(1) Effective speech depends also on the motor neurons in the cervical and thoracic parts of the spinal cord that serve the muscles of breathing.(2) Abdominal and proximal thoracic aortic aneurysms developed a few years later.(3) The rib cage presses down on the pelvis, reducing thoracic and abdominal space.(4) The sympathetic nerve supply to the lung arises in the upper six thoracic segments of the spinal cord.(5) The left bronchial arteries, usually two, arise from the ventral surface of the thoracic aorta.
