746 



SPINAL ACCESSORY NERVE. 



lowest root may be attached to the spinal 

 chord opposite the fourth, fifth, sixth, or 

 seventh cervical nerve, but more frequently 

 between the fifth and sixth ; and that when its 

 roots are extended over a more limited por- 

 tion of the spinal chord, this is compensated 

 for by their being proportionally stronger.* 



Anatomists have differed as widely in their 

 account of the particular column or tract of 

 the spinal chord to which the roots of the 

 spinal accessory are attached, as they have 

 done regarding the extent of the spinal chord 

 over which these roots stretch. This is a 

 point in the anatomy of the nerve which has 

 assumed greater importance since the dis- 

 covery by Sir Charles Bell, of the separate 

 functions of the anterior and posterior roots 

 of the spinal nerves, and is of much more 

 interest to the modern, than it was to the 

 older anatomists. The filaments of origin or 

 roots of this nerve that come from the spinal 

 chord are attached to the chord near the 

 posterior lateral groove separating its posterior 

 and middle columns, and close upon the pos- 

 terior roots of the spinal nerves, so that we 

 can readily understand how some anatomists 

 should describe these roots as arising from 

 the middle column, and others describe them 

 as springing from the posterior column. f 

 Among the modern anatomists we find Bel- 

 lingeri, who has attended particularly to the 

 anatomy of this nerve, describing it as arising 

 from the middle or lateral column of the 



* Huber (De Medulla Spinali, et speciatim de 

 Nervis ab ea provenientibus, p. 13.) says that this 

 nerve commences opposite the seventh cervical, but he 

 afterwards speaks of it arising opposite the sixth. 

 Lobstein (De Nervo Spinali ad Par Vagum Ac- 

 cessorio, p. 233, as reprinted in Ludwig's Script. 

 Neurol. Min. Selec. torn. ii. Lipsia?, 1792) describes 

 it as arising under the sixth pair of cervical nerves 

 by a slender beginning. Bellingeri (De Medulla 

 Spinali, Nervisque ex ea prodeuntibus, p. 74, 1823) 

 places its origin opposite the seventh cervical nerve. 

 Craveilhier (Anatomie Descriptive, torn. iv. p. 899, 

 1835) says that its origin seldom passes below the 

 level of the fifth pair of cervical nerves, but it may 

 arise opposite the sixth and even the seventh pair. 

 Bendz (De Connexu inter Nervum Vagum et Ac- 

 cessorium Willisii, p. 22, 1836) describes its lowest 

 root as arising from the spinal chord in the region 

 of the fifth or sixth cervical nerves, and rarely as low 

 as the posterior root of the seventh cervical. Valentin 

 (Soemmering vom Baue des menschlichen Korpers. 

 Him und Nervenlehre, S. 513, 1841) states that its 

 most frequent origin is opposite the sixth, or between 

 the sixth and seventh cervical nerves ; sometimes it 

 arises opposite the fourth or fifth, or it may extend 

 as far as the seventh, and in rare cases as far as the 

 first dorsal. Krause (Ilandbuch der menchlichcn 

 Anatomie, Erster Band, S. 1066 : Hannover, 1842) 

 says that it usually arises opposite the upper part 

 of the roots of the seventh cervical, seldom higher. 

 Bernard (Archives Ge'ne'rales de Me'decine, 4ieme 

 se'rie, torn. iv. p. 410, 1844) describes it as arising 

 by a series of bifid or trifkl nervous filaments, which 

 extend, in man, from the origin of the pneumogastric 

 to a point opposite the fourth or fifth pair of cervical 

 nerves. 



t Kolando fRecherches Anatomiques sur la Mo- 

 elle Ablongee) and Serres (Anatomie Compare'e 

 clu Cerveau, torn, i.) have stated that the lower 

 fibres of this nerve come from the anterior column 

 of the spinal chord. 



spinal chord*, while BLschofff and Bernard J 

 trace its origin to the posterior column ; and 

 Bendz $ states that while nearly the whole 

 of its roots come from the middle column, a 

 few arise between the posterior roots of the 

 spinal nerves and from the posterior column. || 

 From my own examinations of the attach- 

 ments of this nerve, I had arrived at the con- 

 clu.-ion that it arises from the posterior part 

 of the middle column, and that its middle and 

 interior roots are attached along the course 

 of the decussating fibres of the pyramidal 

 column, which form the posterior part of the 

 middle column of the chord .^f Stilling says** 

 that the lower and middle roots of this nerve 

 can be traced to the anterior grey substances 

 in the chord, from which the anterior roots 

 of the spinal nerves arise, and that, in an 

 anatomical point of view, they must be re- 

 garded as performing the same functions as 

 the anterior roots of the spinal nerves ; while 

 the upper roots, or those which are attached 

 to the medulla oblongata, differ in a marked 

 manner, in regard to their origin, from the 

 lower and middle roots. He states that these 

 upper roots above the first cervical nerve 

 arise from a grey mass in the medulla ob- 

 longata, which he styles the accessory-kernel 

 (accessorius-kcrnf |), and that they resemble 

 closely the lower filaments of origin of the 

 par vagum. These upper roots of the acces- 

 sory do not arise from the gelatinous sub- 

 stance from which, according to Stilling, the 

 posterior roots of the spinal nerves spring, 

 yet they come into closer relation with it the 

 nearer they approach to the commencement 

 of the roots of the vagus. The upper fi- 

 bres of the accessory, though not continuous 

 with the posterior roots of the spinal nerves, 

 are yet, he believes, analogous to these; and 

 this view is strengthened by their presenting 

 the same connection with the roots of the 

 hypoglossal as is found between the roots of 



* De Medulla Spiuali, Nervisque ex ea prode- 

 untibus, pp. 51. 55, 1823. 



f Nervi Accessorii Willisii Anatomia et Physio- 

 logia, p. 11. Darmstadii, 1832. 



J Archives Ge'ne'rales de Me'decine, 4ieme serie, 

 torn. iv. pp. 409, 410, 1844. 



Tractatus de Connexu inter Nervum Yagum 

 et Accessorium Willisii, pp. 22. 39. Hauniae, 1836. 



|| Lobstein (De Nervo Spinali, in Ludwig's 

 Scriptores Nevrologici Minores Selecti, torn. ii. 

 p. 233.) also describes some of the filaments of 

 origin of the spinal accessory as coming from the 

 spinal chord between the fasciculi which consti- 

 tute the posterior roots of the spinal nerves, and 

 has represented these in jig. 1. Those who may 

 wish to ascertain the opinions of other anatomists 

 as to the particular column of the spinal chord into 

 which this nerve is implanted, and the extent of 

 its attachment to the cervical portion of the spinal 

 chord, may consult the monographs of Bischoff and 

 Bendz quoted above, and especially that of the 

 former of these authors. 



^f On some points in the anatomy of the me- 

 dulla oblongata, in Edinburgh Medical and Surgical 

 Journal for 1841. 



** Ueber die Textur und Function der Medulla 

 Oblongata, pp. 55. 57. Erlangen, 1843. 



ft lie describes the position and structure of this 

 accessorius-kern at p. 23. of the work quoted. 



