retinaculum
noun
ret·i·nac·u·lum ˌre-tə-ˈna-kyə-ləm 
plural retinacula ˌre-tə-ˈna-kyə-lə
: any of several fibrous bands of fascia that pass over or under tendons (as at or near the ankle or wrist) and help to keep them in place
Example Sentences
Recent Examples on the Web The carpal tunnel is a literal tunnel of space bordered by the carpal (wrist) bones and their ligaments, and by a connective tissue structure called the flexor retinaculum. 
Dr. Keith Roach, oregonlive, 10 May 2022 The compression is alleviated by surgical release of the retinaculum, which gives the nerve adequate room. Dr. Keith Roach, oregonlive, 10 May 2022
Dr. Keith Roach, oregonlive, 10 May 2022 The compression is alleviated by surgical release of the retinaculum, which gives the nerve adequate room. Dr. Keith Roach, oregonlive, 10 May 2022 Word History
Etymology
borrowed from New Latin retināculum, going back to Latin, "rope holding something in place, cable, hawser," from retinēre "to hold fast, detain, keep possession of" + -ā-, stem formative of verbs + -culum, suffix of instrument and place (going back to Indo-European *-tlom), probably after gubernāculum "steering oar of a ship" (from gubernāre "to steer") or other derivatives of 1st-conjugation verbs — more at retain
First Known Use
circa 1825, in the meaning defined above
Medical Definition
retinaculum
noun
ret·i·nac·u·lum -ləm
plural retinacula -lə
: a connecting or retaining band especially of fibrous tissue see extensor retinaculum, flexor retinaculum, inferior extensor retinaculum, inferior peroneal retinaculum, peroneal retinaculum, superior extensor retinaculum, superior peroneal retinaculum