|Henry Gray (18251861). Anatomy of the Human Body. 1918.|
|distributed to the falciform and coronary ligaments of the liver, the suprarenal gland, inferior vena cava, and right atrium. From the left nerve, filaments pass to join the phrenic branches of the celiac plexus, but without any ganglionic enlargement; and a twig is distributed to the left suprarenal gland.|
Deep Branches of the Cervical Plexus. EXTERNAL SERIES.Communicating Branches.The external series of deep branches of the cervical plexus communicates with the accessory nerve, in the substance of the Sternocleidomastoideus, in the posterior triangle, and beneath the Trapezius.
| Muscular Branches are distributed to the Sternocleidomastoideus, Trapezius, Levator scapulæ, and Scalenus medius.|
| The branch for the Sternocleidomastoideus is derived from the second cervical; the Trapezius and Levator scapulæ receive branches from the third and fourth. The Scalenus medius receives twigs either from the third or fourth, or occasionally from both.|
FIG. 807 Plan of brachial plexus. (See enlarged image)
The Branchial Plexus (plexus brachialis) (Fig. 807).The brachial plexus is formed by the union of the anterior divisions of the lower four cervical nerves and the greater part of the anterior division of the first thoracic nerve; the fourth cervical usually gives a branch to the fifth cervical, and the first thoracic frequently receives one from the second thoracic. The plexus extends from the lower part of the side of the neck to the axilla. The nerves which form it are nearly equal in size, but their mode of communication is subject to some variation. The following is, however, the most constant arrangement. The fifth and sixth cervical unite soon after their exit from the intervertebral foramina to form a trunk. The eighth cervical and first thoracic also unite to form one trunk, while the seventh cervical