i6 



APPLIED ANATOMY. 



A man fell from an electric light pole and was brought to the hospital with bleed- 

 ing from the ear and other symptoms of fracture of the skull. He became wildly 

 delirious, and, feeling sure that the fracture of the base was an extension from the 

 vault, although no depression could be felt, he was trephined above the external 

 auditory meatus and a large epidural effusion of blood evacuated. He recovered 

 and resumed his work. In this case, as soon as the bone was exposed, a thin line 

 of fracture was seen running down to the base in the region of the external ear. 



Fractures by Contrecoup or Counter Stroke. Fractures by counter 

 stroke are now regarded as of much less frequent occurrence than formerly. Charles 

 Phelps found in 147 cases of fracture of the base of the skull 12 which had not 

 extended from the vault. In these, the force had been applied to the parietal region 

 in six, and in five to he occiput; most of the resulting fractures were in the region 



Orbital plate of frontal 



Anterior cerebral fos 



Middle cerebral fossa 



Posterior cerebral fossa 



Cribriform plate of ethmoid 



Lesser wing of sphenoid 

 Optic foramen 

 Anterior clinold process 

 Greater win;.; of sphenoid 



Sella turcica 



Post, clinoid process 



Foramen ovale 



Foramen spinosum 



Body of sphenoid 



Petrous portion of temi>oral 



Body of occipital 



Internal auditory meatus 



Jugular or post, lacerated 

 foramen 



Sigmoid sinus 



Torcular 1 ierophili 



FIG. 22. Interior view of the base of the skull, showing the parts most liable to be involved in fractures. 



of the orbit. Only two of the twelve cases were serious fractures, the remaining ten 

 being slight fissures, which produced no symptoms. 



Hemorrhage in Fractures of the Skull. Hemorrhage is a frequent and most 

 valuable symptom in diagnosing the existence of fracture and in determining its location. 



Fracture through the anterior cerebral fossa may open the frontal, ethmoidal, or 

 sphenoidal cells and cause bleeding from the nose and mouth. 



A fracture through the roof of the orbit causes bleeding into the orbital cavity ; the 

 blood works its way forward and makes its appearance under the conjunctiva of the 

 ball of the eye. Its progress forward toward the lids is blocked by the orbitotarsal 

 ligaments, and it therefore works its way downward to the bulbar conjunctiva, under 

 which it advances to the edge of the cornea. The ordinary ecchymosis of the lids and 

 cellular tissue around the eye is usually due to a rupture of the vessels of the subcuta- 

 neous tissue by a blow from the outside, and not to a fracture of the base of the skull. 



