Tendons provide stability at joints. Learning Objectives Key Points
A tendon is a mechanism by which muscles connect to bone and that transmits force. However, over the past two decades, research has also characterized the elastic properties of tendons and their ability to function as springs. This characteristic allows tendons to passively modulate forces during locomotion, thus providing additional stability with no active work. It also allows tendons to store and recover energy with high efficiency.
Achilles Tendon: The Achilles tendon, also called the calcaneus, provides stability and limits the range of motion at the ankle joint. It’s depicted in this diagram in relation to the tendo calcaneus. During a human stride, the Achilles (calcaneal) tendon stretches as the ankle joint undergoes dorsiflexion. During the last portion of the stride, as the foot undergoes plantar flexion (pointing the toes downward), the stored elastic energy is released. Because the tendon stretches, the muscle is able to function with less or even no change in length, allowing it to generate greater force.
Certain joints exhibit special movements including elevation, depression, protraction, retraction, inversion, eversion, dorsiflexion, plantar flexion, supination, pronation, and opposition. A number of factors influence joint stability. These include:
Typically, the more stable the joint is, the less is its range of motion and vice versa. Aging is another factor that influences motion due to decreased fluid, thinning of cartilage, shortening of ligaments, and loss of flexibility. Limited range of motion is a term meaning that a joint or body part cannot move through its normal range of motion. Joints, particularly hinge joints like the elbow and the knee, are complex structures made up of bone, muscles, synovium, cartilage, and ligaments that are designed to bear weight and move the body through space. The knee consists of the femur (thigh bone) above, and the tibia (shin bone) and fibula below. The kneecap (patella) glides through a shallow groove on the front part of the lower thigh bone. Ligaments and tendons connect the three bones of the knee, which are contained in the joint capsule (synovium) and are cushioned by cartilage.
When a joint does not move fully and easily in its normal manner it is considered to have a limited range of motion. Motion may be limited by a mechanical problem within the joint, swelling of tissue around the joint, spasticity of the muscles, pain or disease.
Motion may be limited because of a problem within the joint, swelling of tissue around the joint, stiffness of the ligaments and muscles, or pain.
A sudden loss of range of motion may be due to: Loss of motion may occur if you damage the bones within a joint. This may happen if you have: Brain, nerve, or muscle disorders can damage the nerves, tendons, and muscles, and can cause loss of motion. Some of these disorders include:
Your health care provider may suggest exercises to increase muscle strength and flexibility.
Make an appointment with your provider if you have difficulty moving or extending a joint.
The provider will examine you and ask about your medical history and symptoms. You may need joint x-rays and spine x-rays. Laboratory tests may be done. Physical therapy may be recommended.
Debski RE, Patel NK, Shearn JT. Basic concepts in biomechanics. In: Miller MD, Thompson SR, eds. DeLee Drez & Miller's Orthopaedic Sports Medicine. 5th ed. Philadelphia, PA: Elsevier; 2020:chap 2. Magee DJ. Primary care assessment. In: Magee DJ, ed. Orthopedic Physical Assessment. 6th ed. St Louis, MO: Elsevier Saunders; 2014:chap 17.
Last reviewed on: 7/25/2020 Reviewed by: C. Benjamin Ma, MD, Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Overview Joint range of motion refers to both the distance a joint can move and the direction in which it can move. There are established ranges that doctors consider normal for various joints in the body. For example, one study determined a normal knee should ideally be able to flex, or bend, to between 133 and 153 degrees. And a normal knee should also be able to extend so that it’s completely straight. A reduction in a normal range of motion in any of the joints is known as limited range of motion. Joint range of motion naturally declines as you age, but it can also occur with a number of conditions. Certain exercises may be helpful for improving and maintaining flexibility in the joints. Medical conditions associated with a limited range of motion in the joints include:
Other causesOther causes of restricted range of motion include: See your doctor about any reductions in the normal range of motion of your joints. You should also go to your doctor if you can’t fully straighten or bend one or more joints or if you’re having difficulty moving a certain joint. People aren’t always aware of their own limited range of motion. You may see a doctor for an unrelated reason and discover that you’re also experiencing a lack of mobility in one or more of your joints. Your initial appointment will likely consist of a physical examination. This will include an assessment of the affected joints. Your doctor may ask questions about your limited range of motion, such as:
Your doctor may also assess the function of your bones, muscles, or nervous system. As a follow-up, your doctor may schedule some tests, such as X-rays of the spine and joints. Your doctor may recommend a course of physical therapy designed to enhance range of motion. In some cases, the position of the joint may become permanently fixed. This means you’ll no longer be able to move the joint past a given point. These are known as contracture deformities. Conditions associated with this complication include:
Range of motion exercises specifically target joint flexibility. You can do range of motion exercises with a physical therapist. Your doctor or physical therapist can also tell you about exercises that you can easily do at home. These can help you maintain or improve joint flexibility, which helps with overall freedom and ease of movement. There are three general categories of range of motion exercises: active, active assistive, and passive. You can do active exercises without the assistance of another person. Active assistive exercises rely on your effort and the effort of another person. This other person is often a physical therapist. These exercises are helpful when it’s painful to flex or extend the joint on your own. Passive exercises rely completely on the effort of the physical therapist or another individual. These are typical performed when the person receiving treatment isn’t physically able to perform the movement on their own. Practicing range of motion exercises can greatly increase your flexibility and ease of movement. However, always speak with your doctor before attempting to perform a range of motion exercise for the first time. Maintaining proper alignment and form are necessary to make sure you don’t injure yourself. |