THE WRIST AND HAND 



1171 



continued down to the finger to the base of the last phalanx. It is the contraction 

 of the palmar fascia, especially of the slips to the two inner fingers, which gives rise 

 to Dupuytren's contraction. 



Synovial membranes.— Beneath the anterior annular ligament lie two syno- 

 vial sacs, one for the lk-.\or longus pollicis, and one for the superficial and deep 

 flexors of the fingers. They extend above the annular ligament to from one anrl a 

 quarter to one inch and a half (81 to 37 mm.) below. That for the long flexor of 

 the thumlj reaches to the base of the last phalanx. That for the finger-flexors gives 



Fkj. 7.37.— Diacijam ok a Vertical Section through the Middle of the Hand. 



Posterior anuular ligament 



Deep transverse ligament 

 Attachmient of common extensor 

 to first phalanx 



Superficial transverse ligament 



Vincula accessoria 



Attachment of common extensor 

 to second phalanx 



Attachment of common extensor 

 to third phalanx 



Qreat palmar bursa 



Anterior annular ligament 



Dorsal interosseous 

 Liumbricalis 

 Palmar fascia 



Flexor profundus digitorum 



Flexor sublimis digitorum 



Ligamentum vaginale 

 Vincula accessoria 



off four processes. The one for the little finger also reaches to the liaseof the last 

 phalanx. Those for the index, middle, and third fingers, end aliout tlu' middle of 

 the metacarpal l)ones. Traced from tlu' insertions of the flexor ])rofundus. the 

 digital synovial sheaths extend upwards into the palm as far as the ))ifurcation 

 of the palmar fascia (page 1169), i.e. into a point al)out opposite to the necks 

 of the metacarpal bones, denoted on the surfice by the crease which corresponds 

 to the flexion of the fingers. Thus, about half an inch (12 mm.) separates the 

 sheaths of the outer three fingei"s from that large synovial sac beneath the annular 

 ligament. There is no synovial sheath beneath the pulp of the fingers or thumb, 



