TIII-: 



MUSCLES OF THK AXILLARY AND 

 CERVICAL REGIONS. 



1, Portion of the cuticularis colli ; 2, An- 

 terior portion of the ni:ist<>iilo-huine- 

 ralis; 3, Posterior portion of ditto ; 4, 

 Sterno-maxillaris ; 5r6ttbMapnlo-hyoi- 

 deus; 6, Sterno-hyoideus ; 7, Sterno- 

 thyroideuu; 8, Scalenus; 9, Sterno- 

 humeralis ; 10, Sterno-aponeuroticus ; 

 11, Sterno-trochineus (pectoralis mag- 

 nus); 12, Portion of the fascia en- 

 veloping the coraco-radialis, receiving 

 part of the fibres of the sterno-trochi- 

 neus; 13, Sterno-prescnpularis; 14, 

 Ita terminal aponeurosis. 



Composition. This muscle 

 is situated between tlio two unti rim- 

 limbs, occupies the iuferior surface of 

 the chest, aud is formed by two por- 

 tions which adhere closely to each other, 

 but are yet perfectly distinct. Following 

 the example of Girard, we will descril 

 these as two particular muscles by the 

 names of tterno-kumeralu, and X//THO- 

 aponeuroticun. 



A. STEKNO-HUMKKALIS. -- Form - 

 Structure. This is a short, bulky muscle, 

 flattened above aud below, contracted at 

 its termination, and composed almost 

 entirely of thick parallel fibres. 



Direction and Attachments. It com- 

 mences on the anterior appendage and the 

 inferior border of the sternum, and is 

 directed obliquely backwards, downwards, 

 and inwards, to reach the anterior ridge 

 of the humerus, where it terminates by 

 an aponeurosis common to it, the mas 

 toido humeralis, and the sterno-aponeuro- 

 ticus. 



Relations. It responds, by its ex- 

 ternal face, to the skin, from which it is 

 separated by a cellular layer, and to the 

 inferior extremity of the cuticularis 

 colli ; by its internal face, to the steruo- 

 aponeuroticus and sterno-prcscapularis. 

 Its anterior border forms, with the nnis- 

 toido-humeralis, a triangular space occu- 

 pied by the subcutaneous, or " plate," vein 

 of the arm. 



Action. It acts principally as an 

 adductor of the anterior limb. 



13. STEHNO-APONEUBOTICUS. Form 

 Structure Direction Attachments. A 

 very wide, thin, and pale quadrilateral 

 muscle formed of parallel fleshy fibres, 

 which arise from the entire inferior 

 border of the sternum, to pass at first 

 outwards, then downwards, and terminate 

 in the following manner : the anterior 

 fibres go to the aponeurosis which attaches 

 the mastoido-humeralis and sterno-hu- 

 moralis to the anterior ridge of the 

 humerus; the posterior fibres are also 

 continued by a very thin fascia, which is 

 spread inside the limb to the external 

 face of the antibrachial apoueurosis. 



Relations. By its superficial face, 



