Obstetrics and Gynecology - A.M. Gromova 2000

Anomalies of the Bony Pelvis
Anatomically Contracted Pelvis
Classification of Contracted Pelvises

Classification of the contracted pelvis by the type of narrowing:

A. Relatively common forms.

1. Justifyingly contracted (generally evenly contracted) pelvis.

2. Transversely contracted pelvis.

3. Flat pelvis:

a) simple flat pelvis;

b) rachitic flat pelvis.

4. Generally contracted flat pelvis.

B. Rare forms:

1. Obliquely displaced and obliquely contracted pelvis.

2. Assimilation pelvis.

3. Funnel-shaped pelvis.

4. Kyphotic pelvis and other miscellaneous forms.

5. Spondylolisthetic pelvis.

6. Osteomalacic pelvis.

7. Pelvis contracted by exostoses and Bone tumors.

T. K. Stepankovska and B. M. Ventskivsky (1994) provide a slightly different classification of the Anatomically Contracted Pelvis by the type of narrowing:

A. Relatively common forms of the contracted pelvis:

1. Transversely contracted pelvis.

2. Flat pelvis:

a) simple flat pelvis;

b) rachitic flat pelvis;

c) pelvis with reduced dimensions of the broad part of its cavity.

3. Generally evenly contracted pelvis.

B. Rare forms:

1. Obliquely displaced and obliquely contracted pelvis.

2. Pelvis contracted due to exostoses, bone tumors, or pelvic fractures with displacement.

3. Other forms of contracted pelvis.

Based on structural features According to the international classification, the following types are distinguished:

1. Gynecoid (normal female) pelvis.

2. Android (male-type) pelvis.

3. Anthropoid pelvis (characteristic of mammals) with an increased anteroposterior diameter exceeding the transverse diameter.

4. Platypelloid (flat) pelvis with a reduced anteroposterior diameter and normal or even increased transverse diameters.

In addition to these four main types, 14 variants of mixed pelvic forms are distinguished, representing various combinations of elements from the "pure" types.

Classification of the contracted pelvis according to the degree of narrowing of the anteroposterior diameter of the pelvic inlet:

Grade I - true conjugate 9-11 cm

Grade II - true conjugate 7.5-9 cm

Grade III - true conjugate 6.5-7.5 cm

Grade IV - true conjugate less than 6.5 cm

The true conjugate is indeed the primary pelvic dimension. However, it should be kept in mind that classification based on the degree of its narrowing is only of orientational value, as there are forms of contracted pelvis that are significantly narrowed in the transverse direction, with a normal or even increased true conjugate. It is also possible to have a narrowing of the anteroposterior diameter of the pelvic inlet while maintaining normal anteroposterior dimensions of the lower pelvic planes.

Class="center">Dimensions of Various Forms of anatomically contracted pelvis