134 ARTHROLOGY. 



The first pair of costo-sternal joints which are close together 

 usually have a common capsular ligament. 



Sternal Articulations. — These bind together the sternal seg- 

 ments. The ligaments in the horse are the superior sternal, 

 extending along the upper surface of the bones, and the intervening 

 fibro-cartilages which eventually ossif}'. 



The cartilaginous appendages of the sternum are the cariniform 

 and xiphoid cartilages. In the horse the former appears as a 

 sharp ridge running from above and before the presternum, down 

 the lower median line of the anterior sternal segments. Its shape 

 bears a marked resemblance to the keel and cut-water of a boat, 

 hence its name. The xiphoid is a flat ovoid plate of cartilage 

 attached to the posterior segment of the meso-sternum ; unlike 

 the cariniform, its sharp edge is placed transversely. It is also 

 called the ensiform cartilage. 



Articulations of the Skull. 



These are all synarthrodial, excepting the temporo-maxillary 

 joints and those between the hyoid bone and its appendages. 

 Collectively, the remaining joints are called the sutures of the 

 skull, and some of these have received special names. 



sutures. 



The straight median suture, extending from the occipital crest 

 to the nasal peak, is the longitudinal one, subdivided into the 

 nasal portion, which is open at the apex, the frontal, and the 

 sagittal, the latter situated between the parietal bones, while 

 joining the nasal and lachrymal bones to the frontal is the trans- 

 verse suture. The coronal suture extends obliquely upwards 

 and backwards from the temporal fossa, between the frontal and 

 parietal bones, while the sutura lirnhosa runs upwards between 

 the parietal and occipital bones, reaching from the temporal bone 

 to the sagittal suture. For structure of sutures see page 126. 



TEMPORO-MAXILLARY JOINT. 



This articulation is a diarthrosis, and it is furnished with 

 cajpsular, external lateral, and posterior ligaments, and also 

 with a meniscus or interarticular disc of cartilage. The joint 



