Henry Gray (18251861). Anatomy of the Human Body. 1918.
On the Scalenus anterior the phrenic nerve is joined by a branch from the fifth cervical.
Branches of Distribution.The branches of distribution of the brachial plexus may be arranged into two groups, viz., those given off above and those below the clavicle.
Dorsal Scapular ..
5, 6 C.
Nerve to Subclavius
5, 6 C.
Long thoracic .
5, 6, 7 C.
To Longus colli and Scaleni
5, 6, 7, 8 C.
FIG. 809 The right brachial plexus (infraclavicular portion) in the axillary fossa; viewed from below and in front. The Pectoralis major and minor muscles have been in large part removed; their attachments have been reflected. (Spalteholz.) (See enlarged image)
The Dorsal Scapular Nerve (n. dorsalis scapulæ; nerve to the Rhomboidei; posterior scapular nerve) arises from the fifth cervical, pierces the Scalenus medius, passes beneath the Levator scapulæ, to which it occasionally gives a twig, and ends in the Rhomboidei.
The Suprascapular (n. suprascapularis) (Fig. 818)arises from the trunk formed by the union of the fifth and sixth cervical nerves. It runs lateralward beneath the Trapezius and the Omohyoideus, and enters the supraspinatous fossa through the suprascapular notch, below, the superior transverse scapular ligament; it then passes beneath the Supraspinatus, and curves around the lateral border of the spine of the scapula to the infraspinatous fossa. In the supraspinatous fossa it gives off two branches to the Supraspinatus muscle, and an articular filament to the shoulder-joint; and in the infraspinatous fossa it gives off two branches