Question

Identify the vertebrochondral ribs from the following?
A. all 12 pairs of ribs
B. ${1^{st}}$ to ${7^{th}}$ pair of ribs
C. ${8^{th}}$, ${9^{th}}$ and ${10^{th}}$ pairs of ribs
D. ${11^{th}}$ and ${12^{th}}$ pairs of ribs

Answer 1

There are 12 pairs of ribs present in humans. By means with which they are attached to the sternum and vertebral column also. The 12 Ribs are basically classified into three types.

Complete answer:
Each Rib is a thin flat bone connected dorsally to the vertebral column and Ventrally with the sternum. Hence they are called bicephalic.
-First 7 pairs of ribs are attached dorsally to the thoracic vertebrae and ventrally to the sternum with the help of hyaline cartilage. So they are called True ribs or vertebro sternal ribs.
-Another ${8^{th}}$, ${9^{th}}$, ${10^{th}}$ pairs of ribs do not articulate directly with the Sternum but join the ${7^{th}}$ rib with the help of hyaline cartilage. These are called false ribs are vertebro- chondral ribs.
-Last 2 pairs i.e ${11^{th}}$ and ${12^{th}}$ of ribs are not connected ventrally and therefore, called floating ribs. It also undergoes the false ribs.

Hence, the correct answer is option (C).

Additional information:
There are three parts of sternum,
i- Prosternum(manubrium),
ii- Mesosternum and
iii- Metasternum (xiphoid process).
Clavicle and last pair of ribs are attached with manubrium. The ${2^{nd}}$ to ${7^{th}}$ pair of ribs are attached with a mesosternum.
The xiphoid process is the smallest part, the lower half of ${7^{th}}$ costal cartilage articulate.
The sternum is a favoured site for obtaining samples of hematopoietic tissue during diagnosis of suspected blood diseases.

Note: Thoracic vertebrae, ribs and sternum together form the rib cage. The manubrium is called the body of the sternum. Sternum is a flat bone on the ventral midline of thorax. And all these pairs constitute a rib cage.