Muscle Weakness

Typical weakness affects usually one side of the body and therefore all muscles on one side are affected. This can result in one leg or arm being not as functionally competent as the other one.

Muscle tone, strength, and co-ordination

Muscle tone is the amount of tension in a muscle when at rest. When muscle tone is normal, the limbs and body feel easy to move. A brain injury may damage the normal control of muscle tone. This may cause decreased muscle tone—the limbs feel floppy and heavy (hypotonicity) or more than normal muscle tone—the limbs feel stiff and tight (hypertonicity). Both affect the person’s ability to control movement.

After a brain injury, muscles may show different degrees of weakness. Some muscles may be stronger in one limb than another. Damage to certain parts of the brain may result in slow, jerky, or uncontrolled movements. You may hear the terms: hemiparesis: muscle weakness on one side of the body only hemiplegia: muscle paralysis (no movement) on one side of the body only

Posture

The head and neck give the eyes, mouth, and tongue a stable base. The trunk (the body between the shoulders and hips) gives us a stable base so we can use our arms and legs.

To move normally, the head, neck, and trunk need to be properly positioned when standing and sitting. A brain injury can affect the muscles that control head, neck, and trunk positions.