THE LIGAMENTS. HI 



os metacarp. /., a synovial capsule 

 to itself, behind, assisted by m. ex- 

 tens, poll., outside, by m. abduct, 

 long., inside, m. interossti and art. 



m. extens. ulna protects it, and 

 unites with os unciforme. Its sy- 

 novial capsule belongs equally to 

 the os metacarp. IV. 



rad. ; has close to it anteriorly m. 

 pollic. minores. 



NOTE. Giinther (d. Handgelenk, &c.) enumerates ninety ligaments in the 

 articulations of the hand. 



Movements: of os melacarpi I.: 1. Flexion, obliquely in- 

 wards and forwards, approximates the thumb to the fifth os mela- 

 carpi (oppositio), and may cause luxation backwards. 



2. Extension, goes so far, that upon the outer side almost a 

 right angle is formed between os. metacarp. I. and the radius ; 

 luxation is prevented by the dense posterior portion of the capsu- 

 lar ligament. 



3. Abduction, the thumb is removed directly outwards from 

 os. metacarp. II. : it may give rise to luxation inwards. 



4. Adduction is limited by os metacarp. II. 



127. IX. The heads of the Metacarpal Bones, 



of the second to the fifth are united together by Kg. transversum, 

 (volare,) which passes from one to another like a bridge, lying 

 below the tendinous sheaths of the m. flexor digit., and serving 

 for the attachment of the m. lumbricales. The central portions 

 of the ossa metacarp. are maintained in their situation by ligg. 

 interossea. 



128. X. Connections of the Fingers. 



A. With the metacarpal bones. Free, ball and socket articu- 

 lation ; that of the thumb, Ginglymus. Articular surfaces : on 

 the metacarpus even, like a head, oval from behind, forwards. 

 On the first phalanx smooth fossa, oval transversely. 



Ligaments: 1. Lig. anteriits s. transversum, very strong and dense on the 

 palmar surfaces of the second to the fifth fingers, filling up the articular cavity; 

 connected with the tendinous sheaths of the mm.flexores y above very loose on 

 the Cottum capituli oss. metacarpi. 



2. Ligg. lateralia, very strong, passing obliquely from behind forwards, and 

 from above downwards, from tubercul. oss. metacarpi to the lig. anterius of either 

 side. On the dorsal surface the tendinous sheath of the m. extensor, takes the 

 place of ligament. [There is, however, a thin delicate capsule.] In the lig. 

 anterius oss. metacarp. I. are placed two ossa sesamoidea. 



Movements: 1. Flexion the most marked, especially in the 

 first, fourth, and fifth joint. The finger can describe a right angle 

 with the centre of the hand. Flexion is limited by the posterior 

 fibres of the Kg. lateralia. 



