Lambda

Dr Daniel J Bell and Dr Craig Hacking et al.

The lambda is the midline bony landmark where the lambdoid sutures and sagittal suture meet, between the occipital and two parietal bones. It may be a depression and therefore palpable. Accessory occiptal bones are common near the lambda, usually associated with the lambdoid sutures.

It is the posterior fontanelle in the neonate and closes by the second month after birth 2 (although normal closure can occur up to 6 months after birth).

It is one of the skull landmarks, craniometric points for radiological or anthropological skull measurement.

History and etymology

The lambda is so-called because of the upside-down V shape formed by the two lambdoid sutures meeting at the lambda. The Greek letter lambda 'Λ' is this shape.

Anatomy: Head and neck
Share article

Article information

rID: 40395
System: Head & Neck
Section: Anatomy
Synonyms or Alternate Spellings:
  • Lambdas

Support Radiopaedia and see fewer ads

Cases and figures

  • Figure 1: lambda
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.