๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
Skin Dimples
Synonym:๏ก Skin fossae
Skin dimples are deep cutaneous depressions that are seen most commonly on the cheeks or chin, occurring in a familial pattern suggestive of autosomal dominant inheritance. Unilateral or bilateral dimples also may be found in a variety of other locations, most often overlying bony prominences such as the acromion process of the scapula, elbow, patella, tibia, and sacrum. These represent regions in which there is close proximity of the skin to the underlying bone during fetal development, and the dimples are thought to result from early fixation of the skin and deficient formation of the subcutaneous tissue.
Bilateral skin dimples on the shoulders overlying the acromion processes can be inherited in an autosomal dominant fashion as an isolated anomaly. In addition, bilateral acromial dimples are a feature of several congenital malformation syndromes, including the 18q deletion syndrome, trisomy 9p syndrome, Say syndrome, and RussellโSilver dwarfism. Skin dimples also may be seen in association with skeletal abnormalities. For example, dimpling may be found overlying the tibial bend in patients with camptomelic dysplasia and over bowing convexities or exostoses of long bones in those with hypophosphatasia. Distal arthrogryposis (โwhistling faceโ) syndrome type 2โA features a characteristic H-shaped dimple on the chin. Although shallow coccygeal dimples are a common isolated finding, larger or deeper midline lumbosacral dimples may represent a cutaneous sign of spinal dysraphism (see above) or a malformation syndrome. Congenital dimples on the thigh have been attributed to intrauterine friction from the opposite great toenail when in the fetal position. Lastly, skin dimples overlying the knees and/or elbows have been reported in association with congenital rubella, Joubert syndrome, limbโmammary syndrome, ulnarโmammary syndrome, and multiple pterygium syndrome (www. ncbi.nlm.nih.gov/omim). In other sites, an enlarging dimple in a young child may indicate an atrophic dermatofibroma or nascent lipoblastoma (see Ch. 117).