If you ask yourself this question I am sure that you are going to know where it is and what it looks like, but probably that is all. That is why I want to write about the Achilles tendon, to make sure that you really know what it is.
The Achilles tendon or calcaneal tendon is the largest, thickest and strongest tendon in the body, being, on average, 15 cm long. It connects three of your calf muscles (gastrocnemius, soleus and plantaris) to your heel bone (calcaneus).
Depending on speed, stride, weight, and terrain; each Achilles tendon may be subject to up to 12 times a person’s body weight during a running or push off.
Gastrocnemius muscle, which means “stomach of leg”, has two heads (lateral and medial) that run from the femur (thigh bone) to the heel. The lateral head originates from the inferior- external part of the femur (lateral condyle) and the medial head originates from the inferior-internal part (medial condyle) of the femur. Its function is flexing the leg at the knee joint (bending the knee) and plantar flexing the foot at the ankle joint, given that it is part of the Achilles tendon.
Soleus muscle runs from the tibia, just below the knee, and fibula to the heel. It is under the gastrocnemius muscle and these two are considered by some scientists to be a single muscle called triceps surae. It is involved in standing and walking. We usually get calf problems because we think we are stretching our calves properly, but the reality is that we normally stretch our gastrocnemius, but not our soleus.
Plantaris muscle is a thin muscle with a long tendon. It can be absent in some people as it is not an important muscle and mostly acts with gastrocnemius muscle flexing the knee and dorsal flexing the foot. It runs from the inferior part of a line located above the lateral condyle of the femur ( lateral supracondylar line) and a ligament called oblique popliteal ligament, to reach the heel becoming part of the Achilles tendon.
The function of your Achilles tendon is to enable the movement called plantar flexion (motion of your foot downwards at your ankle) which allows you to stand on tiptoe, walk, run, jump and go up and down stairs.
The Achilles tendon has a poor blood supply. It is supplied by two arteries: the posterior tibial artery supplies the proximal and distal sections of the Achilles tendon and the peroneal artery supplies the midsection of the Achilles tendon. The midsection blood supply is the poorest, that is why it is the most commonly injured.
It is innervated by the tibial nerve which is a branch of the sciatic nerve ( formed by lumbar and sacral roots).
The most common Achilles tendon injuries are Achilles tendinitis (also known as Achilles tendinopathy), Achilles bursitis and Achilles tendon rupture.
“Do you know a bit better what Achilles tendon is?” Comments are more than welcome.
If you have any questions, do not hesitate to contact me on The Physical Therapy, Physiotherapy Clinic based in Southampton, and I will be happy to help you.
Also, you can read the Spanish version ¿Qué es el tendón de Aquiles?