308 PRACTICAL ANATOMY. 



basis of antagonism. Flexors oppose extensors ; adductors oppose abductors ; 

 pronators oppose supinators ; levators oppose depressors. Nerves that inner- 

 vate and vessels that feed them are as truly antagonistic as are the muscles. 



The general/ /aw of antagonism is this: equality in length, strength, blood, 

 nerve, and fascial environment. Antagonistic groups of muscles are separated 

 from each other by deep fascia, called septa. A group of muscles acting in 

 unison, as the extensors or flexors of the leg, is called a musculature. Adjacent 

 musculatures are separated from each other by deep fascia, called septa. The 

 individual muscles, of which groups are composed, are also separated by deep 

 fascia. Bone is surrounded by deep fascia, called periosteum ; articulations are 

 held in place by deep fascia, called capsular ligament. Vessels and nerves receive 

 their sheath, and glands their capsules from deep fascia i. t\, from the internal 

 division of the same. 



Minor Details. With this understanding of the general distribution of the 

 deep fascia of the thigh, consider some of the minor details : 



1. One characteristic of deep fascia is the presence of openings in the outer 

 or circumferential portion, for the transmission of both centripetal and centrifugal 

 cutaneous vessels and nerves ; in the central or septal portions for the trans- 

 mission of those branches of antagonistic vessels and nerves, called communi- 

 cating and anastomotic, which preserve a physiological balance of power. 

 Instance, the perforating branches of the profunda reaching the hamstrings, 

 and the communications between the anterior crural, obturator, and great sciatic 

 nerves. 



2. Deep fascia is not uniform in tldckness. As structure is the correlative of 

 function, those parts subjected to the greatest degree of tension and use must 

 become thick and strong in comparison with less used parts. 



3. Deep fascia of the leg and thigh receives in some localities special names, 

 founded on no rational or logical ground, but which are perpetuated in anatomy 

 and surgery, and revered, as Egypt points to her ruins. The special names for 

 the deep fascia of the lower extremity are these : (i) The fascia la fa, on the 

 upper front part of the thigh ; (2) the ilio-tibial band, on the outer side of the 

 thigh ; (3) the popliteal fascia, covering the popliteal space ; (4) the internal 

 annular ligament, between the os calcis and internal malleolus ; (5) the external 

 annular ligament, between the os calcis and external malleolus ; (6) the anterior 

 annular ligament, between the malleoli ; (7) the dorsal fascia, on the back of the 

 foot ; (8) the plantar fascia on the sole of the foot ; (9) the ligamcnta vaginalcs 

 as sheaths for the flexor tendons of the toes; (10) the vincula, as interter 

 dinous slips ; (i i) the various intermuscular septa. 



4. Deep Fascia Gives Origin and Insertion to Muscles. This fact is often IK 

 fully appreciated by the student. Instance, the -rastus interims and rastns 

 cxtcrnus, the muscles on the anterior part of the tibia andjftfat/a. Be ever ready 

 to see deep fascia giving origin or insertion to muscles. The glutens maximus 

 has one-of its insertionsjnto the deep fascia ; the ilio-tibial band is in reality only 

 the insertion of the tensor vagina; femoris, by aponeurosis. 



5. Sn/x/irisions of fascia lata are : (i) the iliac and (2) pubic portions. These 

 are separated from each other by a large opening the saphenous. The iliac or 

 anterior portion is attached to the crest of the ilium, to the whole of Poupntt's 

 ligament. The pubic or posterior part covers the pcctineus muscle and gracilis ; 

 is continuous with the femoral sheath behind the femoral vessels. 



Attachments of Ar/> I'\rscin. Deep fascia is continuous with periosteum at 

 subcut.HH-oiis areas. These are called the attachments. Tin- deep fascial attach- 

 ments of the lower limb are as follows. In the region of the hip : (i) To crest ot 

 ilium ; (2) to pubic spine and body ; (3) to ischii. -pubic ramus ; (4) to the tubcr- 

 usity of ischium ; (5) to sacrum and coccyx. In the knee region, demonstrate 



