Latissimus Dorsi

This course describes the anatomy and integrated function of the latissimus dorsi muscle (a.k.a. the lats, lats muscle, back muscle, and lat dorsi muscle). This muscle originates on the thoracic vertebrae, thoracolumbar fascia, lumbar vertebrae, iliac crest, and inferior angle of the scapula (shoulder blade), inserts into the intertubercular groove of the humerus (upper arm), and is innervated by the thoracodorsal nerve. This muscle is the largest skeletal muscle of the upper body, and is located on the posterior thorax (trunk and ribs); superficial to the lumbar extensors and core muscles. The latissimus dorsi is composed of an even distribution of type I muscles fibers and type II muscle fibers; however, the muscle fiber composition may be biased toward type II fibers. The latissimus dorsi muscle crosses the shoulder joint (glenohumeral joint), is the prime mover of shoulder adduction and extension, will contribute to shoulder internal rotation, and may contribute to lumbar extension, lumbar lateral flexion, and lumbar rotation. This course also describes the role of the latissimus dorsi muscle in glenohumeral arthrokinematics, fascial integration, postural dysfunction, and subsystem integration. Sports medicine professionals (personal trainers, fitness instructors, physical therapists, massage therapists, chiropractors, occupational therapists, athletic trainers, etc.) must be aware of the integrated function of the latissimus dorsi for the detailed analysis of human movement, and the development of sophisticated exercise programs and therapeutic (rehabilitation) interventions. Further, this course is essential knowledge for future courses discussing injury prevention and physical rehabilitation (e.g. loss of extensibility (tight lats), latissimus dorsi muscle strain, thoracodorsal nerve injury, recovery from latissimus dorsi flap orthopedic surgery, shoulder impingement, etc.), the synergistic function of the latissimus dorsi (e.g. extension and lateral flexion of the lumbar vertebra in synergy with the erector spinae), and latissimus dorsi exercises and techniques for enhancing sports performance (e.g. shoulder stability, strength, power, upper arm and back hypertrophy, etc.).

Brookbush Institute’s most recommended techniques for the Latissimus Dorsi (see videos below):

• Release: Latissimus Dorsi Self-administered Release Technique
• Stretch: Child's Pose
• Manual: Manual Latissimus Dorsi and Internal Rotator Stretch

Caption: Dissection of the latissimus dorsi muscle