Why is there a crater in my skull? Unpacking the causes of skull indentations

September 28, 2025 •

4 min read

While the human skull is not perfectly smooth, a noticeable depression or 'crater' can be a cause for concern. The potential causes range from benign natural variations to serious medical conditions, making it crucial to understand the underlying factors if you notice a dent in your head.

Quick Summary

A dent or 'crater' in the skull can result from various factors, including head trauma, congenital conditions present from birth, or rare bone diseases like Paget's or Gorham-Stout syndrome. While some indentations are normal anatomical variations, a new or changing dent should always be evaluated by a healthcare provider, especially if accompanied by other symptoms.

Key Points

Not Always Serious: A skull dent can be a harmless natural variation or a lingering mark from an old, minor injury.
Trauma is a Common Cause: Direct impacts to the head can lead to a depressed skull fracture, a serious condition requiring immediate medical attention.
Congenital Variations Exist: Some skull indentations can be present from birth due to natural variations in bone structure, like the cranial sutures.
Rare Bone Diseases: Less common causes include conditions like Paget's disease, Gorham-Stout syndrome, and bone cancer, which affect bone health.
Seek Medical Advice for New Dents: A newly discovered, painful, or growing indentation, especially with other symptoms like headaches or vision problems, should prompt a doctor's visit.
Imaging Can Pinpoint the Cause: To determine the cause, doctors may use imaging tests such as CT scans or MRIs to view the skull's bone structure.

Common causes of skull indentations

Identifying a depression or dent in your skull can be alarming. While it's important to seek medical advice for any new or concerning changes, it's also helpful to understand the possible reasons behind it. These causes can be broadly categorized into trauma, congenital issues, and underlying medical conditions.

Head trauma

Traumatic injuries are one of the most common causes of skull indentations. A direct blow to the head from an accident, fall, or sport-related injury can lead to a depressed skull fracture. In this type of fracture, a piece of the skull is pushed inward towards the brain. The severity can range from mild to life-threatening, and it is considered a medical emergency.

Depressed skull fracture: A severe impact can break the skull and cause a visible dent. This requires immediate medical attention and, in many cases, surgery to prevent brain damage.
Old injury or hematoma: A past injury, even if minor, could have caused a small, healed depression. A hematoma (a collection of blood) that occurred under the scalp could also leave a small indentation after it has been reabsorbed by the body.
Pressure from headgear: In rare cases, continuous, prolonged pressure from tight-fitting headgear, like helmets or headphones, can cause temporary or permanent indentations.

Congenital variations

Not all dents are the result of injury. Some people are born with variations in their skull shape that are entirely normal and harmless.

Cranial sutures: The skull is made of several bony plates that fuse together over time. The junctions where these plates meet, known as sutures, can sometimes leave minor ridges or indentations. In babies, the soft spots, or fontanelles, eventually harden and fuse, but a small residual dip can remain.
Craniosynostosis: This rare congenital defect occurs when a baby's skull plates fuse prematurely. It can restrict the skull's growth, leading to an abnormal head shape, including depressions.

Medical conditions affecting bone health

Certain underlying health issues can affect bone density and regeneration, leading to changes in the skull's shape over time.

Comparison of skull-affecting conditions


Condition	Key Feature	Affect on Skull	When to Suspect	Treatment
Paget's Disease of Bone	Abnormal bone growth and breakdown.	Enlarged and misshapen, sometimes with dents.	Age over 55, bone pain, headaches.	Medications to regulate bone growth.
Gorham-Stout Syndrome	Progressive bone loss.	Can cause visible dents due to bone destruction.	Young adults, bone pain, swelling.	Managing symptoms, radiation therapy.
Osteodystrophy	Thinning of skull bones.	Deformities, often seen with kidney disease.	Older adults or children with chronic kidney disease.	Addressing underlying kidney disease.
Bone Cancer (e.g., Multiple Myeloma)	Abnormal tissue growth.	Bone destruction, leading to depressions or irregularities.	Unexplained bone pain, fatigue, weight loss.	Radiation, chemotherapy, surgery.
Excess Vitamin A	Can soften bones.	Can lead to bony deformities or depressions.	High vitamin A intake, typically from supplements.	Stop supplementation, blood test.

When to see a doctor

While some skull indentations are harmless, it is crucial to consult a healthcare professional for a proper diagnosis, especially if the dent is new, painful, or growing. Seeking medical advice is particularly important if the indentation is accompanied by other symptoms.

Signs that warrant immediate medical attention

Sudden appearance, especially after a head injury.
Severe or persistent headaches.
Vision or hearing problems.
Nausea, vomiting, or dizziness.
Confusion or changes in consciousness.
Fluid leaking from the nose or ears.
Numbness or weakness in any part of the body.

Diagnostic procedures

A doctor may perform a physical exam and review your medical history. To determine the exact cause, they may order imaging tests like X-rays, CT scans, or MRI scans to get a detailed look at the skull's bone structure.

Physical examination: A doctor can often feel the dent and assess its characteristics, size, and location.
Imaging tests: These are crucial for visualizing the bone and underlying structures. A computed tomography (CT) scan is a common and effective tool for examining the skull.
Blood tests: In cases of suspected bone or vitamin issues, blood tests can be used to check for deficiencies or diseases.

For more information on head injuries and when to seek care, you can visit the NHS head injury guide.

Conclusion

A skull indentation can be a frightening discovery, but it is not always a sign of a serious condition. From benign congenital variations to the effects of old, healed injuries, many factors can contribute. However, a new, painful, or growing dent, or one accompanied by other neurological symptoms, requires immediate medical evaluation. Consulting a healthcare professional is the only way to get an accurate diagnosis and ensure proper management, ruling out more serious underlying issues like bone disease or tumors. Your doctor can determine the cause and guide you on the best course of action, which may involve monitoring, medication, or in rare cases, surgery. Always prioritize your health and well-being by seeking expert medical advice for any notable changes in your body.

Frequently Asked Questions

Yes, it is possible for a dent in your skull to be a normal anatomical variation. The skull is not perfectly smooth and has ridges and indentations where the bony plates have fused together. These are typically harmless and present from birth.

A depressed skull fracture is a serious injury where a portion of the skull is pushed inward toward the brain, often due to a strong impact. It is a medical emergency that requires prompt treatment to prevent brain damage.

Yes, certain medical conditions can affect bone health and cause dents. These include Paget's disease of bone, a disorder affecting bone regeneration, and Gorham-Stout syndrome, a rare disease involving bone loss.

Absolutely. An indentation can sometimes be the result of a healed injury from many years ago. A hematoma under the scalp, caused by an old trauma, can also leave a small, lasting dent after it has resolved.

You should see a doctor for a new, painful, or growing skull indentation, or if it is accompanied by other symptoms like headaches, dizziness, or vision changes. If the dent occurred after a head injury, seek immediate medical attention.

In very rare cases, prolonged and continuous pressure from tight-fitting headgear, such as some sports helmets or headphones, has been reported to cause temporary indentations.

A doctor will typically perform a physical examination and take a full medical history. To confirm the cause, they may order imaging tests like a CT scan, MRI, or X-ray to get a detailed view of the skull's bone structure.