Chapter 7
The Skeleton
241
7
twisted a quarter turn. Te fibula does not bear weight, but sev-
eral muscles originate from it.
Homeostatic Imbalance
7.7
A
Pott’s fracture
occurs at the distal end of the fibula, the tibia, or
both. It is a common sports injury. (See Figure 7.33e.)
Check Your Understanding
31.
What lower limb bone is the second largest bone in the body?
32.
Where is the medial malleolus located?
33.
Which of the following sites is not a site of muscle
attachment? Greater trochanter, lesser trochanter, gluteal
tuberosity, lateral condyle.
For answers, see Appendix H.
Foot
Te skeleton of the foot includes the bones of the
tarsus
,
the bones of the
metatarsus
, and the
phalanges
, or toe bones
(Figure 7.34)
. Te foot has two important functions: It sup-
ports our body weight, and it acts as a lever to propel the body
forward when we walk and run. A single bone could serve both
purposes, but it would adapt poorly to uneven ground. Segmen-
tation makes the foot pliable, avoiding this problem.
like two huge checkers lying side by side. Tese are separated
by an irregular projection, the
intercondylar eminence
. Te
tibial condyles articulate with the corresponding condyles
of the femur. Te inferior region of the lateral tibial condyle
bears a facet that indicates the site of the
superior tibiofibular
joint
. Just inferior to the condyles, the tibia’s anterior surface
displays the rough
tibial tuberosity
, to which the patellar liga-
ment attaches.
Te tibial sha± is triangular in cross section. Neither the
tibia’s sharp
anterior border
nor its medial surface is covered
by muscles, so they can be felt just deep to the skin along their
entire length. Te anguish of a “bumped” shin is an experience
familiar to nearly everyone. Distally the tibia is flat where it
articulates with the talus bone of the foot. Medial to that joint
surface is an inferior projection, the
medial malleolus
(mah-
le
9
o-lus; “little hammer”), which forms the medial bulge of
the ankle. Te
fibular notch
, on the lateral surface of the tibia,
participates in the
inferior tibiofibular joint
.
Fibula
Te
fibula
(fib
9
u-lah; “pin”) is a sticklike bone with slightly ex-
panded ends. It articulates proximally and distally with the lat-
eral aspects of the tibia. Its proximal end is its
head
; its distal
end is the
lateral malleolus
. Te lateral malleolus forms the
conspicuous lateral ankle bulge and articulates with the talus.
Te fibular sha± is heavily ridged and appears to have been
Medial
cuneiform
Phalanges
Metatarsals
Tarsals
Navicular
Intermediate
cuneiform
Talus
Calcaneus
(a) Superior view
Cuboid
Lateral
cuneiform
Proximal
Middle
Distal
Trochlea
of talus
Medial
malleolar
facet
Calcaneal
tuberosity
(b) Medial view
Intermediate
cuneiform
Sustentac-
ulum tali
(talar shelf)
Talus
Navicular
First metatarsal
Medial
cuneiform
Calcaneus
(c) Lateral view
Intermediate cuneiform
Lateral cuneiform
Fifth metatarsal
Lateral
malleolar facet
Talus
Navicular
Cuboid
Calcaneus
V
IV
III
II
I
Figure 7.34
Bones of the right foot.
(For a related image, see
A Brief Atlas of the Human
Body
, Figure 31a, c, and d.)
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