An interparietal bone (os interparietale or Inca bone or ''os inca var.'') is a

dermal bone A dermal bone or investing bone or membrane bone is a bony structure derived from intramembranous ossification forming components of the vertebrate skeleton, including much of the skull, jaws, gill covers, shoulder girdle, fin rays ( lepidotrich ...

situated between the parietal and

supraoccipital 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 lies over the occipital lobes of the cere ...

. It is homologous to the

postparietal Postparietals are cranial bones present in fish and many Tetrapod, tetrapods. Although initially a pair of bones, many lineages possess postparietals which were fused into a single bone. The postparietals were Dermal bone, dermal bones situated alo ...

bones of other animals. In humans, it corresponds to the upper portion of the

squama Squama (or squamous, squame) refers to a structure shaped like a decumbent scale of a fish. More specifically, it can refer to: * Squama frontalis * Squama occipitalis * Squama temporalis, the squamous portion of the temporal bone * Squamous cel ...

of the

occipital bone The occipital bone () is a neurocranium, 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 lies over the occipital lob ...

that lies superior to the highest

nuchal line The nuchal lines are four curved lines on the external surface of the occipital bone: * The upper, often faintly marked, is named the highest nuchal line, but is sometimes referred to as the Mempin line or linea suprema, and it attaches to the ep ...

and is completely fused to the supraoccipital. However, in some individuals this portion remains separate from the rest of the occipital bone throughout life. In such cases, this separate bone is particularly referred as Inca bone. Inca bones in humans were first found in the skulls of contemporary

indigenous peoples There is no generally accepted definition of Indigenous peoples, although in the 21st century the focus has been on self-identification, cultural difference from other groups in a state, a special relationship with their traditional territ ...

of the southern

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

as well as in those of

mummies A mummy is a dead human or an animal whose soft tissues and Organ (biology), organs have been preserved by either intentional or accidental exposure to Chemical substance, chemicals, extreme cold, very low humidity, or lack of air, so that the ...

of the

Inca civilization The Inca Empire, officially known as the Realm of the Four Parts (, ), was the largest empire in pre-Columbian America. The administrative, political, and military center of the empire was in the city of Cusco. The Inca civilisation rose fro ...

. Although the Inca bone was originally encountered as a variation in South American and Latin American cranial remains, the variation occurs in people from all geographic regions of the world and is by no means indicative of South/Latin American origin. The existence of this Inca bone has helped to identify the mummified remains which spent 110 years in two German museums as belonging to a young South American woman who was probably a victim of ritual murder practiced around the 17th century.Reconstructing the Life of an Unknown (ca. 500 Years- Old South American Inca) Mummy
/ref> In many other mammals, this bone is completely fused to the supraoccipital as in humans. However in some mammals (for example, rodents, rabbits, and artiodactyls), this bone remains separate from the supraoccipital bone. Classic comparative anatomy have regarded the interparietal as being lost in various mammalian lineages since the interparietal and supraoccipital fuse with each other in the early ontogenetic period in many mammals, but recent study has shown that its presence is confirmed in all extant mammalian orders, particularly in the embryonic period (Koyabu and others, 2012).

References

{{Authority control Bones

See also

References