236 MYOLOGY, OR ANATOMY OF MUSCULAR SYSTEM 



continuous with the dorsal fascia, and sends a prolongation 

 forward over the short flexors of the little toe. 



Central portion has dense white, glistening fibers, from the 

 inner tubercle of the os calcis to the roots of the toes: divides 

 into five processes in front. Thin transverse fibers cover the 

 lumbricals and digital nerves. Identical arrangement as in 

 the palmar fascia; fibers to the digital sheaths, superficial 

 transverse ligament, and skin, and deep processes to the trans- 

 verse metatarsal ligament. 



Two intermuscular septa are between the middle and lateral 

 portions, giving partial origin to muscles. 



Superficial transverse ligament of the toes is in folds of "skin 

 at the interdigital clefts, connected to the tendon sheath 

 beneath. Connects all five digits. 



The Dorsal Region 



1. M. Extensor Brevis Digitorum Pedis. Rises from fore- 

 part and upper and outer surface of the os calcis, in front 

 of the groove for the peroneus brevis tendon, and from the 

 anterior ligament of the ankle. The tendon has several vertical 

 leaflets from which muscular fibers rise, dividing into three 

 bellies which unite with the outer border of the long extensors 

 for the second, third, and fourth toes. 



2. M. Extensor Brevis Hallucis (often described with the 

 above). Origin, two heads outer from the upper surface 

 of the os calcis close by the anterior edge, and connected with 

 the extensor brevis digitorum; inner head from the lower 

 arm of the annular ligament. Tendon is free at the tarso- 

 metatarsal joint, passes under the tendon of the extensor 

 longus hallucis, and is expanded and inserts on the dorsum 

 of the proximal phalanx. 



The Plantar Region 



None corresponding to the palmaris brevis; three groups 

 as in the hand, middle group richer than that of the hand. 

 Great toe, fewer than the thumb group. Little toe group, 

 like number and arrangement. 



