(iii) The muscles of the foot have the same insertions as corre- 
sponding musles in the hand, and the extensor brevis is also inserted 
into the dorsal expansion on the second, third, and fourth toes. 
(iv) The interossei and lumbricals flex the 1st and extend the 
2nd and 3rd phalanges, whilst the common extensor extends all. 
My own dissections have been performed on 32 hands in the 
dissecting-room of the Anatomical Department in the University of 
Manchester. 
At the beginning of the investigation I completely dissected seven 
hands, to become acquainted with the different types of disposition, 
if any, which occur among these muscular insertions. The other 
hands were completely dissected, but in all, the whole of the muscular 
insertions at present under consideration, was completely worked out. 
To assist in the interpretation of results, I have also investigated the 
condition of these tendons in specimens of the following animals: 
Papio Anubis. 
Papio Cynocephalus. 
Papio Sphinx, 
For the investigation of the similar muscles of the foot, I have 
used the same 32 subjects in the manner already stated in the case 
of the hand. The specimens of baboon were also utilised as before. 
I intend in this paper to treat first the muscles of the hand, 
and then to compare with these, the corresponding muscles of the foot. 
Before actually beginning the account of the muscular insertions 
and actions, it is necessary that I should give my views on the so- 
called ‘dorsal expansion of the extensor tendon’. PoıkıEr (2) regards 
it as a fascial sheet originating on both sides of each finger, from 
the lumbrical and interosseous tendons, and composed of three layers, 
the most superficial of which passes over the extensor tendon to 
which it has but little connection, whilst the second and third layers 
pass under the tendon, and are more firmly attached to it. My own 
work has led me to consider this ‘expansion’ as an aponeurotie sheet 
dividing to enclose the several tendons which pass to the dorsum of the 
fingers, but not deriving its fibres from any of these. Its fibres are 
mainly transverse in direction in contra-distinction to the longitudinal 
fibres of the tendons which it encloses. The few fibres in its con- 
stitution which are of a longitudinal character are not continuous 
with those of the tendons enclosed. It acts as a kind of sheath 
