JL LATissnius. 229 



§ 633. Upon Figures 68-Tl are represented the insertion areas or lines of the following 

 muscles ; the list includes all which are inserted upon the humerus : — 



Acromio-dcUoidcus (US), §076; coracoideus, caput brece (70), caput longum (71), g 668 ; 

 oct-jpectoralis, Irn. ectalis (68, 69), § 649; ectopectoralis, Im. entails, dc. caudaUs (69), § 653 ; 

 ectopectoralis, Im. entalis, do. cephaliai (68, 69), § 651 ; eniopectoralis, dv. caudalis (69, 70), 

 § 656 ; entopectoralis, do. cepludica (69, 70), § 658 ; infraspinatus (68), § 678 ; micostalis 

 (68), § 679 ; spino-deltoideus (68), § 674 ; supraspinatus (68, 69), § 675 ; teres {6Q, 70), g 680 ; 

 xiplii-luimc rails (69), § 660. 



As stated in § 670, the insertion of the coracoideus, caput longum, is so variable that 

 the area is here indicated on Fig. 71 by an interrogation point. 



% 634. The origin areas or lines of the following 13 muscles are represented upon 

 Fig" 68-71 :— 



Brachialis (68,71), § 693; entotriceps, dv. brevis (70, 71), § 688, do. caudalis (70, 71), 

 § 687, dv. cephalica (71), § 689, dv. intermedia (68, 71), § 686 ; extensor digitorum com- 

 munis (68, 71), § 697 ; extensor minimi (68, 71), § 698 ; exiensor radialis brevior (68), §696 ; 

 e.vt. rud. longior (68, 71), § 694 ; extensor ulnaris (68), § 699 ; jkxor radialis (70), § 703 ; 

 pronator teres (70, 71), g 701 ; supinator longus (71), § 690. 



M. LATISSIMUS. 



§ 635. Synonymy. — Latissimus dorsi, Q., A, 1,189; G., A, 374; "grand dorsal," 

 S.-D., A, II, 339; "grand dorsal," Cb., A, 317, Fig. 90 ; great dorsal, Ch. (Fl.), A, 303 ; 

 latmimus dorsi, Miv., B, 137. 



Figures.— Ectal aspect (66, 67, 74) ; ental aspect (73, 73, 75) ; insertion area (69, 70) ; 

 transection (99, 100). 



Posture. — Latericumlbent, the venter toward tlie dissector; a 

 block transversely under the thorax just caiidad of tlie elbows. 



Exposure. — Most of the muscle has been exposed by the re- 

 moval of the spino-trapezius and dermo-Tiumeralis, and needs only 

 to have its ectal surface cleared. If the caudal region of the body 

 has not been removed, the corresponding part of the latissimus 

 may be exposed by dividing the skin and the dermo-humeraJis 

 along a dorso-caudal line from the already exposed caudo-ventral 

 border of the latissimus to the crista ilii (§ 230, Fig. 51) of the op- 

 posite side, and reflecting the flap so formed across the dorsimeson. 



General Description. — A large triangular sheet, covering rather 

 more than the dorso-cephalic half of the abdomen and thorax, ex- 

 cepting so much of the latter as is between the scapulae. It arises 

 at the dorsimeson between the pelvis and the oth thoracic spine., 

 and is inserted upon the liumerus, forming part of the bicipital 

 arch (Fig. 73). 



Dissection. — Lift the caudo-ventral border where it crosses the 

 7th rib (which is also the 7th counting from the last), and trace it 

 both ways for 2-3 cm. Trace the cephalic border from the vertebral 



