APPLIED ANATOMY. 



sternomastoid, splenius capitis, and trachelomastoid muscles will have to be cut, 

 because it passes beneath them. The occipitalis major nerve lies to the inner side of 

 the artery. 



Occipital artery v f Superior oblique 



Sternomastoid 

 Trachelomastoid 

 Splenius 



Levator angu 

 scapulae 



Spinal accessory 

 nerve 



Hypoglossal nerve 



FIG. 6. Occipital artery. 



LYMPHATICS OF THE SCALP. 



The lymphatics anteriorly near the median line pass down between the orbits to 

 reach the submaxillary nodes. Those of the anterior parietal and temporal regions 

 empty into the pre-auricular nodes; those of the posterior parietal and temporal, 

 into the nodes behind and below the ear; and those of the occipital region into the 

 occipital nodes. Infectious troubles of these regions, therefore, will cause enlarge- 

 ment of the corresponding nodes. 



AFFECTIONS INVOLVING THE LAYERS OF THE SCALP. 



Wounds of the scalp are common. Incised wounds bleed more freely and the 

 hemorrhage is more difficult to control than in wounds elsewhere on the surface. 

 This is due to the exceedingly free blood supply and to the peculiar arrangement of 

 the blood-vessels in the tissues. 



Small wounds of the scalp do not gape, particularly if they are longitudinal in 

 direction and not very deep. The skin is so intimately bound to the aponeurosis 

 beneath that displacement is impossible. If the cut is deep enough to divide the 

 aponeurosis extensively, especially if the wound is transverse, gaping is marked. 

 This is produced by contraction of the two bellies of the occipitofrontalis muscle, 

 which pulls the edges apart. 



Bleeding is apt to be persistent and hard to control because the arteries running 

 in the deep layers of the skin and fibrous trabeculee are firmly attached and, there- 

 fore, when cut, their lumen cannot contract nor their ends retract. When large 

 flaps are torn in the scalp, they rarely die because of their free blood supply, and 

 sloughing is limited to the parts which are actually contused. As the subaponeur- 

 otic space is often opened, if the wound is sewed too tightly shut, subsequent bleeding 

 instead of escaping externally may extend widely under the aponeurosis. Inasmuch 

 as hair and dirt are often crushed into these wounds, great care should be taken to 



