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Then the clinical examination continues with the assessment of the rotator cuff. The rotator
cuff is a group of four tendons which mobilise the glenohumeral joint around. It is subscapularis,
and if the patient turns around, the supraspinatus, infraspinatus and much smaller teres minor
at the back. We examine each one of them separately.
First, we start with the biggest one, which is the subscapularis. We ask the patient to
do this, put their hands on their chest, elbows as forward as possible, and then we ask the
patient to resist posterial pressure. Okay? Keep your elbows here, don’t let me push
back. This is how we assess subscapularis.
Another test to assess the strength and the function of subscapularis is to ask the patient
to flex slightly their shoulder, flex elbow by 90 degrees, we position our hand on the
patient’s palm, and we ask the patient to pull our hand to touch their stomach. When
subscapularis is intact, the patient can do that; otherwise, the patient cannot overcome
our resistance. This is a modification of the lift-off test.
Otherwise, we can use the lift-off test. We ask the patient to put their hand on ours,
just behind their lumbar spine, and we ask the patient to push us away from them, and
we resist. This is the lift-off test.
The next muscle, which is the commonest to be involved in the pathology of the rotator
cuff is the supraspinatus. Supraspinatus is the muscle which initiates abduction. We ask
the patient first to move their arms out, like this, and we resist them. Push me away
from you. This is the strength of supraspinatus. To further assess the function of the supraspinatus,
we perform the emptying can test. We flex the shoulder by 90 degrees, abducted to be
at the same level as the scapula, and we do the same on the other side. We ask the patient
to keep their thumbs upwards and resist pressure against them. Keep your arms like this. Now
we ask the patient to turn their arms round, and the thumbs pointing down, as if we’re
emptying a can. Resist the pressure. Any pain here? This is the function of the supraspinatus.
Emptying can test can be positive with supraspinatus, rupture, tendinopathy or calcifications.
For the rest of the rotator cuff tendons, the infraspinatus and teres minor, we ask
the patient to flex the elbows and keep them by their side, slightly externally rotate,
and again, resist against our pressure, which is like this. If there is a massive rotator
cuff there with significant and complete rupture of the external rotators, the teres minor
and infraspinatus, we have a positive lag sign. We keep the arm in neutral position,
support the elbow, externally rotate the forearm and the shoulder as possible, and then we
leave the hand. When the hand is left alone, it returns back automatically, because there
is no function of external rotators. This is a positive lag sign pathognomonic for a
posterior rotator cuff tear.