. Quain's Elements of anatomy. lutions of the brain, and by narrower furrows, branching upwards andbackwards fiom the lower border, for the meningeal vessels. The largest of these 36 THE BONES OF THE HEAD. grooves, running from the anterior inferior angle, is sometimes converted into acanal for a short distance. A slight depression along the inner part of the superiorborder forms, with the one of the opposite side, the groove of the longitudmal smus •and a depression at the posterior inferior angle forms a small part of the grooveof the lateral sinus. Near the upper border there are in most sk
. Quain's Elements of anatomy. lutions of the brain, and by narrower furrows, branching upwards andbackwards fiom the lower border, for the meningeal vessels. The largest of these 36 THE BONES OF THE HEAD. grooves, running from the anterior inferior angle, is sometimes converted into acanal for a short distance. A slight depression along the inner part of the superiorborder forms, with the one of the opposite side, the groove of the longitudmal smus •and a depression at the posterior inferior angle forms a small part of the grooveof the lateral sinus. Near the upper border there are in most skulls, but particularlyin those of old persons, small irregular pits, lodging the Pacchionian bodies. Borders.—YlhQ anterior, superior, and posterior borders are deeply serrated. Theinferior border presents in the greater part of its extent a sharp or squamous edge,with a slightly fluted surface directed outwards, and overlapped at its anteriorextremity by the great wing of the sphenoid, and behind that by the squamous part. ^ONT. Ervi. TEMP. SUBF^ NG. PROC. Fig. 36. —Frontal bone, from before. (Drawn by D. Gunn.) f of the temporal bone ; its posterior part is serrated, and articulates with the mastoidportion of the temporal. The anterior border is slightly overlapped by the frontalbone above, but overlaps the edge of that bone below. Varieties.—The parietal foramen varies greatly ; frequently it is absent on one or botlisides ; in extreme cases it has been seen more than half an inch in diameter. As a rareoccurrence the parietal bone is divided by a suture into an upper and a lower part. In senilebones considerable depressions of the outer surface are sometimes met with, the floor of whichis not thicker than paper; usually on both sides and symmetrical (Humphry, Med. ChirTrans., 1890). THE FRONTAL BONE. The frontal bone, arching upwards and backwards above the orbits, forms thefore part of the cranium ; it likewise presents inferiorly two thin horizontal lamin
Size: 1584px × 1577px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectanatomy
