Types of Head Injuries

Quick answer

Head injuries are classified in several overlapping ways: by the part of the head injured, by whether the skull is penetrated (closed or open), by whether brain damage is in one spot or widespread (focal or diffuse), by when the damage happens (primary or secondary), and by severity (mild, moderate or severe).[1][2][3]

By part of the head

MedlinePlus defines a head injury as any trauma to the scalp, skull or brain.[1] This site also covers the face, eyes, ears, jaw and teeth.

Closed vs. open

In a closed head injury, the head strikes an object or is struck, but nothing penetrates the skull. In an open, or penetrating, head injury, an object breaks the skull and enters the brain.[1] MedlinePlus notes that closed injuries are not always less severe than open injuries.[4]

Focal vs. diffuse

NINDS explains that TBI-related damage can stay in one area of the brain, called a focal injury, or occur over a more widespread area, called a diffuse injury.[2] Diffuse axonal injury, which NINDS describes as widespread damage to the brain’s white matter, is one of the most common types of TBI.[2]

Primary vs. secondary

NINDS describes primary injury as damage that is immediate. NINDS notes that much of the damage in severe TBI develops from secondary injuries that occur days or weeks after the initial trauma.[2] NINDS explains that these secondary injuries result from reactive processes that happen after the initial head trauma and can develop over hours, days or weeks.[2]

Types of bleeding

Bleeding can occur in the brain tissue itself or in the layers around the brain.[1]

Epidural hematoma

Bleeding between the inside of the skull and the brain’s outer covering (the dura).[5]

Subdural hematoma

Blood collecting between the dura and the surface of the brain.[6]

Subarachnoid hemorrhage

Bleeding into the space surrounding the brain, the most common form of vascular injury after head trauma.[7]

Learn more: Brain bleeds

Types of skull fractures

MedlinePlus and StatPearls describe these types of skull fractures:[8][10]

  • Linear: a thin-line break without splintering, depression or distortion of the bone
  • Depressed: a break or crushed portion of skull pushed in toward the brain
  • Compound: a break with damage to or loss of the skin and splintering of the bone
  • Basilar: a fracture involving at least one of the bones at the base of the skull, usually caused by substantial blunt force[10]

Learn more: Skull fractures

By severity

TBIs are commonly grouped as mild (also called concussion), moderate or severe.[3] In clinical settings, severity is often described with the Glasgow Coma Scale, where a score of 13 to 15 is mild, 9 to 12 is moderate and 3 to 8 is severe.[9] See Mild, moderate and severe.

This page provides general information from the sources listed below. It is not medical advice and is not a substitute for evaluation by a qualified healthcare provider. In an emergency, call 911.

Sources

  1. MedlinePlus Medical Encyclopedia. “Head injury – first aid.” https://medlineplus.gov/ency/article/000028.htm
  2. National Institute of Neurological Disorders and Stroke. “Traumatic Brain Injury (TBI).” https://www.ninds.nih.gov/health-information/disorders/traumatic-brain-injury-tbi
  3. MedlinePlus Medical Encyclopedia. “Traumatic brain injury.” https://medlineplus.gov/ency/article/000799.htm
  4. MedlinePlus. “Head Injuries.” https://medlineplus.gov/headinjuries.html
  5. MedlinePlus Medical Encyclopedia. “Epidural hematoma.” https://medlineplus.gov/ency/article/001412.htm
  6. MedlinePlus Medical Encyclopedia. “Subdural hematoma.” https://medlineplus.gov/ency/article/000713.htm
  7. “The neuropathology of traumatic brain injury.” PubMed Central. https://pmc.ncbi.nlm.nih.gov/articles/PMC4694720/
  8. MedlinePlus Medical Encyclopedia. “Skull fracture.” https://medlineplus.gov/ency/article/000060.htm
  9. Munakomi S, Margetis K, Iverson LM. “Glasgow Coma Scale.” StatPearls, NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK513298/
  10. Simon LV, Newton EJ. “Basilar Skull Fractures.” StatPearls, NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK470175/

Sources last checked: October 11, 2026

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