What Causes Scapular Winging, or a Shoulder Blade That Sticks Out?
Scapular winging happens when one or both shoulder blades lift away from the rib cage instead of sitting flat. It is usually caused by weakness or nerve damage affecting the muscles that hold the scapula in place. Sometimes, though, what looks like a winged scapula is actually a rib hump from spinal asymmetry, and a standing whole-body image can tell the difference.
Key takeaways
- 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 issue.
- A rib hump caused by scoliosis or spinal rotation can mimic winging, and standing imaging helps distinguish the two.
- An EOS standing scan shows how your spine, ribs and shoulders align under your real weight, something a lying-down scan cannot do.
- Accurate diagnosis guides the right course of action, whether that is physiotherapy, further investigation 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 pin each scapula flat against your back so your arm can move smoothly. When one of those muscles is weak or not firing properly, the blade loses its anchor and lifts outward.
You might notice it when you look in a mirror from behind, or someone may point out that one shoulder blade sticks out more than the other. It often becomes more obvious when you raise your arms, push a door open, or do a wall push-up.
How can you tell if your shoulder blade is winging?
You can often spot scapular winging yourself or with help from someone behind you. Look for these signs.
One shoulder blade clearly sticks out, especially when viewed from behind.
The blade lifts further when you push against a wall or lift your arms in front of you.
One shoulder may sit higher, or clothing hangs unevenly across your back.
Discomfort around the shoulder blade, especially after overhead or repetitive arm use.
A simple self-test is the wall push-up. Stand facing a wall, place both palms flat, and 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 stabilise the shoulder blade against your rib cage. The cause determines 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 causes the blade to wing outward (lateral winging).
Chronic tightness in the chest and weakness in the upper back can pull the scapula out of position over time.
Spinal rotation or rib cage asymmetry can push one blade outward even though the muscles are working normally.
The nerve-related causes often follow a specific event, such as a sports injury, surgery near the neck or shoulder, or carrying heavy loads with a strap pressing on the shoulder. Muscle-related and bony causes tend to develop gradually 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 is more prominent than the other, can look very similar to a winged scapula when viewed from behind. Both produce 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 one-sided
- 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 distinction matters because the management pathways are different. A standing whole-body image shows the rib cage shape, spinal alignment and shoulder blade position all at once, making it straightforward to tell them apart.
How does a standing EOS scan help with scapular winging?
A standing EOS scan captures your entire skeleton from head to feet while you are upright and bearing your own weight. This is important because lying-down imaging relaxes the muscles and changes how the skeleton sits, potentially masking or distorting the problem.
With ScanAlign standing EOS imaging, your spine, rib cage and shoulder blades are captured under gravity. This reveals true spinal rotation, rib asymmetry and scapular position, exactly as they are during daily life. A clinician can see whether the blade is genuinely winging or whether a rib prominence is creating the appearance of winging.
When you lie on a table for a standard X-ray or CT, gravity pulls the scapula back against the ribs and the spine straightens slightly. Subtle rotation and asymmetry can flatten out, making it harder to identify whether the cause is muscular, neural or structural.
EOS also uses about 90% less radiation than a standard X-ray, around ten times less. That makes it a practical option 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 disc involvement, MRI is usually the better choice. The two investigations work well together, with EOS clarifying the skeletal picture and MRI looking at soft tissue detail.
What can be done about a winged scapula?
The right approach depends entirely on the cause, which is why 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 scapular control over time. A physiotherapist will tailor these to the specific muscle involved.
- Postural retraining. Where muscle imbalance from prolonged desk work or poor habits is contributing, addressing the underlying posture can help. A standing alignment assessment shows the bigger picture across your whole skeleton.
- Further nerve investigation. If nerve damage is suspected, your clinician may arrange nerve conduction studies to determine the extent of the injury and likely recovery path.
- Surgical opinion. In persistent cases that do not respond to rehabilitation, some people are referred for a surgical review. This is uncommon.
Not sure whether your shoulder blade issue is winging, a rib prominence, or something else? A free video consultation with our radiographer can help you decide whether a standing scan is the right next step.
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 GP, call 111 or go to A&E. These symptoms need prompt medical assessment rather than an imaging booking.
Frequently asked questions about scapular winging
Usually because one of the stabilising muscles on that side is weaker or not being activated properly. It can also happen if your rib cage is slightly rotated due to spinal asymmetry, pushing one blade outward.
It depends on the cause. Mild winging from postural habits is common and often improves with targeted exercises. Winging from nerve damage may take longer to resolve and benefits from professional assessment.
Some cases, particularly those caused by a temporary nerve stretch, do improve on their own over several months. However, knowing the cause is important so you are not waiting unnecessarily 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 more visible when bending forward. A standing whole-body scan shows both the scapula and 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 targeting the serratus anterior, such as wall slides and push-up variations, are commonly prescribed. However, the right programme depends on which muscle is involved and the severity. 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 GP or consultant referral.
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.
Pricing details are on our FAQs and cost page. You can also ask about cost 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 postural asymmetry from a structural or nerve problem.
Wondering what is behind your shoulder blade sticking out?
A free video consultation with our specialist radiographer can help you decide if a standing alignment scan 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.