Important viva questions of bony pelvis

 

Bony pelvis

Anatomical points

1.      Anterior superior iliac spine and upper part of pubic symphysis lie in the same coronal  plane

2.      Pubis symphysis lies horizontally

3.      The tip of the coccyx and upper part of pubic symphysis lie in same horizontal plane

|Formation of pelvis : two hip bones, sacrum and coccyx

Joint of pelvis :

Pubic symphysis : secondary cartilaginous joint

Sacroiliac joint : plane variety of synovial joint

Divisions of pelvis : greater(false pelvis )  and lesser pelvis (true )

Why greater pelvis is known as false pelvis: it has no body boundary in front

Why lesser pelvis is known as true pelvis: it has complete body boundary

Q. Trace the pelvic inlet and outlet

Q. Content of pelvis in male and female

Q: How pelvic outlet is covered in living body ?

In front by urogenital diaphragm and behind pelvic diaphragm

Q: What is urogenital diaphragm :

 It is formed by deep transverse perinea muscle and sphincter urethrae muscle

Q: What is pelvic diaphragm

It is formed by levator ani and coccygeus muscle

Show the Diameters of pelvis :

Pelvic inlet

	Antero-posterior diameter	Transverse diameter:	Oblique diameter:
Pelvic inlet	Measured between sacral promontory and symphysis pubis Upper border of pubic symphysis:  True or Anatomical conjugate Middle of pubic symphysis:  Obstetric conjugate (most important) Lower border of pubic symphysis: Diagonal conjugate	Maximum transverse diameter	Measured between the sacro-iliac (SI) joint and opposite ilio-pubic eminence
Pelvic cavity	Middle of S3 vertebra to the middle of the back of pubic symphysis	Widest distance across the lateral bony wall of the pelvic cavity	From the lower end of sacroiliac joint to the center of the opposite obturator membrane
Pelvic outlet	Antero-posterior diameters: From the lower border of symphysis pubis to – Anatomical: tip of coccyx Obstetric: tip of sacrum	Transverse diameters: diameter: between 2 ischial tuberosities	From the junction of the ischiopubic ramus to the middle of the opposite sacrotuberous ligament

 

Diameter of female pelvis

	Antero-posterior diameter	Transverse diameter:	Oblique diameter:
Pelvic inlet	11 cm	13	12
Pelvic cavity	12	12	12
Pelvic outlet	13	11	12

Diameter of different conjugate of  female   :

·         True or Anatomical conjugate: 11 cm

·         Obstetric conjugate (most important): 0.5 cm shorter than the true conjugate

·         Diagonal conjugate: 11.5 cm

Shape of pelvis

1.      Gynecoid (50%) – normal female pelvis

2.      Anthropoid (25%) – direct occipito-posterior position is most common in anthropoid pelvis

3.      Android (20%) – male type (face to pubes delivery, persistent occipito-posterior position, deep transverse arrest/non-rotation, dystocia-dystrophica syndrome are most common in android pelvis)

4.      Platypelloid (5%)

Difference between male and female pelvis

 

Topic	Male	Female
Shape of pelvic inlet	Heart shape	Oval
shape of pelvic caviy	conical and long ( long section of a cone)	short and cylindrical ( short section of a cylinder)
sub pubic angle	less , 55-60 degree	More, about  90 degree
ischial spine	inverted	everted
sacrum	longer and narrower	shorter and wider
Obturator foramen	Larger and oval and abruptly curve	Smaller and triangular, gradually curved