482 



THE MUSCLES AND FASCIA 



slips or lateral vincula which join the tendon of the ring finger to the tendon of the 

 little finger and to the tendon of the middle finger are constant. If the middle 

 and little fingers are held flexed the lateral vincula greatly limit the range of exten- 

 sion possible in the ring finger. 



Relations. By its superficial surface, with the fascia of the forearm and hand, the posterior 

 annular ligament, and integument; by its deep surface, with the Supinator [brevis], the Extensor 

 muscles of the thumb and index finger, the posterior interosseous vessels and nerve, the wrist- 

 joint, carpus, metacarpus, and phalanges; by its radial border, with the Extensor carpi radialis 

 brevior; by its ulnar border, with the Extensor minimi digiti and Extensor carpi ulnaris. 



FLEXOR CARPI 



ULNARIS 



FLEXOR SUBLIMI3 

 DIGITORUM 



EXTENSOR LONGUS POLLICI8- 



Origin nf ( EXTENSOR CARPI ULNARIS| 

 aponeurosis-!. FLEXOR CARPI ULNARIS r~ 

 common to: (.FLEXOR PROF. DIGITORUM) 



SUPINATOR [BREVIS] 



EXTENSOR OS8I8 

 METACARPI POLLICIS 

 PRONATOH TERE8 



EXTENSOR BREVIS 



POLLICIS 



EXTENSOR INDICI 



EXTENSOR COMMUNIS DIGITORUM 

 AND EXTENSOR MINIMI DIGITI 



EXTENSOR CARPI ULNARI 



EXTENSOR OSSIS 

 ETACARPI POLLICIS 

 EXTENSOR CARPI 

 RADIALIS LONQIOR 



EXTENSOR CARPI 



RADIALIS BREVIOR 



EXTENSOR BREVIS 



POLLICIS 



EXTENSOR LONGUS 

 POLLICIS 



EXTENSOR COMMUNIS 



DIGITORUM AND 

 EXTENSOR INDICIS 



EXTENSOR COMMUNIS 

 DIGITORUM 



FIG. 360. Diagram showing attachments of muscles of forearm and hand. Posterior aspect. Origins, red; 

 insertions, blue. The origins and insertions of the Dorsal interossei muscles are omitted. (See Fig. 150.) 



The Extensor minimi digiti (m. extensor digiti quinti proprius) is a slender 

 muscle placed on the inner side of the Extensor communis, with which it is gen- 

 erally connected. It arises from the common Extensor tendon by a thin, tendin- 

 ous slip, and from the intermuscular septa between it and the adjacent muscles. 

 Its tendon runs through a separate compartment in the annular ligament behind 

 the inferior radioulnar joint, then divides into two as it crosses the hand, the 

 outermost division being joined by the slip from the innermost tendon of the 

 common Extensor. The two slips thus formed spread into a broad aponeurosis, 

 which, after receiving a slip from the Abductor minimi digiti, is inserted into the 

 second and third phalanges of the little finger. The tendon is situated on the 

 ulnar side of, and is somewhat more superficial than, the common Extensor. 



