Which structures form the origin of the latissimus dorsi?

Which structures form the origin of the latissimus dorsi?

• A. Spinous processes T7-T12, inferior ribs, thoracolumbar fascia, iliac crest
• B. Spinous processes C7-T5
• C. Acromion and spine of scapula
• D. Clavicle

Answer: (A)

The latissimus dorsi has a broad origin from several posterior trunk structures: the spinous processes of T7 through T12, the lower ribs, the thoracolumbar fascia, and the iliac crest. This combination anchors the muscle across the lower back and flank so its fibers can converge toward the humerus to produce extension, adduction, and internal rotation of the arm. The other options point to areas that belong to other muscles—spinous processes from C7 to T5 are typical for rhomboids and parts of trapezius; the acromion and spine of the scapula serve as attachments for the deltoid and trapezius; and the clavicle is a common origin for muscles like pectoralis major rather than latissimus dorsi.

The latissimus dorsi has a broad origin from several posterior trunk structures: the spinous processes of T7 through T12, the lower ribs, the thoracolumbar fascia, and the iliac crest. This combination anchors the muscle across the lower back and flank so its fibers can converge toward the humerus to produce extension, adduction, and internal rotation of the arm. The other options point to areas that belong to other muscles—spinous processes from C7 to T5 are typical for rhomboids and parts of trapezius; the acromion and spine of the scapula serve as attachments for the deltoid and trapezius; and the clavicle is a common origin for muscles like pectoralis major rather than latissimus dorsi.