THE OBTUKATOR NEHVE. 



603 



anterior and a posterior branch, which are separated from one another 

 by the short adductor muscle. 



"a. — The ANTERIOR PORTION communicates with the accessory ob- 

 turator nerve, when thot nerve is present, and descends in front of the 

 adductor brevis and behind the pectineus and adductor longus muscles. 

 It gives branches as follows. 



(a) An articular hmnch to the hip-joint arises near the thyroid membrane. 



(i) Muscular branches are given to the gT.-acilis and adductor longxis muscles, 

 and occasionally also others to the adductor brevis and pectineus. 



(c) The terminal tn-i;/ turns outwards upon the femoral artery, and surrounds 

 that vessel with small filaments. 



(rf) An offset at the lower border of the adductor longus communicates beneath 

 the fascia with the internal cutaneous branch of the anterior crural nerve, and 

 with a branch of the internal saphenous nerve, forming a sort of olexus. 



Fig. 368. — The Lumbar Plexus from Fig. SGS. 



BEFORE, WITH THE DISTRIBUTION OF 



SOME OF ITS Nerves (shghtly altered 

 from Schmidt). \ 



a, the last rib ; b, quadratus lum- 

 borum muscle ; c, oblique and trans- 

 verse muscles cut near the crest of the 

 ilium and turned down ; d, pubes ; c, 

 adductor brevis muscle ; /, pectineus 

 divided and turned outwards ; y, adduc- 

 tor longus ; 1, ilio-hypogastric nerve ; 

 2, ilio-inguinal ; 3, external cutaneous ; 

 4, anterior crural ; 5, accessoiy obtu- 

 rator ; 6, obturator united with the ac- 

 cessory by a loop round the pubes ; 7, 

 genito-crural in two branches cut short 

 near their origin ; 8, 8, lumbar poi-tion 

 of the gangliated sj'mpathetic cord. 



B. — The POSTERIOR or deep 

 part of the obturator nerve, 

 having passed through some 

 fibres of the external obturator 

 muscle, crosses behind the short 

 adductor to the fore part of 

 the adductor magnus, where it 

 divides into many braaches, all 

 of which enter those muscles, 

 excepting one which is pro- 

 longed downwards to the knee- 

 joint. 



(a) The ?« usc7i la r branches supply 

 the external obturator and the great 



adductor muscle, with the short adductor also when this muscle receives no 

 branch from the anterior division of the nerve. 



(b) The articular branch for the knee rests at first on the adductor magnus, 

 but perforates the lower fibres of that muscle, and thus reaches the upper part of 

 the popUteal space. Supported by the popliteal artery, and sendmg filaments 

 around that vessel, the nerve then descends to the back of the knee-joint, and 

 enters the articulation through the posterior Ugament. (Thomson, "London 

 Med. and Sm-g. Jom-nal," Xo. xcr.) 



