis, &c. But an Articulation which is made by a Ligament is termed Synncurosis, as that of the Knee-Pan. Lastly, that which is wrought by the means of Flesh, bears the Name of Syssarcosis; as the Jaw-Bones, the Os Hyoides, and the Omoplata or Shoulder-Blade.
Have the Bones any sense of Feeling or Motion?
They have neither; for their sense of Pain proceeds from nothing else but their Periostium, or the Membrane with which they are cover'd, and their Motion is perform'd only by the Muscles that draw them.
Doth the Marrow afford any Nutriment to the Bones?
No, all the Bones are nourish'd by the Blood, as the other Parts; but the Marrow is to the Bones what the Fat is to the Flesh; that is to say, it is a kind of Oil or Unctuous Substance, which moistens, and renders them less brittle.
Are all the Bones of the same Colour?
No, they follow the Temperament and Constitution of the Persons.