We studied the variations in the ventral rami of 152 brachial plexuses in 77 Korean adults. Brachial plexus were composed mostly of the fifth, sixth, seventh and eighth cervical nerves and the first thoracic nerve (77.0%). In 21.7% of the cases examined, the fourth, fifth, sixth, seventh and eighth cervical and the first thoracic nerves contributed to the plexus. A plexus composed of the fourth, fifth, sixth, seventh and eighth cervical and the first and second thoracic nerves, and a plexus composed of the fifth, sixth, seventh eighth cervical nerves were also observed. The plexuses were classified into three groups according to cephalic limitation, and the plexus of group 2 in which the whole fifth cervical nerve enters the plexus, were observed the most frequent. The average diameter of the sixth and the seventh cervical ventral rami of the plexus was greatest and that of the fifth cervical was smallest. The largest nerve entering the plexus was the sixth or the seventh cervical nerve in about 79% of cases. The dorsal scapular nerve originated from the fifth cervical ventral ramus in 110 cases (75.8%). The long thoracic nerve was formed by joining of roots from the fifth, sixth, and seventh cervical nerves in 76.0% of cases. Also, a branch to the phrenic nerve, the suprascapular nerve, a nerve to the pectoralis major muscle and a nerve to the subscapular muscle arising from the ventral rami of the plexus were observed.
Brachial Plexus/*anatomy & histology ; Cervical Plexus/anatomy & histology ; Female ; Humans ; Male ; Thoracic Nerves/*anatomy & histology

OBJECTIVEThe aim of this study was to examine the effects of deep branches of cervical plexus on trapezius muscle.

METHODSThe evoked electromyography of 32 trapezius of 16 SD rats was examined in different time and results obtained were processed by statistical methods.

RESULTSAfter cutting the accessory nerves, stimulating the deep branches of cervical plexus evoked the myoelectricity, the myoelectricity results varied according to different time.

CONCLUSIONThe deep branches of cervical plexus are another important motorial supply to trapezius muscles. After cutting the accessory nerves, if the branches were undamaged, the shoulder's function would be greatly preserved.

Accessory Nerve ; physiology ; Animals ; Cervical Plexus ; physiology ; Electromyography ; Male ; Muscle, Skeletal ; anatomy & histology ; innervation ; physiology ; Neck Dissection ; adverse effects ; Neck Muscles ; anatomy & histology ; injuries ; physiology ; Rats ; Rats, Sprague-Dawley ; Shoulder ; innervation