Deltoid Muscle - Anterior and Middle Heads
Latissimus Dorsi Muscle – Attachments, Action & Innervation
Latissimus Dorsi is one of four muscles responsible for the thoracobrachial motion. It is large, flat and triangular in shape originating from large parts of the lumbar region and lower thorax to insert on the humerus through a narrow tendon.
Attachments of Latissimus Dorsi: Origin & Insertion
Origin: (proximal attachments)
a. Spinous processes of T7 – L5 vertebrae.
b. Iliac crest of sacrum.
c. Thoracolumbar fascia.
d. Inferior angle of the scapula.
e. Lower three or four ribs.
Insertion: (distal attachments)
Floor of intertubercular (bicipital) groove of humerus.
Actions of Latissimus Dorsi:
b. Medially rotates the arm at the shoulder (glenohumeral) joint.
c. Extends the arm at the shoulder (glenohumeral) joint.