No other animal gets frozen shoulder. Not dogs, not chimpanzees, not horses. It is, as far as we know, a uniquely human condition. That fact alone tells us something important about its origins.
The evolutionary trade-off in the shoulder
The human shoulder is the most mobile joint in the body. That mobility came at a cost. When our ancestors transitioned from quadrupedal locomotion to bipedalism, the forelimb was freed from weight-bearing. The shoulder evolved for overhead reach, throwing, and tool use — becoming shallow and unstable in exchange for its remarkable range of motion.
This instability requires a complex system of muscles, tendons, and the glenohumeral joint capsule to maintain function. When this system is disrupted — by minor trauma, by hormonal changes, by diabetic changes in connective tissue, or by postural strain — the capsule can begin to contract and adhere. The result is the progressive loss of movement we call adhesive capsulitis, or frozen shoulder.
Hormones, connective tissue, and the 40s
Frozen shoulder peaks in incidence between ages 40 and 60 — the perimenopause and menopause transition in women. Oestrogen plays a role in maintaining the pliability of connective tissue; as levels fluctuate and decline, the glenohumeral capsule becomes more susceptible to fibrotic change. The shoulder evolved in a context where women did not live through decades of low-oestrogen biology. Early intervention matters — the fibrotic process is easier to interrupt before the capsule is fully contracted.
What this means at OQ
At OQ, frozen shoulder is treated as a systemic problem, not a local one. The whole-body context — thoracic mobility, cervical function, rib mechanics, and the neurological relationship between the arm and the rest of the spine — all influence how the glenohumeral joint moves and heals.
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