The Achilles tendon or heel cord, also known as the calcaneal tendon, is a tendon of the back of the leg, and the thickest in the human body. It serves to attach the plantaris, gastrocnemius (calf) and soleus muscles to the calcaneus (heel) bone. These muscles, acting via the tendon, cause plantar flexion of the foot at the ankle, and (except soleus) flexion at the knee.
The Achilles tendon or calcaneal tendon is attached to the gastrocnemius and soleus muscles.
|Location||Back of the lower leg|
|Latin||tendo calcaneus, tendo Achillis|
The Achilles tendon connects muscle to bone, like other tendons, and is located at the back of the lower leg. The Achilles tendon connects the gastrocnemius and soleus muscles to the calcaneal tuberosity on the calcaneus (heel bone). The tendon begins near the middle of the calf, and receives muscle fibers on its inner surface, particularly from the soleus muscle, almost to its lower end. Gradually thinning below, it inserts into the middle part of the back of the calcaneus bone. The tendon spreads out somewhat at its lower end so that its narrowest part is about 4 cm (1.6 in) above its insertion.
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. A bursa lies between the tendon and the upper part of the calcaneus. It is about 15 centimetres (6 in) long. Along the side of the muscle, and superficial to it, is the small saphenous vein. The sural nerve the outer border of the tendon about 10 cm below where it attaches to the bone. The tendon is the thickest tendon in the human body. It can receive a load stress 3.9 times body weight during walking and 7.7 times body weight when running.
Acting via the Achilles tendon, the gastrocnemius and soleus muscles cause plantar flexion of the foot at the ankle. This action brings the sole of the foot closer to the back of the leg. The gastrocnemius also flexes the leg at the knee. Both muscles are innervated by the tibial nerve. Because the fibres of the tendon spiral about 90 degrees, fibres from the gastrocnemius tend to attach to the outer part of the bone, whereas fibres from the solus tend to attach closer to the midline.
Vibration of the tendon without vision has a major impact on postural orientation. Vibration of the tendon causes movement backwards and the illusion of a forward body tilt in standing subjects. This is because vibrations stimulate muscle spindles in the calf muscles. The muscle spindles alert the brain that the body is moving forward, so the central nervous system compensates by moving the body backwards.
Inflammation of the Achilles tendon is called Achilles tendinitis. Achilles tendinosis is the soreness or stiffness of the tendon, particularly worse when exercising, and generally due to overuse. The most common symptoms are pain and swelling around the affected tendon. The pain is typically worse at the start of exercise and decreases thereafter. Stiffness of the ankle may also be present. Onset is generally gradual.
It commonly occurs as a result of overuse such as running. Other risk factors include trauma, a lifestyle that includes little exercise, high-heel shoes, rheumatoid arthritis, and medications of the fluoroquinolone or steroid class. Diagnosis is generally based on symptoms and examination.
While stretching and exercises to strengthen the calf are often recommended for prevention, evidence to support these measures is poor. Treatment typically involves rest, ice, non-steroidal antiinflammatory agents (NSAIDs), and physical therapy. A heel lift or orthotics may also be helpful. In those in who symptoms last more than six months despite other treatments, surgery may be considered. Achilles tendinitis is relatively common.
Achilles tendon degeneration (tendinosis) is typically investigated with either MRI or ultrasound. In both cases, the tendon is thickened, may demonstrate surrounding inflammation by virtue of the presence of paratenonitis, retrocalcaneal or retro-achilles bursitis. Within the tendon, increased blood flow, tendon fibril disorganisation, and partial thickness tears may be identified. Achilles tendinosis frequently involves the mid portion of the tendon but may involve the insertion, which is then known as enthesopathy. Though enthesopathy may be seen in the context of advancing age, it is also associated with arthritis such as gout and the seronegative spondyloarthitides. Achilles tendinosis is a known risk factor for calf muscle tears.
Achilles tendon rupture is when the Achilles tendon breaks. Symptoms include the sudden onset of sharp pain in the heel. A snapping sound may be heard as the tendon breaks and walking becomes difficult.
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. Other risk factors include the use of fluoroquinolones, a significant change in exercise, rheumatoid arthritis, gout, or corticosteroid use. Diagnosis is typically based on symptoms and examination and supported by medical imaging. Achilles tendon rupture occurs in about 1 per 10,000 people per year. Males are more commonly affected than females. People in their 30s to 50s are most commonly affected.
Prevention may include stretching before activity. Treatment may be by surgery or casting with the toes somewhat pointed down. Relatively rapid return to weight bearing (within 4 weeks) appears okay. The risk of re-rupture is about 25% with casting. If appropriate treatment does not occur within 4 weeks of the injury outcomes are not as good.
