Fundamentals of Anatomy and Physiology

The Skeletal System

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Figure 7- 23 (C) Femur. (Continued)
of the erect body. Rather it has a unique engineering de-
sign that allows it to bear and distribute the weight of the
body. It is positioned at an angle, slanting downward and
inward so that the two femurs appear as a large let-ter V
(Figure 7-6). Its upper extremity bears a large head that fits
into the acetabulum of the pelvic bone, with an anatomic
neck. Its lower portion is widened into a large

167

lateral condyle and an even larger medial condyle. It ar-

ticulates distally with the tibia.

The patella (pah-TELL-ah), or kneecap, is the larg-

est of the sesamoid bones. It is somewhat flat and tri-

angular, lying right in front of the knee joint, and is

enveloped within the tendon of the quadriceps femoris

muscle. Its only articulation is with the femur. It is a mov-

able bone, and it increases the leverage of the muscles that

straighten out the knee.

The tibia (TIB-ee-ah) is the larger of the two bones

forming the lower leg (Figure 7-24). It is also known as the

shinbone. The rounded condyles of the femur rest on the

flat condyle at the proximal end of the tibia.

The fibula (FIB-you-lah) is also known as the calf-

bone. In proportion to its length, it is the most slender bone

of the body. It lies parallel with and on the lateral side of

the tibia. It does not articulate with the femur but attaches

to the proximal end of the tibia via its head.

The bones of the ankle are known as the tarsal bones

(Figure 7-25). The seven short tarsal bones resemble the carpal

bones of the wrist but are larger. They are ar-ranged in the

hindfoot and forefoot. The tarsal bones of

Lateral Tibial tuberosity^

condyle Medial condyle

Head

Tibia^
Fibula

Medial
Lateral^ malleolus^
malleolus
(A) (B)

Figure 7- 24 The tibia and fibula. (A) Anterior view. (B) Posterior
view.

Lateral

condyle

Fibula

Lateral

malleolus

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