[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Forensic medicine](https://durgical.com/en/forensic-medicine/) › [Mechanical injuries](https://durgical.com/en/forensic-medicine/areas/injuries/) › Skull fractures: linear, depressed, ring and basal

# Skull fractures: linear, depressed, ring and basal

- Finding

The type of skull fracture tells the forensic doctor about the force, the object and the direction of the impact.

Updated Nov 13, 2026

## Key points

- Linear: broad impact; it can cross the middle meningeal artery and cause an extradural haematoma.
- Depressed: a small hard object (hammer); the shape of the defect may match the striking face.
- Ring fracture around the foramen magnum: fall from height onto the feet or buttocks, or violent movement of the head on the neck.
- Basal fracture signs: bruising around the eyes, bruising behind the ear (Battle's sign), blood or clear fluid from the nose or ear.
- No fracture does not mean no brain injury; a fracture does not by itself mean death.

On this page

- The basics Key points
- What it is
- How to tell it apart
- How to recognise it
- How it forms
- Step by step
- Next step: what to do and document
- Common mistakes
- Elsewhere in DurgiPedia

- Study Test yourself

- Connections Connections

## What it is

A skull fracture shows that the head received a substantial impact. Its type gives clues: a linear fracture follows a broad impact; a depressed fracture reproduces a small hard object such as a hammer face; a comminuted fracture shows great force; a basal fracture may follow a blow to the vault or to the jaw and may be seen only from inside. A ring fracture around the foramen magnum forms when the spine is driven into the skull, as in a fall from height onto the feet or buttocks, or when the head is jerked violently. The fracture itself rarely kills; what kills is the bleeding and brain injury that go with it. And a severe brain injury can happen without any fracture.

## How to tell it apart

- Periorbital bruising from a basal fracture appears hours later and without local swelling or abrasion: it is not necessarily a punch to the eye.
- Sutures, vascular grooves and congenital gaps can be mistaken for fractures, especially in children.
- Heat in a fire can split the skull after death; such fractures lack vital reaction and usually do not match a scalp injury.
- Infant skulls deform rather than break; a fracture in an infant needs a believable explanation (see the child abuse pages).

## How to recognise it

- Linear: a single crack, often radiating from the impact point toward the base.
- Depressed: a fragment pushed inward; its outline may be round, square or elongated like the object.
- Comminuted or «spider-web»: several fragments radiating from the impact.
- Basal: across the anterior, middle or posterior fossa; a transverse fracture through both middle fossae is sometimes called a hinge fracture.
- Ring: a circle of bone around the foramen magnum separated from the rest of the base.

## How it forms

- The skull bends inward under the impact and breaks outward at a distance where it is weaker.
- Small contact area plus high force: depression; broad area: linear or comminuted fracture.
- Force through the spine (fall onto the feet) or the jaw can break the base without any vault impact.
- When a second fracture line meets an earlier one, it usually stops there: this can help order several blows.

## Step by step

- Strip the dura from the base and the vault to see all fracture lines.
- Draw or photograph each line with a scale and relate it to the scalp injury above.
- Measure any depressed fragment and compare it with a possible weapon.
- Note fractures stopping at earlier lines to suggest their order.

## Next step: what to do and document

- In a living patient, record the clinical signs of a basal fracture (periorbital bruising, Battle's sign, fluid from the nose or ear) with the time they appeared.
- Keep the CT with bone windows: the fracture pattern supports the reconstruction of the event.
- Describe a depressed fracture by its size and shape; if a weapon is found, the comparison is made by the forensic service.
- In a child with a skull fracture and an inconsistent history, follow the child-protection reporting route.
- Write what you see, not the cause: «bilateral periorbital bruising» rather than «blows to the eyes».

## Common mistakes

- Reading periorbital bruising from a basal fracture as direct blows to the face.
- Calling a suture or a vascular groove a fracture.
- Taking a heat fracture in a burned body as an injury in life.
- Assuming that a skull without fracture means a minor injury.

## Test yourself

Think of the answer, then tap the question to see it.

## Which mechanism typically produces a ring fracture around the foramen magnum?

A fall from height onto the feet or buttocks, which drives the spine into the skull, or a violent movement of the head on the neck.

## What does a depressed skull fracture suggest about the object?

A hard object with a small striking surface, such as a hammer; the shape of the defect can match its face.

## Why may periorbital bruising not mean a blow to the eyes?

A fracture of the anterior skull base lets blood track into the eyelids, producing bruising hours later without local abrasion or swelling.

## How can the order of two blows be estimated from skull fractures?

A later fracture line usually stops where it meets an earlier one.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/forensic-medicine/skull-fractures-linear-depressed-ring-and-basal/)

## Elsewhere in DurgiPedia

- [Brain and spinal cord trauma](https://durgical.com/en/general-pathology/brain-and-spinal-cord-trauma/)

## Connections

## Related 6

- [Head injury in forensic medicine: the scalp and an overview](https://durgical.com/en/forensic-medicine/head-injury-in-forensic-medicine-the-scalp-and-an-overview/)
- [Extradural, subdural and subarachnoid haemorrhage in forensic practice](https://durgical.com/en/forensic-medicine/extradural-subdural-and-subarachnoid-haemorrhage-in-forensic-practice/)
- [Contusions, coup–contrecoup and diffuse axonal injury](https://durgical.com/en/forensic-medicine/contusions-coup-contrecoup-and-diffuse-axonal-injury/)
- [Spinal and cervical injuries](https://durgical.com/en/forensic-medicine/spinal-and-cervical-injuries/)
- [Patterned injuries: what the mark says about the object](https://durgical.com/en/forensic-medicine/patterned-injuries-what-the-mark-says-about-the-object/)
- [Postmortem artefacts: what is not an injury](https://durgical.com/en/forensic-medicine/postmortem-artefacts-what-is-not-an-injury/)

## Related conditions 4

- [Basilar skull fracture](https://durgical.com/en/conditions/basilar-skull-fracture/)
- [Traumatic brain injury](https://durgical.com/en/conditions/traumatic-brain-injury/)
- [Epidural haematoma](https://durgical.com/en/conditions/epidural-haematoma/)
- [Child maltreatment (physical abuse, abusive head trauma, neglect)](https://durgical.com/en/conditions/child-maltreatment/)

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Educational content on forensic and legal medicine; not legal advice and no substitute for the technical guides of Colombia's National Institute of Legal Medicine and Forensic Sciences. Laws change: each page links the official text and says when it was last checked. For a real case, follow the guide in force and ask the competent authority.

Sources: [Basilar Skull Fractures](https://www.ncbi.nlm.nih.gov/books/NBK470175/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Pediatric Skull Fractures](https://www.ncbi.nlm.nih.gov/books/NBK482218/) (StatPearls Publishing (NCBI Bookshelf), 2025); [Blunt Force Trauma](https://www.ncbi.nlm.nih.gov/books/NBK470338/) (StatPearls Publishing (NCBI Bookshelf), 2023).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/forensic-medicine/skull-fractures-linear-depressed-ring-and-basal/