Where skeletal muscle is voluntary, cardiac muscle is autorhythmic (beats involuntarily; generates its own action potentials). 3. Smooth muscle: refers to the muscles that are controlled involuntarily by the brain, like those attached to the base of hair follicles or in the walls of the gastro-intestinal tract.The muscle has a single nucleus in the middle of the cell. Skeletal and cardiac muscle are types of straited muscle.here skeletal muscle is voluntary, cardiac muscle is autorhythmic (beats involuntarily; generates its own action potentials). 3. Smooth muscle: refers to the muscles that are controlled involuntarily by the brain, like those attached to the base of hair follicles or in the walls of the gastro-intestinal tract.
When this results in irritation or damage to the adjacent nerves at the T4 level and the patient experiences diffuse arm pain, pins and needles or numbness in the upper arm the condition is known as T4 syndrome. Causes of T4 syndrome. T4 syndrome typically occurs due to injury to the facet joints or disc at T4 which then affects the nerve root at that level. Injury to these structures can occur during excessive bending, lifting, arching, or twisting movements or due to poor posture.
What is T4 Syndrome? When the spine moves, facet joints and intevertebral discs at T4 vertebra can get stretched or compressed beyond their bearable capacity leading to injured joints and discs. This injury can in turn damage or irritate the nerves in and around T4 level.