Joints are points in your skeleton where separate bones come together to allow movement. If you did not have joints, you would not be able to walk, move your arms, or otherwise perform functions. Because joints just work, we do not usually think about them. They are just there, and we expect them to perform. However, issues can develop in your joints, which can hamper your freedom of mobility.
There are several types of joints. Immovable joints (synarthrosis) do not allow motion. It seems odd that these should be considered joints, but they are places on the body, such as where your skull bones have joined together. Skull bones are separate at birth. They slide over each other so babies can go through the birth canal. Thereafter, they start fusing together with fibrous tissue making the skull one rigid bone group. These joints are called sutures. This process can take until age 20 to complete. The skull is importantly formed to protect the brain from injury from the outside world. We do not think much about these joints unless they fuse improperly, creating a space too small for the developing brain or fusing and altering the head's shape. Correction of this is usually treated with a helmet to remold the skull. Immovable joints are also found where teeth fit into their sockets. They are held in place by the periodontal ligament.
Slightly moveable joints (amphiarthrosis) are bones that are just as their name indicates. These joints only allow a small bit of motion. An example is the individual bones of the spine or the spine vertebrae, where there is some flexibility between each bone that helps with trunk movement and allows adjustments for balance. Cartilage keeps these bones from moving too far. These joints may be fused due to a genetic issue or maybe fused surgically to provide stability to the spinal column after an injury or disease process. Too much movement from the spine vertebrae can lead to spinal cord injury (or additional injury). Too little movement can overwork the spine vertebrae above or below the fusion making the spinal bones unstable over time. This can occur after a spinal fusion but typically takes years if it even occurs. Newer, slightly flexible spinal stabilization rods have reduced this complication immensely. There are also slightly moveable joints on the ends of the tibia and fibula joints which provide little movement but enhance stability and weight bearing. The pubic synthesis is also a fibrocartilage joint between both sides of the pelvis that helps manage upper body weight and allows slight separation of the pelvis for childbirth.
Freely moveable joints (diarthrosis) are those we think the most about. These provide movement to most of the body. The ends of these bones are enclosed in a capsule that contains fluid, so they slide easily with movement. The types of freely moving joints and their locations are provided in this chart:
| Type of Freely Moving Joint |
Joint Form |
Example of Body Location |
| Ball and socket joint |
A round head bone fitting into a cup-shaped bone |
Both shoulders and hips |
| Saddle joint |
A concave (turned inward bone) fits into a convex bone (turned outward). The concave bone looks like the shape of a saddle. The convex bone looks like the shape of a rider. |
Thumbs, shoulders, and inner ear |
| Hinge joint |
Allows flexion and extension only |
Elbows, fingers, knees, ankles, toes |
| Condyloid joint |
Convex and concave bones create an elliptical formation |
Wrists, joints at the junction of the palm of the hand and fingers, joints at the junction of the toes to the foot |
| Pivot joint |
Allows rotation movement |
Neck, wrists, and elbows |
| Gliding (plane) joint |
Surfaces are flat, which allows the bones to slide over each other |
Hands, skull before fusion of bones |
There are medical conditions that can affect your joints. These include arthritis or joint inflammation which includes rheumatoid arthritis, gout, or degenerative arthritis (osteoarthritis). Bursitis is inflammation of the fluid that pads bones. Infection can occur within the joint. Tendonitis is inflammation, irritation, and swelling of a tendon or tendons attached to a joint.
Paralysis can affect joints in a variety of ways. The muscles and tendons around a joint can become lax or weak, which will not then hold the joint in place. This can lead to joint displacement. If the muscles are weak, handling may create a movement that is not within the purpose of a particular joint’s flexibility. For example, this can occur by moving a body part in a rotation when the joint should only be moved in flexion and extension. Another issue is tone or spasticity, where the muscles pull the joint past its functionality. Muscle imbalances can pull joints out of alignment. An example is scoliosis of the spine, where muscle imbalance pulls the spine out of its usual position.
Joint issues due to paralysis can be avoided and reduced. Gentle handling of a joint during movement and exercise is critical to the health of your joints. Moving limbs carefully is essential. One of the most common issues with joint handling is the knee ‘backslapping’ or being stretched beyond its extension forward due to rough handling. This can happen to any joint, like pulling sideways on the leg in positioning or tugging the shoulder in moving the upper body. Knowing your joints' extension and flexion limitations is essential in preventing injury.
Contractions occur with tone or spasticity pulling on a joint continuously or very frequently so that the countermovement of the joint cannot occur. The muscle does not relax, letting the joint return to a neutral position. Treatment of tone or spasticity can be provided by a gentle range of motion to all joints, medication, Botox injections, or implantation of a baclofen pump to calm the muscle cramps. Even though tone or spasticity is being treated, you will need to provide a gentle range of motion to the extremities to keep the joints subtle. Notice if you or your caregiver cannot stretch the joint within its regular range of motion. This could be a change in tone or spasticity, or the start of a contracture. Early contracture treatment is much easier to resolve than late treatment, which may require extensive and invasive procedures.
All joints should be checked for stability, but the shoulders and hips have some particular issues. Shoulder injuries of any type, such as muscle strains or rotator cuff injuries, are common for individuals with paralysis due to moving the weight of their bodies and the use of wheelchair propulsion. Keep up with strengthening exercises to maintain your shoulders. Yes, you are exercising when moving your body and propelling your chair, but that only uses some muscles; keeping all your shoulder muscles healthy is needed. You may investigate some mobility adaptions to protect your shoulders as you age. Many scientists have researched wheelchair propulsion all with the conclusion not to reach back too far on your wheel. This can easily injure your shoulder. Propel your wheelchair by beginning with your arm straight down from your shoulder, not back. You will still have your speed but less shoulder injury.
Paralysis in the arms results in weakened muscles. The weight of an arm dangling from the body can dislocate it from the shoulder. This is called shoulder subluxation. Use an arm tray or trough when in your chair to reduce the pull of your arm from the shoulder joint. There are also shoulder slings that can assist when walking or participating in walking exercises. Shoulder subluxation is painful. That may be your first sign of subluxation. If you have decreased sensation, you may notice increased tone (spasticity), episodes of autonomic dysreflexia if you have AD, or a gap under the skin at the junction of the top of the shoulder/arm connection. This subluxation is measured by finger widths, 1 finger, 2, 3, 4. One finger is a mild subluxation, increasing in severity to four fingers.
The hips are another area in which dislocation can be easily overlooked. With weak muscles that are not functioning well, the hip joint can slowly separate. You may feel pain, or if sensation is an issue, you may notice a rotation in your foot, increased tone (spasticity), or AD. Most people think foot rotation is an issue in the foot, and it could be, but a foot that rotates outward from the body can be a sign of hip displacement. The leg in question can also appear shorter than the other. Avoiding this issue can be accomplished by proper body alignment when seated or in bed with support to the hip joint using pressure dispersing equipment. You will need to work with your healthcare provider, therapist, and nurse to find the right equipment for your needs. The regular exercise provided to the area will help maintain the joint as well.
Most joint issues can be prevented with exercise and proper pressure-dispersing equipment. Knowing how to prevent the issue will help you catch it early to provide quick treatment. Nurse Linda
Pediatric Consideration:
Children can quickly grow out of their equipment as their bodies grow and develop, seemingly overnight sometimes. Keeping in tune with your child’s joint movements, noticing any changes, and providing a range of motion and other exercises will help prevent issues.
Teach your child to care for their bodies even in the areas where sensation may be limited. We all move so quickly. Taking time to care for all your body is an essential habit to form. Nurse Linda
