The thoracic spine, commonly referred to as the dorsal spine, is the central section of the spine that extends from the base of the neck to the bottom of the rib cage. This spine segment plays a vital role in providing flexibility, ensuring the body remains upright, and safeguarding the chest’s organs.
One of its essential components is the cardiac plexus, which is interconnected with the coronary and pulmonary plexuses. The thoracic visceral nerves transmit pain signals from the heart to the upper thoracic spinal cord segments, which can result in pain being referred to the left upper limb in the T1 and T2 dermatomes. Another key element to note is the plexus esophageal. This is derived from the right and left vagus (X) nerves, as well as the thoracic visceral branches of the sympathetic trunk.
The Thoracic Spinal Cord segment originates from the thoracic region. When oriented correctly, the dorsal is at the top, while the ventral lies at the bottom. The dorsal horn is slim and extends to the spinal cord’s edge, whereas the ventral horn has a rounded shape.
Another crucial structure is the vertebral column, also known as the spinal column or spine. This column comprises a series of vertebrae, each separated and united by an intervertebral disc. In total, the thoracic spine consists of 12 bones situated in the back, while the lumbar spine has 5 bones in the lower back region. Additionally, there are 5 sacral bones and 4 coccygeal bones, although the number of coccygeal bones can range from 3 to 5.
When viewed laterally, these spine segments create three distinct curves. The neck (cervical spine) and lower back (lumbar spine) have “c-shaped” curves known as lordosis. In contrast, the chest (thoracic spine) forms a “reverse c-shaped” curve named kyphosis.
The thoracic cage plays a significant role in the thoracic region’s anatomy. This cage is formed by the sternum and 12 pairs of ribs connected to their costal cartilages. Posteriorly, the ribs are anchored to the 12 thoracic vertebrae. The sternum is divided into three parts: manubrium, body, and xiphoid process. The ribs are categorized into true ribs (1-7) and false ribs (8-12).
In the human body, there are 31 pairs of spinal nerves, which are categorized into 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. These nerves usually emerge between adjacent vertebrae. For instance, the spinal nerve T1 exits the vertebral canal below vertebra T1.
It’s also vital to understand the Muscles of the Thoracic Region. One key muscle is the diaphragm, which originates from several areas, including the xiphoid process, costal margin, and more, and inserts into the diaphragm’s central tendon.
Each thoracic spinal nerve has a recurrent meningeal branch that emerges from an intervertebral foramen and divides into a dorsal and ventral ramus. These branches contain multiple fibers, such as motor fibers, sensory fibers, and postganglionic sympathetic fibers.
