Biology
Clinical Significance of the Axillary Arch of Langer
Quick fact
The axillary arch of Langer is present in roughly 7–27% of individuals, and it can compress the brachial plexus or axillary vessels, leading to symptoms mimicking thoracic outlet syndrome.
Why this is interesting
You might think everyone's armpit looks the same inside, but about one in four people has an extra muscle band crossing it—and it can cause surprising symptoms like arm pain or numbness.