Learn about the comparison of pelvic girdles in various vertebrates.
Comparison: Vertebrates # Bufo:
1. The pelvic girdle is a V-shaped structure formed by the partial fusion of two hip bones. Each half of the girdle is exactly identical with the other.
2. Each half consists of
(a) Illium – It is a long cylindrical bone, the anterior end of which articulates with the expanded transverse processes of the 9th vertebra and the posterior end flattens and unites with other bones of the girdle.
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(b) Ischium – It is a small piece of bone. The two ischia of both the halves unite to form the posterior part of the disc.
(c) Pubis – It is a small piece of cartilage, placed at the ventral surface of the disc between the ilium and ischium. The two pubse of both the halves fuse together.
(d) Acetabulum – It is a cavity at the junction of the ilium. Ischium and pubis, into which fits the head of the femur.
Comparison: Vertebrates # Calotes:
1. The pelvic girdle is a formed by the union of two hip bones. Each half of the girdle is exactly identical with the other.
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2. Each half consists of
(a) Ilium – It is a large compressed rod, passes upwards and backwards from the acetabulum to articulate with the sacral region of the vertebral colum.
(b) Ischium – It is a stout bone and runs downwards and backwards. It articulates with its fellow of the opposite side in the ischiatic symphysis. The symphysis form a plate of calcified cartilage and separates the two ischia at their ventral ends.
(c) Pubis – It is a slender bone, runs downward and forward from the acetabulum and meets its fellow in the middle line by public symphysis.
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(i) Epipubis – It is a small nodule of calcified cartilarge, placed between the anterior ends of the pubes.
(d) Acetabulum – It is a cavity at the junction of the ilium, ischium and pubis, into which fits the head of the femur.
Comparison: Vertebrates # Columba:
1. The pelvic girdle is formed by two separate halves, which do not meet with each other. Each half is identical with the other.
2. Each half consists of
(a) Ilium – It is a large, flat bone attached to the whole of the synsacrum. It can be divided into two almost equal halves, the pre- and post-acetabular portions. On the posterior edge of the acetabulum, the ilium is produced into a process, the antirochanter.
(b) Ischium – It is a short, stout bone, runs backward from the acetabulum. Posteriorly, the ischum is connected with the ilium but anteriorly they are separated by an ischiatic formen.
(c) Pubis – It is a slender, curved rod, runs backward from the acetabulum. It lies parallel to the ventral edge of the ischium and separated from it by a large obturator foramen.
(d) Acetabulum – It is a cavity at the junction of the ilium, ischium and pubis into which fits the head of the femur. The acetabulum is not a closed cavity but is perforated by an aperture covered by a membrane.
Comparison: Vertebrates # Cavia:
1. The pelvic girdle is formed by the union of two hip bones. Each half of the girdle or osinnominatum is identical with the other and the two meet ventrally by a pubic symphysis.
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2. Each half consists of
(a) Ilium – It is a stout large bone which runs forward and slightly upwards from the acetabulum. The distal end is broad to articulate with the flank of the scarum.
(b) Ischium – It is a short and flat bone which runs backward from the acetabulum. The posterior margin of the ischium is thickened.
(c) Pubis – It is a slender bone which extends downward and backward from the acetabulum. Ventrally, it joins with its fellow of the opposite side to from the pubic symphysis.
The ischium and the pubis enclose a large foramen, the obturator foramen.
(d) Acetbulum – It is a cavity at the junction of the ilium, ischium and pubis into which fits the head of the femur.
