SCALP 51 



of the occipitalis and frontalis muscles, and, as it moves, it 

 carries with it the skin and superficial fascia with which 

 it is so closely blended. 



Dissection. After the dissector has studied the attachments 

 of the galea aponeurotica, and after he has made himself 

 thoroughly conversant with the nerve and vascular supply of 

 the scalp, and has appreciated the fact that every part of its area 

 is supplied by more than one nerve and that the blood vessels 

 anastomose very freely together, he should next convince him- 

 self of the greater looseness of the areolar layer beneath the galea 

 in the medial area and its greater denseness and closer attach- 

 ment to the various parts of the super jacent epicranius, and the 

 subjacent pericranium at the margins of the scalp area. He 

 may do that by introducing the handle of a scalpel through a 

 median incision in the galea, and passing it forwards and 

 backwards and from side to side. 



The Layer of Loose Areolar Tissue. The layer of loose 

 areolar tissue is the fourth layer of the scalp. It is but slightly 

 vascular and is of loose texture, but is not equally loose over 

 the whole area of the scalp ; on the contrary, in the regions 

 of the temporal and supra-orbital ridges it becomes much 

 denser, and, at the same time, much more closely connected 

 with the galea aponeurotica and the frontalis muscles, whilst 

 posteriorly it disappears where the occipitalis muscles and the 

 galea become attached to the superior nuchal lines. It is 

 on account of those peculiarities that effusions of blood of 

 inflammatory exudations in the areolar layer easily raise the 

 greater part of the scalp from the bone, but such effusions 

 do not readily pass from beneath the scalp into either the 

 facial, temporal, or occipital regions. 



On the fifth day after the body has been placed upon its 

 back, the eighth after it was brought into the room, the 

 dissector of the head and neck must assist the dissector of 

 the upper extremity to display the whole extent of the brachial 

 plexus and the origins of the branches which spring from it ; 

 and he should take the opportunity to revise his own know- 

 ledge of the plexus. 



Dissection. Detach the clavicular head of the sterno- 

 mastoid from the clavicle, and displace the sternal head towards 

 the median plane. When that has been done the anterior and 

 upper parts of the sterno-clavicular joint capsule will be fully 

 exposed, for the pectoralis major, which covered the lower part 

 of the anterior surface, has already been reflected by the dissector 

 of the upper extremity. 



The sterno-clavicular joint is described on p. 37 of Vol. I. 

 After the dissectors have noted that the fibres of the capsule run 



