What Causes Scapular Winging, or a Shoulder Blade That Sticks Out?
Scapular winging is when one or both shoulder blades lift away from the rib cage instead of lying flat. It is usually caused by weakness or nerve damage in the muscles that hold the scapula in place. Sometimes, though, what looks like a winged scapula is really a rib hump caused by spinal asymmetry. A standing whole-body image can tell the difference.
Key points
- A winged scapula is a shoulder blade that visibly lifts off your back, especially when you push against something.
- The most common cause is weakness in the serratus anterior muscle, often from a nerve problem.
- A rib hump caused by scoliosis or spinal rotation can look like winging. Standing imaging helps tell the two apart.
- An EOS standing scan shows how your spine, ribs and shoulders line up under your real body weight. A lying-down scan cannot do this.
- An accurate diagnosis guides the right next step, whether that is physiotherapy, further tests or reassurance.
What is scapular winging?
Scapular winging is when the inner edge or bottom corner of your shoulder blade pushes visibly away from your rib cage. Normally, several muscles hold each scapula flat against your back, so your arm can move smoothly. When one of these muscles is weak or not working properly, the blade loses its anchor and lifts outward.
You might notice it when you look at your back in a mirror. Or someone may tell you that one shoulder blade sticks out more than the other. It often shows more when you raise your arms, push a door open or do a push-up against a wall.
How can you tell if your shoulder blade is winging?
You can often spot scapular winging yourself, or with help from someone standing behind you. Look for these signs.
One shoulder blade clearly sticks out, especially when seen from behind.
The blade lifts further when you push against a wall or raise your arms in front of you.
One shoulder may sit higher, or clothes may hang unevenly across your back.
Discomfort around the shoulder blade, especially after overhead or repeated arm use.
A simple self-test is the wall push-up. Stand facing a wall and place both palms flat on it. Then slowly push yourself away. If one blade lifts or pops out while the other stays flat, that side may be winging.
What causes a winged scapula?
Scapular winging is usually caused by a problem with one of the muscles or nerves that keep the shoulder blade steady against your rib cage. The cause decides whether the blade wings inward (medial winging) or outward (lateral winging).
This nerve powers the serratus anterior muscle. When it is damaged, the blade wings inward. This is the most common cause.
This nerve supplies the trapezius. Damage here makes the blade wing outward (lateral winging).
Long-term tightness in the chest and weakness in the upper back can pull the scapula out of position over time.
Spinal rotation or an uneven rib cage can push one blade outward, even when the muscles are working normally.
The nerve-related causes often follow a specific event. Examples are a sports injury, surgery near the neck or shoulder, or carrying heavy loads with a strap pressing on the shoulder. Muscle-related and bone-related causes tend to develop slowly and may overlap with poor posture habits.
Is it scapular winging or a rib hump?
A rib hump, where one side of the rib cage stands out more than the other, can look very like a winged scapula when seen from behind. Both cause a visible bump near the shoulder blade. But they are two different problems with different causes.
- The shoulder blade itself lifts away from the ribs
- Usually on one side
- Gets worse when you push or lift
- Caused by a muscle or nerve problem at the scapula
- The ribs themselves rotate and push outward
- Often linked to spinal rotation or scoliosis
- Visible when bending forward (the Adams forward bend test)
- Caused by asymmetry in the spine or rib cage
The difference matters because each one is managed in a different way. A standing whole-body image shows the rib cage shape, spinal alignment and shoulder blade position all at once. This makes it simple to tell them apart.
How does a standing EOS scan help with scapular winging?
A standing EOS scan captures your whole skeleton, from head to feet, while you stand upright and carry your own weight. This matters because lying-down imaging relaxes the muscles and changes how the skeleton sits. This can hide or distort the problem.
With ScanAlign standing EOS imaging, your spine, rib cage and shoulder blades are captured under gravity. This shows true spinal rotation, rib asymmetry and shoulder blade position, exactly as they are in daily life. A clinician can see whether the blade is truly winging, or whether a raised area of the ribs is making it look like winging.
When you lie on a table for a standard X-ray or CT scan, gravity pulls the scapula back against the ribs and the spine straightens slightly. Small amounts of rotation and asymmetry can flatten out. This makes it harder to see whether the cause is muscular, nerve-related or structural.
EOS also uses about 90% less radiation than a standard X-ray, around ten times less. That makes it a practical choice when you want a clear, whole-body picture without unnecessary exposure.
