Tarsus (eyelids) is a groove in the inner surface of each eyelid. Along the inner margin of the tarsus are modified sebaceous glands known as tarsal glands (or meibomian glands), aligned vertically within the tarsi: 30 to 40 glands in the upper lid, and 20 to 30 in the lower lid, which secrete a lipid-rich product which helps keep the lacrimal secretions or tears from evaporating too quickly, thus keeping the eye moist. Tarsus (eyelids) The tarsi (tarsal plates) are two comparatively thick, elongated plates of dense connective tissue, about in length; one is found in each eyelid, and contributes to its
Labial glands Labial glands The labial glands are minor salivary glands situated between the mucous membrane and the orbicularis oris around the orifice of the mouth. They are circular in form, and about the size of small peas; their ducts open by minute orifices upon the mucous membrane. Like the parotid and buccal glands, the labial glands are innervated by parasympathetic fibres that arise in the inferior salivatory nucleus, travel with the glossopharyngeal nerve and lesser petrosal nerve to the otic ganglion, where they synapse and then continue to the labial glands. Sympathetic innervation is mediated by postganglionary fibres which arise in