Dynamic measurements of musculus tibialis anterior ligaments with different angles

Abstract

The tibialis anterior muscle is the most medial muscle of the anterior compartment of the leg and responsible for dorsiflexing and inverting the foot. It functions to stabilise the ankle as the foot hits the ground during the contact phase of walking (eccentric contraction) and acts later to pull the foot clear off the ground during the swing phase (concentric contraction). It also functions to ‘lock’ the ankle, as in toe-kicking a ball, when held in an isometric contraction. Essentially, the movements of tibialis anterior are dorsiflexion and inversion of the ankle. When the foot is on the ground the muscle helps to balance the leg and talus on the other tarsal bones so that the leg is kept vertical even when walking on uneven ground. Drop foot is an inability or difficulty in moving the ankle and toes upward (dorsiflexion). In walking, while stepping forward, the front of the foot must be lifted upward to prevent the foot from dragging along the ground. Drop foot is usually caused by nerve damage, but may also be caused by muscle damage, abnormal anatomy, or a combination. Drop foot (a weakness in ankle dorsiflexion) is however not a disease but more like a symptom of an underlying problem (could be neurological, muscular or anatomical problem). It may be temporary or permanent, depending on the causes of it. The most common cause for drop foot syndrome is an injury to the peroneal nerve at the top of the calf behind the knee. Other major causes of drop foot also include multiple sclerosis, amyotrophic lateral sclerosis (ALS), Parkinson's disease, Lou Gehrig's disease, and muscular dystrophy. The aim of the study is to get some numerical data on tibialis anterior muscle during dorsiflexion, plantar flexion, inversion and eversion of the foot. 9 cases were compared with left and right foot including 4 neurological disability and 5 healthy people. In four neurological disabled patients, the muscle force differences between healthy and normal legs are obtained as 9 N/81 N, 49 N/78 N, 182 N/58 N and 89 N/0 N. In conclusion, we obtain some in vivo data showing that there are important differences in forces of muscles between the healthy and drop foot patients. These numerical data will help us to develop new orthosis and drop foot shoes for treatment of drop foot syndrome.