OF THE BACK 415 



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 inward as the root of the spinous pro/less. The first is found between the 

 first and second thoracic; 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 Supraspinales (mm. supraspinales) consist of a series of fleshy bands 

 w r hich lie on the spinous processes in the cervical region of the vertebral column. 



The Interspinales (mm. interspinales) are short muscular fasciculi, placed in 

 pairs between the spinous processes of the contiguous vertebrae, one on each side 

 of the interspinous ligament. In the cervical region they are most distinct, and 

 consist of six pairs, the first being situated between the axis and the third vertebra, 

 and the last between the last cervical and the first thoracic vertebra. They are 

 small narrow bundles, attached, above and below, to the apices of the spinous 

 processes. In the thoracic region they are found between the first and second 

 vertebrae, 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 interspinous space between the last thoracic 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 downward to be 

 inserted into the lower part of the coccyx. It is a rudiment of the Extensor muscle of the caudal 

 vertebrae of the lower animals. 



The Intertransversales (mm. intertransversarii) are small muscles placed 

 between the transverse processes of the vertebrae. In the cervical region they are 

 most developed, consisting of rounded muscular and tendinous fasciculi, which are 

 placed in pairs, passing between the anterior and the posterior tubercles of the 

 transverse processes of two contiguous vertebrae, separated from one another by 

 the anterior division- of the cervical nerve, which lies in the groove between them. 

 In this region there are seven pairs of these muscles, the first pair being between 

 the atlas and axis, and the last pair betw r een the seventh cervical and first thoracic 

 vertebrae. In the thoracic region they are least developed, consisting chiefly of 

 rounded tendinous cords in the intertransverse spaces of the upper thoracic verte- 

 brae; but between the transverse processes of the lower three thoracic vertebrae, and 

 between the transverse processes of the last thoracic and the first lumbar, they are 

 muscular in structure. In the lumbar region they are arranged in pairs, on either 

 side of the vertebral column, one set occupying the entire interspace between the 

 transverse processes of the lumbar vertebrae, the intertransversales laterales; the 

 other set, intertransversales mediales, passing from the accessory process of one 

 vertebra to the mammillary process of the next below. 



The Rectus capitis posticus major (TO. rectus capltis posterior major} 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 

 pass upward and outward, they leave between them a triangular space, in which are 

 seen the Recti capitis postici minores muscles. The superficial surface is crossed 

 by the Complexus; its deep surface lies on the posterior occipito-atlantal ligament. 



The Rectus capitis posticus minor (m. rectus capitis posterior minor), the small- 

 est of the four muscles in this region, is of a triangular shape; it arises by a narrow 

 pointed tendon from the tubercle on the posterior arch of the atlas, and, becom- 

 ing broader as it ascends, is inserted into the rough surface beneath the inferior 



