So now let's look at a case
of a patient with shoulder pain.
This is a 74-year-old man presenting with right
shoulder pain after falling on his outstretched arm.
The pain is constant and he is
unable to lift his arm above his head.
Well, it turns out the shoulder
pain is remarkably common.
16-34% of the general population
actually have shoulder pain at some time.
But similarly to the examples we
gave during the introductory course,
there's a lot of times where we perform
an MRI on people who have no symptoms
and will find stuff.
In fact, 54% of asymptomatic patients
over 60 years old have evidence of a partial
or a full thickness rotator cuff tear.
So when we're doing our physical exam, we have
to make sure that the findings we get on the exam
will actually correlate and necessitate
getting any diagnostic imaging.
With that, a brief review of the anatomy.
Take note of where the
supraspinatus tendon lies.
This is, of course, a right shoulder.
The supraspinatus tendon is wrapping
around the top of the humeral head,
where it inserts very
proximally on the humeral head
compared with the deltoid muscle, which is
basically attached to the clavicle and the acromion
and it wraps much further
down on the humerus itself.
And I highlight this because it
highlights the fact that the deltoid muscle
is really the prominent mover and
shaker for getting your arm around
and having strength to
lift things over your head.
The supraspinatus, the infraspinatus and the rest of
the rotator cuff muscles are designed for stabilizing
the humeral head and
stabilizing your shoulder joint.
Also, take note of the glenoid labrum.
The glenoid fossa, which is
the bony part of your scapula,
is where the humeral head
articulates with the rest of your body.
The glenoid labrum provides
a little bit of extra articulation.
It's a cartilaginous structure that provides
more support on an otherwise fairly unsupported
golf ball on golf tee kind of joint.
Lastly, I'll draw your attention to
the subacromial bursa at the top,
since this is one of the only parts in the body
where muscle is passing between two bones,
in this case, the acromion part of
the scapula and the humeral head.
There is some buffering there and the supraspinatus
lies right underneath the subacromial bursa
so the bursa is providing
a little bit of cushioning
as the rotator cuff is being
moved around in space.
One last point is that the subacromial
bursa is contiguous with the subdeltoid bursa.
They are the same structure just
named differently based on whether you're
proximal underneath the acromion or
more distal underneath the deltoid muscle.
Shown here is a posterior
view of the shoulder on the left
to remind you that the supraspinatus is so
named because it is above the spine of the scapula
and then the infraspinatus
is, of course, beneath it.
In tandem with the infraspinatus is the teres
minor, which has a lot of overlapping functions
with the infraspinatus.
And then on the anterior image shown
on the right is the subscapularis muscle,
which is the primary driver for
internal rotation of the shoulder.
You can also see here that about 4
centimeters in from the end of the acromion
depicted on both the right and left
images is the acromioclavicular joint
articulating with the clavicle on
its way to the sternoclavicular joint.
So quick review question, which rotator cuff
muscles are responsible for external rotation?
Well, the supraspinatus lies
on top of the humeral head,
so that's going to lift your
shoulder up or abduction
And your subscapularis, I have already
mentioned is your primary internal rotator.
so it's the infraspinatus and the teres minor which
have this dual function of doing external rotation.
So having reviewed the anatomy, I like to
think about the different causes of shoulder pain
grouped into four main categories.
The first is capsular disease.
And that's referring to the actual
articulation of the humeral head
with the glenoid fossa and the glenoid labrum.
You can have adhesive capsulitis in that area.
Simply glenohumeral arthritis,
where the humeral head is shifting
around too much with that articulation
or a labral tear where the glenoid labrum
is torn and you, of course, may also have
instability as a result.
Next up, you have disease of the rotator cuff.
Maybe it's tendinosis, maybe it's impingement,
maybe you have problems with the subacromial
or subdeltoid bursa that gets inflamed because there's
there's too much stress in that very tight area.
Calcific tendinitis can
occur with those tendons.
And, of course, you could
also have a complete tear.
In terms of extraarticular structures, that is
structures that are related to shoulder movement,
but that aren't tied directly
to the glenohumeral joint.
You've got the AC joint.
The acromioclavicular joint has
about 15 degrees of range of motion.
The biceps tendon, the long head of
which inserts into the glenoid labrum.
And of course, don't forget about neck pathology,
which is a common cause of, quote, shoulder pain.
And lastly, there are, of course, inflammatory
and infectious causes of shoulder pain as well.
Rheumatoid arthritis can affect the
AC joints and the sternoclavicular joints,
less commonly can affect
the glenohumeral joint.
Septic arthritis, which
I've definitely seen.
And then crystalline arthropathies like gout or
CPPD disease can also afflict the shoulder.
Reviewing these again anatomically,
we have capsular disease,
which is where the
glenohumeral joint is shown here.
We have rotator cuff pathology, again,
involving the subacromial bursa or the
various muscles of the rotator cuff.
Then we have these periarticular structures like
the AC joint, the long head of the biceps tendon.
And that red circle just reminds
us of cervical neck disease as well.
And don't also forget that whenever you're
examining one joint where the pain is located,
examine the joint above and below.
In this case, make sure you take a
look at the elbows as part of your exam.
So we're turning to our case, there's
a lot of different things to look for here,
whether it's rotator cuff tendinopathy
or tear and AC joints separation
in light of the fact that he
fell onto his outstretched arm.
Maybe he fractured something or
maybe it's just biceps tendinopathy.
Let's move on with looking at the skills
required to perform a competent physical exam.