Eyelid lymphatics II - A search for drainage patterns in the monkey and correlations with human lymphatics

Purpose: To study the lymphatic drainage of the cynomolgus monkey through the use of lymphoscintigraphy. Methods: Lymphoscintigraphy with 500 muCi of (99m)Technetium sulfur colloid injected at specific sites around the eyelids was performed with five cynomolgus monkeys in lateral and ventral positions. Results: Lymphoscintigraphy of the monkey eyelid and periocular tissue revealed lymphatic drainage to the parotid lymph nodes from the entire upper eyelid, medial canthus, and lateral lower eyelid and drainage to the submandibular lymph nodes from the medial and central lower eyelid. In addition to draining to the parotid lymph nodes, the central upper eyelid was also seen to drain to the submandibular lymph nodes. Conclusions: Lymphoscintigraphy of the cynomolgus monkey eyelids reveals discrete lymphatic drainage pathways for the upper and lower eyelids and a dual pathway for the central upper eyelid. Future studies will help to clarify the lymphatic drainage pathways of human eyelids.