Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 25 On the Carpus

Names of the carpal bones

Four bones are located in the upper [proximalis] part of the carpus, in the row that faces the forearm. To these we shall assign appropriate names according to the order in which they are arranged, always naming the first [os scaphoideum] (1 in the first five figs.) the bone that constitutes the inner [lateral] side of the upper row, and the second [os lunatum] (2 in the same figs.) the one that follows this and is more distant from the inside; third [os triquetrum] (3 in the same figs.), the one that is closest to the second toward the outside [medial]; fourth [os pisiforme] (4 in the same figs.) the one that occupies the outermost side. 25 Similarly, we shall name the four bones of the lower [distalis] row (5-8 in all figs.) the fifth, sixth, seventh, and eighth, and in this fashion we shall approach the account of the individual bones. The first, second, and third are very strongly and closely joined together and linked in a single row as if they were a single bone, forming the upper area of the carpus in such a way that they are smoothly articulated into the depression [facies articularis carpalis] of the radius and ulna as if they were the head of a single long, wide bone. The first [os scaphoideum] and the second [os lunatum] are placed in a depression (x, y in figs. 1 and 8, ch. 24) carved in the epiphysis of the radius; the third [os triquetrum] leans against the cartilage [discus articularis] (T in figs. 1-3, 8, ch. 24) which we have written begins at the radius and chiefly separates the ulna from the carpus. But the outer side of the third bone also comes into contact with the sharp process [p. styloideus] (R in figs. 1, 2, 5, 10, ch. 24) of the epiphysis of the ulna when we incline the hand to the outside. 26 At the same time, this third bone does not have a depression visually distinguishable in man that is made especially for the sharp process and lined with cartilage, since the process itself protrudes only along the side of the depression where the carpus is contained, acting in the same way as the brows of the other depressions, including the apex (a in figs. 1, 2, 7, ch. 24) of the epiphysis of the radius in this area. 27 This is readily decided even by touch, if when the hand is bent to the inside, one tries to insert the tip of the thumb of the other hand between the carpus and the ulna. Therefore the first three carpal bones are so joined together on their upper [proximalis] surface and so protrude that they make up as it were a single head of the wrist, smooth and covered with cartilage, by which it is articulated to the forearm and is moved in many vigorous motions as if formed of a single large bone. 28



Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 25 On the Carpus