What Is the Latissimus Dorsi Muscle?

The latissimus latissimus dorsi is located under the skin of the lower back and the back of the chest. It is the largest broad muscle of the whole body and has a right-angled triangle. The upper medial area is covered by trapezius. , 1/3 posterior 1/3 of the lateral lip.

The latissimus latissimus dorsi is located under the skin of the lower back and the back of the chest. It is the largest broad muscle of the whole body and has a right-angled triangle. The upper medial area is covered by trapezius. , 1/3 posterior 1/3 of the lateral lip.

Chinese name

Latissimus dorsi

Foreign name

latissimus dorsi

Category

muscle

Innervation

Dorsal thoracic nerve

Latissimus dorsi

1. Start with 3 to 4 muscle teeth from the outside of 3 to 4 ribs. The muscle fibers are obliquely outward and upward, and gradually concentrate. They pass through the posterior wall of the axilla and the medial side of the humerus to the front of the great round muscles. They migrate outside the tendons of the great round muscles to the flat tendons and stop at the small nodules of the humerus.

2. When this muscle is contracted, the humerus is extended, rotated and adducted. Pull up the raised upper arm and move it inward.

3. The latissimus dorsi is innervated by the thoracic and dorsal nerves. Dorsal thoracic nerve belongs to the motor nerve, which comes from the neck 6 ~ 8. It is divided by the posterior brachial plexus in the axillary part, and it accompanies the dorsal and thoracic arteries and veins. It branches with the branches of blood vessels and enters the muscle at the inferior corner of the scapula. Divided into medial and lateral branches, the lateral branches walk down 3 ~ 4cm from the front edge of the latissimus dorsi muscle, the medial branches and the upper edge of the muscles travel parallel inward, the branches of the thoracic and dorsal nerves are accompanied by the branches of the thoracic and dorsal vessels, and the lateral branches Thicker than the inner branch.

4. Blood supply is mainly provided by the thoracic and dorsal artery. The thoracodorsal artery is divided from the inferior scapular artery. The length of the thoracodorsal artery is 7.4cm, and the outer diameter of the starting point is 0.2cm. It crosses the great round muscle downward, travels along the deep side of the front of the latissimus dorsi and the anterior serratus muscle. Disciplines were divided into medial and lateral branches, and the lateral branches walked down about 3cm from the front edge of the latissimus dorsi muscles, which dominated the blood flow of the anterior and lateral parts of the latissimus dorsi muscles and the skin of the lateral chest and back. Transplantation of latissimus dorsi muscle or myocutaneous flap is often done clinically to repair large areas such as the upper limbs, neck, face and chest.

Latissimus dorsi and its starting and ending points

Location: on the lower back and back of the chest.

Starting point: It starts from the seventh to twelfth thoracic spine and all lumbar spinous processes by the aponeurosis.

Stop: small humerus nodules.

Innervation nerve: thoracic and dorsal nerves originating from the spinal nerve brachial plexus.

Latissimus dorsi related clinical techniques and applications

1. The latissimus dorsi muscle flap is one of the most commonly used muscle flaps in the clinic. The latissimus dorsi muscle flap is an ideal flap because of its concealed location, rich blood flow, large cutting range, and strong anti-infective ability. Part of the latissimus dorsi muscles is often removed during surgery. When latissimus dorsi muscle flaps are used to cover wounds instead of muscle function reconstruction, the latissimus dorsi muscles are also cut off when the latissimus dorsi muscles are cut off, so the latissimus dorsi muscles are retained. It also loses its function because it is not innervated. In recent years, according to the anatomical characteristics of the dorsal latissimus dorsi and dorsal nerve, we have retained the innervation of the dorsal dorsi muscle when removing the myocutaneous flap, thereby retaining the function of the undissected latissimus dorsi muscle, reducing the cost of the donor site. The latissimus dorsi muscle flap still has a good blood supply.

2. Imaging applications

In recent years, with the development of multi-slice spiral CT scanning technology, CT angiography has gradually been applied to the microsurgical repair of free flaps. The key to the flap extraction is to dissect the blood vessels that provide its blood supply. However, due to the many types of blood vessels, the anatomy of some musculocutaneous perforating branches is complicated and time-consuming. Preoperative positioning of the vascular pedicle and perforating branches is particularly important. Three-dimensional reconstruction of blood vessels has been achieved. Surgery simulation and preoperative design. The significance of CTA and three-dimensional reconstruction is not only to find vascular variations or deformities, reduce the risk of surgery and reduce the incidence of postoperative complications, but also to understand the vascular flow and diameter before surgery to achieve the purpose of rational design of flaps. The 3D software can segment and reconstruct independent bones, blood vessels, skin, and muscles. The reconstructed graphics can be displayed individually or in combination, which is convenient for observation and measurement of each structure.