Contents -SUBJECT INDEX -BIBLIOGRAPHIC RECORD -ILLUSTRATION INDEX

Henry Gray (1825–1861). Anatomy of the Human Body. 1918.

pages 396

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first, second, and third cervical; the Longus colli, by branches from the second to the seventh cervical nerves.

Actions.—The Longus capitis and Rectus capitis anterior are the direct antagonists of the muscles at the back of the neck, serving to restore the head to its natural position after it has been drawn backward. These muscles also flex the head, and from their obliquity, rotate it, so as to turn the face to one or the other side. The Rectus lateralis, acting on one side, bends the head laterally. The Longus colli flexes and slightly rotates the cervical portion of the vertebral column.

5e. The Lateral Vertebral Muscles

The lateral vertebral muscles (Fig. 387). are:

Scalenus anterior. Scalenus medius. Scalenus posterior.

The Scalenus anterior (Scalenus anticus) lies deeply at the side of the neck, behind the Sternocleidomastoideus. It arises from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebræ, and descending, almost vertically, is inserted by a narrow, flat tendon into the scalene tubercle on the inner border of the first rib, and into the ridge on the upper surface of the rib in front of the subclavian groove.

The Scalenus medius, the largest and longest of the three Scaleni, arises from the posterior tubercles of the transverse processes of the lower six cervical vertebræ, and descending along the side of the vertebral column, is inserted by a broad attachment into the upper surface of the first rib, between the tubercle and the subclavian groove.

The Scalenus posterior (Scalenus posticus), the smallest and most deeply seated of the three Scaleni, arises, by two or three separate tendons, from the posterior tubercles of the transverse processes of the lower two or three cervical vertebræ, and is inserted by a thin tendon into the outer surface of the second rib, behind the attachment of the Serratus anterior. It is occasionally blended with the Scalenus medius.

Variations.—The Scaleni muscles vary considerably in their attachments and in the arrangement of their fibers. A slip from the Scalenus anticus may pass behind the subclavian artery. The Scalenus posticus may be absent or extend to the third rib. The Scalenus pleuralis muscle extends from the transverse process of the seventh cervical vertebra to the fascia supporting the dome of the pleura and inner border of first rib.

Nerves.—The Scaleni are supplied by branches from the second to the seventh cervical nerves.

Actions.—When the Scaleni act from above, they elevate the first and second ribs, and are, therefore, inspiratory muscles. Acting from below, they bend the vertebral column to one or other side; if the muscles of both sides act, the vertebral column is slightly flexed.

6. The Fasciæ and Muscles of the Trunk. a. The Deep Muscles of the Back

The muscles of the trunk may be arranged in six groups:

I. Deep Muscles of the Back. IV. Muscles of the Abdomen.  II. Suboccipital Muscles.  V. Muscles of the Pelvis. III. Muscles of the Thorax. VI. Muscles of the Perineum.

The Deep Muscles of the Back The deep or intrinsic muscles of the back (Fig. 388). consist of a complex group of muscles extending from the pelvis to the skull. They are:

Splenius capitis. Multifidus. Splenius cervicis. Rotatores. Sacrospinalis. Interspinales. Semispinalis. Intertransversarii.