The medial line (midsagittal plane) is on the midline and the central axis of the body, dividing the body vertically into right and left haves. On the back side, the medial line starts from the sagittal suture, the midline of the head, follows the spine to the tail bone. On the front side of the body, the medial line travels down from the sagittal suture of the head, breastbone, navel, and pubic bone. The line continues between the legs down to the ground without anatomic structure. Movements within the sagittal plane are flexion and extension – forward and backward movements of the head, spine, and limbs.
The sagittal suture is a dense, fibrous connective tissue joint between the two parietal bones of the skull.
Down to the back, the sagittal suture moves to the ligaments on the spine.
The nuchal ligament extends from the external occipital protuberance on the skull and median nuchal line to the spinous process of the seventh cervical vertebra in the lower part of the neck. It is the starts of the trapezius and splenius capitis muscles attached to the shoulder and the head separately.
Supraspinous ligament connects the tips of the spinous processes from the seventh cervical vertebra to the sacrum and is the continuous of nuchal ligament down to the spine. Part of the trapezius and latissimus dorsi start from this ligament and connect to the shoulder.
Spinal erectors are a group of muscles and tendons which run from the sacrum or sacral region to the base of the skull. They are paired lying on the left and right of the spine.
Down to the front, the sagittal suture moves to the frontal suture on the forehead. The frontal suture is a fibrous joint that divides the two halves of the frontal bone of the skull.
On the midline of the chest, it raises the pectoralis major and connects to the shoulder.
The white line in the medial line of the abdominal wall (linea alba) is a fibrous structure that runs down the midline of the abdomen from the xiphoid process to the pubic symphysis. It is formed by the fusion of the aponeuroses (deep fascia) of the abdominal muscles, it lies between the left and right rectus abdominis muscles.
The medial line tightness can create tension on the whole body blocking blood and energy circulation. Acupuncture can release tension and improve blood and energy circulation.
