_a_, Ilio-psoas; _b_, tendon of psoas minor; _c_, sacro-coccygeus
ventralis lateralis; _d_, coccygeus; _e_, pyriformis; _f_, obturator
internus; _g_, origin of retractor ani; _h_, _h′_, sartorius; _i_,
rectus femoris; _k_, vastus internus; _l_, pectineus; _m_, adductor;
_n_, gracilis; _o_, semitendinosus; _p_, semimembranosus; _q_,
gastrocnemius, inner head; _q′_, tendon of gastrocnemius; _r_,
superficial digital flexor; _r′_, tendon of _r_; _s_, tarsal tendon
of biceps femoris; _t_, popliteus; _u_, deep digital flexor, outer
head (flexor hallucis longus); _u′_, long digital flexor; _u″_,
common tendon of u and _u′_; _v_, tendon of tibialis posterior; _w_,
tibialis anterior; _x_, tendon of anterior or long digital extensor;
_1_, pelvic surface of ilium; _2_, section of symphysis pelvis; _3_,
tuber ischii; _4_, internal condyle of femur; _5_, ligamentum
patellæ; _6_, _7_, internal surface of tibia; _8_, tarsus; _8′_,
fibular tarsal bone; _9_, metatarsus. (Ellenberger-Baum, Anat. d.
Hundes.)
]
The =semimembranosus= is large and arises from the ischium only. It
divides into two portions: the anterior portion ends on the tendon of
the pectineus, on the femur above the internal condyle, and on the inner
(Vesalian) sesamoid bone; the posterior portion ends on the internal
condyle of the tibia, the tendon passing under the internal lateral
ligament of the stifle joint.
The =rectus femoris= has only one tendon of origin. The single patellar
ligament acts as the tendon of insertion of the quadriceps.
The =capsularis= is usually present, but is small and pale.
The =sartorius= consists of two portions. It arises from the external
angle and border of the ilium. The anterior portion ends on the patella,
the posterior on the internal surface of the tibia, its tendon blending
with that of the gracilis.
The =graciles= are not so much fused at their origin as in the other
animals.
The =pectineus= is long and slender. It arises from the ilio-pectineal
eminence and ends on the internal branch of the linea aspera above the
distal end of the femur.
There are two distinct =adductors=. The small anterior one ends on the
proximal third of the femur, the posterior one on the distal part of the
femur and on the inner face of the stifle joint.
The =quadratus femoris= is short and strong. The other external rotators
of the thigh present no special features.
The =peroneus tertius= is represented by a tendinous band which arises
on the internal surface of the tibia below the crest. It passes downward
on the inner surface of the tibialis anterior, blends with the annular
ligament above the tarsus, and is attached to the joint capsule and the
proximal end of the third metatarsal bone.
Arloing and Lesbre say: “The third peroneus is a proper extensor of
the fifth digit; it is a very feeble, fleshy band, situated behind the
peroneus brevis, which it partially covers. It is attached to the
upper part of the fibula, and is continued by a long, delicate tendon
which passes in the same malleolar groove with the muscle mentioned;
it then crosses behind the tendon of the peroneus longus and extends
to the phalanges of the outer digit, where it joins one of the
branches of the common extensor.”
The =tibialis anterior= is large and superficial. It arises on the
external condyle and crest of the tibia, and is inserted into the first
metatarsal bone, or into the first tarsal and second metatarsal.
There are four =extensors of the digits=.
1. The =anterior= or =long digital extensor= (M. extensor digitalis
longus) is fusiform, and lies largely under the preceding muscle. It
arises from the extensor fossa of the femur. The tendon is bound down by
two annular ligaments, and divides below the tarsus into four branches,
which end on the distal phalanges of the digits (second to fifth).
2. The =lateral digital extensor= (M. extensor digitalis lateralis) is
feeble and semipennate. It arises on the fibula below the head. The
tendon passes under the lateral ligament of the tarsus and joins the
branch of the tendon of the long extensor for the fifth digit.
3. The =extensor hallucis longus= is a very thin muscle which arises
from the fibula under the long extensor. Its delicate tendon accompanies
that of the tibialis anterior to the first metatarsal bone, or becomes
lost in the fascia.
4. The =extensor digitalis brevis= has three divisions. It arises on the
fibular tarsal bone and the adjacent ligaments. The three tendons are
inserted into the second, third, and fourth digits, blending with the
interossei. (Sometimes there is found a tendon to the rudimentary first
digit, which may represent the extensor hallucis brevis. There may be a
fourth belly for the tendon to the second digit.)
The =peroneus longus= arises on the external condyle of the tibia, the
head of the fibula, and the lateral ligament. The long tendon passes
down the leg parallel to the fibula, crosses the plantar (posterior)
surface of the tarsus transversely, and ends on the first metatarsal
bone. A short branch is detached to the external metatarsal bone.
The =peroneus brevis= is semipennate and arises from the distal half or
more of the outer face of the tibia and the fibula. Its tendon
accompanies that of the lateral extensor over the external malleolus of
the tibia, and ends on the proximal end of the fifth metatarsal bone.