1168 



SURGICAL AND TOPOGRAPHICAL ANATOMY 



along the interosseous spaces, and liifuvcate half an inch above the webs of the 

 fingers; the innermost digital does not bifurcate. The digital arteries then descend 

 along the sides of the fingers under the digital nerves, giving off twigs to the sheath 

 of the tendons, which enter by apertures in it, and run in the vincula vasculosa. 

 It is owing to the readiness Avith which these tiny twigs are strangled by inflamma- 

 tion that slougliing of the tendon takes place so readily and irreparal^ly. The deep 

 palmar arch, formed by the radial and communicating branch of the ulnar, lies 

 about lialf an inch nearer to the wrist than the superficial. 



Fasciae and sheaths. — The two annular ligaments bind down and hold in 

 place the numerous tendons about the wrist. The anterior, when healthy, cannot 

 be detected. It is attached to the pisiform and cuneiform bones on the inner, and 

 to the scaphoid and trapezium on the outer, side. The ulnar nerve and vessels, the 

 superficialis vola?, and palmar cutaneous branches of the median and ulnar pi^iss over 



Fig. 733. — Diagram ok the Geeat Palmar Bur.sa. 



triuar portion of palmar bursa 

 Radial portion of palmar bursa 



Anterior annular ligament 



Lumbricalis 



Deep transverse 

 ligament 



Superficial transverse ligament 



it. The ulnar artery and nerve are especially ])r()teeted l)y their position between the 

 pisiform and hook of the unciform, and also l)y a process of the flexor carpi ulnaris, 

 which passes between the two bones, thus forming a kind of tunnel. The flexor 

 carpi radialis passes through a separate sheath formed by the ligaments and the 

 groove in the trapezium ; while beneath the ligament lie the flexor tendons, the 

 median nerve, and accompanying artery. Attached to its upper border is the deep 

 fascia of the forearm, and to its lower the palmar fascia and the palmaris longus 

 tendon, while from the outer and inner parts arise some of the thenar and hypo- 

 tlienar muscles. The U])per ])or(ler of the anterior annular ligament corresponds 

 to the lower of the two lines wliich cross the wrist just above the thenar and hypo- 

 thenar eminences. The large synovial sheath, for all the flexors of the fingers, 

 reaches beneath and below the anterior ligament as far as the middle of tlie palm, 

 and al)Ove tlie wrist for an inch and a lialf or two inches (37 to 50 mm.). 



