In this lecture we are going to look at the arm.
So we are going to start off by looking at the
arm in cross section and returning to the
brachial fascia we spoke about. We will also
look at how it forms the intermuscular septae.
We will then look at the anterior compartment, the
biceps brachii, brachialis and coracobrachialis
muscles and some neurovascular relations in
the anterior compartment. We will then look at the
cubital fossa that lies directly anterior
to the elbow joint, its boundaries and the
contents and then we will finish by looking
at the posterior compartment, specifically
triceps brachii and again some neurovascular
relations. So if we look at the compartments
of the arm to start within, this is a section
through the arm and we can see that we have got
the humerus here and then lying anteriorly
we have got this surface here where we have got
a subcutaneous tissue and the superficial
fascia and then we have got this line here
that is running around the muscles and that
is the brachial fascia. So we are going to
look at that in a bit more detail.
When looking at cross sections, it is important
to realize as this diagram here indicates
that we are actually looking at it from below.
So here we are looking at it from below.
So this is the medial aspect here, this is the
lateral aspect, this is the posterior aspect
and this is the anterior aspect. So the transverse
section of the arm reveals the brachial fascia
forms two muscular compartments. It does this
by way of the lateral intermuscular septum
and the medial intermuscular septum. So what
we can see here is the humerus and then on
the outside we have got the brachial fascia.
We can see the brachial fascia dives deep
here laterally into the depths of the arm
and attaches to the humerus. We can also see
similar here, where we have the brachial fascia
running around the outside and then we have
got this medial intermuscular septum running
in head. And that creates two compartments contain
the anterior compartment and it contains the
posterior compartment. The anterior compartment
is the flexor compartment. The posterior compartment
is the extensor compartment. So they flex
the elbow joint and they extend the elbow
joint muscles in these compartments.
Importantly though it's important to remember that some of these
muscles also act on the glenohumeral joint
as we will see. So the majority of the muscles
in the arm do act on the elbow joint and
principally there are two types of movements.
We have flexion and extension. We also have
pronation and supination. So the muscles we
have in the arm act on the elbow joint and
they also act on the radio-ulnar joints which
like pronation and supination to work out.
So we will come back to this, as we progressed
through the course.