When MRI is the better tool: EOS shows bones, joints and alignment. If your clinician suspects nerve damage, a soft tissue tear or a disc problem, MRI is usually the better choice. The two tests work well together. EOS makes the skeletal picture clear, and MRI looks at soft tissue detail.
What can be done about a winged scapula?
The right approach depends entirely on the cause. This is why an accurate diagnosis comes first. ScanAlign is a diagnostic imaging clinic, not a treatment provider. But understanding your options can help you have better conversations with your treating clinician.
- Targeted physiotherapy. If winging is caused by weakness in the serratus anterior or trapezius, structured rehabilitation exercises can improve control of the shoulder blade over time. A physiotherapist will tailor these to the specific muscle involved.
- Posture retraining. Where muscle imbalance from long hours of desk work or poor habits is playing a part, working on the underlying posture can help. A standing alignment assessment shows the bigger picture across your whole skeleton.
- Further nerve tests. If nerve damage is suspected, your clinician may arrange nerve conduction studies to find out how serious the injury is and the likely path of recovery.
- Surgical opinion. In long-lasting cases that do not respond to rehabilitation, some people are referred for a review by a surgeon. This is uncommon.
Before you start treatment, or change the one you are on, it is worth getting a detailed diagnosis. Knowing whether the cause sits in the pelvis, the legs or the spine changes what will actually help.
Not sure whether your shoulder blade problem is winging, a raised area of the ribs or something else? A free video consultation with our radiographer can help you decide whether a standing scan is the right next step before you plan a trip to London.
Book a free video consultationWhen to seek urgent help
If you notice sudden weakness in your arm, numbness spreading down from your neck or shoulder, or difficulty lifting your arm after an injury, contact your doctor straight away or go to your nearest emergency department. These symptoms need prompt medical assessment rather than an imaging booking.
Frequently asked questions about scapular winging
Usually because one of the muscles that keep it steady on that side is weaker or not working properly. It can also happen if your rib cage is slightly rotated because of spinal asymmetry, which pushes one blade outward.
It depends on the cause. Mild winging from posture habits is common and often improves with targeted exercises. Winging from nerve damage may take longer to settle and benefits from a professional assessment.
Some cases, especially those caused by a temporary nerve stretch, do improve on their own over several months. But knowing the cause is important, so you are not waiting without need or missing something that would benefit from physiotherapy.
A wall push test can help at home. If the blade lifts when you push, it is more likely true winging. A rib hump is usually easier to see when you bend forward. A standing whole-body scan shows both the scapula and the rib cage clearly to settle the question.
The serratus anterior is a muscle that wraps around your rib cage from the front and attaches to the inner edge of your shoulder blade. It holds the blade flat against the ribs. When it is weak or paralysed, the blade lifts off, causing medial winging.
Exercises that target the serratus anterior, such as wall slides and different types of push-up, are commonly prescribed. But the right programme depends on which muscle is involved and how severe the problem is. A physiotherapist can design a plan once the diagnosis is clear.
No. ScanAlign is a private, self-pay clinic. You can book directly, without a referral from your doctor or a specialist.
Yes. EOS uses about 90% less radiation than a standard X-ray, around ten times less. It is designed for low-dose, weight-bearing imaging.
The price for patients travelling from abroad is confirmed during your free video consultation.
Yes. Rounded shoulders and a forward head posture can tilt the shoulder blades away from the rib cage. This is not true nerve-related winging, but it can look similar. A standing scan helps separate posture-related asymmetry from a structural or nerve problem.
Wondering why your shoulder blade sticks out?
A free video consultation with our specialist radiographer can help you decide if a standing alignment scan in London is the right next step.
Book a free video consultationWritten by Abbas Dhami (Specialist Diagnostic Radiographer)
Sources
- Martin RM, Fish DE. Scapular winging: anatomical review, diagnosis, and treatments. Current Reviews in Musculoskeletal Medicine. 2008;1(1):1-11.
- NHS. Shoulder pain. nhs.uk/conditions/shoulder-pain.
- Desy NM, Bhatt S, Guttman D. Scapular winging: a guide to diagnosis and management. Journal of the American Academy of Orthopaedic Surgeons. 2020;28(5):e214-e222.
This page is general information and not a diagnosis.
ScanAlign is the trading name of CoreMed Solutions Ltd and operates under The Harley Street Hospital's CQC licence.