Related Experiment Video
Updated: Aug 19, 2026

Combined Recording of Mechanically Stimulated Afferent Output and Nerve Terminal Labelling in Mouse Hair Follicle Lanceolate Endings
Published on: May 7, 2016
Ultrastructure of nerve endings in the stapedius muscle of the squirrel monkey
T Yoshihara1, H Kaname, T Ishii
1Department of Otolaryngology, Tokyo Women's Medical College, Japan.
Abstract:
The stapedius muscle of the squirrel monkey (Saimiri sciureus) was studied electron microscopically with regard to neuromuscular junctions, muscle-tendon junctions and tendons. Two types of neuromuscular junctions were identified. The first type which was predominant in number showed well-developed primary and secondary synaptic clefts. They were almost the same with those of other mammalian skeletal muscles. The second type showed a flat-shaped junction with fewer secondary synaptic clefts. Muscle-tendon junctions were characterized by many interdigitations between the muscle fibers and tendon. The tendon was composed of collagen fibers, approximately 70-100 nm in diameter. Muscle spindles were not present, while nerve endings resembling the Golgi tendon organ were found adjacent to the tendon and the muscle-tendon junctions. These findings suggest that a feedback system may exist and regulate the fine contractile function of this muscle.
Related Concept Videos
Hair Cells
The Cochlea
The Auditory Ossicles
The aptly named stapes look very much like a stirrup. The three ossicles are unique to mammals, and each plays a role in...
Anatomy of the Ear

