Why are there holes in my skull? Understanding Normal Anatomy and Health Concerns

September 28, 2025 •

4 min read

Anatomical studies show the human skull is naturally perforated by numerous small openings called foramina to allow crucial structures to pass through. So, why are there holes in my skull? It’s not just about natural passages; new or unusual dents can signal underlying medical issues that require attention.

Quick Summary

The skull naturally contains small openings called foramina that allow nerves and blood vessels to pass through, a completely normal part of anatomy. However, new or noticeable holes can also be caused by trauma, congenital conditions like encephalocele, rare diseases, or surgical procedures.

Key Points

Foramina are normal: Your skull contains numerous natural openings called foramina that allow nerves and blood vessels to pass through, a normal part of healthy anatomy.
Trauma can cause dents: A depressed skull fracture, resulting from a blow to the head, can cause a noticeable and serious indentation that requires immediate medical attention.
Congenital defects are a cause: Rare conditions like encephalocele occur when the skull bones don't fully fuse, leaving a hole that is present from birth.
Bone diseases can alter skull shape: Paget's disease, Gorham-Stout syndrome, and certain cancers can cause abnormal bone growth or loss, leading to new or changing depressions over time.
Surgical holes are common: Burr holes are intentionally drilled by neurosurgeons during procedures to relieve pressure or drain fluid and may leave a permanent, benign indentation.
Monitor for other symptoms: Any new dent accompanied by headaches, vision changes, confusion, or balance issues warrants immediate medical evaluation.

The Intricate Anatomy of Your Skull

Beyond its function as a protective shell for the brain, the human skull is a complex structure with multiple natural openings designed to facilitate essential bodily functions. These openings, known as foramina (singular: foramen), canals, and fissures, are pathways for nerves and blood vessels that serve the brain, face, and other structures in the head and neck.

For example, the largest hole at the base of the skull, the foramen magnum, allows the spinal cord to connect with the brain. Other, smaller foramina enable the facial nerve, optic nerve, and numerous arteries and veins to pass through without being compressed by the surrounding bone. Knowing this basic anatomy can help distinguish between a normal feature and a potential health concern.

Potential Causes of Skull Depressions and Perforations

While natural foramina are part of a healthy skull, newly formed or significant dents are not. If you have noticed an unusual indentation, it is important to consider the potential causes, which range from traumatic injuries to rare medical conditions.

Traumatic Injuries

Blunt force trauma to the head, such as from an accident or a fall, can cause a depressed skull fracture. This is a serious injury where a section of the skull is pushed inward towards the brain. This type of fracture often requires emergency medical treatment. Symptoms can include headaches, impaired vision, confusion, or a loss of consciousness.

Congenital Conditions

Some individuals are born with skull deformities, which can present as indentations. Encephalocele is a rare birth defect where the bones of the skull do not close completely, leaving an opening through which brain tissue and surrounding membranes can protrude. In other cases, a congenital skull depression may result from pressure in the womb or during delivery, which often resolves on its own. Premature fusion of the skull's bones, a condition called craniosynostosis, also alters head shape.

Acquired Bone Diseases

Rare bone disorders can lead to abnormal remodeling of bone tissue, creating noticeable irregularities in the skull:

Paget's Disease of Bone: This chronic condition disrupts the natural cycle of bone breakdown and regrowth, causing bones to become enlarged, misshapen, and weakened. It can affect the skull, leading to headaches, hearing loss, and sometimes a visible enlargement or denting.
Gorham-Stout Syndrome: A very rare disorder, also known as "vanishing bone disease," causes progressive bone loss and replacement with other tissue. While it can affect any bone, it may lead to skull indentations.
Bone Cancer: Malignant tumors can either originate in the skull or spread from other parts of the body, leading to bone destruction and visible indentations. Examples include multiple myeloma or certain types of osteosarcoma.

Surgical Causes

Neurosurgeons sometimes intentionally create small openings, called burr holes, in the skull. This procedure is typically performed to relieve pressure on the brain, drain blood from a hematoma, or during other surgical interventions. The bone is often replaced or, in some cases, the opening is left to heal, which can leave a permanent impression. For more information on this procedure, you can read about it on the Johns Hopkins Medicine website.

How to Tell the Difference: Natural vs. Abnormal Holes

Distinguishing a normal anatomical variation from a potentially serious issue is key. Use the table below to compare the characteristics of natural foramina with new or abnormal depressions.


Feature	Natural Foramina	New or Abnormal Depressions
Appearance	Small, rounded openings, typically symmetrical.	Irregular shape, asymmetrical, can be large or small.
Location	Predictable locations at the base of the skull or within bone plates.	Can appear anywhere on the skull.
Sensation	Not usually felt unless specifically probing the area.	Often associated with pain, swelling, or tenderness.
Symptoms	No accompanying symptoms under normal circumstances.	Can be accompanied by headaches, vision changes, confusion, or seizures.
Onset	Present from birth or early development.	Develops suddenly after an injury or gradually over time.

When to See a Doctor

It is always wise to consult a healthcare professional about any new or concerning changes to your body. Specifically, you should seek immediate medical attention if a new dent appears following any head trauma. For non-traumatic dents, schedule an appointment with a doctor, especially if you experience any of the following symptoms:

Persistent or worsening headaches
Changes in vision or hearing
Balance problems or dizziness
Confusion, memory loss, or behavioral changes
Numbness or weakness in any part of your body
Fever or a stiff neck

Conclusion

While the concept of why are there holes in my skull might sound alarming, the reality is that many of these are essential, natural parts of our anatomy. However, paying close attention to new or changing dents and depressions is vital for your health. Distinguishing between normal anatomy and a potential medical problem is the first step toward a proper diagnosis and care. Always consult a healthcare provider for any concerns to ensure your peace of mind and well-being.

Frequently Asked Questions

Not necessarily. Your skull has natural openings, or foramina, that are completely normal and crucial for nerves and blood vessels. However, new or sudden indentations from trauma, disease, or birth defects can be serious and should be evaluated by a doctor.

The largest hole in the skull is the foramen magnum, located at the base of the skull. It is the opening through which the brainstem connects to the spinal cord, allowing communication between the brain and the rest of the body.

A small indentation from a minor injury might be temporary swelling and heal, but a depressed skull fracture, where bone is pushed inward, requires immediate medical evaluation. Never assume a dent after head trauma will heal without a doctor's assessment.

A skull deformity from Paget's disease can feel like an irregular or enlarged area on the bone. It may cause accompanying headaches or hearing loss. The onset is typically gradual, and it's not always painful.

The 'soft spots' on a baby's head, called fontanelles, are not holes but fibrous tissue separating the unfused skull plates. They allow the skull to flex during birth and the brain to grow. They naturally close within the first few years of life.

A doctor will take a thorough medical history and perform a physical exam. To determine the cause of an indentation, they may order imaging tests like a CT scan, MRI, or X-ray for a detailed look at the bone and brain.

Yes, many people live with normal foramina or even surgical burr holes. However, living with an untreated depressed fracture or encephalocele can be dangerous and lead to severe complications, highlighting the importance of medical evaluation.