annular ligament

: a ringlike ligament or band of fibrous tissue encircling a part:

a : any of the transverse bands holding in place the extensor and flexor tendons of the wrist and ankle

b : a strong band of fibers surrounding the head of the radius and retaining it in the radial notch of the ulna

— called also orbicular ligament

c : any of several strengthening bands of the tendon sheaths of the digits

d : a ring attaching the base of the stapes to the oval window