The Achilles' tendon is often tested as part of a neurological examination. In this examination, the tendon is hit with a tendon hammer. This tests the S1 and S2 spinal nerves: a normal response is plantar flexion (downward movement) of the foot.
Level or portion of tendon affected 
Apart from humans, the Achilles tendon is short or absent in great apes, but long in arboreal gibbons and humans. It provides elastic energy storage in hopping, walking, and running. Computer models suggest this energy storage Achilles tendon increases top running speed by >80% and reduces running costs by more than three-quarters. 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."
The oldest-known written record of the tendon being named for Achilles is in 1693 by the Flemish/Dutch anatomist Philip Verheyen. 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." The tendon has been described as early as the time of Hippocrates, who described it as the "tendo magnus" (Latin: great tendon) and by subsequent anatomists prior to Verheyen as "chorda Hippocratis".
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. As the heel by which she held him was not touched by the water, it was his one vulnerable spot (hence the expression "Achilles' heel") and he was eventually killed by a poison dart to the heel. The name thus also refers to the particularly disabling and painful effect of an injury to this tendon. The first closed rupture was described by Ambroise Pare in the sixteenth century.
The Achilles tendon is also known as the "tendo calcaneus" (Latin: calcaneal tendon). Because eponyms (names relating to people) have no relationship to the subject matter, most anatomical eponyms also have scientifically descriptive terms. The term calcaneal comes from the Latin calcaneum, meaning heel.
Vocatum passim chorda Achillis, & ab Hippocrate tendo magnus. (Appendix, caput XII. De musculis pedii et antipedii, p. 269)
Abadie's symptoms of tabes dorsalis may be elicited during clinical examination. Pinching of, or the application of firm pressure to, the Achilles tendon does not result in pain in tabes dorsalis. This is because the sense of deep pain has been abolished.It is named for Joseph Louis Irenée Jean Abadie, a French neurologist.Accessory soleus muscle
In humans, the accessory soleus muscle is the most common accessory muscle in the ankle. It is often asymptomatic.The muscle inserts on the anterior aspect of the soleus muscle or on the posterior aspect of the tibia or the muscles of the deep posterior compartment. It lies anterior to the calcaneal tendon and terminates on the calcaneal tendon or the superior or medial aspect of the calcaneus via fleshy fibers or a distinct tendon.Present in approximately 3% (or 10%) of people, this muscle usually appears as a distant belly, medial to the Achilles tendon. Clinically, the accessory soleus may be associated with pain and edema during periods of prolonged exercise.Achilles tendinitis
Achilles tendinitis, also known as achilles tendinopathy, is when the Achilles tendon, found at the back of the ankle, becomes irritated. The most common symptoms are pain and swelling around the affected tendon. The pain is typically worse at the start of exercise and decreases thereafter. Stiffness of the ankle may also be present. Onset is generally gradual.It commonly occurs as a result of overuse such as running. Other risk factors include trauma, a lifestyle that includes little exercise, high-heel shoes, rheumatoid arthritis, and medications of the fluoroquinolone or steroid class. Diagnosis is generally based on symptoms and examination.While stretching and exercises to strengthen the calf are often recommended for prevention, evidence to support these measures is poor. Treatment typically involves rest, ice, non-steroidal antiinflammatory agents (NSAIDs), and physical therapy. A heel lift or orthotics may also be helpful. In those whose symptoms last more than six months despite other treatments, surgery may be considered. Achilles tendinitis is relatively common.Achilles tendon rupture
Achilles tendon rupture is when the Achilles tendon, at the back of the ankle, breaks. Symptoms include the sudden onset of sharp pain in the heel. A snapping sound may be heard as the tendon breaks and walking becomes difficult.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. Other risk factors include the use of fluoroquinolones, a significant change in exercise, rheumatoid arthritis, gout, or corticosteroid use. Diagnosis is typically based on symptoms and examination and supported by medical imaging.Prevention may include stretching before activity. Treatment may be by surgery or casting with the toes somewhat pointed down. Relatively rapid return to weight bearing (within 4 weeks) appears okay. The risk of re-rupture is about 25% with casting. If appropriate treatment does not occur within 4 weeks of the injury outcomes are not as good.Achilles tendon rupture occurs in about 1 per 10,000 people per year. Males are more commonly affected than females. People in their 30s to 50s are most commonly affected. The tendon itself was named in 1693 after the Greek hero Achilles.Adolf Metzner
Adolf Metzner (25 April 1910 – 5 March 1978) was a German athlete who competed in the 1932 Summer Olympics and in the 1936 Summer Olympics. After finishing his career due to Achilles tendon rupture he became a carpenter in the Bavaria region of Germany. In 1947 he worked with Ernst Gadermann to develop the first telemetric measurements of the ECG in athletes.Ankle jerk reflex
The ankle jerk reflex, also known as the Achilles reflex, occurs when the Achilles tendon is tapped while the foot is dorsiflexed.
