see Skin Preparation.
The supine position is used with the patient‘s head rotated for temporal access. Extremes of head rotation can obstruct the jugular venous drainage, and a shoulder roll can combat this problem or lateral positioning (park bench position).
1. clot removal: lowers ICP and eliminates focal mass effect. Blood is usually thick coagulum, thus exposure must provide access to most of clot. Craniotomy permits more complete evacuation of hematoma than e.g. burr holes.
3. prevent reaccumulation: (some bleeding may recur, and dura is now detached from inner table) place dural tack-up sutures to edges of craniotomy and use central “tenting” suture.