DISSECTION OF THE ANTERIOR LIMB. 43 



close-meshed network having little or no communication with the deep 

 set. This venous envelope of the foot is divided into a solar, a laminal, 

 and a coronary plexus. Where the solar and laminal plexuses meet, a 

 composite venous vessel runs in company with the circumflex artery of 

 the toe. These two plexuses communicate freely with each other, 

 and with the coronary plexus. This last consists of a central part, 

 which underlies the coronary cushion, and of two lateral parts, which 

 on each side ramify oil both surfaces of the lateral cartilage. By 

 the convergence of branches belonging to this cartilaginous division 

 of the coronary plexus, the digital veins are formed ; and these drain 

 away the blood from both the intra-osseous and extra-osseous systems 

 of vessels. 



Directions. — The terminal portion of the deep flexor tendon, and the 

 synovial apparatus developed in connection with it, should now be 

 examined. 



The Deep Flexor tendon (Plates 10 and 11) when it reaches the 

 upper border of the navicular bone widens out to form what is called the 

 plantar aponeurosis. This plantar aponeurosis plays over the navicular 

 bone by means of the navicular sheath, and is covered posteriorly by a 

 fibrous layer which ultimately blends with it. It becomes inserted into 

 the semilunar crest of the os pedis, and into the bone behind that crest. 

 The above-mentioned fibrous layer was first described by Bouley, and 

 designated by him the reinforcing sheath of the perforans. This expan- 

 sion is attached on each side by a slip to the lower half of the first 

 phalanx, and it serves to maintain the plantar aponeurosis against the 

 navicular bone. 



The Navicular or Small Sesamoid Sheath (Plate 10, Fig. 2). This 

 is a synovial apparatus developed in connection with the perforans 

 tendon where it plays over the navicular bone. It lines the deep face 

 of the tendon, and is reflected on to the navicular bone and inter-osseous 

 ligament. It also extends above the navicular bone, where it is in 

 contact with the synovial membrane of the cofiin-joint and that of the 

 metacarpo-phalaugeal sheath. 



THE SHOULDER-JOINT. 



This joint is formed between the glenoid fossa of the scapula and the 

 head of the humerus. It is enclosed by a single capsular ligament 

 lined internally by the synovial membrane. The absence of lateral or 

 other retaining ligaments in connection with the joint is compensated 

 for by the numerous tendons which pass from one bone to the other in 

 close relation to the capsular ligament. These muscles are as follows : — 

 the supraspinatus, infraspinatus, teres minor, biceps, and small scapulo- 

 humeralis. The last passes over the joint behind, where some of its 



