a connecting band; a fraenum; as, the retinacula of the ileocaecal and ileocolic valves.-one of the annular ligaments which hold the tendons close to the bones at the larger joints, as at the wrist and ankle.-one of the retractor muscles of the proboscis of certain worms.-a small gland or process to which bodies are attached; as, the glandular retinacula to which the pollinia of orchids are attached, or the hooks which support the seeds in many acanthaceous plants.