Question

The diagram below shows two fused bones of a mammal.

1. Identify the fused bones. 
2. Name:
   • The bone that articulates at the point labelled A. 
   • The structure labelled B.
3. State the type of joint formed at structure B.
4. Name: the structure labelled C
5. State two functions of the structure named in 4 above 
6. Name the structure labelled D
7. State what happens to the structure during childbirth.

Answer 1

1. Pelvic girdle/Pubic bones/ innominate bones;
2.    
   • Sacral vertebra/Sacrum;
   • Acetabulum
3. Ball and socket joint;
4. Obturator foramen
5.  
   • Its an aperture through which blood vessels nerves and muscles pass;
   • Reduce the weight of the pelvic girdle;
6. Pubis symphysis;
7. It relaxes thus expanding the size of pelvic cavity;