Tension in the lumbrical muscle.
D005385:Fingers / Q000033:anatomy & histology*; D006225:Hand / Q000033:anatomy & histology*; D006801:Humans; D009119:Muscle Contraction; D009129:Muscle Tonus; D009132:Muscles / Q000033:anatomy & histology* / Q000502:physiology; D013710:Tendons / Q000033:anatomy & histology