In this lecture, we’re going to look at the
leg. So we’ll start off by looking at
the leg in cross-section and returning to the
deep fascia and the various intermuscular septae.
We’ll then look at the various muscles
within each of the three compartments.
So we’ll look at the muscles in the anterior
compartments, and their function and innervation.
We’ll then look at the muscles in the lateral
compartment, their function and innervation.
And then finally, we’ll look at the muscles
within the posterior compartment and detail
their function and innervation as well. First
of all, let’s return to a familiar view
which is of a cross-section of the lower limb,
and this time, we have got a section through
the leg. We have the anterior surface here,
and we have the lateral surface here, and
the medial surface and the posterior surface.
Remember, we’re looking at this from the
inferior view. So within the subcutaneous
tissue, we find the great saphenous vein and
the small saphenous vein. Remember those from
the previous lectures. And then we can see
we’ve got our two bones within the leg. We
have the tibia which is positioned more
medially, and actually, we can see here, it runs
very superficial. The sharp anterior aspect
of the tibia can be palpated through the skin.
Then we have the fibula, a much smaller bone
that is more important with providing surface
area for muscle attachments. So what we can
see with this transverse section is that we have
three compartments, and these three compartments
are formed by the interosseous membrane which we
can see running between the tibia and the fibula.
And then we have the anterior intermuscular
septum we can see here. And we’ve got a
posterior intermuscular septum which we can see
here. These two septae and the interosseous
membrane are separating the leg into an anterior
compartment, a lateral compartment, and a
very substantial posterior compartment. Within
here, we can see the number of muscles which
we’re going to go on a detail. We can also
see some important blood vessels.
We’ve got the tibial nerve here. We’ve got the
anterior tibial arch we can see here, and
the deep fibular nerve, which we’ll cover
during this lecture. So we have those three
compartments that have been created by the
various septae and the interosseous membrane.
And within the anterior compartment, we have
muscles which were associated with extension
and dorsiflexion. Within the lateral compartment,
we have muscles which are primarily associated
with eversion. And in the posterior compartment,
we have muscles associated with flexion and
plantar flexion. The posterior compartment
itself is divided into superficial and deep
layers. And we’ll see this as we group the muscles
separately. This is done via a transverse
intermuscular septum, which we can see running
along in this direction. And that separates
these muscles which we can see here; flexor
hallucis longus, tibialis posterior, and flexor
digitorum longus from the most superficial
muscles being gastrocnemius and soleus.
So this transverse intermuscular septum separates
the posterior compartment into two layers.