Abnormal thumb morphology Adducted thumb HP:0005646 HP:0001181 In the resting position, the tip of the thumb is on, or near, the palm, close to the base of the fourth or fifth finger. UMLS:C3554617 Adducted thumbs Thumb-in-palm pattern Thumb-in-palm deformity Inward turned thumb The thumb is both flexed and adducted. Lesser degrees of adduction than that specified here may warrant the use of this term, for example, when the tip of the thumb lies near the base of F2 or F3.