Tummarna

Tummarna is the definite plural form of tumme in Swedish, meaning the thumbs. In anatomical and medical usage, tummarna refers to the pair of opposable digits at the hand's base that are crucial for grip and dexterity.

Anatomically, the thumb has a proximal and distal phalanx and a metacarpal bone, and it is opposable thanks to the carpometacarpal joint at the base of the first metacarpal, a saddle-shaped joint that permits flexion, extension, abduction, adduction, and rotation into opposition. The motion is supported by the thenar muscle group (including abductor pollicis brevis, flexor pollicis brevis, opponens pollicis) and by tendons such as flexor pollicis longus and extensor pollicis longus. The thumb's skin pad and fingerprints provide sensory feedback and grip friction.

Function, variation, and clinical relevance: The thumbs enable powerful grip and precise manipulation, contributing to tool use. Variations include polydactyly (extra thumb) and hypoplastic thumbs. Common problems affect the base joint, the first carpometacarpal joint, potentially leading to osteoarthritis; injuries include fractures of the distal phalanx or metacarpal base and ligament sprains. Treatments range from splinting and therapy to surgical options like trapeziectomy or CMC joint fusion when conservative care is insufficient.

Culturally, the thumbs are linked to gestures such as the thumbs-up sign for approval, and the term tummarna appears in Swedish-language anatomy, medical, and educational texts.