Inca Bone Report

There are many techniques followed in the field of Forensic Investigations to establish the identity of an unknown. Even, anatomical variations like developmental anomalies can also be used for this purpose. The occurrence of Inca bone occurring due to a persistent Mendosal suture, though rare, is one such variation in humans. The knowledge of Inca bone in human skull is useful in identifying an unknown. We report a case of incidental finding of true inter parietal or Inca bone in an adult human skull.
Key words: Mendosal suture, inter parietal bone, Inca bone, identification.
Introduction:
Identification is an important aspect of Forensic investigations especially in case of unknown, dismembered bodies or in cases of skeletal remains. Many
The inter-parietal human skull vault, also known as the cranial vault, is formed by the paired parietal and temporal bones and unpaired frontal, occipital, sphenoid and ethmoid bones.5 The occipital bone is formed from cartilage and membrane.6 The portion may remain separated from the-supra-occipital part by a suture and is called the inter-parietal or inca bone. The supra occipital part ossify by both cartilaginous and inter membranous ossification but inter parietal part by inter membranous ossification only. The segment of supra occipital bone between the highest and superior nuchal lines form the intermediate segment. It ossifies inter membranously and probably never separates from the cartilaginous supraoccipital part. True inter parietal bones or Inca bones are bounded by lambdoid suture or suture mendosa. They were previously known as os incae. Os inter parietal Goethe's ossicles. Inca bone resembles triangular architecture monument designs of Inca tribals of South America (1200-1597 AD). The members of Royal family of Inca tribe had crown like configurations on their head, hence this ossicle has been known as
During the 3rd fetal month, irregular ossification centers appear in the membranous tissue behind the cartilaginous supra occipital bone plate. In the 4th fetal month, similar irregular ossification centers appear on the internal surface of supra occipital plates. In the 5th fetal month, these ossification centers fuse with root of the secondary inter-parietal part in the midline (Fig. 3). Inter-parietal and supra occipital portion fuse by birth and obliteration of mendosal suture by 2 yrs.
In our case, the inter parietal bone with its suture formed by upper and lower nuclei of third pair medial and lateral nuclei of second pair on left side and medial nucleus of second pair on right side (Fig.