THE SINUSES OF THE DURA MATER 687 
glossus, and another in the genio-hyoideus. The vein is at first covered by the 
mylo-hyoideus, perforates that muscle, runs back along the omo-hyoideus in rela- 
tion to the mandibular lymph glands, and joins the external maxillary near the 
posterior border of the jaw. 
The sublingual vein (V. sublingualis) is smaller than the preceding. It re- 
ceives veins from the skin and muscles of the mandibular space, the sublingual 
gland, and the gums. It opens into the external maxillary vein near the lingual or 
joins the latter. 
7. The thyroid vein (V. thyreoidea) is a large vessel which joins the jugular 
near the external maxillary vein. It receives anterior thyroid, laryngeal, and 
pharyngeal radicles, and sometimes a posterior thyroid vein. 
8. Muscular, tracheal, cesophageal, and parotid veins. 
9. The cephalic vein (V. cephalica) enters the jugular near its termination. 
It will be described with the veins of the thoracic limb. 
10. The inferior cervical vein (V. cervicalis ascendens) accompanies the as- 
cending branch of the artery. It may open into the brachial vein. 
THE SINUSES OF THE DuRA MATER 
These (Sinus dur matris) are blood-spaces between the meningeal and peri- 
osteal layers of the dura mater and are lined with endothelium. In many places 
ZL Sa 
i 4 
Fic. 588.—Meptan Section or Heap or Horse, Upper Part wita Serrum Nast REMOVED. 
a, Lateral mass of ethmoid bone; 6, dorsal turbinate; c, ventral turbinate; d, d’, turbinate folds; e, frontal sinus; 
J, falx cerebri; g, tentorium cerebelli; A, medial surface of hemisphere; i, cerebellum; &, occipital bone; &’, occipital 
condyle; k’”, paramastoid process; /, external acoustic meatus; m, temporal condyle; n, temporal canal; J, branches 
of ethmoidal artery; 2, 2’, branches of sphenopalatine artery; 3, 3’, branches of sphenopalatine vein; 4, branches of 
ethmoidal nerve; 5, 5’, branches of sphenopalatine nerve; 6, artery of corpus callosum; 7, dorsal longitudinal sinus; 8, 
straight sinus; 9, vena magna cerebri; 10, ventral longitudinal sinus; 11, 11’, transverse sinuses; 12, dorsal petrosal sinus; 
13, occipital sinus; 14, dorsal cerebral vein; 15, corpus callosum; 16, fornix. (After Ellenberger, in Leisering’s Atlas.) 
the lumen is crossed by fibrous strands. They receive the cerebral veins (Vv. 
cerebri), meningeal veins (Vv. meningez), diploic veins (Vv. diploice), and com- 
municate with veins outside of the cranium; their connections with the latter 
are by means of emissary veins (Emissaria). They convey the blood directly or 
indirectly to the jugular veins. Some are paired, others unpaired. They may be 
divided into dorsal and basilar systems. 
The dorsal system comprises the following: 
The dorsal longitudinal or sagittal sinus (S. sagittalis dorsalis) is situated in 
the convex border of the falx cerebri along the internal parietal crest. It begins 
at the crista galli and ends near the tentorium osseum at the confluence of the 
sinuses (Confluens sinuum) formed by the junction with the straight sinus. It 
receives most of the ascending cerebral veins. Along each side are small pouches 
(Lacunz laterales) into which the veins open. The lumen of the sinus is very 
irregular; it is traversed by fibrous bands and is partially divided by a longitu- 
dinal septum. 
