26 



THE MUSCLES OF THE UPPER LIMB. 



From this tendon there arise, 1, a fleshy slip to join the ring- finger tendon. 2. a belly which 

 terminates in the index finger tendon, and 3, a small belly furnishing the little finger 

 tendon. Of the four tendons, that to the middle finger is the largest, and that to the little 

 finger much the smallest. A slender fasciculus usually passes from the outer part of 

 the condylo-ulnar head of the muscle to the beginning of the tendon, of the flexor longu* 

 pollicis. 



Relations. In the forearm the flexor sublimis is for the most part concealed by the 

 pronator teres, flexor carpi radialis and palmaris longus ; but between the last muscle and 

 the flexor carpi ulnaris a narrow strip is superficial from the internal condyle down to the 



Fig. 236. DEEP ANTERIOR MUSCLES OF THE FOREARM. 

 (Allen Thomson. ) i 



The superficial muscles of the forearm and hand, together with 

 the lumbricales, have been removed, and the place of the anterior 

 annular ligament of the carpus is marked by two dotted lines, 

 a, surface of the humerus above the coronoid fossa ; b, coronoid 

 process of the ulna ; c, head of the radius covered by the orbicular 

 ligament ; + , internal lateral ligament of the elbow-joint ; d, 

 lower end of the radius ; e, that of the ulna ; /, scaphoid and 

 trapezium bones ; 1, supinator brevis ; 2, flexor longus pollicis : 

 3, flexor profundus digitorurp ; 3', its tendons, where they are 

 about to pass under the annular ligament ; 4, pronator quadratu* 

 on the lower part of the radius ; 5, adductor obliquus, and 6, 

 adductor transversus pollicis ; 7, first dorsal interosseous muscle ; 

 8, in the second space, is placed between the first palmar and 

 the second dorsal interosseous muscles ; in the third space, between 

 the third dorsal and the second palmar ; in the fourth space, 

 between the fourth dorsal and the third palmar. (For the lum- 

 bricales, see figs. 237 and 242. ) 



annular ligament. Its radial origin is crossed by the radial 

 vessels. It rests on the flexor longus pollicis and flexor pro- 

 fundus digitorum, the median nerve, which passes between 

 the two heads, and the ulnar vessels. In the palm of the 

 hand, its tendons are covered by the palmar fascia, the super- 

 ficial palmar arterial arch, and the branches of the median 

 nerve ; and they lie in front of the accompanying tendons of 

 the flexor profundus. 



Varieties. Absence of the radial head has been observed. 

 In some cases the slip from the deep part of the muscle 

 forms the chief part of the ring finger division : or there 

 may be also a slip from the deep part to the middle finger 

 tendon. An accessory slip is sometimes present, passing- 

 from the tuberosity of the ulna to the index and middle 

 finger portions. The little finger portion of the muscle is 

 occasionally absent, and has been seen replaced by a slip 

 arising from the ulna, or from the annular ligament and 

 palmar fascia, or by a slip from the flexor profundus, or by 

 the fourth lumbrical muscle. A slip is frequently given 

 from the inner head of the muscle to the flexor profundus. 



The DEEP-SEATED MUSCLES of the front of the 

 forearm are the flexor profundus digitorum. flexor 

 longus pollicis, and pronator quadratus. 



The flexor profuudus digitorum or flexor perforans, a large and thick 

 muscle, arises from the inner and anterior surfaces of the ulna for three-fourths of 

 its length, from the ulnar half of the interosseous membrane for the same distance, 

 and from the aponeurosis attaching the flexor carpi ulnaris to the ulna. It divides 

 inferiorly into four tendons, only one of which, that for the index finger, is distinct 

 from the others above the wrist the rest being connected together as far as the 

 palm. In the palm the tendons, as they diverge, give origin to the lumbricales 

 muscles. In front of the fingers they are bound to the first and second phalanges. 

 by the sheath common to them and the perforated tendons. Opposite the first 



