THE FASOLE OF THE HIP AND THIGH. 241 



experiments and pathological observations of Duchenne, whose interesting work l may be 

 advantageously consulted on these and other muscular movements. Poore attributes to the 

 lumbricales the special function of drawing down and relaxing the flexor tendons, while 

 actively producing extension of the middle and last phalanges through their insertion into the 

 extensor aponeurosis ("The Lancet," Sept. 3, 1881, p. 407). 



With respect to the interosseous muscles, it is farther to be observed that, besides being 

 flexors of the first and extensors of the second and third phalanges in the manner previously 

 stated, they severally exercise an abducting or adducting action on certain fingers, or direct 

 them away from or towards the middle line of the hand, according to the places of their 

 respective insertions ; and thus the four dorsal interosseous muscles are abductors of the 

 index, middle and ring fingers, and the three palmar interosseous muscles are adductors of 

 the index, ring, and little fingers respectively. 



While the muscles of the thumb produce for the most part the several movements indi- 

 cated by their names, these movements, in consequence of the position of the first metacarpal 

 bone, take place in directions which differ from those of the corresponding movements of the 

 fingers. Thus, extension, being movement in the direction of the dorsal surface of the digit, 

 occurs in nearly the same plane as abduction of the fingers ; and in abduction, the thumb 

 moving in the direction of its radial border is carried more forwards than outwards. 

 Opposition is produced by the combined action of the flexor brevis, the adductors, and the 

 opponens muscles. 



The little finger is withdrawn from the others by its abductor, as the ring finger is with- 

 drawn from the middle finger by the fourth dorsal interosseous muscle ; and the abductor 

 acting with the long flexors, likewise assists the flexor brevis in keeping the first phalanx 

 firmly down in grasping. The opponens draws forwards the fifth metacarpal bone, so as to 

 render the hand narrower and deepen the hollow of the palm. 



While the palmaris loiiyus has the effect of tightening the palmar fascia, the palmaris 

 Jtrevis draws up and wrinkles the integument over the hypothenar prominence. 



II. THE MUSCLES AND FASCL2E OP THE LOWER LIMB. 



The muscles which pass between the trunk and the lower limb, viz., the psoas, 

 pyriformis, and part of the gluteus maximus, are so few in number and so intimately 

 connected with others belonging strictly to the limb, that it is unnecessary to 

 describe them as a distinct group, as has been done in the case of the more numerous 

 and considerable muscles which attach the upper limb to the trunk. 



THE FASCLE OF THE HIP AND THIGH. 



The superficial fascia of the lower limb is similar to and continuous with that 

 of other parts of the body. Over the gluteal region it is very thick, and assists in 

 forming the prominence of the buttock. On the front of the thigh it covers the 

 lymphatic glands and the superficial vessels and nerves ; it passes freely over 

 Poupart's ligament, becoming continuous with the subcutaneous layer of the 

 abdominal fascia, and internally it passes into the dartos tunic of the scrotum and 

 into the superficial fascia of the perineum. In the neighbourhood of the groin a thin 

 layer of condensed areolar tissue, placed beneath the glands and superficial vessels, 

 can be raised from the surface of the fascia lata, and this is sometimes described 

 separately as a deep layer of superficial fascia. This structure is continued across 

 the saphenous opening of the fascia lata, to the margins of which it is closely 

 attached, and being here perforated by numerous small foramina for the passage of 

 blood-vessels and lymphatics, it receives the name of cribriform fascia. 



The deep fascia of the thigh or fascia lata is a strong aponeurotic mem- 

 brane, consisting of white shining fibrous tissue, and forming a continuous sheath 

 round the limb. It is attached superiorly to the back of the sacrum and coccyx, to 



1 G. B. Duchenne, "Physiologie des Mouvements, &c.," Paris, 1867. 



