A study of the abnormalities and variations of the sacrum was made on 400 gross sacral specimens and 800 X-ray films.It consisted of segments,spina bifida occulta,flotting spinous process....etc. The composition of sacrum varied a great deal,the segments ranged from 4 to 9.In the series of gross specimens,with normal 5 segments:285 cases(71.2%); Co became incorporated in sacrum:62 cases(15.5%);sacralisation of L_5:22 cases (5.5%);lumbarisation of S_1:13 cases(3.3%);others:18 cases(4.5%);spina bifida occulta located in S_1 and S_2:115 cases(28.7%);sacral canal entirely opened:12 cases(3%).While in X-ray film series,with normal 5 segments;640 cases(80%); Co became incorporated in sacrum:70 cases(8.75%);sacralisation of L_5:67 cases (8.37%);lumbarisation of S_1:7 cases(0.87%);spina bifida occulta located in S_1 and S_2:153 cases(19.1%);sacral canal entirely opened:41 cases(5.1%);flot- ting spinous process:86 cases(10.7%). The size of sacral biatus was measured,the mean width of the base being 18.22mm,the average length between the apex and the base 26.7 mm,the A-P diameter of the canal at the level of apex 5.45mm.The apex was most common- ly located at the level of S_4 or S_5. Examination of articular surface of upper articular process showed that they inclined obliquely in most cases,but could also be coronal or sagittal.Both arti- cular surfaces were symmetrical in 65%,asymmetrical in 21.7%,markedly asym- metrical in 13.3%. The articular surface was extending from upper 2-3(1/2)segments,they were found symmetrical in 86.7%, asymmetrical in 13.3%. In the gross specimens,the curve of the sacrum was also studied,straight. superiorly and flexed inferiorly:17.2%,gently flexed:54%,markedly flexed:11.8%, flat and straight:11%,hyperextended superiorly and flexed inferiorly:6%.In the X-ray film series,“horizontal sacrum”was found in 4.5%. The spinous process of the sacrum remained rudimentary,leaving only the tubercle.Its number was studied. 2 cases with marked anomaly were reported.One girl aged 1,with rudi- mentary sacrum,only 2 segments,the coccyx wanting,L_2-L_5 sacralized.A boy aged 6,had V-shaped defect in the sacrum.Both cases presented remarkable clinical disturbances. The clinical significance relating the abnormalities and variations of the sacrum was briefly discussed.

160 cases of x-ray films of male foot have been studied with a view to examine thesupernumerary foot bone, the number of sesamoid bone beneath the head of metatarsus,the correlation of certain foot bone and the cortical thickness of metatarsus. The supernumerary bone in the foot is quite large in number (35%), among which theaccessory scaphoid (14.4%), the accessory fibula (8.75%), the intermetatarsal bone (4.37%)and the os trigonum (2.5%) are most frequently found. Their number, position, shapeand dimensions are quite different. The sesamoid bone beneath the metatarsal head may be absent: occasionally it maybe fissured into two pieces. In one case, its maximum number reaches as many as eight. The study of the correlation of certain foot bone shows: (1) The mean value of the intermetatarsal angle between Ⅰ and Ⅱ metatarsus isa approximately 10?(min. 3--4, max. 15?), left side 9.14?+2.4?, right side 9.75??2.34?. (2) The mean value of the intermetatarso-digital angle of hallux is approximately18--19, (min. 8--9?, max. 30?), left side 19.35??15.4?, right side 18.71??4.9?. (3) The mean value of the Bohler's angle is apporximately 30?, (min. 12?, max.65?), left side 32.03?+12.9?, right side 37.21??11.75?. (4) The mean value of the breadth of protruding scaphoid tuberosity is 0.6 cm,(min. 0.1 cm, max. 1.3 cm.). (5) The head of the first metatarsus is frequently lying proximal to the second.Their distance varies from 0.9 cm. to+0.5 cm. The cortex of the second metatarsus in the thickest, its medial side is thicker thanthe lateral side. The thickness of Ⅰ, Ⅲ, Ⅳ and Ⅴ metatarsus decreases in order. The above mentioned findings are discussed anatomically.