Occipital bone

Occipital bone: Anatomy & FunctionKey facts about the anatomy of the occipital bone.
~ 3 min

In this pdf-note, we will learn about the structure of the occipital bone (os occipitale). It is located in the posteroinferior part of the cranium and is the bone that connects the cranium with the cervical spine.

Occipital bone (os occipitale)
Occipital bone (os occipitale)

There are several parts of the occipital bone:

  • Basilar part (pars basilaris)

Basilar part (pars basilaris)
Basilar part (pars basilaris)
  • Squamous part of the occipital bone (squama occipitalis)

    Squamous part of the occipital bone (squama occipitalis)
    Squamous part of the occipital bone (squama occipitalis)
  • Lateral part (pars lateralis) – paired

    Lateral part (pars lateralis)
    Lateral part (pars lateralis)

    All these parts surround the so-called foramen magnum of the occipital bone (foramen occipitale magnum).

    Foramen magnum (foramen occipitale magnum)
    Foramen magnum (foramen occipitale magnum)

    At the age of 17-20 years, the basilar part fuses with the posterior surface of the body of the sphenoidal bone, resulting in the formation of the so-called clivus (clivus).

    Clivus (clivus)
    Clivus (clivus)

    The basilar part has two surfaces:

  • Superior (cerebral) surface (facies superior / cerebralis)

  • Inferior surface (facies inferior)

    On the basilar part in the lateral region, there is a groove for the inferior petrosal sinus (sulcus sinus petrosi inferioris).

    Groove for the inferior petrosal sinus (sulcus sinus petrosi inferioris)
    Groove for the inferior petrosal sinus (sulcus sinus petrosi inferioris)

    On this groove, there is a pharyngeal tubercle (tuberculum pharyngeum), to which the posterior wall of the pharynx is attached.

    Pharyngeal tubercle (tuberculum pharyngeum)
    Pharyngeal tubercle (tuberculum pharyngeum)

    The lateral parts are located on the flanks of the foramen magnum.

    Here on the lower surface of each flank, there is an occipital condyle (condylus occipitalis), which connects to the superior articular surface of the atlas.

    Occipital condyle (condylus occipitalis)
    Occipital condyle (condylus occipitalis)

    Just above the condyle there is a sublingual canal (canalis nervi hypoglossalis), in which the sublingual nerve passes.

    Sublingual canal (canalis nervi hypoglossalis)
    Sublingual canal (canalis nervi hypoglossalis)

    There is also a condylar fossa (fossa condylaris) above the condyle.

    Condylar fossa (fossa condylaris)
    Condylar fossa (fossa condylaris)

    In its inferior part, there is a condylar canal (canalis condylaris), in which the condylar emissary vein passes.

    Condylar canal (canalis condylaris)
    Condylar canal (canalis condylaris)

    Laterally from the condyle, there is a jugular notch (incisura jugularis), which is bounded posteriorly by a rather large jugular process (processus jugularis).

    Jugular notch (incisura jugularis)
    Jugular notch (incisura jugularis)
    Jugular process (processus jugularis)
    Jugular process (processus jugularis)

    This notch is connected to the notch of the temporal bone of the same name, resulting in the formation of a jugular foramen (foramen jugulare).

    Jugular foramen (foramen jugulare)
    Jugular foramen (foramen jugulare)

    There is also an intrajugular process (processus intrajugularis), which divides the foramen into two compartments.

    Intrajugular process (processus intrajugularis)
    Intrajugular process (processus intrajugularis)

    In the anterior compartment of the lateral part, on each side there is a jugular tubercle (tuberculum jugulare), which is the place of insertion of the atlanto-occipital membrane.

    Jugular tubercle (tuberculum jugulare)
    Jugular tubercle (tuberculum jugulare)

    On the cerebral surface of the lateral part there is a groove for the sigmoid sinus (sulcus sinus sigmoidei), in which the sinus venosus of the same name is located.

    Groove for the sigmoid sinus (sulcus sinus sigmoidei)
    Groove for the sigmoid sinus (sulcus sinus sigmoidei)

    The occipital part has two surfaces:

  • External surface (facies externa)

  • Internal (cerebral) surface (facies interna / cerebralis)

    On the external surface, there is an external occipital protuberance (protuberantia occipitalis externa).

    External occipital protuberance (protuberantia occipitalis externa)
    External occipital protuberance (protuberantia occipitalis externa)

    The external occipital crest (crista occipitalis externa) arises from it in the inferior direction.

    External occipital crest (crista occipitalis externa)
    External occipital crest (crista occipitalis externa)

    Laterally, the superior nuchal line (linea nuchalis superior) arises.

    Superior nuchal line (linea nuchalis superior)
    Superior nuchal line (linea nuchalis superior)

    Slightly inferiorly on the external surface of the occipital bone, there is also an inferior nuchal line (linea nuchalis inferior).

