Has anyone told you that you are UNSTABLE? An unstable shoulder can be very dramatic or more often a silent issue that rears its ugly head only in certain situations or movements. Who would have thought that your shoulder could give way on you? What does giving way mean? People will describe looseness, laxity, a weak feeling, instability, that their shoulder is not in the right place. Normally a shoulder provides stability with ligaments, cartilage and muscles. Compared to other joints the shoulder provides for a large amount of range of motion. The ball is oversized compared to the cup and that provides enough range of motion for reaching overhead, off to the side, behind your back, and across your body. Like a golf ball sitting on a golf tee the shoulder humeral head sits precariously on the socket with very little constraint coming from the shape of the socket.
The stability of the shoulder therefore has to come from chiefly the ligaments of the shoulder. The ligaments attach to the bone through the labrum. The labrum is the cartilage that surrounds the shoulder joint. The ligaments of the shoulder are called the glenohumeral ligaments and they act as stabilizers in certain positions. Superior middle and inferior glenohumeral ligaments form the capsule in front of the joint. Below are pictures from the outside of the shoulder and then looking at the inside of the shoulder.
The most important one for providing stability for the front of the joint is the inferior glenohumeral ligament (IGHL) when the arm is overhead. When your arm is abducted and externally rotated as in a snatch or overhead position, the IGHL is taut and prevents your shoulder from sliding forward as seen below. In the diagram, the bottom picture labelled ER shows what happens to the ligament when the arm is externally rotated as in the snatch or overhead lockout. Notice how the ligament rolls up and forms a barrier to limit translation of the humeral head forward.
You can see when the arm rotates into external rotation (ER), the ligament tightens up and forms a buttress to prevent anterior or forward sliding of the humeral head out of the socket. If you have a tear in the ligament or the attachment site of the ligament the labrum then you will have a floppy wall and this allows the head to roll out. If it rolls halfway out, this is called a subluxation. If it rolls all the way out, this is called a dislocation.
We have a name for the test that a doctor does to see if the ligaments are loose in the front. It is called the Apprehension test.
As you can see the arm is abducted and externally rotated. The examiner then asks the patient to rotate the arm forward just liked they are throwing a pitch. If the patient does not like that feeling or feels like something bad is going to happen, they have apprehension about being in that position compared to their opposite side. To make the test a little worse an examiner can push the shoulder humeral head forward and worsen the sense of instability that occurs.
We have a name for the tear that can occur in the front of the joint labrum; it is called a Bankart tear after the doctor who made this pathology famous. A Bankart repair is when the labrum can be reattached to the shoulder socket and recreate the tight wall of ligament in the front.
The recovery from this surgery is 4-6 months for normal sports. Heavy overhead lifting and gymnastic maneuvers would be 5 to 8 months.
How can you avoid getting a Bankart tear or becoming unstable in your shoulder? There are certain tips that I recommend for athletes. When performing overhead squats or snatches, please don’t get into the Flying V position I call it.
This Flying V places an inordinate amount of stress on the front of your shoulder and those glenohumeral ligaments. In the pictures below, the one on the left is looking good, butt below parallel, weight in line with shoulders and weight is in between hips and knees forming a long triangle. The middle picture is bad because of the strain on the shoulders anteriorly especially if you are unstable. I have seen dislocations with this maneuver that people have shown me on videotape. The bottom line is to keep it vertical and avoid the stress. One may not be able to, because of hamstring tightness not allowing them to get into squat or ankle mobility preventing this. In these cases, I recommend being very careful with one rep max exercises, because one’s clean and jerk is entirely different than their squat due to mobility issues. Work the flexibility of the hamstring and ankles to prevent the forward tilt that can occur when these structures are tight.
The next 321GoMD.com article will be about multidirectional shoulder instability and posterior shoulder instability.