Müller's muscle tendon: Microscopic anatomy in asians

Purpose: To describe the anatomic characteristics of Müller's muscle tendon. MATERIALS AND Methods: Twelve postmortem, buffered formalin (10%)-fixed eyelids (6 right, 6 left) of 10 Asians (aged 62 to 92 years at death; mean age: 77.1 years) were used. Full-thickness sagittal sections of the upper eyelid specimens were dehydrated and embedded in paraffin and cut in 7-μm-thickness sagittal sections. Sliced sections were stained with elastica van Gieson. The concentration of the elastic fibers in Müller's muscle tendon was analyzed and compared with the concentration in the levator aponeurosis. Fat deposition and the dimensions of Müller's muscle tendon were also analyzed. Results: Both Müller's muscle tendon and the levator aponeurosis contained elastic fibers, which were more abundant in Müller's muscle tendon. Fat deposition in Müller's muscle tendon was demonstrated only in one specimen from an 84-year-old male. The average length of Müller's muscle tendon was 2.56 mm (range: 1.40-5.64 mm), and the average thickness of the tendon was 0.27 mm (range: 0.08-0.88 mm). There was no correlation between cadaver age and muscle length or thickness. Conclusions: Müller's muscle tendon is rich in elastic fibers with minimal age-related fat deposition.