From the Research
No, an arm span of 90 cm in a 15-year-old boy who is 150 cm tall is not eunuchoid. Eunuchoid proportions are characterized by an arm span that exceeds height by at least 5 cm. In this case, the boy's arm span (90 cm) is actually significantly less than his height (150 cm), showing the opposite pattern of eunuchoid proportions. Typically, in normal development, arm span is approximately equal to height, with a difference of less than 5 cm considered normal. Eunuchoid proportions often result from delayed epiphyseal closure due to testosterone deficiency, causing disproportionate growth of the limbs compared to the trunk. This boy's measurements suggest his arm span is unusually short relative to his height, which might warrant further evaluation for other skeletal or developmental conditions, but it definitely does not fit the pattern of eunuchoid proportions, as also suggested by studies on growth and development 1. Some studies have investigated the relationship between sex chromosomes and height, but these do not directly apply to the assessment of eunuchoid proportions in this context 2. Other research has focused on bone age assessment and its applications in diagnosing and treating various diseases, including those related to growth and development 3, but the key factor here is the direct measurement and comparison of arm span to height. The most recent and relevant study on the topic of growth and development, particularly in relation to congenital hypogonadotropic hypogonadism, suggests that body disproportion, including eunuchoid habitus, is associated with factors such as age at the beginning of puberty induction and duration of growth during induction 1. However, the specific case of a 15-year-old boy with an arm span of 90 cm and a height of 150 cm does not align with eunuchoid proportions as defined by the excess of arm span over height.