What is a reduction in the normal movement of a joint?

The range of motion of a joint is often measured with devices such as a goniometer or inclinometer. These devices allow range of motion to be measured in degrees and then compared to accepted normal values. Flexibility can also be measured with functional tests. These tests allow the measurement of joint range of motion within the context of common patterns of movement. Using range of motion testing, areas of inflexibility can be identified and addressed.

• Increased neuromuscular coordination
• Return of muscle to natural resting state
• Modifying blood pooling, recirculation

Typical areas of assessment include hamstrings, lower back, iliotibial band (IT band) and hip. In order to realize the benefits of stretching, a regular stretching routine must be incorporated into your normal training program. Also, it is important to remember that gaining flexibility takes time and dedication. It may take several weeks of consistent, daily stretching to notice improvement. Stretch after each training session with stretches that will target the largest joints in your body. Stretching for a continuous amount of time (20+ minutes), not just after each training session several times per week, can also be very beneficial. Once these have been performed, move on to stretches that will more specifically address your areas of inflexibility. There are an unlimited number of stretches that can be performed to address all of the body’s joints, but there are specific guidelines that should be followed for all stretches:

• Maintain the stretch position for 30 seconds to begin but 1-2 minutes is ideal. Stretching should be completed statically. Static stretching calls for gradually stretching through a muscle’s full range of motion until you feel resistance or mild discomfort. Gradually release the stretch
• Repeat Frequency: Daily

A stretching routine should cover all the major muscle groups of the body as well as any specific muscle groups that are being utilized in a sport or activity. The movement of other areas of the body, other than the muscle group being stretched, should be minimized. Maintain a regular breathing pattern when stretching. Stretching will not head off delayed-onset muscle soreness - the kind that generally occurs the day after unaccustomed The debate as to when to perform a stretching routine is controversial. It is generally agreed upon that stretching at the end of an exercise session will greatly benefit you. Stretching before an exercise session though is generally not recommended unless it is preceded by a 5-minute cardiovascular warm-up. Warming up before stretching increases the blood flow and temperature of the muscles, ligaments and tendons, improving the elasticity and optimal functioning of the muscles and connective tissue. Stretching when muscles are cold could lead to a strain or pull. Begin each stretch slowly and gently – Stretch to the point of tightness and then just beyond. You should feel pulling or tightness, but not pain. Stay relaxed and do not bounce.

Stretching is most often thought of as a way to loosen muscles, but it is also effective in increasing the mobility of all soft tissues that restrict flexibility. Stretching will not head off delayed-onset muscle soreness - the kind that generally occurs the day after unaccustomed strenuous exercise.

The functional classification divides joints into three categories: synarthroses, amphiarthroses, and diarthroses. A synarthrosis is a joint that is immovable. This includes sutures, gomphoses, and synchondroses. Amphiarthroses are joints that allow slight movement, including syndesmoses and symphyses. Diarthrosesare joints that allow for free movement of the joint, as in synovial joints.

Movement at Synovial Joints

The wide range of movement allowed by synovial joints produces different types of movements. The movement of synovial joints can be classified as one of four different types: gliding, angular, rotational, or special movement.

Gliding Movement

Gliding movementsoccur as relatively flat bone surfaces move past each other. Gliding movements produce very little rotation or angular movement of the bones. The joints of the carpal and tarsal bones are examples of joints that produce gliding movements.

Angular Movement

Angular movements are produced when the angle between the bones of a joint changes. There are several different types of angular movements, including flexion, extension, hyperextension, abduction, adduction, and circumduction. Flexion, or bending, occurs when the angle between the bones decreases. Moving the forearm upward at the elbow or moving the wrist to move the hand toward the forearm are examples of flexion.Extension is the opposite of flexion in that the angle between the bones of a joint increases. Straightening a limb after flexion is an example of extension. Extension past the regular anatomical position is referred to as hyperextension. This includes moving the neck back to look upward, or bending the wrist so that the hand moves away from the forearm.

Abduction occurs when a bone moves away from the midline of the body. Examples of abduction are moving the arms or legs laterally to lift them straight out to the side. Adductionis the movement of a bone toward the midline of the body. Movement of the limbs inward after abduction is an example of adduction.Circumduction is the movement of a limb in a circular motion, as in moving the arm in a circular motion.

Rotational Movement

Rotational movement is the movement of a bone as it rotates around its longitudinal axis. Rotation can be toward the midline of the body, which is referred to as medial rotation, or away from the midline of the body, which is referred to as lateral rotation. Movement of the head from side to side is an example of rotation.

Special Movements

Some movements that cannot be classified as gliding, angular, or rotational are called special movements. Inversion involves the soles of the feet moving inward, toward the midline of the body. Eversion is the opposite of inversion, movement of the sole of the foot outward, away from the midline of the body. Protraction is the anterior movement of a bone in the horizontal plane. Retractionoccurs as a joint moves back into position after protraction. Protraction and retraction can be seen in the movement of the mandible as the jaw is thrust outwards and then back inwards. Elevation is the movement of a bone upward, such as when the shoulders are shrugged, lifting the scapulae. Depression is the opposite of elevation—movement downward of a bone, such as after the shoulders are shrugged and the scapulae return to their normal position from an elevated position.Dorsiflexion is a bending at the ankle such that the toes are lifted toward the knee. Plantar flexion is a bending at the ankle when the heel is lifted, such as when standing on the toes. Supination is the movement of the radius and ulna bones of the forearm so that the palm faces forward. Pronation is the opposite movement, in which the palm faces backward. Opposition is the movement of the thumb toward the fingers of the same hand, making it possible to grasp and hold objects.

Types of Synovial Joints

Synovial joints are further classified into six different categories on the basis of the shape and structure of the joint. The shape of the joint affects the type of movement permitted by the joint (Figure 19.26). These joints can be described as planar, hinge, pivot, condyloid, saddle, or ball-and-socket joints.

Figure 19.26. 
Different types of joints allow different types of movement. Planar, hinge, pivot, condyloid, saddle, and ball-and-socket are all types of synovial joints.

Planar Joints

Planar joints have bones with articulating surfaces that are flat or slightly curved faces. These joints allow for gliding movements, and so the joints are sometimes referred to as gliding joints. The range of motion is limited in these joints and does not involve rotation. Planar joints are found in the carpal bones in the hand and the tarsal bones of the foot, as well as between vertebrae (Figure 19.27).

Figure 19.27. 
The joints of the carpal bones in the wrist are examples of planar joints. (credit: modification of work by Brian C. Goss)

Hinge Joints

In hinge joints, the slightly rounded end of one bone fits into the slightly hollow end of the other bone. In this way, one bone moves while the other remains stationary, like the hinge of a door. The elbow is an example of a hinge joint. The knee is sometimes classified as a modified hinge joint (Figure 19.28).

Figure 19.28. 
The elbow joint, where the radius articulates with the humerus, is an example of a hinge joint. (credit: modification of work by Brian C. Goss)

Pivot Joints

Pivot joints consist of the rounded end of one bone fitting into a ring formed by the other bone. This structure allows rotational movement, as the rounded bone moves around its own axis. An example of a pivot joint is the joint of the first and second vertebrae of the neck that allows the head to move back and forth (Figure 19.29). The joint of the wrist that allows the palm of the hand to be turned up and down is also a pivot joint.

Figure 19.29.  The joint in the neck that allows the head to move back and forth is an example of a pivot joint.

Condyloid Joints

Condyloid joints consist of an oval-shaped end of one bone fitting into a similarly oval-shaped hollow of another bone (Figure 19.30). This is also sometimes called an ellipsoidal joint. This type of joint allows angular movement along two axes, as seen in the joints of the wrist and fingers, which can move both side to side and up and down.

Figure 19.30. 
The metacarpophalangeal joints in the finger are examples of condyloid joints. (credit: modification of work by Gray’s Anatomy)

Saddle Joints

Saddle joints are so named because the ends of each bone resemble a saddle, with concave and convex portions that fit together. Saddle joints allow angular movements similar to condyloid joints but with a greater range of motion. An example of a saddle joint is the thumb joint, which can move back and forth and up and down, but more freely than the wrist or fingers (Figure 19.31).

Figure 19.31. 
The carpometacarpal joints in the thumb are examples of saddle joints. (credit: modification of work by Brian C. Goss)

Ball-and-Socket Joints

Ball-and-socket joints possess a rounded, ball-like end of one bone fitting into a cuplike socket of another bone. This organization allows the greatest range of motion, as all movement types are possible in all directions. Examples of ball-and-socket joints are the shoulder and hip joints (Figure 19.32).

Figure 19.32. 
The shoulder joint is an example of a ball-and-socket joint.

Concept in Action

Watch this animation showing the six types of synovial joints.

Rheumatologist

Rheumatologists are medical doctors who specialize in the diagnosis and treatment of disorders of the joints, muscles, and bones. They diagnose and treat diseases such as arthritis, musculoskeletal disorders, osteoporosis, and autoimmune diseases such as ankylosing spondylitis and rheumatoid arthritis.

Rheumatoid arthritis (RA) is an inflammatory disorder that primarily affects the synovial joints of the hands, feet, and cervical spine. Affected joints become swollen, stiff, and painful. Although it is known that RA is an autoimmune disease in which the body’s immune system mistakenly attacks healthy tissue, the cause of RA remains unknown. Immune cells from the blood enter joints and the synovium causing cartilage breakdown, swelling, and inflammation of the joint lining. Breakdown of cartilage causes bones to rub against each other causing pain. RA is more common in women than men and the age of onset is usually 40–50 years of age.

Rheumatologists can diagnose RA on the basis of symptoms such as joint inflammation and pain, X-ray and MRI imaging, and blood tests. Arthrography is a type of medical imaging of joints that uses a contrast agent, such as a dye, that is opaque to X-rays. This allows the soft tissue structures of joints—such as cartilage, tendons, and ligaments—to be visualized. An arthrogram differs from a regular X-ray by showing the surface of soft tissues lining the joint in addition to joint bones. An arthrogram allows early degenerative changes in joint cartilage to be detected before bones become affected.

There is currently no cure for RA; however, rheumatologists have a number of treatment options available. Early stages can be treated with rest of the affected joints by using a cane or by using joint splints that minimize inflammation. When inflammation has decreased, exercise can be used to strengthen the muscles that surround the joint and to maintain joint flexibility. If joint damage is more extensive, medications can be used to relieve pain and decrease inflammation. Anti-inflammatory drugs such as aspirin, topical pain relievers, and corticosteroid injections may be used. Surgery may be required in cases in which joint damage is severe.

Summary

The structural classification of joints divides them into bony, fibrous, cartilaginous, and synovial joints. The bones of fibrous joints are held together by fibrous connective tissue; the three types of fibrous joints are sutures, syndesomes, and gomphoses. Cartilaginous joints are joints in which the bones are connected by cartilage; the two types of cartilaginous joints are synchondroses and symphyses. Synovial joints are joints that have a space between the adjoining bones. The functional classification divides joints into three categories: synarthroses, amphiarthroses, and diarthroses. The movement of synovial joints can be classified as one of four different types: gliding, angular, rotational, or special movement. Gliding movements occur as relatively flat bone surfaces move past each other. Angular movements are produced when the angle between the bones of a joint changes. Rotational movement is the movement of a bone as it rotates around its own longitudinal axis. Special movements include inversion, eversion, protraction, retraction, elevation, depression, dorsiflexion, plantar flexion, supination, pronation, and opposition. Synovial joints are also classified into six different categories on the basis of the shape and structure of the joint: planar, hinge, pivot, condyloid, saddle, and ball-and-socket.

Exercises

1. Synchondroses and symphyses are:
   1. synovial joints
   2. cartilaginous joints
   3. fibrous joints
   4. condyloid joints
2. The movement of bone away from the midline of the body is called ________.
   1. circumduction
   2. extension
   3. adduction
   4. abductino
3. Which of the following is not a characteristic of the synovial fluid?
   1. lubrication
   2. shock absorption
   3. regulation of water balance in the joint
   4. protection of articular cartilage
4. The elbow is an example of which type of joint?
   1. hinge
   2. pivot
   3. saddle
   4. gliding
5. What movements occur at the hip joint and knees as you bend down to touch your toes?
6. What movement(s) occur(s) at the scapulae when you shrug your shoulders?

Answers

1. B
2. D
3. C
4. A
5. The hip joint is flexed and the knees are extended.
6. Elevation is the movement of a bone upward, such as when the shoulders are shrugged, lifting the scapulae. Depression is the downward movement of a bone, such as after the shoulders are shrugged and the scapulae return to their normal position from an elevated position.

Glossary

abductionwhen a bone moves away from the midline of the bodyadductionmovement of the limbs inward after abductionamphiarthrosisjoint that allows slight movement; includes syndesmoses and symphysesangular movementproduced when the angle between the bones of a joint changesarticulationany place where two bones are joinedball-and-socket jointjoint with a rounded, ball-like end of one bone fitting into a cuplike socket of another bonecartilaginous jointjoint in which the bones are connected by cartilagecircumductionmovement of a limb in a circular motion.condyloid jointoval-shaped end of one bone fitting into a similarly oval-shaped hollow of another bonedepressionmovement downward of a bone, such as after the shoulders are shrugged and the scapulae return to their normal position from an elevated position; opposite of elevationdiarthrosisjoint that allows for free movement of the joint; found in synovial jointsdorsiflexionbending at the ankle such that the toes are lifted toward the kneeelevationmovement of a bone upward, such as when the shoulders are shrugged, lifting the scapulaeeversionmovement of the sole of the foot outward, away from the midline of the body; opposite of inversionextensionmovement in which the angle between the bones of a joint increases; opposite of flexionfibrous jointjoint held together by fibrous connective tissueflexionmovement in which the angle between the bones decreases; opposite of extensiongliding movementwhen relatively flat bone surfaces move past each othergomphosisthe joint in which the tooth fits into the socket like a peghinge jointslightly rounded end of one bone fits into the slightly hollow end of the other boneinversionsoles of the feet moving inward, toward the midline of the bodyjointpoint at which two or more bones meetlateral rotationrotation away from the midline of the bodymedial rotationrotation toward the midline of the bodyoppositionmovement of the thumb toward the fingers of the same hand, making it possible to grasp and hold objectspivot jointjoint with the rounded end of one bone fitting into a ring formed by the other boneplanar jointjoint with bones whose articulating surfaces are flatplantar flexionbending at the ankle such that the heel is lifted, such as when standing on the toespronationmovement in which the palm faces backwardprotractionanterior movement of a bone in the horizontal planeretractionmovement in which a joint moves back into position after protractionrotational movementmovement of a bone as it rotates around its own longitudinal axissaddle jointjoint with concave and convex portions that fit together; named because the ends of each bone resemble a saddlesupinationmovement of the radius and ulna bones of the forearm so that the palm faces forwardsynarthrosisjoint that is immovablesyndesmosisjoint in which the bones are connected by a band of connective tissue, allowing for more movement than in a suturesynovial jointonly joint that has a space between the adjoining bones

What is normal movement of a joint?

What movement is reduction?

What reduces a joints range of motion?

What is the loss of mobility of a joint?