Bony Pelvis

Bony pelvis or bones of hip consist of sacrum, 1st three coccygeal vertebrae and two Os-coxae. Each formed by the ilium, ischium and pubis

Sacrum
S. No.MareCow
1It consist of 5 sacral segments, base and apex.It consist of 5 sacral segments.
2It is shorter than the cow.It is longer than the mare.
3It is triangular in shape.It is roughly triangular in shape.
4Dorsal surface presents 5 sacral spines which have tuberous summits and 4 pairs of dorsal sacral foramina.Dorsal surface presents spines fuse to form median sacral crest. Articular processes fuse to form lateral sacral crest and 4 pairs of dorsal sacral foramina.
5Ventral surface lodges 4 transverse lines.Ventral surface presents 4 transverse groove and 4 pairs of foramina.
6Pelvic surface presents transverse lines.pelvic surface is concave in both directions and presents groove for middle sacral artery.
7Smooth notches are present on either side of the body of 1st sacral segment.No notches on either side of the body of 1st sacral segment.
8Articular surface directed dorso-laterally which is slightly concave in its length. It is rough, irregular and articulates with ilium. Portion lateral to the foramina is formed by the fusion of the transverse processes.Articular surfaces are concave and semicylindrical in curvature medially and process are large and widely separated.
9Alae are the lateral part of the base (wing). Ventral margin of the base projects & form sacral promontory.
Sacrum of Mare vs Cow
S. No.BuffaloSheep
1I consist of 5 sacral segments.It consist of 4 sacral segments.
2No vascular groove on the ventral aspect.No vascular groove on the ventral aspect.
3Spines are fused.Spines are not fused except 1st and 2nd which may be partially united.
4Sacral promontory flattened dorso-ventrally more than the cow.Sacral promontory is not much flattened dorso-ventrally.
54th and 5th sacral vertebrae are not fused but laterally attached.The last segment may remain separate or undergo partial fusion.
6Transverse processes of last segment are not distinct.Transverse processes of last segment are distinct and outstanding.
Sacrum of Buffalo vs Sheep
S. No.SowBitch
1It consist of 4 sacral segments.It consist of 3 sacral segments.
2Pelvic surface is less curved as compared to cow.It is short, wide and quadrangular in shape.
3Fusion of vertebrae is less complete.Fusion of vertebrae is complete.
4Spines are less developed & commonly absent.Spines are fused to form median crest which is notched. On either side 2 tubercles are the vestiges of the fused articular processes.
5Middle of the dorsal surface is flattened, smooth and presents opening.Pelvic surface is deeply concave and has two pairs of foramina.
6Anterior processes are very large.Anterior processes are large and have extensive, slightly concave facets. Wings are prismatic and bear laterally, auricular surface on its lower part.
7Transverse lines are distinctSacral canal is compressed dorso-ventrally
8Transverse processes of last vertebrae project backward.
Sacrum of Sow vs Bitch
Coccygeal vertebrae 
S. No.MareCow
1These (Cy) are 15 to 21 (18) in number.These (Cy) are 18 to 20 in number.
2Spinous processes are short and have double summit.
31st vertebra presents groove on postero-medial aspect of the body.It is longer and better developed than horse.
4Ventral surface has a groove for coccygeal artery.Ventrally, median sacral groove for median coccygeal artery.
5These are ill developed.First 5 to 6 vertebrae have complete arches and spinous processes.
6Bodies of first 3 vertebrae are flattened dorso-ventrally and constricted in the middle.In anterior part of series, anterior articulating processes do not articulate and ventral spines form a groove for middle coccygeal artery.
Coccygeal vertebrae of Mare vs Cow
S. No.SheepSow
1These (Cy) are 16 to 18 (3 – 24) in number.These (Cy) are 20 to 23 in number.
2Transverse processes are long and thin.First 3 or 4 vertebrae are specially characterized by the presence of functional articular processes.
3No haemal processes on the ventral surface of the body.
Coccygeal vertebrae of Sheep vs Sow
Diameters of Pelvic inlet
  1. Sacro-pubic (Conjugate) diameter :- It is measured from sacral promontory to the anterior margin of pubis symphysis.
  2. Transverse (Bis-iliac) diameter :- Measured at its greatest width just above psoas tubercle.
    • Superior bis-iliac diameter :- It is measured at upper 3rd of pelvic inlet and receives greatest width of the fetus at shoulder in anterior presentation and hip in the posterior presentation.
    • Inferior bis-iliac :- It is measured at the lower 4th of pelvic inlet at elbow of fetus in anterior presentation and stifle in posterior presentation.
  3. Vertical diameter of inlet :- It is measured between anterior end of symphysis pubis and articulation of sacral 3rd and 4th vertebra.
  4. Oblique / sacro-iliac / ilio-sacral diameter of inlet :- It is measured from sacro-iliac joint of one side through the center of pelvic cavity to the psoas tubercle of opposite side. It is intermediate between sacro-pubic and superior bis-iliac diameter.
Diameter of Pelvic outlet
  • Superio-inferior (Vertical) diameter :- It is measured between the summit of ischial arch and articular of coccygeal 1st and 2nd vertebrae.
  • Transverse diameter :- It is measured between two ischiatic spines (Chauveau).
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