The _levator scapulæ_, from the transverse processes of the upper cervical vertebræ to the posterior border of the scapula, serves to raise the angle of the scapula, and the _rhomboideus major_ and _minor_, from the ligamentum nuchæ, the seventh cervical, and the upper dorsal vertebræ to the root of the spine of the scapula, draw the inferior angle back and up. [Illustration: FIG. 35.--Muscles of the trunk from behind (left side, superficial; right side, deep): 1, Sternomastoid; 2, splenius; 3, trapezius; 4, latissimus dorsi; 5, infraspinatus; 6, teres minor; 7, teres major; 8, deltoid; 9, external oblique of abdomen; 10, gluteus medius; 11, gluteus maximus; 12, levator anguliscapulæ; 13, rhomboideus minor; 14, rhomboideus major; 15, part of longissimus dorsi; 16, tendons of insertion of iliocostalis; 17, supraspinatus; 18, infraspinatus; 19, teres minor; 20, teres major; 21, serratus magnus; 22, upper, and 22´, lower part of serratus posticus inferior; 23, internal oblique; 24, gluteus medius; 25, pyriformis and superior and inferior gemelli; 26, 26´, portions of obturator internus; 27, tendon of obturator internus; 28, quadratus femoris. (Dorland’s Dictionary.)] The _blood supply_ in the cervical region and about the shoulders comes from branches of the subclavian artery, such as the suprascapular and the transversalis colli. Lower down the supply comes from the posterior branches of the intercostals, dorsal branches of the lumbar, and branches of the internal iliac. The muscles of the back are supplied by the _spinal nerves_, the spinal accessory also going to the trapezius muscle. CHAPTER VII. THE CHEST. The chest or thorax occupies the upper part of the trunk in front and is a dome-shaped cavity containing and protecting the heart and lungs. Its walls are formed by the dorsal vertebræ at the back, the ribs at either side, and the sternum and costal cartilages in front, all well covered with muscles. The floor is formed by the diaphragm. Through the upper opening of the chest pass the trachea, the esophagus, and many important vessels and nerves. [Illustration: FIG. 36.--Thorax (anterior view.) (Ingals.)] The shape of the chest may vary in disease. Thus, in rickets there is the prominent “pigeon” breast and the rosary, that is, a bead at the juncture of each rib with the costal cartilage, while in emphysema the chest is enlarged in all directions and barrel-shaped. In severe cases of lateral curvature it is distorted but may be improved by exercises.