Latissimus dorsi – the swimmer’s muscle
The latissimus dorsi muscle is a large sweeping muscle that connects the lower half of the body (pelvis) to the arm itself. Because of its many actions associated with movements of swimming, it’s known as the swimmer’s muscle.
What does the latissimus dorsi muscle mean?
The name of the latissimus dorsi muscle describes its size and location. Latissimus comes from the Latin word “latus” meaning wide, and dorsi comes from the Latin word “dorsum” meaning back.
Where does the latissimus dorsi muscle attach?
- Thoracolumbar aponeurosis (fancy way of saying a common tendinous sheath). It connects the attachments to the areas below with the exception of the inferior angle of the scapula.
- T7-L5 – on the spinous processes (the parts that stick out that we can feel on our back).
- Crest of the ilium (top back portion of the pelvis)
- Inferior (bottom) angle of the scapula
- Bicipital groove – A divot in the bone that the biceps tendon lays in.
What actions does the latissimus muscle do?
- Medial (internal) rotation of the shoulder joint
- Extension of the shoulder joint
- Adduction of the shoulder joint
- Depression of the scapula
Assists these actions
- Lateral flexion of the trunk
- Extension of the spine
Postures where this muscle contracts
The “lats” contract to bring the upper arms toward the body in adduction.
The lats help stabilize the shoulder in bakasana (below).
Postures where this muscle lengthens
The lats are lengthened with the arms abducted and flexed (below).