372 



MUSCLES AND FASCIJE. 



Abductor Minimi Digiti. 

 Flexor Brevis Minimi Digiti. 

 Flexor Ossis Metacarpi Minimi Digiti 

 (Opponens). 



Palmar Region. 

 Lumbricales. 

 Interossei Palmares. 

 luterosaei Dorsales. 



Fig. 235. Dissection of Upper Extremity. 



Dissection of Pectoral Region and Axilla (Fig. 235). The arm being drawn away from the 

 side at nearly right angles with the trunk, and rotated outwards, make a vertical incision through 

 the integument in the median line of the chest, from the upper to the lower part of the sternum ; 

 a second incision along the lower border of the Pectoral muscle, from the ensiform cartilage to 



the other side of the axilla ; a third, from 

 the sternum along the clavicle, as far as its 

 centre ; and a fourth, from the middle of 

 the clavicle obliquely downwards, along 

 the interspace between the Pectoral and 

 Deltoid muscles, as low as the fold of the 

 armpit. The flap of integument is then 

 to-be dissected off in the direction indicated 

 in the figure, but not entirely removed, as 

 it should be replaced on completing the 

 dissection. If a transverse incision is now 

 made from the lower end of the sternum to 

 the side of the chest, as far as the poste- 

 rior fold of the armpit, and the integument 

 reflected outwards, the axillary space will 

 be more completely exposed. 



/. Dissection of 



PECTORAL REGION 



and AXILLA 



FASCIA OF THE THORAX. 



ELBOW 



PALM of HAND 



The superficial fascia of the tho- 

 racic region is a loose cellule-fibrous 

 layer, continuous with the super- 

 ficial fascia of the neck and upper 

 extremity above, and of the ab- 

 domen below; opposite the mamma, 

 it subdivides into two layers, one 

 of which passes in front, the other 

 behind that gland ; and from both 

 of these layers numerous septa pass 

 into its substance, supporting its 

 various lobes. From the anterior 

 layer, fibrous processes pass forward 

 to the integument and nipple, in- 

 closing in their areolas masses of 



fat. These processes were called by Sir A. Cooper the ligamenta suspensoria, 

 from the support they afford to the gland in this situation. On removing the 

 superficial fascia, the deep fascia of the thoracic region is exposed. It is a thin 

 aponeurotic lamina, covering the surface of the great Pectoral muscle, and 

 sending numerous prolongations between its fasciculi. It is attached, in the 

 middle line, to the front of the sternum ; and, above, to the clavicle. It is very 

 thin over the upper part of the muscle, somewhat thicker in the interval between 

 the Pectoralis Major and Latissimus Dorsi, where it closes in the axillary space, 

 and divides at the margin of the latter muscle into two layers, one of which 

 passes in front, and the other behind it; these proceed as far as the spinous 

 processes of the dorsal vertebrao, to which they are attached. At the lower 

 part of the thoracic region, this fascia is well developed, and is continuous with 

 the fibrous sheath of the Recti muscles. 



ANTERIOR THORACIC EEGION. 

 Pectoralis Major. Pectoralis Minor. 



Subclavius. 



The Pectoralis Major (Fig. 236) is a broad, thick, triangular muscle, situated 

 at the upper and fore part of the chest, in front of the axilla. It arises from 



