Condyloid canal
Encyclopedia
The condylar canal is a canal in the condyloid fossa
of the lateral parts of occipital bone
behind the occipital condyle
. Resection of the rectus capitus posterior major and minor muscles reveals the bony recess leading to the condylar canal, which is situated posterior and lateral to the occipital condyle. It is immediately superior to the extradural vertebral artery
, which is making a loop above the posterior C1 ring to enter the foramen magnum. The anteriomedial wall of the condylar canal thickens to join the foramen magnum rim and connect to the occipital condyle.
Through the condylar canal, the occipital emissary vein
connects to the venous system including the suboccipital venous plexus
, occipital sinus
and sigmoid sinus
.
It is not always present, and can have variations of being a single canal or multiple smaller canals in cluster.
Condyloid fossa
Behind either condyle of the lateral parts of occipital bone is a depression, the condyloid fossa , which receives the posterior margin of the superior facet of the atlas when the head is bent backward; the floor of this fossa is sometimes perforated by the condyloid canal, through which an...
of the lateral parts of occipital bone
Lateral parts of occipital bone
The lateral parts of the occipital bone are situated at the sides of the foramen magnum; on their under surfaces are the condyles for articulation with the superior facets of the atlas....
behind the occipital condyle
Occipital condyle
The occipital condyles are undersurface facets of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra....
. Resection of the rectus capitus posterior major and minor muscles reveals the bony recess leading to the condylar canal, which is situated posterior and lateral to the occipital condyle. It is immediately superior to the extradural vertebral artery
Vertebral artery
The vertebral arteries are major arteries of the neck. They branch from the subclavian arteries and merge to form the single midline basilar artery in a complex called the vertebrobasilar system, which supplies blood to the posterior part of the circle of Willis and thus significant portions of the...
, which is making a loop above the posterior C1 ring to enter the foramen magnum. The anteriomedial wall of the condylar canal thickens to join the foramen magnum rim and connect to the occipital condyle.
Through the condylar canal, the occipital emissary vein
Occipital emissary vein
The occipital emissary vein is a small emissary vein which passes through the condylar canal....
connects to the venous system including the suboccipital venous plexus
Suboccipital venous plexus
The Suboccipital Venous Plexus drains the back of the head.It communicates with the external vertebral venous plexuses. The external vertebral venous plexuses travel inferiorly from this suboccipital region to drain into the brachiocephalic vein...
, occipital sinus
Occipital sinus
The occipital sinus is the smallest of the cranial sinuses.It is situated in the attached margin of the falx cerebelli, and is generally single, but occasionally there are two....
and sigmoid sinus
Sigmoid sinus
The sigmoid sinuses , within the human head, are two areas beneath the brain which allow blood to drain inferiorly from the posterior center of the head. They drain from the transverse sinuses and converge with the inferior petrosal sinuses to form the internal jugular vein...
.
It is not always present, and can have variations of being a single canal or multiple smaller canals in cluster.