CAM morphology: the hip bump that a third of pain-free people also have.

A scan found a bony ridge on your femur. Before you plan around it, it helps to know how often that ridge means nothing.

This page is about understanding the condition and the role the brain and nervous system can play in it. It is not a diagnosis. Your own clinicians know your case.

What CAM morphology is

Your hip is a ball-and-socket joint. The ball is the rounded top of the femur (thigh bone) and the socket is the acetabulum, part of the pelvis. In CAM morphology, the ball is not perfectly round. There is a bump or ridge of extra bone where the head of the femur meets the neck, usually at the front and top.

The concern is mechanical. When the hip flexes and rotates, the bump can press against the rim of the socket. With enough repetition this can damage the cartilage lining the joint and the labrum (the ring of cartilage around the socket rim), which may lead to pain, stiffness and, years later, osteoarthritis. When the bump actually causes this pinching and symptoms, the condition is called femoroacetabular impingement, or FAI.

Here is the part that often gets missed: CAM morphology is a shape, not a diagnosis of pain. It is common, it often forms during adolescence in people who play sports, and most people who have it never know.

The neuroplastic contribution

Neuroplastic symptoms are real symptoms produced by learned pathways in the brain and nervous system, a sensitized alarm system, rather than by ongoing damage in the body. They are not imaginary and not 'all in your head', and because the brain can change, they can be unlearned.

The ATNS Index of Neuroplastic Symptoms does not say that CAM morphology is a neuroplastic symptom. Cartilage wear is real. What the index says is that if the structural abnormality does not fully explain the patient's symptoms, or if the response to treatment is atypical or insufficient, then an evaluation for neuroplastic symptoms is appropriate and likely to be helpful.

That matters because of a simple mismatch. If a third of pain-free adults have the same bony shape you do, the shape cannot be the whole story of your pain. Something else decides who hurts. Often that something is how sensitized the nervous system has become, how much fear surrounds the hip, and how much the person has been told to protect it. A scan report that describes 'deformity' and 'impingement' can itself raise the threat level, and a brain that expects damage with every step will produce pain with every step. Our guide to hurt versus harm explains why this is so common with structural findings.

What the research shows

The strongest evidence on CAM morphology concerns how common it is in people with no symptoms. A 2018 CT study of 100 asymptomatic adults used an alpha angle above 55 degrees as the cutoff and found CAM deformity in 31 percent of pain-free hips, most often at the front-upper part of the femoral head-neck junction. A lateral radiograph study of asymptomatic adult volunteers, using a slightly lower cutoff, found the CAM shape in about 19 percent. A 2025 CT study of asymptomatic young adults reported CAM morphology in roughly 15 percent, with additional people showing pincer or mixed shapes.

The figures vary because studies use different imaging and different cutoffs, and men have higher rates than women. But the conclusion is consistent: CAM morphology is frequently found in people who have no hip pain at all, and one review notes that the morphology on its own does not equal a diagnosis of impingement.

Research has not directly tested a neuroplastic explanation for CAM-related pain. The closest evidence comes from hip arthroscopy cohorts for FAI, where preoperative central sensitization and pain catastrophizing scores predicted pain after surgery (see our FAI article). Together these findings support the index's advice: when the shape and the symptoms do not line up, look at the nervous system too.

Signs the brain may be part of the picture

• Your scan shows CAM morphology but the pain is in a place or pattern that does not match the impingement position (deep flexion and rotation).
• Pain is present at rest, at night, or in positions that do not load the hip.
• Pain has spread to the back, groin, thigh or the other hip.
• Injections or surgery helped less, or for less time, than your surgeon expected.
• Pain started or flared during a stressful period rather than after a specific injury.
• You feel afraid to move the hip and have started avoiding activities you used to enjoy.

A solution that addresses it

There is an approach that addresses the brain's contribution to hip pain: pain reprocessing. It combines education about neuroplastic symptoms, somatic tracking (attending to a sensation with curiosity rather than fear), reducing the sense of threat around the joint, a graded return to walking, squatting and sport, emotional awareness and expression, and acceptance and commitment skills. Trained clinicians deliver it, and digital programs increasingly make it available at home. It can run alongside physiotherapy.

Cindra is a daily AI companion built around these approaches, with daily check-ins, short practices and plain-language lessons for people whose symptoms have a neuroplastic component. You can join the waitlist.

What to do next

First, make sure the structural picture is clear. See an orthopaedic specialist or sports physician, have the hip examined (not just imaged), and ask whether your symptoms, your examination and your scan actually agree. Ask specifically how much of your pain the CAM shape is likely to explain. Locking, giving way, a hip that will not bear weight, fever, or pain after a fall need prompt medical review.

If the answers are uncertain, or if treatment has not worked as expected, ask whether your pain could fit a neuroplastic pattern. Then start learning and practising: read about central sensitization, use pacing to rebuild activity, and give the hip a chance to prove it is stronger than the report made it sound.

This article is for general education and is not medical advice, and it does not diagnose or treat any condition. Persistent symptoms deserve a proper medical assessment to rule out disease or injury before a neuroplastic explanation is considered. If your symptoms are new, changing, or come with red-flag signs such as fever, unexplained weight loss, numbness or weakness, chest pain, or loss of bladder or bowel control, see a clinician promptly.