Understanding the Importance of Anatomical Pulleys in Physiotherapy

As a physiotherapist, it is essential to have a good understanding of the human body's anatomy and how it works. One of the essential structures in the body that plays a significant role in movement and biomechanics is the anatomical pulley. In this article, we will explore what an anatomical pulley is, its types, and its importance in physiotherapy.

What is an Anatomical Pulley?

A pulley is a simple mechanical machine that consists of a wheel that turns readily on the axle, usually grooved for a rope or a wire cable. In the human body, the pulley is replaced by a bone, cartilage, or ligament, and the cord is replaced by a muscle tendon. The tendon is lubricated by synovial fluid, and the surface of the tendon is covered by a thin visceral synovial membrane. The tendon is lubricated so that it may easily slide over the pulley.

Classification of Anatomical Pulleys

There are mainly four classes of pulleys in the human body. The first three of them are an example of the fixed pulley, and the fourth one is an example of the movable pulley.

Class 1 Anatomical Pulley

The pulley is attached to the fixed point, acting as the first-order lever. This type of pulley is used to alter the direction of the force by which the resistance or the traction can be applied to the body parts. An improved muscle action comes from the muscle-tendon passing over external support, serving as the pulley.

For example, in the knee complex, the presence of the patella improves the efficiency of the quadriceps muscle as the pulley will increase the angle of insertion of the patellar ligament into the tibial tuberosity. The action of the muscle at the joint is altered because of the pulley.

Class 2 Anatomical Pulley

In this type of pulley, the pulley is responsible for the action of the muscle at the joint. Therefore, the action of the muscle at the joint is altered because of the pulley.

For example, the lateral malleolus of the fibula acts as a pulley for the peroneus longus muscle. If it were not for the malleolus, this muscle instead of passing behind the lateral malleolus to be inserted into the base of the first metatarsal and to produce ankle plantar flexion and eversion, it would have produced ankle dorsiflexion and eversion because of its passage in front of the ankle joint. So here, the pulley is a bone.

Class 3 Anatomical Pulley

This type of pulley is also called the movable pulley, where the muscle acts as a pulley, and the muscle is its own pulley.

For example, the biceps muscle increases in size, so because of that, its angle of insertion will increase. The muscle underneath acts as a pulley for another muscle, which passes over it, e.g., the brachialis will raise the biceps, giving it a better angle of insertion.

Importance of Anatomical Pulleys in Physiotherapy

The knowledge of anatomical pulleys is crucial in physiotherapy, as it allows us to understand the muscle's actions and their roles in movement. It also helps in identifying the areas of the body that may have restricted movement, and we can work on improving those areas by exercising and stretching the muscles.

Moreover, understanding the anatomical pulleys also helps in diagnosing and treating injuries. For instance, if there is a problem with a specific pulley, such as inflammation or a tear in the tendon, it can help to ease the diagnosis.