Muscle · Elbow

Palmaris longus

Musculus palmaris longus

A slender muscle with a short belly and a long thin tendon running down the middle of the front of the wrist. It is a weak wrist flexor and it tightens the palmar fascia, but its real significance is practical: it is absent in roughly one person in seven — in one or both arms — with no loss of function at all, which is why it is a favourite donor tendon for surgical repairs. When present, its tendon is the midline landmark of the wrist, and the median nerve lies just beneath and slightly to the thumb side of it.