Tendons

A tendon or sinew is a tough band of dense fibrous connective tissue that connects muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tension.

tendon at the back of the lower leg

tendon attached to the medial epicondyle of the humerus

A retinaculum (: retinacula) is a band of thickened deep fascia around tendons that holds them in place. It is not part of any muscle and primarily functions to stabilize tendons. The term retinaculum is Neo-Latin, derived from the Latin verb retinere (to retain). Specific retinacula include:

tendon attached to the lateral epicondyle of the humerus

the tendon of the quadriceps femoris muscle, continuous with the patellar tendon