of all of the tendons from the anterior compartment.
Let’s move on to the lateral compartment
now, and the lateral compartment contains
two muscles, and these are fibula muscles.
The lateral compartment, which we can see
here, contains fibularis longus which has
a long tendon and is more superficially located,
and fibularis brevis which is deeper to fibularis
longus and contains a shorter tendon. So we
have fibularis longus. It originates from
the head and proximal two-thirds of the lateral
fibula, and it passes through the first metatarsal
and medial cuneiform. Fibularis brevis is
coming from the mid-portion of the lateral
fibula, and it passes to the base of the fifth
metatarsal. So what we can see is that the
tendon of fibularis longus actually passes
deep underneath the foot. And we’ll see
this in a later lecture. We’ll see the pathway
of this tendon. Here, we’ve got the fifth
metatarsal here where fibularis brevis is
attaching to. But actually, fibularis longus
passes underneath the foot to attach to the
base of the first metatarsal.
Contractions of these muscles support eversion. So they
evert the foot. They can also assist in plantar flexion,
but this is quite weak. The muscles in the
lateral compartment are supplied by the superficial
fibular nerve. We saw the muscles in the anterior
compartment are supplied by the deep fibular nerve
while these in the lateral compartment
are supplied by the superficial fibular nerve.
And the superficial and the deep fibular nerves
come away from the common fibula. If you remember,
the common fibula is a branch that’s coming away
from the sciatic. And this split superficial
to deep occurs at the neck of the fibula.
So it can be prone to damage because this
is quite a superficial landmark. So here we
can see we have the lateral compartments of
the leg, and we’ve also got a close-up here
of the foot. We can see the lateral aspect
of the foot. We can see, again, we’ve got
tibialis anterior, we’ve got extensor digitorum
longus, and we’ve got extensor hallucis longus,
these muscles from the anterior compartment.
We can also see running in the anterior compartment
here, we’ve got that fibularis tertius tendon.
And these are running underneath the extensor
retinaculum, the Y-shaped extensor retinaculum,
the inferior and the superior parts of it. We
can also see now on this lateral compartment,
we have fibularis longus and we have fibularis
brevis. We can see these some important evertors
of the foot, and they’re attaching to the base
of the fifth metatarsal of your fibularis brevis,
and going under the foot to attach
to the base of the first metatarsal of your
fibularis longus. These are going to be supplied
by those superficial fibular nerves, and also
perforating branches of the anterior tibial
artery. And we’ll look at this in a later
lecture. We’ll look at a detailed review
of the blood supply in a later lecture.
The fibular muscles also have a retinacula that
helps to hold them in place, the fibular retinacula.
We have superior and inferior ones. We can
see that the tendons of fibularis longus,
we can see running down here, and fibularis
brevis running down here, are running posterior
to the lateral malleolus as they enter the
foot deep to this fibular retinaculum.
We can see we have two parts to it. We have a
superior one, we can see here, running from
the lateral malleolus to the calcaneus. And
we can see an inferior portion which is the
continuation of the inferior extensor retinaculum.
So we can see them here in greater detail
on this lateral view of the foot. We can see
the tendons, fibularis longus and fibularis brevis
running down in this direction as they’re
running posterior to the lateral malleolus.
We can see we have this superior one here
and we have the inferior portion here.
And these are holding the tendons tight
against the lateral aspect of the foot.