It is a type of stretch reflex that tests the function of the gastrocnemius muscle and the nerve that supplies it.
A positive result would be the jerking of the foot towards its plantar surface. Being a deep tendon reflex, it is monosynaptic. It is also a stretch reflex.
These are monosynaptic spinal segmental reflexes. When they are intact, integrity of the following is confirmed: cutaneous innervation, motor supply, and cortical input to the corresponding spinal segment.Calf (leg)
The calf (Latin: sura) is the back portion of the lower leg in human anatomy. The muscles within the calf correspond to the posterior compartment of the leg. The two largest muscles within this compartment are known together as the calf muscle and attach to the heel via the Achilles tendon. Several other, smaller muscles attach to the knee, the ankle, and via long tendons to the toes.Clubfoot
Clubfoot is a birth defect where one or both feet are rotated inwards and downwards. The affected foot, calf and leg may be smaller than the other. In about half of those affected, both feet are involved. Most cases are not associated with other problems. Without treatment, people walk on the sides of their feet, which causes problems with walking.The exact cause is usually unclear. A few cases are associated with distal arthrogryposis or myelomeningocele. If one identical twin is affected, there is a 33% chance the other one will be as well. Diagnosis may occur at birth or before birth during an ultrasound exam.Initial treatment is most often with the Ponseti method. This involves moving the foot into an improved position followed by casting, which is repeated at weekly intervals. Once the inward bending is improved, the Achilles tendon is often cut, and braces are worn until the age of four. Initially, the brace is worn nearly continuously and then just at night. In about 20% of cases, further surgery is required.Clubfoot occurs in about 1 in 1,000 newborns. The condition is less common among Chinese and more common among Māori people. Males are affected about twice as often as females. Treatment can be carried out by a range of healthcare providers and can generally be achieved in the developing world with few resources.Dean Kenneally
Dean Kenneally (born 8 March 1967 in Victoria) is an Australian physiotherapist whose area of expertise is hamstring injuries on athletes. Kenneally is the primary team physio for Chelsea FC.Previously he has worked for Tottenham Hotspur, as well as the Australian and English national athletics teams.During his active sports career he was an 800 metres runner. His greatest achievement was a silver medal at the 1991 Universiade. He also participated at the 1994 Commonwealth Games, finishing 5th in his heat while affected by an achilles tendon injury incurred 12 days before the heat on 23 August 1994. He also won the Australian 800m Championship in 1990, was placed 3rd in 1991, 2nd in 1992 later running his lifetime best of 1:46.54 in Dijon, France on 12 June 1992 before placing 7th in the World Cup in Havana, Cuba on 26 September 1992. Following an operation on his achilles tendon on 15 April 1995, and a stress fracture of the foot in 1997, he retired to concentrate on his successful Physiotherapy career.
He was educated at Wesley College, Melbourne.Enthesitis
Enthesitis is inflammation of the entheses, the sites where tendons or ligaments insert into the bone. It is an enthesopathy, a pathologic condition of the entheses. Manifest in inflammation or occasionally in fibrosis and calcification, enthesitis can be caused by recurring stress or by inflammatory autoimmune disease. A common autoimmune enthesitis is at the heel, where the Achilles tendon attaches to the calcaneus.
It is associated with HLA B27 arthropathies such as ankylosing spondylitis, psoriatic arthritis, and reactive arthritis. Symptoms include multiple points of tenderness at the heel, tibial tuberosity, iliac crest, and other tendon insertion sites.Huw Bennett
Huw Bennett (born 11 June 1983) is a former Wales international rugby union hooker, who played most of his rugby career for the Ospreys.
Starting his club rugby in Clevedon, Somerset, Bennett has since represented both Wales and England at various age level; England U16s and England U18s, Wales U19s and Wales U21s. He made his debut for the Wales national senior side against Ireland during Wales' 2003 Rugby World Cup warm-ups, and was included in the squad for the 2003 Rugby World Cup in Australia - he played in the games against Canada and Tonga. In 2004, he played against Scotland and France as part of the 2004 Six Nations Championship, in which Wales finished fourth. He was named in the squad for the 2004 summer tour to Argentina and South Africa, where he made his first international start in the second Test against Argentina. Bennett did not play any tests in 2005, but was re-selected for the squad that would tour Argentina for their 2006 Summer tour. He played for Wales during the 2007 Rugby World Cup, playing just once - against Japan. Following this, he was selected for the 2008, 2009, 2010 and 2011 Six Nations Championship squads which included a Grand Slam victory in 2008, and subsequently also played in the 2011 Rugby World Cup acting as first choice Hooker.
