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 4 On the Structural Relationships of Bones

Arthrodia

A)rqrwdi/a is a type of joint with a lightly and superficially hollowed depression and a low head, as if it were made by the attachment of flat surfaces. 30 And whereas in enarthrosis it is easy to tell which is the head and which the depression, in arthrodia both are so obscure that you do not know to which bone you should ascribe the depression or the head, just as if you were to imagine two flat surfaces pressing into each other. By this type [articulatio plana] the three inner bones [os cuneiforme mediale, intermedium, laterale] of the tarsus are joined to the navicular bone, the metatarsal bones to those of the tarsus, some carpal bones to metacarpals, the fourth bone of the carpus [os pisiforme], which will be called the upright bone, 31 to the third carpal bone [os triquetrum], and the clavicle to the acromion [articulatio acromio-clavicularis]. 32 In these joints the motions are so obscure that they may be perceived only with great difficulty.



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 4 On the Structural Relationships of Bones