114 



OS 1NNOMINATUM ILIUM. 



row of phalanges ; the second row, with the first and third ; and the third, 

 with the second row. 



Attachment of Muscles. To the base of the first phalanx of the thumb 

 four muscles, abductor pollicis, flexor brevis pollicis, adductor pollicis, 

 and extensor primi internodii ; and to the second phalanx, two, the flexor 

 longus pollicis, and extensor secundi internodii. To the first phalanx of 

 the second, third, and fourth fingers, one dorsal and one palmar interos- 

 seous, and to the first phalanx of the little finger, the abductor minimi 

 digiti, flexor brevis minimi digiti, and one palmar interosseous. To the 

 second phalanges, the flexor sublimis and extensor communis digitorum ; 

 and to the last phalanges, the flexor profundus and extensor communis 

 digitorum. 



PELVIS AND LOWER EXTREMITY. 



The bones of the pelvis are the two ossa innominata, the sacrum, and 

 the coccyx ; and of the lower extremity, the femur, patella, tibia and 

 fibula, tarsus, metatarsus, and phalanges. 



Fig- 55.* Os INNOMINATUM. The os inno- 



minatum (os coxae) is an irregular 

 flat bone, consisting in the young 

 subject of three parts, which meet at 

 the acetabulum. Hence it is usually 

 described in the adult as divisible 

 into three portions, ilium, ischium, 

 and pubes. The ilium is the supe- 

 rior, broad, and expanded portion 

 which forms the prominence of the 

 hip, and articulates with the sacrum. 

 The ischium is the inferior and strong 

 part of the bone on which we sit. 

 The 05 pubis is that portion which 

 forms the front of the pelvis, and 

 gives support to the external organs 

 of generation. 



The JLIU^I may be described as 

 divisible into an internal and external 

 surface, a crest, and an anterior and posterior border. 



The internal surface is bounded above by the crest, below by a promi- 

 nent line, the linea ilio-pectinea, and before and behind by the anterior 

 and posterior borders ; it is concave and smooth for the anterior two-thirds 

 of its extent, and lodges the iliacus muscle. The posterior third is rough, 

 for articulation with the sacrum, and is divided by a deep groove into two 

 parts , an anterio* or auricular portion, which is shaped like the pinna, 



*The os innominatum of the right side. 1. The ilium; its external surface. 2. The 

 ischium. 3. The os pubis. 4. The crest of the ilium. 5. The superior curved line. 

 G. The inferior curved line. 7. The surface for the gluteus maxim us. 8. The anterior 

 superior spinous process. 9. The anterior inferior spinous process. 10. The posterior 

 superior spinous process. 11. The posterior inferior spinous process. 12. The spine 

 yf the ischium. 13. The great sacro-ischiatic notch. 14. The lesser sacro-ischiatic 

 notch. 15. The tuberosity of the ischium, showing its three facets. 16. The ram us of 

 he ischium. 17. The body of the os pubis. 18. The ramus of the pubis. 19. The 

 acotabulum. 20. The foramen thyroideum. 



