The bone of the thigh, which happens to be the largest bone in the body, is known as
the femur. Anatomically the thigh is the femoral region. The thigh is not actually part of
the leg. Remember anatomically the leg is between the knee and the ankle. The thigh
is however part of the lower extremity. If we look at the thigh it has some similarities
to the humerus. But it has other things that are not quite similar. It has a nice rounded
head, this makes a good ball and socket joint for the hip joint. If I take the head of this
femur and plug it into the acetabulum of the os coxa that we just learned, now we have
a hip joint. Notice a ball and socket joint gives an extreme range of movement. Which
of course is very important for our motility. Now compare this to the shoulder joint, this
joint is designed to be very strong and weight-bearing. Remember our shoulder joint, we didn't have
much of a ball and socket. We have the head of the humerus in the glenoid cavity of the
scapula. But it didn't really fit in like a ball and socket. In that particular incidence
we were relying on the muscles around the joint for the stability. Here we have good
bony stability as well as muscle stability. Now if we look at this femur, the proximal
end has the head, and where the head is attached to the rest of the femur we have what is known
as the anatomical neck. Then we have two very large protrusions, the large protrusion laterally
is known as the greater trochanter. The smaller protrusion posteromedially is the lesser trochanter.
So those are similar to the greater and lesser tubercle of the humerus. Only here we have
the greater trochanter and the lesser trochanter. And on the femur anteriorly there is a raised
line between the greater and lesser trochanter, anteriorly, known as the intertrochanteric
line. Posteriorly there's actually a crest of bone between the greater and lesser trochanter,
known is the intertrochanteric crest. So the intertrochanteric line on the anterior femur,
intertrochanteric crest on the posterior femur. Anatomical neck connects to head to the rest
of the femur. The surgical neck is right below the lesser trochanter. Surgical neck right
below the lesser trochanter. Now the remainder of the shaft of the femur is not very exciting.
Anteriorly it is fairly smooth, uneventful. Posteriorly there is a ridge that runs down
the length of the shaft of the femur. This ridge is known as the linea aspera. The linea
aspera. As we get down to the distal end of the femur we have the portion of the femur
that it's going to be involved in the knee joint. We have the smooth articulating surfaces
that are going to be involved in the knee joint, known as the medial condyle and the
lateral condyle. And then the bone surrounding that area is known as the medial epicondyle
and lateral epicondyle. Also if you follow along the medial shaft of the femur and we
go out onto the medial epicondyle, just before it takes a sudden turn and drops off, there
is a very small little lump there known as the adductor tubercle. Now the students in
the A & P one class or not responsible for adductor tubercle. However many of the anatomy
3000 students you may well be responsible for the adductor tubercle. So how do we tell
whether this is a left or a right femur? First of all I think it should be obvious to you,
you need to know where it is, it's in the thigh, and you need to know that the head
of the femur helped form the hip joint. So the head much point in toward the rest of
your pelvis. It wouldn't make sense to have the head pointing away from the rest of the
body. So the head most point in toward the rest of the pelvis and, there is a line down
the posterior femur called the linea aspera. So point the head medially, have the linea
aspera in the back, and that should tell you this is a left femur