Asterion (anatomy)

Asterion (Anatomy)

The asterion is a significant anatomical landmark located on the human skull. It is the point where three cranial sutures meet: the lambdoid suture, the parietomastoid suture, and the occipitomastoid suture. This convergence occurs near the posterior part of the skull, specifically at the junction of the parietal bone, the occipital bone, and the temporal bone.

Anatomical Significance

The asterion is an important reference point in neurosurgery and cranial surgery due to its proximity to the transverse sinus and the sigmoid sinus, which are major venous channels within the skull. Accurate identification of the asterion can help surgeons avoid damaging these structures during procedures.

Location and Structure

The asterion is located on the lateral aspect of the skull. It is typically found approximately 4 cm above the midpoint of the mastoid process of the temporal bone. The exact position of the asterion can vary slightly between individuals, and it may be influenced by factors such as age and cranial morphology.

Cranial Sutures

• Lambdoid Suture: This suture is located between the parietal bones and the occipital bone. It is named for its resemblance to the Greek letter lambda (λ).
• Parietomastoid Suture: This suture connects the parietal bone with the mastoid portion of the temporal bone.
• Occipitomastoid Suture: This suture joins the occipital bone with the mastoid portion of the temporal bone.

Clinical Relevance

The asterion is used as a landmark in various clinical procedures, including:

• Cranial Surgery: Surgeons use the asterion to orient themselves when accessing the posterior cranial fossa.
• Radiology: The asterion can be identified in CT scans and MRI as a bony landmark to assess the position of the transverse sinus.

Variations and Anomalies

The position and prominence of the asterion can vary among individuals. In some cases, the asterion may be less distinct due to variations in the fusion of the cranial sutures. These variations can be congenital or acquired due to factors such as craniosynostosis.

See Also

• Cranial Sutures
• Skull Anatomy
• Neurosurgery

External Links

• [Asterion - Wikipedia](https://en.wikipedia.org/wiki/Asterion_(anatomy))

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