Latissimus Dorsi is an extrinsic muscle in the shoulder connecting the humerus to the trunk.

Shape and position. Two in number and with a fan shape, each dorsal muscle covers the lower two-thirds of the back on either side of the spine (1). Like the trapezius muscles, the latissimus dorsi muscles are part of the thoraco-appendicular muscles (1). The muscles in this group connect the skeleton of the upper limbs with that of the trunk.

Structure. The latissimus dorsi muscle is a skeletal muscle, that is to say a muscle placed under the voluntary control of the central nervous system.

Origin. The latissimus dorsi muscle is inserted at different points: on the spinous processes from the thoracic vertebra T6 to the sacrum, on the iliac crest (upper edge of the iliac bone), and on the last 3 or 4 ribs.

Termination. The latissimus dorsi muscle is inserted on the bottom of the intertubercular groove of the humerus, at its upper end (1).

Innervation. The latissimus dorsi muscle is innervated by the thoracodorsal nerve originating from the cervical vertebrae C6 to C8 (1).

Directly or indirectly, the latissimus dorsi muscles participate in certain body movements such as:

• Movement of the humerus. The latissimus dorsi muscles act on the humerus in extension, adduction, and medial rotation movements.
• Movement to climb. The latissimus dorsi muscles, in synergy with the major pectoral muscles, bring the body back towards the arms, thus allowing to climb.

Different problems can be associated with the latissimus dorsi muscles. They can be manifested by back pain or lumbago, pain localized respectively in the back and lumbar region.

Muscle pain without lesions. (2)

• Cramp. Sometimes occurring in the latissimus dorsi muscle, it corresponds to an involuntary, painful and temporary contraction of a muscle.
• Contracture. It is an involuntary, painful, and permanent contraction of a muscle such as the latissimus dorsi muscle.

Muscle injury. The latissimus dorsi muscle can suffer muscle damage with pain. (2)

• Elongation. First stage of muscle damage, elongation corresponds to a stretching of the muscle caused by micro-tears and resulting in muscle disorganization.
• Breakdown. Second stage of muscle damage, the breakdown corresponds to a rupture of muscle fibers.
• Rupture. The last stage of muscle damage, it corresponds to a total rupture of a muscle.

Tendinopathies. They designate all the pathologies that can occur in tendons such as those associated with the latissimus dorsi muscle.3 The causes of these pathologies can be varied. The origin can be intrinsic as well with genetic predispositions, as extrinsic, with for example bad positions during the practice of sport.

• Tendinitis: It is an inflammation of the tendons.

Lumbago. This pathology is due to deformations or tears in the ligaments or muscles located in the lumbar vertebrae.

Drug treatments. Depending on the pathology diagnosed, different treatments may be prescribed to reduce pain and inflammation.

Surgical treatment. Depending on the type of pathology diagnosed, surgery may be performed.

Physical treatment. Physical therapies, through specific exercise programs, can be prescribed such as physiotherapy or physiotherapy.

Physical examination. First, a clinical examination is performed in order to observe and assess the symptoms perceived by the patient.

Medical imaging examination. X-ray, CT, or MRI exams can be used to confirm or further the diagnosis.

The Latin name for the latissimus dorsi muscle, latissimus dorsi, has for meaning “the largest muscle of the back”. This name was chosen because it covers a large part of the back. (1)