foramen magnum

Information about foramen magnum

Bone: Foramen magnum
Occipital bone. Inner surface.
subject #31 129
MeSH Foramen+Magnum
In anatomy, in the occipital bone, the foramen magnum (Latin: 'great hole') is one of the several oval or circular apertures in the base of the skull (the foramina), through which the medulla oblongata (an extension of the spinal cord) enters and exits the skull vault.

Apart from the transmission of the medulla oblongata and its membranes, the foramen magnum transmits the vertebral arteries, the anterior and posterior spinal arteries, the membrana tectoria and alar ligaments.

Importance

In humans, the foramen magnum is farther underneath the head than in great apes. Thus, in humans, the neck muscles do not need to be as robust in order to hold the head upright. Comparisons of the position of the foramen magnum in early hominid species are useful to determine how comfortable a particular species was when walking on two limbs (bipedality) rather than four.

Additional images


Occipital bone. Outer surface.

Base of skull. Inferior surface.

Base of the skull. Upper surface.


The foramen magnum is the border line above which is the brain, and below, the spinal cord.

See also

External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
Human cranial bones
 •  • [ e]
occipital bone: Foramen magnum | Squama occipitalis (Inion | Nuchal lines | Planum occipitale | Planum nuchale | Internal occipital protuberance | Sagittal sulcus | Internal occipital crest) | Lateral parts (Hypoglossal canal | Condyloid fossa | Condyloid canal | Jugular process | Jugular tubercle) | Basilar part (Pharyngeal tubercle) parietal bone: Parietal eminence | Temporal line | Parietal foramen frontal bone: Squama frontalis (Frontal suture | Frontal eminence | Superciliary arches | Glabella | Supraorbital foramen | Zygomatic process | Sagittal sulcus | Frontal crest | Foramen cecum) | Pars orbitalis (Frontal sinus | Frontonasal duct) temporal bone: Squama temporalis (Articular tubercle | Suprameatal triangle | Mandibular fossa | Petrotympanic fissure) | Mastoid portion (Mastoid foramen | Mastoid process | Mastoid notch | Occipital groove | Sigmoid sulcus | Mastoid antrum) | Petrous portion (Hiatus of the facial canal | Internal auditory meatus | Subarcuate fossa | Carotid canal | Aqueduct of cochlea | Jugular fossa | Inferior tympanic canaliculus | Mastoid canaliculus | Styloid process | Stylomastoid foramen | Jugular foramen | Petrosquamous suture) | Tympanic part (Suprameatal spine) | Zygomatic process sphenoid bone: Sphenoidal sinuses | Ethmoidal spine | Optic foramen | Sella turcica | Fossa hypophyseos | Dorsum sellae | Posterior clinoid processes | Carotid groove | Lingula sphenoidalis | Sphenoidal conchæ | Great wings (Spina angularis | Foramen rotundum | Foramen ovale | Foramen Vesalii | Foramen spinosum | Infratemporal crest | Sulcus tubae auditivae | Small wings | Superior orbital fissure | Anterior clinoid process | Optic foramen) | Pterygoid processes (Pterygoid fossa | Scaphoid fossa | Lateral pterygoid plate | Medial pterygoid plate | Pterygoid hamulus | Sphenoidal conchæ | Sphenoidal sinuses) ethmoid bone: Cribriform plate | Crista galli | Perpendicular plate | Labyrinth | Ethmoid sinus | Uncinate process | Middle nasal concha | Superior meatus | Superior nasal concha | Middle meatus
Facial bones
maxilla: Incisive fossa | Maxillary sinus | Incisive fossa | Canine fossa | Infraorbital foramen | Anterior nasal spine | Alveolar canals | Orbitofrontal cortex | Infraorbital canal | Pterygopalatine canal | Zygomatic process | Agger nasi | Anterior lacrimal crest | Alveolar process | Incisive foramen | Incisive canals | Foramina of Scarpa | Premaxilla | Anterior nasal spine lacrimal bone: Posterior lacrimal crest zygomatic bone: Zygomaticofacial foramen | Zygomaticotemporal foramen | Zygomaticoörbital foramina palatine bone: Pterygopalatine fossa | Pterygoid fossa | Horizontal plate | Posterior nasal spine | Perpendicular plate | Pterygopalatine canal | Sphenopalatine foramen | Pyramidal process | Orbital process | Sphenoidal process mandible: Symphysis menti | Mental foramen | Mylohyoid line | Ramus mandibulae | Mandibular foramen | Mandibular canal others: nasal bone | inferior nasal conchae | vomer bone
composite structures
Cranial sutures: Coronal | Lambdoidal | Occipitomastoid | Parietomastoid | Sphenofrontal | Sphenoparietal |Sphenosquamosal | Sphenozygomatic |Squamosal | Zygomaticotemporal | Zygomaticofrontal | Frontal/Metopic | Sagittal | Frontoethmoidal | Petrosquamous | Sphenoethmoidal | Sphenopetrosal Asterion | Nasion | Pterion | Dacryon | Inferior orbital fissure
 •  • [ e]
Foramina of the skull (and canals and fissures)
Foraminacecum - ethmoidal (anterior, posterior) - incisive - jugular - lacerum - magnum - mandibular - mastoid - mental - optic - orbital (infraorbital, supraorbital) - ovale - palatine (greater, lesser) - parietal - rotundum - sphenopalatine - spinosum - stylomastoid - zygomaticofacial - zygomaticotemporal
Canalscarotid - condylar - hypoglossal - incisive - pterygoid
Fissuresorbital (inferior, superior) - petrotympanic
otherexternal acoustic meatus - internal acoustic meatus - cribriform plate
Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
..... Click the link for more information.
Anatomy (from the Greek ἀνατομία anatomia, from ἀνατέμνειν
..... Click the link for more information.
The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoid in shape and curved on itself. It is pierced by a large oval aperture, the foramen magnum, through which the cranial cavity communicates with the vertebral canal.
..... Click the link for more information.
skull is a bony structure found in many animals which serves as the general framework for the head. The skull supports the structures of the face and protects the head against injury.