    Inferior nuchal line (linea nuchalis inferior)
    Inferior nuchal line (linea nuchalis inferior)

    And in the superior part of the bone, there is the highest nuchal line (linea nuchalis suprema).

    Highest nuchal line (linea nuchalis suprema)
    Highest nuchal line (linea nuchalis suprema)

    Muscles and fascia are attached to these structures.

    The following pits form most of the cerebral surface of the squamous part:

  • Cerebral fossa (fossa cerebralis)

  • Cerebellar fossa (fossa cerebellaris)

Cerebral fossa (fossa cerebralis)
Cerebral fossa (fossa cerebralis)
Cerebellar fossa (fossa cerebellaris)
Cerebellar fossa (fossa cerebellaris)

On the cerebral surface, there is a cruciform eminence (eminentia cruciformis), which is the confluence of the snus venosi.

Cruciform eminence (eminentia cruciformis)
Cruciform eminence (eminentia cruciformis)

Here in the center, there is an internal occipital protuberance (protuberantia occipitalis interna).

Internal occipital protuberance (protuberantia occipitalis interna)
Internal occipital protuberance (protuberantia occipitalis interna)

On the flanks of the cruciform eminence, there is a groove for the transverse sinus (sulcus sinus transversi).

Groove for the transverse sinus (sulcus sinus transversi)
Groove for the transverse sinus (sulcus sinus transversi)

The groove for the superior sagittal sinus (sulcus sinus sagittalis superioris) arises upward from the eminence.

Superior sagittal sinus (sulcus sinus sagittalis superioris)
Superior sagittal sinus (sulcus sinus sagittalis superioris)

And from the bottom the eminence continues into the internal occipital crest (crista occipitalis interna).

Internal occipital crest (crista occipitalis interna)
Internal occipital crest (crista occipitalis interna)
Dictionary

Occipital bone: Anatomy & Function

occipital bone
os occipitale
basilar part
pars basilaris
squamous part of the occipital bone
squama occipitalis
lateral part
pars lateralis
foramen magnum
foramen occipitale magnum
clivus
clivus
cerebral surface
facies superior / cerebralis
inferior surface
facies inferior
groove for the inferior petrosal sinus
sulcus sinus petrosi inferioris
pharyngeal tubercle
tuberculum pharyngeum
occipital condyle
condylus occipitalis
hypoglossal canal
canalis nervi hypoglossi
condylar fossa
fossa condylaris
condylar canal
canalis condylaris
jugular notch
incisura jugularis
jugular process
processus jugularis
jugular foramen
foramen jugulare
intrajugular process
processus intrajugularis
jugular tubercle
tuberculum jugulare
groove for the sigmoid sinus
sulcus sinus sigmoidei
external surface
facies externa
internal surface
facies interna / cerebralis
external occipital protuberance
protuberantia occipitalis externa
external occipital crest
crista occipitalis externa
superior nuchal line
linea nuchalis superior
inferior nuchal line
linea nuchalis inferior
highest nuchal line
linea nuchalis suprema
cerebral fossa
fossa cerebralis
cerebellar fossa
fossa cerebellaris
cruciform eminence
eminentia cruciformis
internal occipital protuberance
protuberantia occipitalis interna
groove for the transverse sinus
sulcus sinus transversi
groove for the superior sagittal sinus
sulcus sinus sagittalis superioris
internal occipital crest
crista occipitalis interna
occipital bone
os occipitale
basilar part
pars basilaris
squamous part of the occipital bone
squama occipitalis
lateral part
pars lateralis
foramen magnum
foramen occipitale magnum
clivus
clivus
cerebral surface
facies superior / cerebralis
inferior surface
facies inferior
groove for the inferior petrosal sinus
sulcus sinus petrosi inferioris
pharyngeal tubercle
tuberculum pharyngeum
occipital condyle
condylus occipitalis
hypoglossal canal
canalis nervi hypoglossi
condylar fossa
fossa condylaris
condylar canal
canalis condylaris
jugular notch
incisura jugularis
jugular process
processus jugularis
jugular foramen
foramen jugulare
intrajugular process
processus intrajugularis
jugular tubercle
tuberculum jugulare
groove for the sigmoid sinus
sulcus sinus sigmoidei
external surface
facies externa
internal surface
facies interna / cerebralis
external occipital protuberance
protuberantia occipitalis externa
external occipital crest
crista occipitalis externa
superior nuchal line
linea nuchalis superior
inferior nuchal line
linea nuchalis inferior
highest nuchal line
linea nuchalis suprema
cerebral fossa
fossa cerebralis
cerebellar fossa
fossa cerebellaris
cruciform eminence
eminentia cruciformis
internal occipital protuberance
protuberantia occipitalis interna
groove for the transverse sinus
sulcus sinus transversi
groove for the superior sagittal sinus
sulcus sinus sagittalis superioris
internal occipital crest
crista occipitalis interna
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