94 TRANSACTIONS OF THE [JAN. 9, 
3. Musculus ulni-metacarpalis dorsalis.—A short muscle, 
originating on the ulna and inserted at the carpal end of the 
third metacarpal. Helps to flex the hand. 
4. Hxtensor metacarpi radialis.—Originates on the upper 
outer condyle of the humerus, and is inserted on the first meta- 
carpal. Helps to extend the hand. 
5. Extensor metacarpi ulnaris.—It has nearly the same origin 
as the last; is inserted on the second and third metacarpals, and 
draws the hand down towards the forearm. 
6. Flexor digitorum sublimis.—Originates at the internal con- 
dyle of the humerus, and is inserted on the digits, which it helps 
to flex. 
%. Flexor digitorum profundus.—Originates on the inner face 
of the upper third of the ulna, and is inserted into the second 
or terminal phalange of the long finger, which it helps to ex- 
tend. 
8. Haxtensor digitorum communis.—Originates on the head of 
the humerus, and is inserted on the basal phalanges of the 
first and second digits. It draws the first finger against the 
second, and also helps to extend the second finger. 
9. Hxtensor pollicis longus.—Runs from the inner edges of 
the upper third of both ulna and radius, and acts on the so- 
called thumb. 
10. Hatensor indicis longus.—Runs from the middle of the 
radius to both the first and second phalanges of the third finger, 
both of which it extends, and at the same time opens the six 
outer primaries, independently of the extension of the meta- 
carpus. 
We come now to the muscles situated wholly within the 
hand, eight in number. The new muscle claimed by Prof. 
Trowbridge is situated, if I am not mistaken, in the hand, and 
occupies the space between the metacarpal bones, which space 
it quite fills. I clearly understood this to be the muscle in 
question, and if so we may be able to identify it. Continuing 
with the enumeration: 
11. Musculus interosseus dorsalis. A small muscle attached 
to the inner side of both the second and third metacarpals. It 
extends the phalanges of the third finger. 
12. Abductor indicis.—Runs from the outside of the second 
metacarpal to the base of the first phalange of the second digit, 
helping to extend it. 
13. Flexor pollicis.—Originates on the upper part of the 
second metacarpal, and runs to the base of the thumb. 
14. Abductor pollicis Another thumb-muscle, to the move- 
ment of which its function is strictly related. 
15. Musculus interosseus palmaris.—Originates along the 