The skull can be subdivided into two parts: the cranium and the mandible.
..... Click the link for more information.
bone location foramen vessels nerves
frontal - supraorbital foramen supraorbital artery, supraorbital vein supraorbital nerve
frontal anterior cranial fossa foramen cecum emissary veins to superior sagittal sinus -
..... Click the link for more information.
The medulla oblongata is the lower portion of the brainstem.

Location

By anatomical terms of location, it is rostral to the spinal cord and caudal to the pons, which is in turn ventral to the cerebellum.
..... Click the link for more information.
spinal chord is a thin, tubular bundle of nerves that is an extension of the central nervous system from the brain and is enclosed in and protected by the bony vertebral column.
..... Click the link for more information.
The vertebral arteries are branches of the subclavian arteries.

Cervical

They arise, one on each side of the body, then enter deep to the transverse process of the level of the 6th cervical vertebrae (C6).
..... Click the link for more information.
In human anatomy, the anterior spinal artery is the blood vessel that supplies the anterior portion of the spinal cord. It arises from branches of the vertebral arteries and is supplied by the anterior segmental medullary arteries, including the artery of Adamkiewicz, and courses
..... Click the link for more information.
The posterior spinal artery (dorsal spinal artery) arises from the vertebral artery, adjacent to the medulla oblongata.

Path

It passes posteriorly to descend the medulla passing in front of the posterior roots of the spinal nerves.
..... Click the link for more information.
Tectorial membrane can refer to:
  • Tectorial membrane (cochlea)
  • Tectorial membrane (axis)

..... Click the link for more information.
The alar ligaments connect the sides of the dens (on the axis, or the second cervical vertebra) to tubercles on the medial side of the occipital condyle.

They are short, tough, fibrous cords that attach the skull to C1 vertebra and function to check side-to-side movements
..... Click the link for more information.
Bipedalism is standing, or moving for example by walking, running, or hopping, on two appendages (typically legs). An animal or machine that usually moves in a bipedal manner is known as a biped (/'baɪ.
..... Click the link for more information.
The posterior cranial fossa is part of the intracranial cavity, located between the foramen magnum and tentorium cerebelli. It contains the brainstem and cerebellum.

This is the most inferior of the fossae. It houses the cerebellum, medulla and pons.
..... Click the link for more information.
The State University of New York Health Science Center at Brooklyn, better known as SUNY Downstate Medical Center, is an academic medical center and is the only one of its kind in the Borough of Brooklyn in New York City.
..... Click the link for more information.
Georgetown University is a private, Jesuit, research university, located in Washington, D.C.'s Georgetown neighborhood. Father John Carroll founded the school in 1789, though its roots extend back to 1634.
..... Click the link for more information.
Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
..... Click the link for more information.
Public domain comprises the body of knowledge and innovation (especially creative works such as writing, art, music, and inventions) in relation to which no person or other legal entity can establish or maintain proprietary interests within a particular legal jurisdiction.
..... Click the link for more information.
Henry Gray's Anatomy of the Human Body (or Gray's Anatomy as it has commonly been shortened) is an English-language human anatomy textbook widely regarded as a classic work on the subject.
..... Click the link for more information.
skull is normally made up of 22 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, synarthrodial (immovable) joints formed by bony ossification, with Sharpey's fibres permitting some flexibility.
..... Click the link for more information.
The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoid in shape and curved on itself. It is pierced by a large oval aperture, the foramen magnum, through which the cranial cavity communicates with the vertebral canal.
..... Click the link for more information.
The squama of the occipital bone, situated above and behind the foramen magnum, is curved from above downward and from side to side.

External surface

The external surface
..... Click the link for more information.
The inion is the most prominent projection of the occipital bone at the lower rear part of the skull. The ligamentum nuchae and trapezius muscle attach to it.

The term external occipital protuberance (protuberantia occipitalis externa
..... Click the link for more information.
The nuchal lines are four curved lines on the external surface of the occipital bone:
  • The upper, often faintly marked, is named the highest nuchal line, and to it the galea aponeurotica is attached.

..... Click the link for more information.
planum occipitale (or occipital plane), and is covered by the Occipitalis muscle.

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.
..... Click the link for more information.
planum nuchale (or nuchal plane), is rough and irregular for the attachment of several muscles.

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.
..... Click the link for more information.
internal occipital protuberance.

See also

  • external occipital protuberance

External links

  • Roche Lexicon - illustrated navigator, at Elsevier 34257.000-2
  • Diagram at uni-mainz.

..... Click the link for more information.
sagittal sulcus, the edges of which unite below to form a ridge, the frontal crest; the sulcus lodges the superior sagittal sinus, while its margins and the crest afford attachment to the falx cerebri.

It also is part of the parietal, and occipital bones.
..... Click the link for more information.
internal occipital crest; it bifurcates near the foramen magnum and gives attachment to the falx cerebelli; in the attached margin of this falx is the occipital sinus, which is sometimes duplicated.
..... Click the link for more information.
occipital bone: Foramen magnum | Squama occipitalis (Inion | Nuchal lines | Planum occipitale | Planum nuchale | Internal occipital protuberance | Sagittal sulcus | Internal occipital crest) | Lateral parts (Hypoglossal canal | Condyloid fossa | Condyloid canal | Jugular process |
..... Click the link for more information.

This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.