180 LABOKATORY MANUAL OF HUMAN ANATOMY 



Fourth Layer of Muscles of the Sole. 



(a) Plantar interosseous muscles (Mm. inter ossei plantar es). 



(b) Dorsal interosseous muscles (Mm. inter ossei dor sales). 



Determine the form, position, origin, insertion, action, and 

 innervation of each, and compare them with their homologues in 

 the hand. Note that they are covered by a thin layer of inter- 

 osseous fascia (fascia interossea). 



The points of insertion of the M. tibialis posterior will now 

 be exposed. Dissect out the different reflections of its tendons 

 and determine to what bones each is attached. 



Dissect out the tendon of the M. peronaeus longus. Note 

 that it runs in a sulcus covered over by the ligamentum longum 

 plantae. Dissect down to the tendon and trace it to its insertion, 

 noting the plantar synovial sheath (vagina tendinis M. peronaei 

 longi plant aris). (Vide Spalteholz, Fig. 407.) What role does it 

 play in maintaining the arch of the foot 1 



JOINTS OF THE LOWER EXTREMITY. 



The hip- joint has been studied already. The other joints 

 should now be carefully dissected. 



Arterial Anastomosis about the Knee-joint. 



Before dissecting the knee-joint, review the various blood- 

 vessels about the knee and study the most important anasto- 

 moses. (Fig. 73.) 



Knee-joint (Articulatio genu). (Figs. 73-77.) 



Remove the popliteal vessels and nerves. The tendons of the 

 muscles surrounding the joint should be left in place, so that 

 their relations to the different ligaments may be studied. Divide 

 the M. quadriceps extensor about eight centimetres above the 

 patella and allow the lower part to remain in situ. Trace each 

 of the articular arteries to its termination. Study the following : 



(a) Articular capsule (capsula articularis) . 



(b) Fibular collateral ligament (Lig. collaterale fibulare) (0. T. long 



external ligament). 



(c) Tibial collateral ligament (Lig. collaterale tibiale) (0. T. internal 



lateral ligament). 



(d) Oblique popliteal ligament (Lig. popliteum obliquum) (0. T. pos- 



terior ligament). 



(e) Arcuate popliteal ligament (Lig. popliteum arcuatum). 



Observe the retinaculum Lig. arcuati. 



