109 



CHAPTER II, 



ON THE LIGAMENTS. 



THE bones are variously connected with each other in the construc- 

 tion of the skeleton, and the connection between any two bones con- 

 stitutes a joint or articulation. If the joint be immovable, the sur- 

 faces of the bones are applied in direct contact ; but if motion be in- 

 tended, the opposing surfaces are expanded, and coated by an elastic 

 substance, named cartilage ; a fluid secreted by a membrane closed on 

 all sides lubricates their surface, and they are firmly held together by 

 means of short bands of glistening fibres, which are called ligaments 

 (ligare, to bind). The study of the ligaments is named syndesmology _ / 

 (trvv together, $urp,os bond), which, with the anatomy of tKe~arlicuIar- ^ ** 

 tions, forms the subject of the present chapter. 



The forms of articulation met with in the human frame may be 

 considered under three classes : Synarthrosis, Amphi-arthrosis, and 

 Diarthrosis. 



SYNARTHROSIS (<v, uofyutri; articulation) is expressive of the fixed 

 form of joint in which the bones are immovably connected with each 

 other. The kinds of synarthrosis are four in number. 1. Sutura. 

 2. Harmonia. 3. Schindyksis. 4. Gomphosis. The characters of 

 the three first have been sufficiently explained in the preceding chap- 

 ter, p. 52. It is here only necessary to state that, in the construction 

 of sutures, the substance of the bones is not in immediate contact, * 

 but is separated by a layer of membrane which is continuous exter- -A. 

 nally with the pericranium and internally with the dura mater. It is 

 the latter connection which gives rise to the great difficulty sometimes 

 experienced in tearing the calvarium from the dura mater. Cruveil- 

 hier describes this interposed membrane as the sutural cartilage ; I 

 never saw any structure in the sutures which could be regarded as 

 cartilage, and the history of the formation of the cranial bones would 

 seem to point to a different explanation. The fourth, Gomphosis 

 (yfl^(paj,anail),is expressive of the insertion of one bone into another, 

 in the same manner that a nail is fixed into a board ; this is illus- 

 trated in the articulation of the teeth with the alveoli of the maxillary 

 bones. 



AMPHI-ARTHROSIS (.(*,$} both, ci^utrt;) is a joint intermediate 

 in aptitude for motion between the immovable synarthrosis and the 

 movable diarthrosis. It is constituted by the approximation of sur- 

 faces partly coated with cartilage lined by synovial membrane, and 



