930 



NEUROLOGY 



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1 



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 enlarge- 

 ment; 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 communi- 

 cates 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 scapulae, and Scalenus medius. 



The branch for the Sternocleidomastoideus is derived -from the second cervical; 

 the Trapezius and Levator scapulae receive branches from the third and fourth. 

 The Scalenus medius receives twigs either from the third or fourth, or occasionally 

 from both. 



from. FC. 



To Rhomboidei- 

 To join the phrenic 



Suprascapular 

 To Subclavius 



Lateral anterior 

 thoracic 



To Longus colli 

 and Scaleni 



To Longus colli 

 and Scaleni 



To Longus colli 

 and Scaleni 



Long thoracic 



To Longus colli 

 and Scaleni 



Median 



Ulnar / Medial brachial 

 Medial antibrachial cutaneous 

 cutaneous 



FIG. 807. Plan of brachial plexus. 



The Brachial 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 cer- 

 vical 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 



