A retinaculum (plural ''retinacula'') is a band of thickened

deep fascia Deep fascia (or investing fascia) is a fascia, a layer of dense connective tissue that can surround individual muscles and groups of muscles to separate into fascial compartments. This fibrous connective tissue interpenetrates and surrounds the m ...

around

tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...

s that holds them in place. It is not part of any

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

. Its function is mostly to stabilize a tendon. The term retinaculum is

New Latin New Latin (also called Neo-Latin or Modern Latin) is the revival of Literary Latin used in original, scholarly, and scientific works since about 1500. Modern scholarly and technical nomenclature, such as in zoological and botanical taxonomy ...

, derived from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

verb ''retinere'' (to retain). Specific retinacula include: * In the wrist: **

Flexor retinaculum of the hand The flexor retinaculum (transverse carpal ligament, or anterior annular ligament) is a fibrous band on the palmar side of the hand near the wrist. It arches over the carpal bones of the hands, covering them and forming the carpal tunnel. Structu ...

Extensor retinaculum of the hand The extensor retinaculum (dorsal carpal ligament, or posterior annular ligament) is an anatomical term for the thickened part of the antebrachial fascia that holds the tendons of the extensor muscles in place. It is located on the back of the fore ...

* In the ankle: **

Flexor retinaculum of foot The flexor retinaculum of foot (laciniate ligament, internal annular ligament) is a strong fibrous band in the foot. Structure The flexor retinaculum of the foot extends from the medial malleolus above, to the calcaneus below. This converts a s ...

Superior extensor retinaculum of foot The superior extensor retinaculum of the foot (transverse crural ligament) is the upper part of the extensor retinaculum of foot which extends from the ankle to the heelbone. The superior extensor retinaculum binds down the tendons of extensor ...

Inferior extensor retinaculum of foot The inferior extensor retinaculum of the foot (cruciate crural ligament, lower part of anterior annular ligament) is a Y-shaped band placed in front of the ankle-joint, the stem of the Y being attached laterally to the upper surface of the calca ...

** Superior fibular retinaculum ** Inferior fibular retinaculum * In the knee: **

Lateral retinaculum The lateral retinaculum is the fibrous tissue on the lateral (outer) side of the kneecap (patella). The kneecap has both a medial (on the inner aspect) and a lateral (on the outer side) retinaculum, and these help to support the kneecap in its posi ...

** Medial patellar retinaculum

References

{{reflist Tendons