THE VERTEBRAL MUSCULATURE. 265 
The following may be made out on the posterior surface: 
(a) The cut margins of the falciform, coronary, and left trian- 
gular ligaments. 
(b) The hiatus aorticus, an aperture enclosed by the two crura 
and serving for the transmission of the aorta. 
(c) The hiatus oesophageus, ventral to the foregoing, and 
serving for the passage of the oesophagus. 
(d) The foramen venae cavae, situated slightly to the right 
and serving for the transmission of the vena cava inferior. 
(e) The superior phrenic arteries (aa. phrenicae superiores) 
arise from the aorta at about the point of origin of the 
eleventh intercostals or from one of the lacter, and enter the 
crura. 
The inferior phrenic arteries are minute branches arising at the base 
of the coeliac. 
(f) The inferior phrenic veins (vv. phrenicae inferiores), one 
on either side of the foramen venae cavae, at which point 
they enter the inferior cava. 
The superior phrenic veins pass forward from the diaphragm, 
opening into the superior cavals. 
XII. THE VERTEBRAL AND OCCIPITAL MUSCULATURE. 
Dissection on the dorsal surface of the body from the occiput 
backward; also on the lateral and ventral surfaces of the neck. 
The serratus posterior muscle lies on the dorsolateral surface 
of the thorax. It arises from the dorsal spinous ligament of the 
neck (ligamentum nuchae) and from the lumbodorsal fascia back to 
the last rib, and is inserted on the lateral surfaces of the eight pos- 
terior ribs. 
The splenius muscle is a somewhat triangular sheet arising 
from the ligamentum nuchae and inserted on the supraoccipital and 
mastoid portions of the skull, extending also to the transverse pro- 
cess of the atlas. 
These two muscles should be divided, the serratus posterior being removed 
from the surface. 
1. The long muscles of the vertebral column. 
Apart from the iliopsoas, psoas minor, and quadratus lum- 
borum—muscles of appendicular insertion lying on the ventral 
surface of the vertebral column—the vertebral musculature com- 
