1888. ] 103 [ Stowell. 
tral border several filaments to the M. genio-hyo-glossus (Fig. Ge-hy-gl.); 
these filaments by their interlacing form a terminal plexus. 
N. lingualis.—The hypoglossal nerve follows the artery along its ental 
border and supplies terminal filaments to distal 30 mm. of the tongue 
(fig. Ter.). 
SUMMARY. 
A. ANATOMICAL. 
Ectal Origin—-The nerve arises by 12-16 funiculi along a line 4mm. 
laterad of the ventri-meson, which line marks the dorsal border of the cau- 
dal half of the area elliptica. The origin is nearly surrounded by arteri- 
oles from the A. cerebellosa. 
Foramen of Exit.—-Foramen condylare. 
Principal Rami, their Origins and Distributions. 
1. NV. cervico-hypo-glossus (descendens noni) ; origin at the angle as the 
nerve bends around the A. occipitalis, distribution to the M. omo-hyoideus 
and to the M. sterno-thyroideus. 
2. WN. thyro-hyoideus ; origin immediately peripherad of the last nerve, 
distribution to the M. thyro-hyoideus and to the M. sterno-hyoideus. 
3. IV. stylo-glossus ; arises at a point 15 mm. ventrad of the A. carotidea, 
distribution to the M. stylo-glossus. 
4. WV. hyo-glossus ; origin (2-8 rami) 5-10 mm. peripherad of the last 
nerve, distribution to the M. hyo-glossus ; joins the N. lingualis in a 
plexus. 
5. WV. genio-hyoideus ; origin at the dorsal border of the M. genio-hyoid- 
eus, to which muscle it is distributed. 
6. WV. genio-hyo-glossus ; origin as the nerve trunk bends around the lin- 
gual artery. 
7, NV. lingualis ; terminal filaments to the distal 830 mm. of the tongue. 
Communicating Rami. 
1. To the cervical sympathic ganglion. 
2. To the N. vagus in the plexus gangliformis and in the G. inferius. 
3. A large accession at the angle from the first myelic nerve. 
4, The communicans noni to the N. cervico-hypoglossus. 
5. With the N. lingualis (R. of N. trigeminus) in the terminal plexus. 
B. PrysroLo@roan. 
The N. hypoglossus is the motor nerve of the tongue ; it innerves sev- 
eral muscles which move the os hyoides ; it is directly related to mastica- 
tion and to deglutition ; it is essential to distinct articulation ; in function 
it is possibly a mixed nerve, the sensibility however is referred by some 
physiologists to the accessions from the myelic nerves ; it possesses vaso- 
motor fibres, which are possibly derived from the communicating rami. 
