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XIV. — A Revised Description of the Dorsal Interosseous Muscles of the Human Hand, 

 with Suggestions for a Neiv Nomenclature of the Palmar Interosseous Muscles 

 and some Observations on the Corresponding Muscles in the Anthropoid Apes. 

 By David Hepburn, M.D., CM., F.R.S.E., Lecturer on Regional Anatomy in 

 the University of Edinburgh. (With a Plate.) 



(Read 16th March 1896. ) 



The main features of the scope of this paper are indicated by its title, from which 

 it will be seen that I do not regard the current descriptions, which appear in text- 

 books of human anatomy, as providing an adequate conception either of the attach- 

 ments or of the functions of the muscles at present named "Dorsal and Palmar 

 Interosseous." It may seem strange, in connection with such an exact (and, accord- 

 ing to some, exhausted) science as human anatomy, that it should be possible to 

 doubt the accuracy of modern text-books concerning such an apparently elementary 

 consideration as the description of a group of muscles in the human hand ; but we must 

 bear in mind, first, the ease with which a statement is handed on from author to author 

 without renewed investigation, if only, in the first instance, it has been stamped with 

 the approval of a recognised authority, and second, that these descriptions were originally 

 constructed with little or no reference to the facts of comparative anatomy. It is only 

 by a series of careful comparisons that we can arrive at a proper understanding of the 

 homologies of individual muscles or of groups of muscles in the human subject. 



I propose, therefore, to direct special attention to the " Dorsal Interosseous " muscles 

 :>f the human hand for the purpose of showing that they have been incompletely dis- 

 sected, and as a result imperfectly described in current anatomical text-books ; and that, 

 when this group of muscles is accurately treated, the number of " Palmar Interosseous" 

 GQUscles is greatly increased, and the palmar group takes its place as the Intermediate 

 Stratum of the intrinsic muscles of the manus, and as such should be described under 

 ;he term Short Flexors of the various digits. 



The present views regarding the attachments and functions of these groups of muscles, 

 is recorded in the works of Gray, # Macalister^ Cunningham,;}; and Quain,§ may be 

 )rieny summarised as follows : — 



First. — There are four Dorsal Interosseous and three Palmar Interosseous muscles, 

 ,nd the former are larger muscles than the latter. 



Second. — Each dorsal muscle possesses two heads of origin, the fibres of which con- 



* Gray's Anatomy, Descriptive and Surgical. 

 t Macalister, A Text-Booh of Hitman Anatomy, 1889. 

 I Cunningham, Manual of Practical Anatomy, 1893. 

 § Quain's Anatomy, 10th ed., vol. ii. part ii., 1892. 



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