Biomedical Engineering Reference
In-Depth Information
knee to the ankle. The upper end of the tibia has two articulating
facets into which the condyles of the femur fit to form the knee joint.
The lower end of the tibia articulates with one of the tarsals to form
the ankle joint. The fibula is smaller than the tibia and is situated
on the outside and slightly behind it. The upper end articulates with
the tibia but does not form part of the knee joint. The lower end
forms part of the ankle joint. Regarding the ankle, there are seven
short, thick tarsal bones, the largest of which is the heel bone (cal-
caneum), which presses firmly onto the ground when one stands,
walks, or runs. The arch is formed partly by some of the tarsals but
mainly by the five long metatarsals, which extend from the tarsals to
the toes. The arch of the foot is modified for receiving the weight of
the body. There are 14 short phalanges in the toes of each foot. The
big toe has two phalanges and the other toes have three each. There
are 60 bones in the lower limb:
• The femur (2) is commonly called the thigh bone. It is the longest,
strongest, and heaviest bone in the body. Distally, it articulates
with the tibia at the knee joint. The head (epiphysis) articulates
with the pelvis at the acetabulum.
• The tibia (2), also known as the shinbone or shankbone, is the
larger and stronger of the two bones in the leg below the knee
in vertebrates and connects the knee with the ankle bones. It is
commonly recognized as the strongest weight-bearing bone in
t h e b o dy.
• The fibula (2) is the slender lateral bone of the leg. It does not
bear weight. The term “peroneal” is synonymous with fibu-
lar and has been used in the past interchangeably. The fibula
articulates with the tibia superiorly and with the talus inferi-
orly and is anchored in between to the tibia by the interosse-
ous membrane. The superior and inferior ends of the bone are
palpable, but muscles cover its middle portion. The inferior end
of the fibula, or the lateral malleolus, is more prominent and
more posterior and extends about 1 cm more distally than the
medial malleolus. It articulates with the tibia and with the lat-
eral surface of the talus; the talus fits between the two malleoli.
Posteromedially, a malleolar fossa gives attachment to liga-
ments. Posteriorly, a groove on the lateral malleolus is occupied
by the peroneal tendons. The classic (Pott's) fracture at the ankle
involves the lower end of the fibula.
• The patella (2) is the kneecap. It is a triangular sesamoid bone
embedded in the tendon of insertion of the quadriceps femoris
muscle. The superior border of the patella is the base of the
triangle, and lateral and medial borders descend to converge at
the apex. The patella can be moved from side to side when the
