The Tensor Tarsi Muscle is a small muscle located in the foot that helps support the arch. Its name is derived from its function of "tensing" or stretching the tarsus, or ankle bone. The spelling of "tensor" is pronounced /ˈtɛnsər/, with a silent "s" and the stress on the first syllable. "Tarsi" is pronounced /ˈtɑrsi/ with the stress on the first syllable. "Muscle" is pronounced /ˈmʌsəl/, with a silent "c" and the stress on the second syllable.
The tensor tarsi muscle is a small, thin muscle located within the eyelid that plays a significant role in the ocular function. It is also known as the musculus tensor tarsi or the Müller's muscle. The muscle originates from the superior tarsal plate and runs parallel to the upper eyelid, surrounding the superior conjunctival fornix.
The primary function of the tensor tarsi muscle is to assist in the elevation and stabilization of the upper eyelid. It achieves this by contracting and pulling the upper eyelid upwards, contributing to the opening and widening of the eye. This allows for improved visual perception and protection of the ocular surface.
The tensor tarsi muscle is an involuntary or smooth muscle, and its action is regulated by the sympathetic nervous system. It receives neural signals from the superior cervical ganglion, which controls the involuntary movements of various muscles in and around the eye.
Additionally, the tensor tarsi muscle aids in tear drainage by compressing the lacrimal sac during eyelid closure. This action helps to facilitate the flow of tears into the nasolacrimal duct, preventing tear overflow onto the face.
In summary, the tensor tarsi muscle is a small muscle situated within the upper eyelid. Its main functions include elevating and stabilizing the eyelid, contributing to tear drainage, and aiding in visual perception.