Human Anatomy Part 1 - K. A. Diubenko, A. K. Kolomiitsev, Yu. B. Chaikovsky 2002

Special Part
Myology, myologia [the study of muscles] - Muscles and fascia of the lower limb
Fascia of the lower limb

The following fasciae are distinguished in the lower extremity: the gluteal fascia, iliac fascia, fascia lata, crural fascia, and pedal fasciae.

1. The gluteal fascia, fascia glutea (BNA), is a continuation of the fascia thoracolumbalis; it originates from the sacrum and the outer lip of the iliac crest (labium externum cristae iliacae), covers the gluteal Muscle group, extends inferiorly, and continues into the fascia lata of the thigh.

2. The iliac fascia, fascia iliaca, is the FASCIA OF THE internal pelvic surface; it originates on the inner surface of the inner lip of the iliac crest (labium internum cristae iliacae) from the lateral surface of the bodies of the lumbar vertebrae, covering the iliacus, psoas major, and psoas minor Muscles. Upon reaching the inguinal ligament, the fascia fuses with it; medially, it separates from the ligament and extends onto the pectineus muscle while covering the iliopsoas muscle. Fascicles originating from the Inferior surface of the inguinal ligament are termed the iliopectineal arch (arcus iliopectineus) and reach the iliopectineal eminence (eminentia iliopectinea). Consequently, two lacunae are formed beneath the inguinal ligament: the muscular lacuna (lacuna musculorum), through which pass the iliopsoas muscle and the femoral nerve, and the vascular lacuna (lacuna vasorum), transmitting the femoral artery and femoral vein (see Fig. 189).

3. The fascia lata (fascia lata) surrounds the Muscles of the thigh; anteriorly, it fuses with the inguinal ligament, posteriorly with the gluteal fascia, and inferiorly it continues into the crural fascia. On the lateral aspect of the thigh, the fascia forms the iliotibial tract (tractus iliotibialis), which extends from the region of the anterior superior iliac spine (spina iliaca anterior superior) down to the lateral condyle of the Tibia. Slightly inferior to the inguinal ligament, the fascia splits into two layers: deep and superficial. The deep layer covers the femoral nerve and passes posterior to the femoral vessels, whereas the superficial layer passes anterior and lateral to the femoral vessels. It terminates in a free falciform margin (margo falciformis) that bounds the saphenous opening (hiatus saphenus s. fossa ovalis, BNA). The superior region of the falciform margin—the superior horn (cornu superius)—attaches to the inguinal ligament, turns underneath it, and fuses with the lacunar ligament; the inferior region—the inferior horn (cornu inferius)—fuses with the Deep Layer of the fascia lata. The great saphena vein (v. saphena magna) arches over it to empty into the femoral vein. The saphenous opening is covered by the cribriform fascia (fascia cribrosa), which adheres to the falciform margin. The oval fossa corresponds to the outer ring of the femoral canal. From the fascia lata, the lateral intermuscular septum of the thigh (septum intermusculare femoris laterale) extends deeply, attaching along the lateral lip of the linea aspera (labium laterale lineae asperae) and separating the vastus lateralis from the Posterior Thigh Muscles. The medial intermuscular septum of the thigh (septum intermusculare femoris mediale) attaches to the medial lip of the linea aspera and separates the medial and anterior muscle groups of the thigh.

4. The crural fascia (fascia cruris) is a continuation of the fascia lata; it sends two intermuscular septa deep into the leg. The anterior intermuscular septum of the leg (septum intermusculare anterius cruris) separates the anterior muscle group from the lateral group, while the posterior intermuscular septum of the leg (septum intermusculare posterius cruris) runs between the lateral and posterior muscle groups. On the anterior surface of the leg, fibers are woven into the fascia in the form of a transverse band. Stretching over the extensor tendons at the level of the malleolar base between the BONES OF THE leg, this ligament is termed the superior extensor retinaculum (retinaculum musculorum extensorum superius) (Fig. 187). Slightly distal to this, on the anterior aspect of the ankle joint, lies the inferior extensor retinaculum (retinaculum musculorum extensorum inferius), which features lateral and medial bands. In places, this ligament divides into deep and superficial layers that encircle the extensor tendons to form four fibrous canals (see Fig. 187): the lateral canal transmits the tendons of the extensor digitorum longus and fibularis (peroneus) tertius muscles; the second transmits the tendon of the extensor hallucis longus; and the third transmits the tendon of the tibialis anterior. The tendons passing through these canals are enclosed by synovial sheaths. The fourth canal contains the dorsal artery and vein of the FOOT and the deep fibular nerve.

Thickening of the fascia on the medial side of the leg in the region of the medial malleolus forms the flexor retinaculum (retinaculum musculorum flexorum) (Fig. 188A), which spans across the tendons of the tibialis posterior, flexor digitorum longus, and flexor hallucis longus muscles, forming three osteofibrous canals for them, as well as one fibrous canal for the posterior tibial artery and tibial nerve. These tendons are enclosed within three synovial sheaths (see Fig. 188A).

Posterior to the lateral malleolus lies the superior fibular (peroneal) retinaculum (retinaculum musculorum peroneorum fibularium superius), which overlies the tendons of the fibularis (peroneus) longus and brevis muscles enclosed within a single osteofibrous canal. Subsequently, these tendons pass through two separate canals beneath the inferior fibular (peroneal) retinaculum (retinaculum musculorum peroneorum inferius). The fibular tendons are contained within two independent synovial sheaths (Fig. 188B) in the region beneath the inferior fibular retinaculum.

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Fig. 187. Extensor retinacula and synovial sheaths of the dorsal surface of the foot (after R. D. Sinelnikov)

5. The pedal fasciae (fasciae pedis) are a continuation of the crural fascia. The dorsal fascia of the foot (fascia dorsalis pedis), in the area of the muscles, divides into two layers that form compartments for the SUPERFICIAL MUSCLES OF the dorsal foot, with the deep layer separating the interosseous muscles from the toe extensors. On the plantar surface, the superficial fascia is thicker and, in the central region, consists of fibrous fascicles forming a fibrous plate known as the plantar aponeurosis (aponeurosis plantaris). The deep fascia of the sole fuses with the surfaces of the Metatarsal Bones, forming—together with the dorsal interosseous fascia of the foot—four intermetatarsal spaces that lodge the interosseous muscles.

Fig. 188. Synovial sheaths of the foot (after R. D. Sinelnikov):

A - medial surface