336 



VIII. Ligaments of the Sternum. 



The first piece of the sternum is united to the second either by an amphi- 

 arthrodial joint a single piece of true fibro-cartilage uniting the segments or 

 by a diarthrodial joint, in which each bone is clothed with a distinct lamina of 

 cartilage, adherent on one side, free and lined with synovia! membrane on the 

 other. In the latter case the cartilage covering the gladiolus is continued without 

 interruption on to the cartilages of the second ribs. Mr. Rivington has found the 

 diarthrodial form of joint in about one-third of the specimens examined by him ; 

 Mr. Maisonneuve more frequently. It appears to be rare in childhood, and is 

 formed, in Mr. Rivington's opinion, from the amphiarthrodial form by absorption. 

 The diarthrodial joint seems to have no tendency to ossify at any age, while the 

 amphiarthrodial is more liable to do so, and has been found ossified as early as 

 thirty-four years of age. The two segments are further connected by an 



Anterior Intersternal Ligament and a 

 Posterior Intersternal Ligament. 



The Anterior Intersternal Ligament consists of a layer of fibres, having a 

 longitudinal direction ; it blends with the fibres of the anterior chondro-sternal 

 ligaments on both sides, and with the tendinous fibres of origin of the Pectoralis 

 major. This ligament is rough, irregular, and much thicker below than above. 



The Posterior Intersternal Ligament is disposed in a somewhat similar 

 manner on the posterior surface of the articulation. 



IX. Articulation of the Pelvis with the Spine. 



The ligaments connecting the last lumbar vertebra with the sacrum are similar 

 to those which connect the segments of the spine with each other viz : 1. The 

 continuation downward of the anterior and posterior common ligaments. 2. The 

 intervertebral substance connecting the flattened oval surfaces of the two bones 

 and forming an amphiarthrodial joint. 3. Ligamenta subflava, connecting the 

 arch of the last lumbar vertebra with the posterior border of the sacral canal. 

 4. Capsular ligaments connecting the articulating processes and forming a double 

 arthrodia. 5. Inter- and supraspinous ligaments. 



The two proper ligaments connecting the pelvis with the spine are the lumbo- 

 sacral and ilio-lumbar. 



The Lumbo-sacral Ligament (Fig. 239) is a short, thick, triangular fasciculus, 

 which is connected above to the lower and front part of the transverse process 

 of the last lumbar vertebra, passes obliquely outward, and is attached below to 

 the lateral surface of the base of the sacrum, becoming blended with the anterior 

 sacro-iliac ligament. This ligament is in relation, in front, with the Psoas 

 muscle, and represents the anterior costo-transverse ligament. 



The Ilio-lumbar Ligament (Fig. 239) passes horizontally outward from the 

 apex of the transverse process of the last lumbar vertebra to the crest of the ilium 

 immediately in front of the sacro-iliac articulation. It is of a triangular form, 

 thick and narrow internally, broad and thinner externally. It is in relation, in 

 front, with the Psoas muscle ; behind, with the muscles occupying the vertebral 

 groove ; above, with the Quadratus lumborum. 



X. Articulations of the Pelvis. 



The ligaments connecting the bones of the pelvis with each other may be 

 divided into four groups : 1. Those connecting the sacrum and ilium. 2. Those 

 passing between the sacrum and ischium. 3. Those connecting the sacrum and 

 coccyx. 4. Those between the two pubic bones. 



1. ARTICULATIONS OF THE SACRUM AND ILIUM. 



The sacro-iliac articulation is formed between the lateral surfaces of the 

 sacrum and ilium. The anterior or auricular portion of each articular surface 



