A sprain is a stretch or a tear of the ligaments (bands of tissue that hold bones together) supporting the ankle joint.
Links
[1] https://www.thechildren.com/sites/default/files/PDFs/Trauma/13234e_anklesprain.pdf
[2] https://www.thechildren.com/sites/default/files/articles/crutch-walking_0.pdf
[3] https://www.thechildren.com/sites/default/files/articles/ankle-sprain-support-and-compression.pdf
[4] https://childrenfoundation.com/donate-now/
[5] https://www.thechildren.com/departments-and-staff/departments/department-of-trauma