PLATE XLII. 

 THE SUBOCCIPITAL TRIANGLE. 



In this dissection the trapezius was completely removed on the right side to expose 

 the complexus and splenius, on the left the splenius was cut away from its origin from 

 the ligamentum nucluo and aupraspinous ligament and turned outwards, showing its 

 division into splenius colli and capitis. The complexus was then divided about its 

 centre, and the ends turned up and down to expose the suhoccipital triangle which lies 

 beneath it. 



The suboccipital triangle corresponds to the space between the inferior curved Una 

 of the occiput and the level of the spine of the axis, and is bounded 

 Internally. By the rectus capitis posticus major and minor. 

 Externally. By the superior oblique. 

 Below. By the inferior oblique. 

 Floor. Formed by the posterior occipito-atlantal ligament and the posterior arch of the 



atlas. 

 Contents. Suboccipital nerve and its branches to the recti postici, obliques, and 



complexus ; vertebral artery with some muscular branches and the 



commencement of the vertebral vein. 



The following diagram shows the arrangement of the posterior primary branches 

 of the upper cervical nerves. It may be remembered as a general rule that all the 

 internal branches of the posterior divisions of the spinal nerves as far as the sixth dorsal 



Great occipital 



Superior oblia ( U 

 Complexus 



Recta lateral! 



Itilernal branches 

 l~a skin 



External 

 branches 

 !b muscle 



(thoracic) give off cutaneous branches, while the external supply muscles. Below, this 

 arrangement is reversed, the outer branches giving off the cutaneous twigs, and the 

 internal, muscular ; the exceptions being the first cervical, which does not split, and 

 the first two lumbar, which supply no skin branches at all. (a) Posterior and 

 (b) anterior divisions of the suboccipital nerve. 



