THE ANTERIOR LIMB. 
(b) The deltoideus: 
Acromial portion. 
Scapular portion. 
portion of deltoid tuberosity. 
Origin: Infraspinous fascia. 
211 
Origin: The Acromion. Insertion: Distal 
The end of 
the muscle forms a curved line over the dorsal portion of the 
infraspinatus, leaving only a 
small triangular portion of 
the latter exposed. Insertion: 
The distal portion of the mus- 
cle passes beneath the meta- 
cromion, which also serves as 
a point of attachment, and is 
replaced on the lateral surface 
of the humerus, beneath the 
acromial portion, by a long 
thin tendon, through which 
it is inserted. 
~The scapular portion of the| 
deltoideus should be separated 
from the infraspinatus and divid- 
‘ed, the distal end being reflected 
together with the metacromion. 
(d) The infraspinatus. 
Origin: Posterior por- 
tion of the lateral sur- 
face of the scapula, in- 
cluding the spine. In- 
sertion: Greater tub- 
ercle of the humerus. 
The muscle fills the 
infraspinous fossa. 
Anterior 
Lateral 

Posterior 
Fic. 74. Transverse section through the 
distal portion of the arm; semidiagrammatic; 
a.b., brachial artery; a.c.1., radial collateral 
artery; b., biceps; br.l. and br.m., lateral and 
medial heads of the brachialis; d., deltoideus 
(insertion);  e.a.p., extensor antibrachii 
parvus; f., bracnial fascia; h., humerus; 
n.m, me cian nerve; n.r., radial nerve; n.u., 
ulnar nerve; tr. I-tr.3, long, lateral, and 
medial heads of the triceps; v.b., brachial 
vein; v.c., cephalic vein. 
(e) 
The supraspinatus. Origin: Anterior portion of the lateral 
surface of the scapula (supraspinous fossa), supraspinous 
fascia, and, to a certain extent, the subscapular fascia. 
Insertion: Greater tubercle of the humerus. 
The extent of this muscle is evident only after removal of the 
loosely attached fleshy parts of the pectorals from its surface. 
