Foramen magnum
Last revised by Derek Smith ◉ on 11 Sep 2021
Citation, DOI, disclosures and article data
Citation:
Maingard J, Smith D, Rasuli B, et al. Foramen magnum. Reference article, Radiopaedia.org (Accessed on 01 Oct 2023) https://doi.org/10.53347/rID-25317
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25317
Article created:
19 Oct 2013, Julian Maingard ◈
Disclosures:
At the time the article was created Julian Maingard had no recorded disclosures.
View Julian Maingard's current disclosuresLast revised:
11 Sep 2021, Derek Smith ◉
Disclosures:
At the time the article was last revised Derek Smith had no recorded disclosures.
View Derek Smith's current disclosuresRevisions:
17 times, by 8 contributors - see full revision history and disclosures
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The foramen magnum is the largest foramen of the skull and is part of the occipital bone 1. It is oval in shape with a large anteroposterior diameter 2.
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Gross anatomy
The foramen magnum is found in the most inferior part of the posterior cranial fossa 3. It is traversed by vital structures including the medulla oblongata 1. In the midline, the anterior margin is the basion and the posterior margin is the opisthion.
Relations
- anteriorly: basilar part of occipital bone
- anterolaterally: occipital condyles, hypoglossal canal, jugular foramen
- posteriorly: squamous part of occipital bone with the internal occipital crest
Contents
- medulla oblongata
- meninges
- spinal root of the accessory nerve
- vertebral arteries
- anterior and posterior spinal arteries
- tectorial membrane and alar ligaments 2
Radiographic features
CT
- at the level of the foramen magnum CSF is seen to surround the medulla which is reduced or absent in tonsillar herniation
Related pathology
- foramen magnum meningioma 2
- cerebral herniation
- Chiari malformations
Quiz questions
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References
- 1. Avci E, Dagtekin A, Ozturk AH et-al. Anatomical variations of the foramen magnum, occipital condyle and jugular tubercle. Turk Neurosurg. 2010;21 (2): 181-90. doi:10.5137/1019-5149.JTN.3838-10.1 - Pubmed citation
- 2. Boulton MR, Cusimano MD. Foramen magnum meningiomas: concepts, classifications, and nuances. Neurosurg Focus. 2006;14 (6): e10. Pubmed citation
- 3. Drake. Gray's Basic Anatomy: with STUDENT CONSULT Online Access, 1e (Grays Anatomy for Students). Churchill Livingstone. ISBN:1455710784. Read it at Google Books - Find it at Amazon
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common carotid artery
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arterial supply
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