MUSCLES OF THE PELVIC LIMBS. 215 
The interossei of the third and fourth digits are alike. 
Origin from the ventral surface of the base of the metatar- 
sal. The muscles cover the ventral surface of the shaft. At 
the head each divides and passes onto the sides of the 
metatarsal. 
Jnsertion.—Each half of the muscle shows a tendency to 
divide into two parts. One of these, the more superficial and 
ventral, ends in a tendon which joins the extensor tendon near 
the distal end of the first phalanx. The other part is inserted 
by short tendon- and muscle-fibres into the side of the base of 
the first phalanx; one of the parts is therefore a middle, and the 
other a long, adductor or abductor, the adductores and abduc- 
tores digiti tertii and quarti. 
The fifth digit has five short muscles. 
M. abductor medius digiti quinti. 
Origin from the ventral surface of the calcaneus and from 
the fifth metatarsal. 
Jusertion by a slender tendon into the lateral side of the 
base of the first phalanx of the fifth digit. 
M. adductor medius digiti quinti. 
Origin with the adductor medius digiti secundi. 
/nsertion on the inner side of the base of the phalanx of the 
fifth digit. 
M. opponens digiti quinti. 
Origin by a flat tendon from the middle of the ligament 
which covers the peroneal canal. It passes obliquely outward 
parallel to the last. 
Jusertion on the inner side of the shaft of the fifth metatar- 
sal. 
The two remaining muscles of the fifth digit take origzz 
from the outer part of the ligament covering the peroneal canal. 
They cover the ventral surface of the shaft. 
Jnsertion.—The lateral one is inserted into the lateral sesa- 
moid and is therefore an abductor brevis. The medial one is 
inserted into the extensor tendon and is therefore an adductor 
longus. 
C. MUSCLES OF THE TARSUS.—M. calcaneometatarsalis 
(part of M. adductor minimi digiti ?).—A weak muscle made up 
