OF THE BACK. 279 



which is small and somewhat quadrilateral in form, arises from the upper and 

 back part of the transverse process, and is inserted into the lower border and 

 outer surface of the lamina of the vertebra above, the fibres extending as far 

 inwards as the root of the spinous process. The first is found between the first 

 and second dorsal ; the last, between the eleventh and twelfth. Sometimes, the 

 number of these muscles is diminished by the absence of one or more from the 

 upper or lower end. 



The Supra-spinales consist of a series of fleshy bands, which lie on the spinous 

 processes in the cervical region of the spine. 



The Inter-spinales are short muscular fasciculi, placed in pairs between the 

 spinous processes of the contiguous vertebrae. 



In the cervical region, they are most distinct, and consist of six pairs, the first 

 being situated between the axis and third vertebra, and the last between the last 

 cervical and the first dorsal. They are small narrow bundles, attached, above 

 and below, to the apices of the spinous processes. 



In the dorsal region, they are found between the first and second vertebras, and 

 occasionally between the second and third : and below, between the eleventh and 

 twelfth. 



In the lumbar region, there are four pairs of these muscles in the intervals 

 between the five lumbar vertebrae. There is also occasionally one in the inter- 

 spinous space, between the last dorsal and first lumbar, and between the fifth 

 lumbar and the sacrum. 



The Extensor Coccygis is a slender muscular fasciculus, occasionally present, 

 which extends over the lower part of the posterior surface of the sacrum and 

 coccyx. It arises by tendinous fibres from the last bone of the sacrum, or first 

 piece of the coccyx, and passes downwards to be inserted into the lower part of 

 the coccyx. It is a rudiment of the Extensor muscle of the caudal vertebras 

 present in some animals. 



The Inter-transversales are small muscles placed between the transverse pro- 

 cesses of the vertebras. 



In the cervical region, they are most developed, consisting of two rounded 

 muscular and tendinous fasciculi, which pass between the anterior and posterior 

 tubercles of the transverse processes of two contiguous vertebrae, being separated 

 from one another by the anterior branch of a cervical nerve, which lies in the 

 groove between them, and by the vertebral artery and vein. In this region, there 

 are seven pairs of these muscles, the first being between the atlas and axis, and 

 the last between the seventh cervical and first dorsal vertebra. 



In the dorsal region, they are least developed, consisting chiefly of rounded 

 tendinous cords in the inter-transverse spaces of the upper dorsal vertebrae ; but 

 between the transverse processes of the lower three dorsal vertebras and the first 

 lumbar, they are muscular in structure. 



In the lumbar region, they are four in number, and consist of a single muscular 

 layer, which occupies the entire interspace between the transverse processes of 

 the lowest lumbar vertebrae, whilst those between the transverse processes of the 

 upper lumbar are not attached to more than half the breadth of the process. 



The Rectus Capitis Posticus Major, the larger of the two Recti, arises by a, 

 pointed tendinous origin from the spinous process of the axis, and, becoming 

 broader as it ascends, is inserted into the inferior curved line of the occipital bone 

 and the surface of bone immediately below it. As the muscles of the two sides 

 ascend upwards and outwards, they leave between them a triangular space, in 

 which are seen the Recti capitis postici minores muscles. 



Relations. By its superficial surface, with the Complexus, and, at its insertion, 

 with the Superior oblique. By its deep surface, with the posterior arch of the 

 atlas, the posterior occipito-atloid ligament, and part of the occipital bone. 



The Rectus Capitis Posticus Minor, the smallest of the four muscles in this region, 

 is of a triangular shape; it arises by a nnrrow, pointed tendon from the tubercle 

 on the posterior arch of the atlas, and, becoming broader as it ascends, is inserted 



