Carpal tactile hair organ

The carpal tactile hair organ is a set of vibrissae (4 to 6 vibrissae 20 to 30 mm long in cats) which protrude from the hairs of the general coat, on the caudal aspect of the distal end of the forearm.

Because of the importance of the follicular blood sinuses, the carpal tactile hair organ is easily palpable as a small elevation of the skin about 4 mm in diameter. It is also visible as an increase in skin opacity on X-ray or CT scan, particularly in cats.

The carpal tactile hair organ is described in several species, particularly in those that use their thoracic limbs not only for locomotion, but also for catching prey, holding food or climbing: it is thus described in rodents and carnivores (with the exception of the dog). It is absent in rabbits and ungulates. This organ is supplied by relatively large branches of the ulnar nerve and artery. The carpal tactile hair organ should not be confused with the carpal glands described in pigs.