Human Anatomy - Kotsan I. Y. 2009

Skeleton of the Lower Limb
Bones of the Free Lower Limb

The BONES OF THE free lower limb include the Femur, the bones of the leg (crus), and the Bones of the FOOT.

The femur is the largest and longest tubular bone in The Human Body (Fig. 69). It consists of a shaft (corpus) and two extremities: proximal and distal.

At the proximal end is the spherical femoral HEAD (caput ossis femoris). A small depression, the fovea of the head of the femur (fovea capitis femoris), is visible on the head, to which the intra-articular ligament of the femoral head attaches. Downward and outward from the head lies the femoral neck (collum femoris), which transitions into the bone shaft at an angle. In men, this angle is obtuse (about 130°), while in women it is nearly a right angle. At the junction between the neck and the shaft are two prominences: the greater trochanter (trochanter major), directed upward and laterally, and the lesser trochanter (trochanter minor), located lower and directed backward and medially. On the Medial surface of the greater trochanter, directly at its base, is the trochanteric fossa (fossa trochanterica). Anteriorly, the intertrochanteric line (linea intertrochanterica) runs between the two trochanters, and posteriorly lies the intertrochanteric crest (crista intertrochanterica).

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Fig. 69. Femur, right

a — anterior view: 1 — fovea of the head of the femur, 2 — neck of the femur, 3 — medial epicondyle, 4 — patellar surface, 5 — lateral epicondyle, 6 — intertrochanteric line, b — posterior view: 1 — head of the femur, 2 — greater trochanter, 3 — trochanteric fossa, 4 — intertrochanteric crest, 5 — gluteal tuberosity, 6 — linea aspera, 7 — medial lip, 8 — lateral lip, 9 — popliteal surface, 10 — lateral condyle, 11 — intercondylar fossa, 12 — medial condyle, 13 — lesser trochanter

The shaft of the femur (corpus ossis femoris) is nearly cylindrical in shape, slightly curved with a forward convexity, and appears twisted along its longitudinal axis. The surface of the shaft is smooth anteriorly and laterally. On the posterior surface, the linea aspera runs longitudinally, featuring two Lips: lateral and medial (labium laterale et labium mediale). At the midpoint of the femur, these lips lie closely apposed to one another, while diverging superiorly and inferiorly. The upper ends of the lips extend toward the greater and lesser trochanters. The lateral lip expands and thickens significantly superiorly, forming the gluteal tuberosity (tuberositas glutealis), to which the gluteus maximus Muscle attaches. If the gluteal tuberosity is well-developed, the largest bony prominence at this site is designated as the third trochanter (trochanter tertius). The medial lip continues superiorly into the pectineal line (linea pectinea), which reaches the lesser trochanter. The lower ends of the lips gradually diverge, bounding the smooth, triangular popliteal surface (facies poplitea). The pronounced Development of the linea aspera is one of the important distinctive Features of the human femur, driven by the adaptation to bipedalism.

The distal end of the femur is thickened and slightly flattened in the anteroposterior direction. It features two massive condyles: medial and lateral (condylus medialis et condylus lateralis). Both condyles possess articular surfaces that serve for articulation with the Tibia. Anteriorly, the articular surfaces of the condyles merge, forming the concave patellar surface (facies patellaris), against which the posterior side of the Patella rests. On the outer surface of the lateral condyle and the inner surface of the medial condyle are the lateral and medial epicondyles (epicondylus lateralis et epicondylus medialis), respectively, which serve as attachment sites for Muscles and ligaments. Above the medial epicondyle, the site of attachment of the adductor magnus muscle — the adductor tubercle (tuberculum adductorium) — is visible. On the posterior surface of the femur, between the condyles, lies the deep intercondylar fossa (fossa intercondylaris). Superior to the intercondylar fossa runs the intercondylar line (linea intercondylaris), which separates the intercondylar fossa from the popliteal surface.

The condyles and epicondyles of the femur are readily palpable beneath the Skin in a living person, especially when the leg is flexed at the knee joint.

To distinguish the right femur from the left, one should remember that its head is directed upward and medially; the greater trochanter points upward, laterally, and slightly backward; and the medial condyle is larger than the lateral.

The femur is exceptionally strong. Under compression, it can withstand loads exceeding 1,500 kg.

Fig. 70. Patella (right)

A — anterior view: 1 — Base of the patella, 2 — apex of the patella, 3 — anterior surface, B — posterior view: 1 — base of the patella, 2 — articular surface, 3 — apex of the patella.

Anterior to the distal end of the femur lies the patella or kneecap (patella) (Fig. 70). It is the largest sesamoid bone in the Skeleton. It is embedded within the tendon of the quadriceps femoris muscle, is easily palpable through the skin, and when the knee is extended, it easily shifts sideways as well as upward and downward. In shape, the patella resembles a biconvex lens. One distinguishes the base of the patella (basis patellae), which is directed upward, and the apex of the patella (apex patellae), directed downward. The anterior surface of the patella is rough, whereas the posterior surface is smooth and features an articular surface (facies articularis) for articulation with the femur. The posterior surface also bears a vertical articular crest (crista patellae), which divides it into a lateral (larger) and a medial (smaller) facet. This feature allows one to distinguish between right and left patellar specimens.