Lambda is the junction between
The lambdoid suture lies between the occipital bone and the two parietal bones.sutural or Wormian bones are common along this suture. Lambda, parietal foramina, and obelion have been examined in the norma veicalis. Ref BDC volume:3,6th edition
Occipital and frontal bones
Frontal and temporal bones
Parietal and occipital bones
Frontal and parietal bones
Head and neck