Now let’s move
on to the foot and look at the numerous
bones that make up the foot, both the tarsals,
the metatarsals, and the phalanges.
We’ve got a whole series of pictures that show different
views of the foot. We can see that we have
tarsus, these seven bones that help to form the main body of the foot,
and then we can see we have the metatarsus
that contains these metatarsals, and then
we can see we have the phalanges.
But for the tarsus, we can have the calcaneus, the
talus, navicular, cuboid, and three cuneiforms.
Here, we can locate, if we look more superiorly,
the talus, and this is going to allow articulation
between the tibia and the fibula via the two
malleoli. Then inferior to the talus underneath,
we have the calcaneus. We can see the calcaneus
is then going to articulate with the cuboid,
we can see here. And directly in front of
the talus, we can see we have the navicular.
So we’ve got the talus here. We’ve got the
navicular. And then we move lateral and
we find the cuboid. We then have three cuneiforms
that are positioned anterior to the navicular bone.
We have the medial, the intermediate, and the
lateral. So we have the talus,
we have the calcaneus here, we have the navicular,
the cuboid, and then three cuneiforms - medial,
intermediate, and lateral. If we then look at
the metatarsus, here we have five metatarsals.
These connect to the phalanges, and toe 1
is the shortest metatarsus. So it’s not
as long as the 2, 3, 4, and 5. So the
phalanges had a similar arrangement as we
had in the hand. So toe 1 has two phalanges,
a proximal and a distal. And toe 2 to 5
has a proximal, a middle, and a distal. And this
is repeated from toes 2, 3, 4, and 5.
So let’s have a look at a bit more detail
at these tarsal bones. Let’s start off with
the calcaneus. We can see it’s the largest,
the strongest of the tarsal bone, and articulates
with the talus superiorly and the cuboid bone
anteriorly. We can see it here. We can see
if we have a plantar view here, a lateral
view and a dorsal view. This is the calcaneus.
Medially, if we look at this medial aspect
of the calcaneus, we see it forms what’s
known as the sustentaculum tali. And this
helps to support the talus. It’s like a
shelf and it helps to support the talus superiorly,
the sustentaculum tali. We’ll later on appreciate
some important tendons, blood vessels and
nerves pass underneath the sustentaculum tali
as they cross posteriorly to the medial malleolus
to the enter the sole of the foot.
We also have the calcaneal tuberosity. We can see
that here, this large inferior bulge, the
calcaneal tuberosity, and that’s an important
attachment site for the calcaneal tendon.
So now if we look at the talus, then that
sits superior to the calcaneus, and we have
a head, we have a neck, and we have a body.
So we can see the neck of the talus here in
this lateral view, and if we move on to the
medial view, we see most anteriorly, we have
the head, then we have the neck, and then
we can see we have posteriorly the body.
We can see how it’s passing down and attaching to
the calcaneus in line with the sustentaculum tali.
And here, we can see the talus. The trochlear
surface which we can see here, so
we have the trochlear surface similar to the
trochlear that we have in the upper limb,
allows for articulation with the two malleoli
coming from the tibia and the fibula.
And we’ll appreciate that this is wedge shaped
allowing for strengthening of the ankle joint
during various movements. Now let’s turn
to the navicular. This is a flattened boat
shaped bone. And it is located between the
talus posteriorly, and the three
cuneiforms anteriorly. We can see it here clearly in
this dorsal view. On the lateral view, we
can see it’s lying medial to the cubiod
bone, and on this medial view, we can see
it’s running against the medial surface of
the foot. On the inferior surface of the
navicular, we see a medially orientated tuberosity,
and these were important for muscle attachments.
If we then look at the cuboid bone, we can see the
cuboid is located in between the calcaneus,
and the fourth and fifth metatarsals. Medially,
we would have the lateral cuneiform bone.
So here we can see the cuboid. The cuboid
itself has a tuberosity which we can again
see on the plantar view, and we also see it
has a groove for the fibularis longus tendon.
We’d appreciate that when we look at the
fibula muscles in a later lecture. If we now
move to the cuneiforms, now these forms a row
of bones that is directly anterior to
the navicular. And we have from medial to lateral,
we have a medial, intermediate, and a lateral
cuneiform. We can see the three here in this
dorsal view, and we can see the three here
in this plantar view. All of these three bones
articulate with the navicular posteriorly
and the metatarsals anteriorly. So now let’s
talk about those metatarsals. We have five
metatarsals, and these run forward to connect
to the phalanges of the digits. Toe 1 has
the shortest metatarsal, and we can see that
here. It’s very large, it’s very substantial,
it’s made up of a base, it’s made up of
a shaft, and it’s made up of a head.
So we have this very broad large first metatarsal,
but it’s also the shortest. If we look at
metatarsals 2, 3, 4, and 5, we see they have
a base, a shaft, and a head, but these are
much thinner. We can then see just like the
digits in the hand, digit 1 has two phalanges,
a proximal and a distal. So we can see the
proximal and distal phalanges of the first
digit, the toe. And then digits 2, 3, 4, and
5 have both proximal, have all proximal, middle,
and distal phalanges.