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.
C1-C4 nerve injury. There nerves are somewhat different in the neck compared to the lower nerves at C5-T1. Compression of these nerve roots can cause neck pain but generally do not connect to any muscles. Injury to these nerves will therefore not cause arm weakness. Even within this group, the first two nerves (C1 and C2) are different as these two nerves (AKA the greater and lesser occipital nerves) supply sensation to the back of the skull and irritation can generate headaches.