In 2012, he was re-selected again for Wales playing in the 2012 Six Nations Championship Grand Slam side, starting against Ireland, his fiftieth test cap, and Scotland, his final cap for Wales. During the match against Scotland, he was substituted at half time following an injury he picked up. This was later revealed to be an Achilles tendon injury, which was expected to keep Bennett out of the game for up to four to six months. This later led to Bennett joining French club Lyon earlier than expected to start his 12-week recovery. However, in June 2013, Bennett announced his retirement due to recurring Achilles tendon rupture injury, and would leave Lyon without ever playing for the team.On the 11 May 2014, Huw Bennett joined the Wales Coaching team, and was appointed as assistant strength and conditioning coach.Jesper Helledie
Jesper Helledie is a retired male badminton player from Denmark. Though a highly regarded prospect in men's singles as a young player, he eventually became a doubles specialist, overcoming two ruptures of his Achilles tendon during his career.Marcell Harris
Marcell Harris (born June 9, 1994) is an American football safety for the San Francisco 49ers of the National Football League (NFL). He played college football for Florida. Harris had 102 tackles and two interceptions between 2014 and 2016. Due to a torn Achilles tendon, he missed the 2017 season.Plantar fasciitis
Plantar fasciitis is a disorder of the connective tissue which supports the arch of the foot. It results in pain in the heel and bottom of the foot that is usually most severe with the first steps of the day or following a period of rest. Pain is also frequently brought on by bending the foot and toes up towards the shin. The pain typically comes on gradually, and it affects both feet in about one third of cases.The causes of plantar fasciitis are not entirely clear. Risk factors include overuse such as from long periods of standing, an increase in exercise, and obesity. It is also associated with inward rolling of the foot, a tight Achilles tendon, and a lifestyle that involves little exercise. While heel spurs are frequently found it is unclear if they have a role in causing the condition. Plantar fasciitis is a disorder of the insertion site of the ligament on the bone characterized by micro tears, breakdown of collagen, and scarring. Since inflammation plays either a lesser or no role, a review proposed it be renamed plantar fasciosis. The diagnosis is typically based on signs and symptoms; ultrasound is sometimes useful. Other conditions with similar symptoms include osteoarthritis, ankylosing spondylitis, heel pad syndrome, and reactive arthritis.Most cases of plantar fasciitis resolve with time and conservative methods of treatment. For the first few weeks, those affected are usually advised to rest, change their activities, take pain medications, and stretch. If this is not sufficient, physiotherapy, orthotics, splinting, or steroid injections may be options. If these measures are not effective, extracorporeal shockwave therapy or surgery may be tried.Between 4% and 7% of the general population has heel pain at any given time: about 80% of these are due to plantar fasciitis. Approximately 10% of people have the disorder at some point during their life. It becomes more common with age. It is unclear if one sex is more affected than the other.Plantaris muscle
The plantaris is one of the superficial muscles of the superficial posterior compartment of the leg, one of the fascial compartments of the leg.
It is composed of a thin muscle belly and a long thin tendon. While not as thick as the achilles tendon, the plantaris tendon (which tends to be between 30 and 45 cm in length) is the longest tendon in the human body. Not including the tendon, the plantaris muscle is approximately 5–10 cm long and is absent in 8-12% of the population. It is one of the plantar flexors in the posterior compartment of the leg, along with the gastrocnemius and soleus muscles. The plantaris is considered an unimportant muscle and mainly acts with the gastrocnemius.Retrocalcaneal bursitis
Retrocalcaneal bursitis is an inflammation of the bursa located between the calcaneus and the anterior surface of the Achilles tendon. It commonly occurs in association with rheumatoid arthritis, spondyloarthropathies, gout, and trauma.
The pain is usually on the back of the heel and swelling appears on lateral or medial side of the tendon.Simmonds' test
Simmonds' test (also called the Thompson test or Simmonds-Thompson test) is used in lower limb examination to test for the rupture of the Achilles tendon. The patient lies face down with feet hanging off the edge of the bed. If the test is positive, there is no movement of the foot (normally plantarflexion) on squeezing the corresponding calf, signifying likely rupture of the Achilles tendon.Tendon rupture
Tendon rupture is a condition in which a tendon separates in whole or in part from tissue to which it is attached, or is itself torn or otherwise divided in whole or in part.Examples include:
Achilles tendon rupture
Anterior cruciate ligament injury
Biceps femoris tendon rupture and Quadriceps tendon rupture
Patellar tendon ruptureTenotomy
A tenotomy is a surgical act which involves the division of a tendon. It and related procedures are also referred to as tendon release, tendon lengthening, and heel-cord release.
When it involves the Achilles tendon, it is called "Achillotenotomy".
It has been used in the treatment of cerebral palsy.It has also been used for hammer toe.As an alternative to SLAP lesion labral repair, the tendon of the long head of the bicep can be released.Achilles tenotomy is commonly used as part of the Ponseti Method of treating clubfoot.