Drxon— On the Development of the Branches of the Fifth Cranial Nerve in Man. 59 
The main trunk is very short, and passes forwards and a little downwards. 
Unlike the superior maxillary nerve its fibres are not constricted at its origin. 
The main trunk practically at once breaks up into a number of branches. The 
chief of these are—inferior dental with its mylo-hyoid branch, lingual, long 
buccal, and auriculo-temporal. The inferior dental is more a continuation of 
the direction of the main nerve trunk than the other branches are. In addition 
to these branches, which are easily identified, there are other twigs, which pass 
into the developing muscles. One such large branch, arising from the outer side 
of the nerve, and running almost horizontally forwards, ends in branches to 
the muscles, developing on the outer side of Meckel’s cartilage. The other 
muscular twigs pass inwards from the main trunk near its origin, and are shorter 
although numerous. The long buccal nerve is the highest branch of the inferior 
maxillary, and passes forwards, describing a slight curve which is convex upwards. 
The nerve reaches as high as the outer limit of the mouth cleft, where it ends. 
The fibres to form the long buccal nerve come upwards from the inferior 
maxillary nerve, just in front of the point, where the chief part of the motor 
root, crosses outwards over the main nerve. Only the proximal and terminal 
parts of the long buccal are shown in the figure (fig. 16, Plate II.). The length 
of the long buccal is 0°8 mm. 
The outer muscular branch, into which most of the fibres of the motor root can 
be traced, runs horizontally forwards, describing a curve slightly convex outwards. 
This nerve becomes constantly smaller and smaller, its fibres passing into the 
developing muscles. Its length is 0°5 mm. 
The inner muscular branches pass directly inwards from the main trunk. 
They are short and stout, being about 0°25 mm. in length. 
The auriculo-temporal branch (fig. 17, Plate II.) arises immediately beyond the 
nerves just described, and before the inferior maxillary divides into lingual and 
inferior dental. The nerve from its origin passes downwards and forwards, to 
the outer side of Meckel’s cartilage, and ends in two branches, near the front 
of the external auditory depression. The length of the auriculo-temporal is 
0-8 mm. 
The inferior maxillary nerve, having given off the above branches, lies upon 
the upper surface of Meckel’s cartilage just behind its inner turned up end. Here 
it divides into inferior dental and lingual nerves. The inferior dental passes for- 
wards and inwards on the outer side of the high inner end of Meckel’s cartilage, 
the lingual on the other hand passes forwards and inwards, internal to the cartilage. 
Just after the lingual and inferior dental nerves have separated from one another, 
they communicate by a very well marked connecting branch. The inferior dental 
nerve is the longest of the two terminal branches of the inferior maxillary, and 
passes forwards and inwards, at first, close to the outer surface of Meckel’s 
TRANS, ROY. DUB. SOC. N.S. VOL, VI., PART II, K 
