Bones and Joints of the
Lower Extremity
Last Updated: March 9, 2021
access_time17 min
Learning Objectives (5)
After completing this brick, you will be able to:
● Describe the shape, location, and articulations of the bones of the
thigh.
● 1
● Describe the shape, location, and articulations of the bones of the
lower leg.
● 2
● Describe the shape, location, and articulations of the bones of the foot.
● 3
● Describe the articulations and range of motion of the joints of the
lower extremity, including the hip.
● 4
● Describe the ligaments protecting the knee and their clinical
significance.
● 5
CASE CONNECTION
While playing in a charity kickball game, a friend experiences an
inversion injury with her right ankle. You help her to the bench; it is
clear that she can’t bear weight on the ankle. “I’m sure it will be
okay,” she says, trying to tough it out. She agrees to ice it. By the end
of the game, her ankle is very swollen, and it is tender over the lateral
,malleolus. She isn’t sure she can drive herself home, and you tell her
you’re happy to drive and also make a stop at the clinic to get her
ankle evaluated. She resists the idea. “I’ve sprained my ankle before. I
just need to rest.”
What will you tell your friend about the importance of getting an x-
ray? Consider your answer as you read, and we’ll revisit at the end of
the brick.
General Organization of the Lower
Extremity Bones and Joints
The lower extremity is part of the lower appendicular skeleton. Recall
that the appendicular skeleton includes not only the upper and lower
extremities, but also their attachment bones to the axial skeleton,
including the pelvis. We won’t discuss the pelvic bones here, because
the pelvis is not usually considered part of the lower extremity and is
discussed separately.
So how many bones are there in the lower extremity? Thirty! It also is
home to three big joint articulations: the hip, knee, and ankle, plus the
many small joints in the feet (the subtalar joints) and a couple others.
,We will cover all of these, going from proximal to distal. Discussion
of the bones is immediately followed by the joints that connect them.
Bones of the Lower Extremity
Anatomically, the lower extremity spans from the hip all the way
down to and including the foot. It’s composed of three broad regions:
the thigh (between the hip joint and the knee joint), lower leg
(between the knee joint and the ankle joint), and the foot. These are
helpful landmarks to remember because most bones and muscles span
these joints and can be easily remembered by location.
Just like the upper extremity, the lower extremity (Figure 1) starts
with a single large proximal bone (the femur), then two interacting
lower leg bones (the tibia and fibula), and then multiple bones in the
foot. The complexity of the foot is evolutionarily important, since
some primates use their feet to dangle from branches!
,
Lower Extremity
Last Updated: March 9, 2021
access_time17 min
Learning Objectives (5)
After completing this brick, you will be able to:
● Describe the shape, location, and articulations of the bones of the
thigh.
● 1
● Describe the shape, location, and articulations of the bones of the
lower leg.
● 2
● Describe the shape, location, and articulations of the bones of the foot.
● 3
● Describe the articulations and range of motion of the joints of the
lower extremity, including the hip.
● 4
● Describe the ligaments protecting the knee and their clinical
significance.
● 5
CASE CONNECTION
While playing in a charity kickball game, a friend experiences an
inversion injury with her right ankle. You help her to the bench; it is
clear that she can’t bear weight on the ankle. “I’m sure it will be
okay,” she says, trying to tough it out. She agrees to ice it. By the end
of the game, her ankle is very swollen, and it is tender over the lateral
,malleolus. She isn’t sure she can drive herself home, and you tell her
you’re happy to drive and also make a stop at the clinic to get her
ankle evaluated. She resists the idea. “I’ve sprained my ankle before. I
just need to rest.”
What will you tell your friend about the importance of getting an x-
ray? Consider your answer as you read, and we’ll revisit at the end of
the brick.
General Organization of the Lower
Extremity Bones and Joints
The lower extremity is part of the lower appendicular skeleton. Recall
that the appendicular skeleton includes not only the upper and lower
extremities, but also their attachment bones to the axial skeleton,
including the pelvis. We won’t discuss the pelvic bones here, because
the pelvis is not usually considered part of the lower extremity and is
discussed separately.
So how many bones are there in the lower extremity? Thirty! It also is
home to three big joint articulations: the hip, knee, and ankle, plus the
many small joints in the feet (the subtalar joints) and a couple others.
,We will cover all of these, going from proximal to distal. Discussion
of the bones is immediately followed by the joints that connect them.
Bones of the Lower Extremity
Anatomically, the lower extremity spans from the hip all the way
down to and including the foot. It’s composed of three broad regions:
the thigh (between the hip joint and the knee joint), lower leg
(between the knee joint and the ankle joint), and the foot. These are
helpful landmarks to remember because most bones and muscles span
these joints and can be easily remembered by location.
Just like the upper extremity, the lower extremity (Figure 1) starts
with a single large proximal bone (the femur), then two interacting
lower leg bones (the tibia and fibula), and then multiple bones in the
foot. The complexity of the foot is evolutionarily important, since
some primates use their feet to dangle from branches!
,
