PLATE XI. 

 THE DEEP PALMAR ARCH AND MUSCLES OF PALM. 



In this dissection of the palm, the superficial arch, median nerve, flexor tendons, 

 and lumbricales have been removed in order to show the deep arch. The annular 

 ligament has also been divided, and the tendons cut off and left to show their relative 

 position whilst passing under it. 



Note on the Short Muscles of t)te Thumb. The so-called inner head of the flexor 

 b re vis pollicis at least, the part visible in the plate is better named the adductor obliquus, 

 lnT.-iiise Von Bischoff has shown that the true inner head of this muscle is a small slip 

 which arises from the base of the first metacarpal bone, and passes to be inserted into 

 the ulnar sesamoid bone of the thumb ; whereas the rest of the mass, which usually is 

 known as the inner head of the flexor brevis, is in reality an oblique adductor, while the 

 so-called adductor of Gray, etc., should be called the adductor transversus. A table can 

 thus be established, comparing the muscles of the thumb with those of the great toe : 



Abductor pollicis with the abductor hallucis. 



Adductor transversus pollicis with the adductor transversus hallucis (transversus 

 pedis). 



Adductor obliquus pollicis with the adductor obliquus hallucis (the ordinary adductor). 

 Flexor brevis pollicis with the flexor brevis hallucis. 



a Radial head. a Tibial head. 



b Intcrosseus primus volaris. b Fibular head. 



The flexor ossis metacarpi (opponens) pollicis has no homologue in the human foot ; 

 it is really a segmentation of the outer head of the flexor brevis pollicis ; but in the 

 orang an opponens hallucis, which is closely connected with the flexor brevis hallucis, 

 has been described. The interosseus primus volaris is the true ulnar head of the 

 flexor brevis pollicis. 



This classification is taken from a paper by Dr. Cunningham in the ' Report of the 

 Challenger Expedition,' vol. v. p. 187, to which the reader must be referred for more 

 information, as well as to an excellent paper by Dr. St. John Brooks in the Journal 

 of Anatomy and Physiology, -vol. xxii. 



