334 Proceedings of the Royal Irish Academy. 



the specimen to Professor Macalister, that no corresponding structure 

 had been observed by him before. He informed me afterwards, how- 

 ever, that a ligamentous band, having the position and attachments 

 of the one in question, was described by Lauth as a normal structure in 

 human anatomy. Lauth has given it the name of ligamentum transver- 

 sale occiintis, and describes it in the following words : — " Unmittelbar 

 iiber diesen Bandern^ fiudet man das Queerband des Hinterhauptbeins 

 (L. transversale occipitis), welches von einer seite des Hinterhaupt- 

 loches an die andere geht, ohne sich an den Zahnfortsatzes zu 

 heften." — {Anatomie, Bd. i. s. 101). 



I have since found that it is noticed in the French work of 

 Beaunis and Bouchard under the name of ^'■ligament transverse occipital 

 de Lauth^^ (8™* ed. p. 133). These anatomists look upon it as being 

 formed by the superior fibres of the check ligaments, passing, as they 

 describe it, without interruption from one occipital condyle to the other, 

 over the summit of the odontoid process. Luschka, in his very perfect 

 description of the anatomy of this part, also observes that it is not un- 

 usual for the uppermost bundles of fibres of the check (superior lateral) 

 ligaments to interlace with one another so as to form an upper ligamen- 

 tum transversale. From his description, however, I am not disposed 

 to think that he ever saw it largely developed as an independent 

 structure. Henle (Biinderlehre) also describes an inconstant mem- 

 branous band formed by a few of the fibres of the check ligaments 

 interlacing with one another in the middle line behind the upper part 

 of the odontoid process, and so stretching across from one occipital 

 condyle to the other; but even he does not mention any case in which 

 it had been seen to attain anything like a considerable size, although 

 he quotes all the known deviations from normal structure in this as 

 well as in other regions of the human body. A slight allusion is 

 also made to the interlacement of some of the upper fibres of these 

 ligaments in Qiiain's Anatomy (8th ed.), but not in such a manner as 

 to lead the reader to expect that a strong separate band might be 

 found in this situation. 



From the evidence brought forward, I think myself justified in 

 describing the specimen before the Academy to-night as an anomalous 

 structure, and one of some interest, as must all the structures be, normal 

 and abnormal, which enter into the formation of the very important 

 articulations which connect the vertebral column with the brain-case, 

 and which, accordingly, are concerned in the preservation of the vital 

 structures which lie in their immediate neighbourhood. I should, 

 however, have hesitated to bring it under the notice of anatomists if 

 I had not been encouraged by Professor Macalister; to whose kindness 

 and courtesy I am indebted for the chief part of the information 

 which I have been able to collect on the subject. 



' i.e., Ligamenta alalia. 



