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A MANUAL OF ANATOMY 



Flexor Profundus 



Flexor 

 Sublimis 



_Ligamentum 

 Longum 



decussating fibres. Each fibro-osseous canal is lined by synovial 

 membrane, which is reflected over the contained tendons in such a 

 manner as to furnish a separate investment for each. The synovial 

 sheaths of the index, middle, and ring 

 fingers extend into the palm as far as 

 the heads of the metacarpal bones, and 

 they have no connection with the great 

 palmar bursa. The synovial sheath of 

 the little finger, however, is as a rule con- 

 tinuous with the large inner compartment 

 of that bursa. The synovial membranes 

 of the sheaths form ce.tain bands, called 

 vincula accessoria tendinum, which are of 

 two kinds — ligamenta brevia and ligamenta 

 longa. The ligamenta brevia are two in 

 number — one for the superficial and one 

 for the deep flexor tendon. They are broad, 

 laterally compressed, triangular bands which 

 connect each tendon, close to its insertion, 

 with the distal end of the phalanx above 

 that into which it is inserted. The liga- 

 menta Imtga, few and inconstant, are narrow 

 cords which pass between the tendons and 

 the phalanges, or from one tendon to the 

 other. The fibro-osseous canal for the 

 tendon of the flexor longus pollicis isj 

 similar to those of the other flexor tendons,j 

 and its synovial membrane is continuoi 

 with the outer compartment of the great palmar bursa. 



Lumbricales. — ^These are four tapering muscles which are con- 

 nected with the deep flexor tendons in the palm, and they receive 

 numerical names, the most external being the first. The first anc' 

 second arise each from the outer side of the deep flexor tendon for the 

 index and middle fingers, and the third and fourth arise from the 

 adjacent sides of the two deep flexor tendons between which eacl 

 lies, the tendons involved being those for the middle, ring, anc 

 little fingers. Each muscle tapers off, and ends in a tendon whichJ 

 turning round the outer side of a metacarpo-phalangeal jointj 

 expands, and is inserted into the outer side of the broad expansioi 

 of the extensor tendon on the back of the first phalanx. 



Nerve-supply — First. — ^The digital branch of the median to th€ 

 outer side of the index finger. Second. — The digital branch of th€ 

 median, which divides to supply the contiguous sides of the indej 

 and middle fingers. Third and Fourth. — The deep division of the 

 ulnar nerve. 



Action. — (i) To flex the metacarpo-phalangeal joint, and (2) 

 to extend the interphalangeal joints. 



Anterior Annular Ligament. — This is a strong fibrous band 

 which bridges over the concavity on the palmar aspect of the carpus, 



Fig. 202. — The Flexor 

 Tendons of a Finger. 



