32 
PRIMROSE : THE ANATOMY OF THE ORANG OUTANG 
the forearm between^ its two heads, the deep head separating the nerve 
from the ulnar artery. It was inserted into the radial border of the 
radius by an insertion 2 cm. wide immediately below the upper third of 
the bone. The high insertion of the pronator radii teres corresponds to 
that found by Langer^ in his Orang. This, he points out, differs from 
the condition found in man, where the muscle in question is inserted 
below the middle of the bone. It also implies a shorter extent of 
attachment of the supinator brevis, which is attached above the pronator 
This circumstance led Langer to assert that it is only the lower part of 
the radius which is so enormously elongated in the Orang compared 
with the condition found in man. Langer’s Orang was young, but in 
the adult animal dissected by Fick^ he found the position of the inser- 
tion of the pronator similar to that occurring in man ; he therefore con- 
cludes that either the high insertion is characteristic of the young 
Orang thus differing from the old animal, or that Langer’s case was 
abnormal — my specimen would go to prove the truth of the former 
hypothesis. In Bischofif’s Gorilla the coronoid head of the muscle was 
absent, but Macalister^ found it in his specimen. Chapman^ found 
both heads in the Orang. The coronoid head is frequently absent in 
man (Testut). 
The Flexor carpi radialis arose from the common origin of the flexors 
from the internal condyle and the intermuscular septum, also from an 
oblique line on the outer border of the radius in common with the flexor 
sublimis digitorum ; it was inserted into the base of the second metacarpal 
bone, after passing through the groove in the trapezium. Fick and 
Langer both describe a radial origin in the Orang. The radial head 
occurs as an occasional variation in man. 
The Palmaris longus arose in common with the other flexors from the 
internal condyle and from the fascia over it. It lay immediately sub- 
jacent to the fascia of the forearm until it reached a point 3 cm. above 
the wrist joint, where it perforated the fascia and continued down upon 
its superficial aspect. Crossing the anterior annular ligament it proceeded 
to its insertion into the palmar fascia. There is a very definite slip to 
the base of the thumb, and from this the abductor pollicis arises in part. 
In both Orangs dissected by Fick there was a slip to the abductor 
pollicis and he describes, in addition, another slip to the flexor minimi 
digiti. Bischoff states that the palmaris longus was absent in the 
1 Loc. cit., p. 179. 
2 Loc. cit. I, p. 22. 
3 Loc. cit., p. 502. 
4 Loc. cit., p. 162. \ 
