What three bones fuse during childhood to form the coxal bone?
ischium, coccyx, ilium
sacrum, ilium, coccy x
pubis, sacrum, ischium
ilium, ischium, pubis
The Correct Answer and Explanation is :
The correct answer is:
ilium, ischium, pubis
Explanation
The coxal bone, also known as the hip bone or pelvic bone, is formed by the fusion of three bones: the ilium, ischium, and pubis. This process begins in early childhood and is typically complete by the end of adolescence, around 20–25 years of age. Here’s a detailed explanation of each component and their fusion:
- Ilium:
- The ilium is the broad, fan-shaped part of the coxal bone and the largest of the three components. It forms the superior portion of the pelvis and provides attachment points for muscles that move the hip and stabilize the trunk.
- The ilium articulates with the sacrum at the sacroiliac joint, forming the posterior part of the pelvic girdle.
- Ischium:
- The ischium forms the lower and back portion of the coxal bone. It features a prominent structure called the ischial tuberosity, which supports the body’s weight when sitting.
- The ischium contributes to the obturator foramen and acetabulum, which are vital for the structure and function of the pelvis and hip joint.
- Pubis:
- The pubis forms the anterior portion of the coxal bone and contributes to the structure of the pelvic cavity. The two pubic bones meet at the pubic symphysis, a cartilaginous joint that allows slight movement and flexibility during activities such as walking or childbirth.
Fusion Process
During childhood, the ilium, ischium, and pubis are separated by cartilage. Around puberty, these bones begin to fuse at a structure called the triradiate cartilage, located in the acetabulum, the socket for the head of the femur. The fusion creates a single, solid bone that supports the body’s weight, provides attachment for muscles, and facilitates movement of the lower limbs.