Palaeopathological study on an adult skeleton of Jomon period from Irie shell mound, Hokkaido

Abstract

In 1966 and 1967, from the Irie shell mound located at Abuta-cho on the coast of Uchiura Bay (Volcanic Bay), southern Hokkaido, many archaeological materials and fifteen human skeletal remains belonging to the Jomon period were excavated.
In the present paper, a fairly well preserved adult skeleton labeled "Irie No.9" showing characteristic pathological changes on the bones is reported from the palaeopathologieal point of view.
The skeleton of Irie No. 9 is estimated to be about 17-20 years old or postadescent, but the sex of this individual cannot be determined due to the pathological condition of the skeleton. The gracial structure of the skull seems to be within normal range in size and shape. However, the extreme weakness of the glabella, supereiliary arches and protrusion of the external occipital protuberance and slight development of the temporal lines are not usually seen in Jomon skulls. These morphological characters of the skull may be the result of a chronic disorder during his or her life time. Trunk bones such as the ribs and vertebrae seem to be within normal limits in their growth. In the vertebral column, particularly in the atlas, axis and cervical vertebrae, neither pathological lesions nor abnormal conditions are observed.
With regard to the limb bones of Irie No.9, however, they show no structures for muscle attachment on the bone surface such as tuberosities, crists and lines. Thus all long bones are extremely slender and there is unusual bowing in the axial direction of the bones. This pathological morphology of the long bones might be the result of a transverse growth disturbance of the bones and of severe disused atrophy of the bones over an extended period during the patient's lifetime.
Some of the diseases which might initially occur during infancy or childhood, and which might cause the long bones of the limbs to ultimately change after a long period of time and exhibit severe disused atrophy are listed in Table 4. Although among these diseases it is of course not easy to diagnose exactly, pathological condition of the long bones of Irie No. 9 closely resemble the final features of the limb bones in the quadiplegie of poliomyelitis anterior acuta (PAA or Infantile spinal paralysis) rather than those of the Duchenne type of PMD, AMC, CP and some sorts of demyelinating and/or degenarative diseases in motor nervous system.
PAA caused by poliomyelitis virus mainly affects the anterior horn area (cornu anterius) of the spinal cord, and usually (about 90 percent in Japan) involves infants under 5 years old. Although, paralysis of PAA commonly appears on one side of the lower extremity, in some cases (about 3 to 4% in Japanese), a flaccid type of quadriplegie without any cystoplegie and rectal incontinence continues for such a long time after the initial infecton that disused atrophy occurs in the limb bones.
Irie No.9, who probably experienced PAA during infancy, seem to have suffered from such severe flaccid quadriplegie for an extended period, and must have been obliged to spend his or her whole life in bed. In spite of the resulting inadequateness of daily life and the lack of his or her productive activity in the society, however, Irie No. 9 was able to live for a comparatively long period in the complete paralytic condition.
In this context, it seems to be most interesting to observe that the Irie people must have taken every possible care of this patient, and that such a handicapped individual was given such careful treatment and was hospitably accepted by the primitive society of the huntinggathering Jomon population in this country.