Neck pain – Low back pain – Role of latissimus dorsi (the bridge)

The latissimus dorsi is the most powerful muscle in the back and pain and spasms in this muscle can cause significant low back pain and aggravation of neck pain.

It is a very large triangular muscle that extends from the armpit to the lower back. It arises from the six lower thoracic vertebrae, the lumbosacral fascia, the crest of the pelvic bone called the iliac bone, and also from the three or four lower ribs. It inserts into the floor of the groove in the upper front of the arm bone (humerus) known as the bicipital groove and is very close to the shoulder joint.

Its action is to bring the arm closer to the body (adduction), roll the arm inward as when placing the hand on the back of the body (internal rotation) and bring the arm back (extension). The innervation of this muscle is the thoracodorsal nerve that carries the fibers of the spinal nerve root from the C6, C7 and C8 nerve roots.

This very powerful muscle can lift the body off the ground like walking on crutches, climbing up a pole, and supporting the body on the horizontal bar. In these activities, you work in conjunction with the pectoralis major and abdominal muscles. It is used in swimming, especially in the downward run of a front crawl, and most swimmers have overdeveloped latissimus dorsi muscles, giving them a V-shape with broad shoulders that taper to a small waist.

Rowing activities is primarily the function of the latissimus dorsi muscle. In baseball pitching, it contracts very strongly in the late cocking phase. Arm acceleration, as in throwing activities, involves lengthening the contraction of the latissimus dorsi muscle, making this muscle prone to injury.

Aerial activities, especially counter resistance such as climbing, are conditions that require lengthening the contractions that injure this muscle. Pull-down and chin-lift activities require a tremendous latissimus dorsi shortening contraction.

This muscle also elevates the lower ribs and helps with breathing. Many patients with latissimus dorsi pain and spasm will complain of pain when breathing deeply and pain on the sides of the chest wall.

The latissimus dorsi muscle is the bridge between the lower back and the neck. Therefore, the neck and the entire lower and middle back must be treated to treat this muscle properly. Without the latissimus dorsi muscle working properly, lifting activities will be performed by shrugging the shoulders. Therefore, pain along the slope of the shoulders, which is mainly due to pain in the trapezius muscles, cannot be treated with local treatment only in the trapezius muscle. Therefore, pain in the trapezius muscle area will reappear unless the latissimus dorsi muscle is treated first.

Similarly, treatment of low back pain should always involve treatment of the latissimus dorsi muscle. Due to its attachments to the thoracolumbar fascia, the latissimus dorsi muscle can never be adequately treated until the gluteus maximus muscle is included in treatment.

Any symptoms of pain and discomfort affecting the back must therefore involve the “trio treatment” involving the gluteus maximus, latissimus dorsi and trapezius muscles.

Since the latissimus dorsi muscle is constantly exposed to lengthening contractions with activities of daily living, most people have chronic tension and shortening of this muscle. This leads to a significant limitation of the range of motion of the shoulder for internal rotation and extension.

Therefore, further injury to the commonly injured C6 and C7 nerve roots will further strain and shorten the latissimus dorsi muscle, making it very difficult to treat.

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