THE BONES OF THE HEAD 129 



squamosal suture. The squamo-mastoid suture is a harmonic 

 suture, and ankylosis usually takes place in the course of the first 

 year of hfe. The suture, however, may persist until puberty, or 

 even throughout life. Even though ankylosis takes place at the 

 normal period of life, it may occiu" in such an imperfect manner 

 that the suture is drilled by several channels. Under these circum- 

 stances, pus may find an exit from the t^-mpanic cavity to the 

 exterior. 



The petro-sphenoidal suture connects a portion of the anterior 

 border of the petrous part of the temporal bone with the outer 

 portion of the posterior border of the great wing of the sphenoid. 

 It lies obliquely, its direction being inwards and forwards. 



The petro-basilar suture connects the inner half of the posterior 

 border of the petrous portion of the temporal bone with the lateral 

 border of the basilar portion of the occipital bone. Its direction is 

 forvvards and sHghtly inwards, and it is a harmonic suture. Su- 

 periorly it is grooved for the inferior petrosal venous sinus. 



Orbital Sutures. — The orbito-spheno-frontal suture connects the 

 anterior border of the small wing of the sphenoid with the posterior 

 border of the orbital plate of the frontal. It Ues transversely at 

 the back part of the roof of the orbit, and is finely serrated. 



The orbito-malo-maxUlary suture connects the lower part of the 

 posterior border of the orbital plate of the malar with the postero- 

 internal boundary of the rough superior surface of the malar process 

 of the superior maxilla. It is situated on the outer part of the 

 floor of the orbit, and extends forwards and inwards from the 

 anterior end of the spheno-maxillarj' fissure to the infra-orbital 

 margin at a point above, and slightly internal to, the infra-orbital 

 foramen. It is a hmbous suture, the orbital plate of the malar 

 slightly overlapping the contiguous part of the superior maxilla. 



The orbito-palato-maxillary suture connects the orbital process of 

 the palate bone with the back part of the internal border of the 

 orbital plate of the superior maxilla. It is situated on the pos- 

 terior part of the floor of the orbit. Its direction is antero-posterior, 

 and it is a harmonic suture. 



The orbito-palato-ethmoidal suture connects the orbital process 

 of the palate bone with the back part of the inferior border of the 

 OS planum, or orbital plate, of the ethmoid. It hes on the back 

 part of the inner wall of the orbit, where that wall meets the floor. 

 Its direction is antero-posterior, and it is a harmonic suture. 



The spheno-malar suture connects the anterior border or malar 

 crest of the great wing of the sphenoid with the upper part of the 

 posterior border of the orbital plate of the malar. It is situated 

 towards the front part of the outer wall of the orbit. Its direction 

 is vertical, and it is a limbous suture, the orbital plate of the malar 

 sUghtly overlapping the malar crest of the sphenoid. 



The fronto-malar suture connects the external angular process of 

 the frontal bone and the short serrated border directly behind that 

 process with the superior or frontal process of the malar and the 



9 



