Small nails
Page most recently updated 7 September 2026
This page focuses on small nails as a morphologic feature of conditions that may also be associated with psychiatric manifestations, such as psychosis, mania, autism spectrum disorder, ADHD, OCD, and self-injurious behaviours. The page begins with a clinical definition of small nails based on the standardized Elements of Morphology terminology, together with visual examples from the same source. This is followed by a list of conditions in which small nails have been described in association with psychiatric manifestations.
Of note, to optimize clinical utility, the list does not include conditions associated with intellectual disability in the absence of other psychiatric features.
Each condition listed below is linked to a dedicated page within this resource. These pages describe the psychiatric manifestations associated with each condition, as well as other morphologic and broader clinical features, allowing the differential diagnosis to be considered from multiple perspectives.
Small nails
Image credit: National Human Genome Research Institute (NHGRI), Elements of Morphology.
Definition
Subjective:
Small nail: A nail that is diminished in length and width.
Narrow nail: Decreased width of nail.
Short nail: Decreased length of nail.
Note: It may be preferable to describe the patient as having both Short nail and Narrow nail.
Synonyms: Micronychia.
Replaces: Hypoplastic nails.
Selected references and further reading — Morphologic lens
Allanson JE, Biesecker LG, Carey JC, Hennekam RCM. Elements of morphology: introduction. Am J Med Genet A. 2009;149A(1):2-5.
Hennekam RCM, Biesecker LG, Allanson JE, Hall JG, Opitz JM, Temple IK, Carey JC; Elements of Morphology Consortium. Elements of morphology: general terms for congenital anomalies. Am J Med Genet A. 2013;161A(11):2726-2733.
Jones KL, Jones MC, del Campo M. Smith's recognizable patterns of human malformation. 8th ed. Philadelphia: Elsevier; 2021.
Reardon W. The bedside dysmorphologist: a guide to identifying and assessing congenital malformations. 2nd ed. Oxford: Oxford University Press; 2016.