The =iliac fascia= (Fascia iliaca) covers the ventral surface of the
iliacus and psoas muscles, over which it is tightly stretched (Fig.
450). It is attached internally to the tendon of the psoas minor,
externally to the inguinal (Poupart’s) ligament and the external angle
of the ilium. Its anterior part is thin. Posteriorly, it is in part
attached to the ilium, in part becomes continuous with the pelvic
fascia. It furnishes surfaces of origin for the sartorius, cremaster
externus, and transversus abdominis muscles.
The =pelvic fascia= (Fascia pelvis) lines the cavity (parietal layer)
and is reflected on the viscera at the pelvic outlet (visceral layer).
Laminæ are detached from it to strengthen the various peritoneal folds.
The =superficial fascia= of the =gluteal region= is continuous with the
aponeurosis of the panniculus. It covers and partly blends with the deep
fascia. The =gluteal fascia= (Fascia glutea) covers the superficial
muscles of the region, and detaches intermuscular septa, which pass
between the muscles. It is attached to the sacral spines, the dorsal
sacro-iliac ligament, and the angles of the ilium, and is continuous in
front with the lumbo-dorsal fascia, behind with the coccygeal fascia.
Its deep face gives origin to fibers of the superficial and middle
glutei, the biceps femoris, and the semitendinosus, so that care is
necessary in dissecting it off these muscles. The chief =intermuscular
septa= are: (1) One which passes between the superficial gluteus and the
biceps femoris; (2) one between the biceps and semitendinosus, from
which a lamella is detached which passes between the middle and
posterior portions of the biceps and is attached to the tuber ischii;
(3) one between the semitendinosus and semimembranosus, which is
attached to the sacro-sciatic ligament and tuber ischii; it furnishes
origin for fibers of the long head of the semimembranosus.
The =fascia lata= is continuous with the preceding, and covers the
muscles on the outer surface and front of the thigh. It is tendinous and
very strong, and for the most part easily separable from the underlying
muscles. It furnishes insertion to the tensor fasciæ latæ and to the
biceps femoris (in part), by both of which it is tensed. At the stifle
it is attached to the patella and the inner and outer straight
ligaments. Internally it is continuous with the internal femoral fascia.
It furnishes the following =intermuscular septa=: (1) One which passes
between the vastus externus and biceps femoris to be attached to the
external trochanter of the femur; (2) two which pass between the three
branches of the biceps femoris; (3) a fourth between the biceps femoris
and semitendinosus.
The =internal femoral fascia= (Fascia femoralis medialis) covers the
superficial muscles on the inner surface of the thigh. At its upper part
it is joined by part of the aponeurosis of the external oblique muscle
(Lamina femoralis) (Fig. 450). The posterior part is thin. It is
continuous with the fascia lata in front and the crural fascia below. At
the stifle it fuses with the tendons of the sartorius and gracilis.
The =crural fascia=, or fascia of the leg (Fascia cruris), consists of
three layers. Two of these invest the entire region and may, therefore,
be termed the =common fasciæ=. The superficial layer is a continuation
of the fasciæ of the thigh, while the second layer may be regarded
chiefly as a continuation of the tendons of the superficial muscles of
the hip and thigh (biceps femoris, semitendinosus, tensor fasciæ latæ,
sartorius, and gracilis). The two layers frequently fuse, and are
attached chiefly to the patellar ligaments and the crest and internal
surface of the tibia. About the middle of the leg the two layers unite
behind the deep flexor of the digit and form a strong band which passes
downward in front of the tendons of the gastrocnemius and superficial
flexor, to be attached with the latter to the anterior and inner part of
the tuber calcis. This may be regarded as an accessory or tarsal tendon
of insertion of the biceps femoris and semitendinosus. The third layer
forms sheaths for the muscles, furnishing origin in part to their
fibers. Two important =intermuscular septa= are detached, viz.: (1) One
which passes between the anterior and lateral digital extensors to be
attached to the fibula and the external border of the tibia; (2) one
between the lateral extensor and the deep flexor.
The =tarsal fascia= (Fascia tarsi) fuses with the ligaments and bony
prominences of the region. It is strong and tendinous in front, and
joins the tendon of the anterior extensor below the joint. Laterally, it
is thin and fuses with the ligaments. Posteriorly, it is very thick and
strong, forming an annular ligament which stretches from the internal
lateral ligament to the fibular tarsal bone and the plantar ligament.
This converts the groove at the back of the hock into a canal, in which
are the deep flexor tendon with its synovial sheath and the plantar
nerves. In front of the tarsus and above and below it there are three
=annular ligaments= (Ligamenta transversa). The proximal one binds down
the tendons of the anterior extensor, peroneus tertius, and tibialis
anterior on the distal end of the tibia. The middle one stretches from
the fibular tarsal bone to the outer tendon of the peroneus tertius,
forming a loop around the tendon of the anterior extensor. The distal
band stretches across the proximal extremity of the large metatarsal
bone and incloses the tendons (and sheaths) of the two extensors of the
digit.
The =metatarsal= and =digital fasciæ= do not differ materially from
those of the corresponding regions of the thoracic limb.