Joint mobility is one of the important indicators in rehabilitation, whether it is neurological or orthopedic rehabilitation. Good joint mobility reflects an important aspect of joint function. Especially in sports system injuries, limited joint mobility means that there is a significant loss of joint function. Imagine if you can’t bend your elbow (elbow joint), you can’t feel your face when you wash it, you can’t reach your mouth when you eat, your daily life becomes a problem! If the leg (actually the knee) can’t bend, you can’t squat, you can’t go up and down stairs, you can’t even squat in the toilet, so what function is there to speak of? The angle of the joint is a common name. The professional name is joint mobility, or ROM, which includes different aspects such as active joint mobility (AROM) and passive joint mobility (PROM). In terminology, joint mobility refers to the arc of motion or angle of rotation through which a joint moves. In layman’s terms, it is the angle formed by the limb at the axis of the joint. Any measurement has to have a standard or starting point before the measurement can begin, and the same is certainly true for joint mobility, where a position of 0° has to be specified before the angle can be measured. Each joint has a different 0° position. The human body has a so-called anatomical posture, and kinesiology also has the basic kinematic posture of the human body, that is, feet apart and shoulder width, completely natural upright, hands naturally on the sides of the body. The anatomical posture of the human body and the kinematic posture of the human body In this posture, our joints are in the 0° position, and the angle of each joint is measured using this posture as the starting point. For example, the knee joint, when standing straight is 0 °, the greater the bending is the greater the angle, bending to the head when squatting is about 135-160 °, because each person’s individual differences, so the angle of bending to the head is not determined. But one thing is certain, no one can bend to 180 °, two bones together is 180 °, this time the leg has long been broken! The reason for the 180° joke is that I am afraid that people will count a straight leg as 180°, and I do hear people describing the angle of the knee joint in this way all the time in my daily work. So remember, there is no 180° angle of the knee! If we look closely, we will see that many people (usually more so in women) when they straighten their leg or elbow (elbow), they will go a little past full extension, that is, a little straighter than in a straight line, showing an opposite angle. This angle is called hyperextension, which means overstretching. In general, this angle is normal and is caused by subtle differences in anatomy, but if there is no hyperextension and you suddenly find it after an injury, you should pay close attention to it! mini cute interphalangeal joint protractor So how can we measure the angle of the joint ourselves during rehabilitation exercises? Professional measurement requires a special goniometer, and with a goniometer you also need expertise. Take the knee for example, to measure the knee flexion angle, the midpoint of the lateral joint space of the knee should be used as the axis, with the high point of the outer ankle at one end and the greater trochanter at the other. It is also important to note the need to measure in a standard body position, and the need to pay attention to reduce subjective error, and a host of other considerations. Really hurry to learn, and so these are figured out, the leg has long been delayed. So I changed a bit, organized some simple methods, can be more accurate in the practice of their own joint angle measurement. Of course, this is not a substitute for joint mobility measured by a professional. Because you need to convert the measurement of the angle into the measurement of the distance, but this measurement is much less difficult, you can know the progress or regression of your joint angle by the change of the distance. Knee: For less than 90°, sit on a high chair or table so that your feet are not on the ground, and then measure the distance from your heel to the vertical surface of the table. Of course, you must sit upright, the buttocks must not leave the table, and the thighs need to be padded a little higher underneath so that the thighs are parallel to the table from the side. Because the thigh root must be thicker than near the knee, the actual thigh is tilted after sitting flat. At the same time, the thighs should not leave the table, to ensure that the position and posture of the sitting is the same every time you measure. The smaller the distance, the greater the angle of knee flexion, and the closer to 90°. If the distance is greater than 90°, you can sit on the bed and bend your leg as much as possible, and then measure the distance from the heel to the transverse gluteal crease. The so-called transverse gluteal crease is the place where the gluteus maximus and the thigh meet. When we stand, there is an obvious fold of skin between the hip and the leg, and its position is relatively constant. By the same token, this distance can indicate the angle of knee flexion, the smaller the distance, the greater the angle of knee flexion. And we can also measure both legs at the same time, so we can know how much difference there is between the injured leg and the good leg. Knee extension can also be measured indirectly by distance. Sit on a hard bed or table with your leg straight and flat on the bed or table. Note that it should not be a soft place, otherwise the buttocks and heels will sink a little because of the weight, and the measurement will be very inaccurate. After sitting, measure whether there is a gap between the knee joint and the bed surface, if not, the knee joint has been straightened to 0°, if there is a gap, measure the distance, the greater the distance, the worse the angle of straightening, and the more the difference between 0°. Again, you can learn the gap by comparing the two legs. Elbow joint: when flexing the palm of the hand facing you, after flexing well, measure the distance between the wrist at the transverse line to the shoulder. Again, the smaller the distance, the greater the angle of elbow flexion. For extension, sit in front of a table and place your arm flat on the table, palm up, and measure the distance between the horizontal line of the wrist and the table. Again, the smaller the distance, the better the angle of elbow extension, the closer to 0°. Rotation of the elbow joint: In addition to flexion and extension, there is also an angle of rotation of the elbow joint. With the arms clamped tightly against the sides of the body and the elbows bent to 90°, the hands are held in a fist with the thumbs up and the thumbs pointing exactly up, which is 0°. Rotating the small arm so that the palm is down is an internal rotation of 90°; rotating in the opposite direction so that the palm is up is an external rotation of 90°. You can also measure the size of the internal or external rotation angle by the distance from the thumb to the horizontal. Ankle joint: Sitting on a bed with a straight leg and the lower leg flat on the bed with the toe directly above is the 0° position of the ankle joint. Toe up is the dorsiflexion of the ankle joint. The distance from the toe to the knee joint (the position of the knee joint is constant, as long as the same position is measured each time, the error will be small) can represent the angle of dorsiflexion of the ankle. Toe down is the plantar flexion of the ankle joint. By measuring the distance from the toe to the bed, the angle of ankle flexion can be reflected. Shoulder joint: The angle of the shoulder joint is too complicated, including forward flexion, back extension, abduction, adduction, internal rotation, external rotation, etc. It is difficult to measure the angle of the shoulder joint by yourself, like the posture of raising your hand in surrender, which is the external rotation of the abduction 90° position. You can stand with your back against the wall so that your body does not move with you when you lift your arms. The vertical distance from the horizontal wrist to the wall can reflect the size of the forward bending angle. The distance from the elbow to the ear can be used to measure the degree of abduction. The distance from the wrist to the opposite scapula is measured at the highest point behind the hand. There are also hip and wrist joints, as well as the cervical spine and lumbar spine and some of the above-mentioned joint angles, it is difficult to measure yourself, only to let professionals to measure the angle to objectively know the situation of joint mobility. However, you can judge whether your joint mobility has improved by how easy it is to perform a particular movement. If you find it easier to perform a movement that was difficult to do through practice and treatment over a period of time, it means that your joint mobility (or muscle strength, or joint control, or swelling and pain) has improved.