[1][2][3][4][5][6][excessive citations] It serves to attach the plantaris, gastrocnemius (calf) and soleus muscles to the calcaneus (heel) bone.

In his widely used text Corporis Humani Anatomia he described the tendon's location and said that it was commonly called "the cord of Achilles.

[9] Verheyen referred to the mythological account of Achilles being held by the heel by his mother Thetis when she dipped him in the River Styx as a baby to render his body invulnerable.

The Achilles tendon connects the gastrocnemius and soleus muscles to the calcaneal tuberosity on the calcaneus (heel bone).

[11] The tendon is covered by the fascia and skin, and stands out prominently behind the bone; the gap is filled up with areolar and adipose tissue.

The sural nerve accompanies the small saphenous vein as it descends in the posterior leg, traveling inferolateral to it as it crosses the lateral border of the Achilles tendon.

[11] Acting via the Achilles tendon, the gastrocnemius and soleus muscles cause plantar flexion of the foot at the ankle.

[15] Vibration of the tendon causes movement backwards and the illusion of a forward body tilt in standing subjects.

Achilles tendinosis is the soreness or stiffness of the tendon, particularly worse when exercising, and generally due to overuse.

[21] While stretching and exercises to strengthen the back are often recommended for prevention, evidence to support these measures is poor.

[22][23][24] Treatment typically involves rest, ice, non-steroidal antiinflammatory agents (NSAIDs), and physical therapy.

In both cases, the tendon is thickened, may demonstrate surrounding inflammation by virtue of the presence of paratenonitis, retrocalcaneal or retro-achilles bursitis.

[27] Rupture typically occurs as a result of a sudden bending up of the foot when the calf muscle is engaged, direct trauma, or long-standing tendonitis.

[27][26] Other risk factors include the use of fluoroquinolones, a significant change in exercise, rheumatoid arthritis, gout, or corticosteroid use.

This tests the S1 and S2 spinal nerves: a normal response is plantar flexion (downward movement) of the foot.

[38] It has been suggested that the "absence of a well-developed Achilles tendon in the nonhuman African apes would preclude them from effective running, both at high speeds and over extended distances.