The Achilles tendon is the largest and strongest tendon in the human body, connecting the calf muscles (gastrocnemius and soleus) to the heel bone (calcaneus) at the back of the lower leg. This robust structure enables plantarflexion, the downward pointing of the foot, which is fundamental for walking, running, and jumping. A complete tear, or rupture, of this tendon significantly impairs mobility and is a serious injury that requires prompt medical attention. Recognizing the immediate signs of this injury is the first step toward appropriate treatment and recovery.
Acute Symptoms and Sensations
The moment an Achilles tendon rupture occurs is often marked by an immediate and distinct physical and auditory event. Many individuals describe a sudden, sharp pain that feels exactly like being kicked or shot in the back of the calf or heel. This sensation is the feeling of the tendon fibers snapping and is frequently accompanied by an audible “pop” or snapping sound.
Following the initial intense pain, the discomfort may quickly subside into a dull ache, which can be misleading. Despite the pain lessening, the mechanical integrity of the lower leg has been compromised, making it difficult to bear weight or push off the ground. The rupture most commonly occurs in the area roughly two to six centimeters above the tendon’s attachment to the heel bone.
Observable Signs and Self-Testing
After the initial trauma, several physical signs become evident, indicating a possible complete tear of the tendon. The most obvious functional deficit is the inability to perform a proper heel raise or stand on the toes of the injured leg, as the connection between the calf muscle and the heel is broken. Even simple walking will be impaired, with the person unable to push off the ball of the foot to propel themselves forward.
Visually, the ankle and lower calf area will typically begin to show swelling and possibly bruising shortly after the injury. A specific physical sign is a noticeable indentation or gap in the soft tissue, which can sometimes be felt or seen about two inches above the heel bone where the tendon has separated. The foot on the injured side may also hang differently when the person is sitting or lying down, often resting in a more dorsiflexed (upward pointed) position compared to the uninjured foot.
A simple self-assessment, adapted from the Thompson Test (or calf squeeze test), provides a strong indication of a rupture. To perform this safely, the person should lie face down with their feet hanging relaxed over the edge of a bed or chair. Gently squeeze the calf muscle belly (gastrocnemius and soleus) above the site of the suspected injury. If the Achilles tendon is intact, this squeezing action will cause the foot to point downward (plantarflex). A positive sign for a rupture is the absence of this downward foot movement when the calf is squeezed, confirming the loss of connection between the muscle and the heel.
Immediate Post-Injury Care and Next Steps
Once a rupture is suspected, the immediate focus should shift to minimizing swelling and preventing further harm while waiting for professional medical evaluation. The R.I.C.E. protocol—Rest, Ice, Compression, and Elevation—is the standard first aid approach for managing this type of soft tissue injury. It is important to avoid putting any weight on the injured leg, utilizing crutches or other assistance to keep the limb completely rested.
Applying ice wrapped in a towel to the back of the calf and heel for periods of 15 to 20 minutes can help control pain and limit the inflammatory response. Compression with an elastic bandage can also help reduce swelling, but care must be taken not to wrap it so tightly that it cuts off circulation. The injured foot should be elevated above the level of the heart as often as possible to assist with swelling reduction.
A suspected Achilles rupture requires immediate consultation with a healthcare provider, ideally in an emergency department or with an orthopedic specialist. A doctor will confirm the diagnosis, often using the Thompson test, and may utilize imaging such as an ultrasound or MRI to visualize the extent of the tear. Prompt diagnosis is important because treatment, which may be surgical repair or non-surgical immobilization, has better outcomes when started soon after the injury. Delaying professional treatment can complicate the healing process and affect the long-term functional recovery of the ankle.