Abstract:

This study made an pathological analysis of an archaeological case example of human unilateral humeral hypoplasia from the Eastern Zhou Dynasty(770-221 BC) Guanzhuang site, located in Xingyang City, Henan Province, central China. Individual M45, a female (according to the morphology of the os coxa and skull, and long bones) aged approximately 30 years old at her time-of-death, presents severe abnormal morphological changes on the right humerus. From a macro perspective, abnormal shortening, flatter humeral head, higher anatomical neck, and lesser tubercle displaced anterior-distally were observed on the right humerus. Radiographic analysis showed that wider bone marrow cavity diameter and slight osteoporosis in the region of the deltoid tuberosity, and the cancellous bone at the trochanter of the right deltoid is more pronounced than on the left one, showing a honeycomb shape. In addition, bone defect was found at the region of the deltoid tuberosity and also below the anatomical neck. The asymmetric development of upper limb bones, including the humerus, is generally attributed to physiological or pathological induced bone remodeling. Physiological causes include genetic and behavioral factors. The asymmetry caused by physiological genetic factors does not affect the normal development of bone, and the degree of asymmetry is relatively low, in the range of 1% or less. Behavioral factors are mainly related to activities and bone loading patterns, including occupation, habitual activities, etc. The difference between two humerus caused by behavioral factors is reflected in the difference of the cross-section and the strength of the two humerus, most of which are transverse differences. Differential diagnosis was made in this study, including metabolic diseases, endocrine diseases, focal fibrocartilage hypoplasia, metaphyseal cartilage hypoplasia, Kashin Beck disease, osteogenesis imperfecta, humeral shortening and cartilage hypoplasia. According to the analysis, it is more likely that the humeral asymmetry found in M45 has affected the proximal growth centre of the right humerus, possibly linked to childbirth trauma, or the cessation of humeral growth and development caused by trauma to the growth plate in early childhood.

Key words: Eastern Zhou, humerus, development, pathology