. Journal of anatomy. shape. Along each side of the post-sphenoid area the bone is formedfrom the lingulal centres. Each lingulal centre leads to the formation ofVOL. LI. (third SER. VOL. XII.)—JAN. 1917. 9 128 Dr V. Zachary Cope a triangular portion of bone with a small base posteriorly (correspondingto groove for the internal carotid artery) and a thin tapering portion whichends in an acute angle opposite the posterior end of the pre-sphenoid. Themajor part of the lateral aspect of the pre-sphenoid is in contact with thebone formed from the great wing of the sphenoid. The lingulal areaunites
. Journal of anatomy. shape. Along each side of the post-sphenoid area the bone is formedfrom the lingulal centres. Each lingulal centre leads to the formation ofVOL. LI. (third SER. VOL. XII.)—JAN. 1917. 9 128 Dr V. Zachary Cope a triangular portion of bone with a small base posteriorly (correspondingto groove for the internal carotid artery) and a thin tapering portion whichends in an acute angle opposite the posterior end of the pre-sphenoid. Themajor part of the lateral aspect of the pre-sphenoid is in contact with thebone formed from the great wing of the sphenoid. The lingulal areaunites with the body of the sphenoid before birth, but the fusion takesplace from above downwards, and for some little time after birth indica-tions of the groove between body and lingula can be seen (see fig. 2). Thelingula unites with the great wing at a later date after birth. The sphenoidal sinus is developed primarily at the expense of thatportion of the bone formed from the pre-sphenoidal nucleus. During iphenol of. pal sphenoid Fig. 2.—Under surface of sphenoid at birth (alisplienoidnot present), to show incomplete fusion betweenlingulw and body centres. childhood this area becomes almost completely hollowed out, but an antero-posterior septum remains between the two sinuses, and the burrowingair-cavity still respects the boundaries of the areas developed from thenuclei of the post-sphenoid, the lingula, and the great wing. This conditionmay persist until adult life, but as a rule some time between puberty andadult age the sinus extends backwards or sideways or in both there is evidence to show that the bone formed at the line of fusionof two bony centres may be, and often is, of a denser and more resistantnature than the tissue on either side of that line. This fact would accountfor the restriction of the sinus to the pre-sphenoid during childhood, andwould offer an explanation for the frequent incomplete destruction of someof these by the
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectanatomy, bookyear1867
