Morphology of C5 ventral nerve rootlets as part of dissociated motor loss of deltoid muscle.
METHODS
This study analyzed anatomic characteristics of cervical ventral rootlets. After total vertebrectomy, detailed morphology of the ventral rootlets was studied from the anterior.


BACKGROUND
The clinical study showed the predominance of ventral root lesion. There are few studies concerning the morphologic pathogenesis of cervical amyotrophy and detailed cervical ventral rootlet anatomy.


METHODS
Thirty-six embalmed adult human cadavers were studied. The measurements for the ventral rootlets of C5 to C8 were made as follows: 1) angle between the rootlet and spinal cord, 2) longitudinal width of the ventral rootlet origin, and 3) length of the ventral rootlets.


RESULTS
The C5 ventral rootlets were shorter and issued more obtusely from the cervical spinal cord than lower rootlets. The spinal cord segment of the deltoid muscle, indicated by the longitudinal widths of the C5 and C6 ventral rootlet exits from the spinal cord, were wider than the C7 and C8 segments. Preforaminal anterior compression at the C4-C5 disc level might affect the lower part of the C5 ventral rootlets and upper part of the C6 ventral rootlets.


CONCLUSIONS
Short C5 ventral rootlets appeared to become taut and easily injured by hemilateral anterior compression. Spinal cord lesion resulting from localized anterior compression at the single disc level might not play as important a role in the pathogenesis of dissociated motor loss of the deltoid muscle because of the wider spinal segments of C5 and C6.
Department of Orthopaedic Surgery, Tokyo Medical and Dental University School of Medicine.
K
K
Shinomiya
A
A
Okawa
K
K
Nakao
K
K
Mochida
H
H
Haro
T
T
Sato
S
S
Heima
D000368:Aged; D001132:Arm; D002102:Cadaver; D002574:Cervical Vertebrae / Q000601:surgery; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000150:complications; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation* / Q000473:pathology; D010243:Paralysis / Q000209:etiology / Q000473:pathology; D011183:Postoperative Complications / Q000209:etiology; D013117:Spinal Cord Compression / Q000209:etiology / Q000473:pathology; D013126:Spinal Nerve Roots / Q000033:anatomy & histology* / Q000473:pathology