The scalene muscles are located in the front of the chest and neck, and their fibers overlap each other in a ladder-like pattern. For this feature they got their name in Latin: scala - “ladder”.
The main function of these muscles is to bring the anterior (clavicular) and posterior (thoracic) segments of both shoulder blades and wings to the midline. In addition, these muscles form part of the infraspinatus fascia, a tough sheath that covers the anterior surface of the upper limb, attaches to the collarbone, and is involved in producing tendons of strength. An important task of this fascia is to maintain the ligamentous apparatus around the clavicular area. Other functions of the fascia include restricting the movement of the lungs in relation to the chest, holding the shoulder, and holding the scapula in position when the arm rotates.
The function of the scalene muscles in terms of movement of the upper limbs is in three directions: upward shift, forward shift and external rotation of the shoulder. The pelvic scalenes are also involved in dorsal rotation from the shoulder joint to the spine. They work through the ligament connecting the first cervical vertebra to the second to bring the thoracoscapular area to the midline.