250 



THE MUSCLES. 



Structure and Attactmients. — Tlie first 

 portion is generally paler than the second, 

 and is composed of longitudinal fleshy fibres 

 deeply intersected by tendinous strips. It 

 takes its origin, by its superior extremity, 

 from the dorsal angle of the scapula. The 

 anterior portion is deeper-coloured and more 

 tendinous than the other. Its superior ex- 

 tremity, included within two fibrous folds 

 resulting from the duplicature of the scapular 

 aponeurosis, is fixed, through the medium of 

 these, to the tuberosity of the scapular spine. 



These two muscular bodies unite in- 

 feriorly, and terminate together on the del- 

 toid imprint or eubtrochiterian crest by 

 tendinous and muscular fasciculi. 



Belations. — This muscle responds : out- 

 wardly, to the scapular aponeurosis, with 

 which it may be said to form one body; 

 inwardly, to the subspinatus, the short ab- 

 ductor of the arm, and the large and short 

 extensors of the fore-arm. 



Action. — It gives a very marked abduc- 

 tion movement to the humerus, and also 

 makes it pivot outwards. It acts, besides, 

 as a flexor of that bone, when its action is 

 combined with that of the adductor of the 

 arm. It should also be considered as a 

 powerful tensor of the scapular aponeurosis. 



3. Short Abductor of the Arm, or Teres 

 'Minor. (Pig. 85, 2, 3.) 



Synonyms. — Scapulo-humeralis minor — Oirard. 

 (Teres minor — Percivall. Scapulo-trochiterius, 

 medium and parvum — Leyh.^ 



Volume — Situation — Direction, — ^A small 

 elongated muscle, situated below the pre- 

 ceding and the subspinatus, along the pos- 

 terior border of the scapula, whose direction 

 it follows. 



Form— Structure. — In its inferior half it 



1, 1, Long abductor of the arm ; 1', Its humeral 

 insertion; 2, Superspinatns ; 3, Subspinatus; 

 3', Its tendon of insertion ; 4, Short abductor 

 of the arm ; 5, Biceps ; 6, Anterior brachialis ; 

 7, Large extensor of the fore-arm; 8, Short 

 extensor of the fore-ai-m; 9, Anconeus; 11, Anterior extensor of the metacarpus; 11', 

 Its tendon ; 12, Aponeurosis separating that muscle from the anterior brachialis ; 13, 

 Oblique extensor of the metacarpus ; 14, Anterior extensor of the phalanges ; 14', Its 

 principal tendon; 15, The small tendinous branch it furnishes to the lateral extensor; 

 16, Latei'al extensor of the phalanges; 16', Its tendon; 17, The fibrous band it 

 receives from the carpus ; 18, External flexor of the metacarpus ; 19, Its metacarpal 

 tendon ; 20, Its supracarpal tendon ; 21, Ulnar portion of the perforans ; 22, Tendon 

 of the perforans ; 23, Its carpa Uigameut ; 24, Its reinforcing phalangeal sheath ; 

 25, Tendon of the perforatus. 



EXTERNAL MUSCLES OF THE 

 EIGHT ANTEEIOE LIMB. 



