Do women and men have different clavicles?

From the Guidelines

Yes, women and men typically have different clavicles (collarbones). Male clavicles tend to be longer, thicker, more robust, and have more pronounced muscle attachment sites compared to female clavicles. Female clavicles are generally shorter, thinner, less curved, and have less pronounced muscle markings. These differences develop during puberty under the influence of sex hormones, particularly testosterone, which promotes greater bone mass and muscle development in males. The differences in clavicle morphology are significant enough that forensic anthropologists can use clavicle measurements as one factor in determining the biological sex of skeletal remains, with accuracy rates of approximately 80-90% 1. However, there is considerable overlap between sexes, and individual variation exists based on factors like genetics, activity levels, and overall body size. These anatomical differences reflect the broader skeletal sexual dimorphism in humans, where male bones generally develop to be larger and more robust than female bones.

Key Differences

• Male clavicles are longer and thicker
• Female clavicles are shorter and thinner
• Muscle attachment sites are more pronounced in males
• Clavicle curvature and muscle markings also differ between sexes

Clinical Implications

The treatment of clavicle fractures may need to consider these sex-based differences, as the choice of surgical technique or implant may be influenced by the size and shape of the clavicle 1. However, the current evidence does not provide clear guidance on how these differences should be taken into account in clinical practice. Further research is needed to fully understand the implications of sex-based differences in clavicle morphology for the treatment of clavicle fractures.

Treatment Considerations

• Surgical treatment of displaced midshaft clavicle fractures may be associated with higher union rates and better early patient-reported outcomes than nonsurgical treatment 1
• The choice of implant, such as a precontoured plate, may be influenced by the size and shape of the clavicle 1

From the Research

Clavicle Differences Between Women and Men

• The shape and size of the clavicle can vary significantly between individuals, with studies indicating differences in length, curvature, and other morphological parameters between women and men 2, 3, 4.
• Research has shown that clavicles in men are generally longer, wider, and thicker than those in women, with statistically significant differences in length, sigmoid shape, and medial curvature 2, 4.
• A study using radiographic assessment found that all measured parameters of the clavicle were greater in men than in women, except for the length-to-midshaft diameter ratio, which was not significant 3.
• Another study using three-dimensional statistical shape analysis found that the sternal angle was larger in women than in men, and that right clavicles had a greater medial depth than left clavicles, especially in women 4.

Bilateral Asymmetry

• Studies have also found bilateral asymmetry in the clavicle, with significant differences in length and medial curvature between the left and right clavicles in both men and women 2, 3, 4.
• One study found that the right clavicle was longer than the left clavicle in both men and women, while another study found that the right clavicle had a greater medial depth than the left clavicle, especially in women 3, 4.

Growth and Development

• The clavicle continues to grow during adolescence and early adulthood, with substantial growth potential after age 18 years and remodeling potential up to age 25 years 5.
• Longitudinal studies have found that clavicular growth rates vary by age and sex, with male patients experiencing greater growth rates than female patients at ages 12-15 and 16-19 years 5.