The asterion is a meeting point between three sutures between bones of the skull. It is an important surgical landmark.
Structure
In human
anatomy
Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having i ...
, the asterion is a visible (
craniometric) point on the exposed
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...
. It is just posterior to the
ear. It is the point where three
cranial sutures
In anatomy, fibrous joints are joints connected by fibrous tissue, consisting mainly of collagen. These are fixed joints where bones are united by a layer of white fibrous tissue of varying thickness. In the skull the joints between the bones ar ...
meet:
* the
lambdoid suture
The lambdoid suture (or lambdoidal suture) is a dense, fibrous connective tissue joint on the posterior aspect of the skull that connects the parietal bones with the occipital bone. It is continuous with the occipitomastoid suture.
Structure
T ...
.
*
parietomastoid suture.
*
occipitomastoid suture
The occipitomastoid suture or occipitotemporal suture is the cranial suture between the occipital bone and the mastoid portion of the temporal bone.
It is continuous with the lambdoidal suture.
See also
* Jugular foramen
Additional images
Fil ...
.
It is also the point where three cranial bones meet:
* the
parietal bone
The parietal bones () are two bones in the skull which, when joined at a fibrous joint, form the sides and roof of the cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is n ...
.
* the
occipital bone
The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cer ...
.
* the mastoid portion of the
temporal bone
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex.
The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears. ...
.
In the adult, it lies 4 cm behind and 12 mm above the center of the entrance to the
ear canal
The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna (anatomy), pinna to the eardrum and is about in length and in di ...
. Its relation to other anatomical structures is fairly variable.
Clinical significance
Neurosurgeons
Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the surgical treatment of disorders which affect any portion of the nervous system including the brain, spinal cord and per ...
may use the asterion to orient themselves, in order to plan safe entry into the skull for some operations, such as when using a retro-sigmoid approach.
Etymology
The asterion receives its name from the Greek ἀστέριον (''astērion''), meaning "star" or "starry".
The ''Mercedes point'' is an alternative term for the asterion, for its resemblance to the
Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquarte ...
logo.
References
{{Authority control
Human head and neck
Skull