SURFACE MARKINGS OF SPECIAL REGIONS OF HEAD AND NECK 1291 



SURFACE MARKINGS OF SPECIAL REGIONS OF HEAD AND NECK. 



The Cranium. Scalp. The soft parts covering the upper surface of the skull 

 form the scalp and comprise the following layers (Fig. 1196) : (1) skin, (2) subcuta- 

 neous tissue, (3) Occipitalis frontalis and galea aponeurotica, (4) subaponeurotic tissue, 

 (5) pericranium. The subcutaneous tissue consists of a close mesh-work of fibers, 

 the meshes of which contain fatty tissue; the fibers bind the skin and galea aponeu- 

 rotica firmly together, so that when the Occipitalis or the Frontalis is in action 

 the skin moves with the aponeurosis. The subaponeurotic tissue, which intervenes 

 between the galea aponeurotica and the pericranium, is much looser in texture, 

 and permits the movement of the aponeurosis over the underlying bones. 



Subcutaneous tissue 



Galea aponeurotica 

 Pericranium 





Superior sagittal sinus 



Fio. 1 196. Diagrammatic section of scalp. 



Bony Landmarks (Fig. 1193). In addition to the bony points already described 

 which can be determined by palpation, the following are utilized for surface 

 markings: 



Auricular Point. The center of the orifice of the external acoustic meatus. 



Preauricular Point. A point on the posterior root of the zygomatic arch imme- 

 diately in front of the external acoustic meatus. 



Asterion. The point of meeting of the lambdoidal, mastooccipital, and masto- 

 parietal sutures; it lies 4 cm. behind and 12 mm. above the level of the auricular 

 point. 



Pterion.- The point where the great wing of the sphenoid joins the sphenoidal 

 angle of the parietal; it is situated 35 mm. behind, and 12 mm. above, the level 

 of the frontozygomatic suture. 



Inion. The 'external occipital protuberance. 



Lambda. The point of meeting of the lambdoidal and sagittal sutures; it is 

 in the middle line about 6.5 cm. above the inion. 



Bregma. The meeting-point of the coronal and sagittal sutures; it lies at the 

 point of intersection of the middle line of the scalp with a line drawn vertically 

 upward through the preauricular point. 



A line passing through the inferior margin of the orbit and the auricular point 

 is known as Reid's base line. The lambdoidal suture can be indicated on either 





