OSTEOLOGY. 53 



In general characters tliey resemble tlie dorsal vertebrae ; 

 we shall, therefore, only notice their peculiarities. These 

 vertebrre are five or six in number, are larger than the 

 dorsal, and each presents a large foramen magnum and 

 transverse processes ; also has no articulatory surfaces for 

 the heads of the ribs. The superior spinous processes 

 resemble those of the posterior dorsal ; all look forwards ; 

 are- short and stout, elongated from above downwards, 

 tuberous at their upper extremities, anteriorly presenting a 

 sharp margin, posteriorly a double margin, both for attach- 

 ment of the interspinous ligaments. The oblique processes 

 tend to assume a peculiar rounded hinge-like character; 

 those on the posterior part present a rounded convexity, 

 elongated from behind forwards, looking outwards and 

 ' downwards . The anterior ohlique pirocesses have articulatory 

 surfaces looking upwards and inwards. The intervertebral 

 gaps are large, the transverse processes, formed by a single 

 root, extend directly outwards, those of the anterior ver- 

 tebrae having a slight inclination backwards, those of the 

 posterior forwards. Their length is characteristic of the 

 vertebrae of this region. They are flattened from above 

 downwards, and of the first five vertebrae are tuberous at 

 their free extremities, affording attachment to quadratus 

 lumborum, psoas magnus, and indirectly to some of the 

 .abdominal muscles. 



The anterior and posterior margins are sharp, affording 

 .attachment to intertransversales lumborum ; the upper and 

 under surf axes are smooth ; the former affords attachment 

 to longissimus dorsi, which occupies the space between 

 this and the superior spinous process ; the latter to the 

 ipsoae muscles. When six lumbar vertebrae exist the trans- 

 verse process of the sixth is much shorter than the rest, 

 .and presents articular synovial facets^hoth on its anterior and 

 its posterior margins, ovoid and elongated from side to side, 

 separated by grooves from the amphiarthrodial facets of 

 the body. These present special ligaments, and the poste- 

 rior one slants from without inwards and backwards, being 

 in connection with the first sacral transverse process. 

 The anterior slopes in a similar direction, articulating 

 vwith a corresponding facet on the posterior part of 

 rthe fifth lumbar transverse process. The latter, where 

 there are only five lumbar vertebrae, is modified to join the 

 .sacrum. Most horses present six, most asses five, lumbar 



