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 21 On the Scapuli

The cartilage which often augments the socket of the scapula

Since Nature carved out this depression of the scapula rather lightly for the sake of loose movements and made it not very wide or long (in addition to special ligaments of this joint,


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which we shall discuss in the second book together with the muscles, and certain processes of the scapula which you shall hear prevent dislocations of the joint 35 when we describe those too in the course of our account), she many times fashions in this depression a certain cartilage [c. fibrosa] made like a ligament [labrum glenoidale] by which she increases the cavity, makes it deeper, and substantially corrects its excessive propensity for dislocation 36 without at the same time obstructing the very loose and different motions of the arm which we very much need. This cartilage is put around the cavity, attached neither to the scapula nor to the humerus, linked only to the ligaments [ll. capsularia] surrounding and embracing the joint. The outer surface of this cartilage is thick, gradually thinning toward the middle of the cavity; it ends well short of the center, as if someone were increasing the cavity’s circumference with a ring whose shape had been forged into a triangle whose outer side faces the outer circumference of the joint and whose inner side rests in the cavity; above, it faces the head of the humerus, 37 so that two of its angles touch the circumference of the joint while the third faces the center of the cavity. 38 You will readily see this product of Nature’s diligence, so delightful to behold, in quadrupeds and birds even if a human body is not at hand, since the cavities of the tibia bone are always enlarged by the same artifice [menisci medialis at lateralis]. By virtue of this cartilage, whenever it is found, the cavity of the scapula is deepened and at the same time the cartilage readily yields to impact and compression of the bones without restricting the free movement of this joint.



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 21 On the Scapuli