cutaneous appendageGo to external page http://purl.obolibrary.org/obo/UBERON_0000021
Anatomical projection that protrudes from the skin. Examples: hair, nail, feather, claw, hoof, horn, wattle, spur, beak, antler, bristle and some scales. [ https://orcid.org/0000-0002-6601-2165 ]
Synonyms: skin appendage
Mammary glands develop by similar mechanisms, and there is an argument for including them here (e.g. http://www.ncbi.nlm.nih.gov/pubmed/20484386), but these structures do not fit the current definition (lactiferous glands are part of the integumentary system in FMA). Note the FMA class is a subdivision of epidermis, which may be too restrictive for our purposes here.