258 



THE VASCULAR SYSTEM. 



Fig. 17: 



with the hindmost part of the J\[. ohliqitiis ahdomhm extermis, 

 and the hinder portion of the posterior lymph-heart. Anteriorly 

 the floor is depressed between the M. ohliquvs abdominis and the 

 M. ghUaeus, the depression leading to a canal, which communicates 

 with the abdominal cavity. 



B. The Lymph-sacs of the Anterior Extremity. 

 a. The septa. 



(i) The axillary septum [Septiiui axiUare), (Fi^s. I'joa, a", 

 171) is practically a portion of the ventral septum, which divides 

 at the I'oot of the arm to enclose it. The dorsal and ventral por- 

 tions of this circular septum have received special names. 



a. The dorsal axillary sej)tum 

 {Septum axillare dorsale) crosses the 

 M. triceps and joins the pectoral 

 septum. 



/3. The ventral axillary septum 

 {Septuiii axil/are dorsale) passes 

 throug-h the axilla and joins the 

 pectoral septum. 



The circular axillary septum has 

 attached to it the following : — 



(2) The posterior brachial sep- 

 tum (/SV^y /'///;/ hrachiale poslicinn (Fig. 

 169 tv); it is attached along the 

 middle line of the extensor surface of the arm (long head of the 

 M. tricejjs) to the elbow and to the forearm [M3I. anconaei), then passes 

 obliquely over the volar surface of the hand to the fourth finger. 



(3) I'l^'^ anterior brachio-ulnar septum [Septum hrachiale anticnm 

 iilnare), (Fig. 1 70 /') commences at the same point as the foregoing^, 

 passes obliquely over the outer head of the M. triceps, and is con- 

 tinued over the M.jlexor antitjrachii lateralis, M. supinator longus, and 

 M. extensor digitorvm commnnis, to the dorsal surface of the fourth 

 finger. 



(4) The anterior braehio-radial septum [Sepdum. hracliiale an- 

 ticum, radiale), (Fig. 170 s") passes from the outer angle of the wall 

 of the pectoral lymph-sac, over the inner head of the il/. triceps and 

 M. flexor carpi radialis to the thumb. 



b. The lymph-sacs are enclosed by these three septa ; they are 

 four in number : — 



