Question

What is the difference between a true rib and floating rib?

Answer 1

Our body is made up of two types of skeletal system . One is an exoskeleton and the other one is endoskeletal. Exoskeleton is an external rigid ,supportive covering present outside the body. Endoskeleton is present inside the body. It consists of bones (axial and appendicular skeleton).

Complete answer:
The thoracic cage or rib cage protects the vital organs like heart and lungs within the thorax. It consists of the thoracic vertebrae, the ribs and the sternum. There are 12 pairs of ribs. These are thin flat bones connected dorsally to the vertebral column and ventrally to the sternum. The sternum or breastbone is a flat bone. It is located on the ventral midline of thorax. Being sword-shaped it has three parts: the manubrium (handle), body or gladiolus (blade) and the xiphoid process (tip). Clavicles or collar (digit bones articulate with the manubrium of the sternum.
The sternum is a favoured site for obtaining samples of hematopoietic (blood forming) tissue during diagnosis of suspected blood diseases.
Ribs are of three types:
i) True ribs (Vertebrosternal ribs)
ii) False ribs (Vertebrochondral ribs)
iii) Floating ribs (Vertebral ribs)

True Ribs	Floating ribs
The first seven pairs of ribs are called true ribs.	The 11th and 12th pair of ribs are called floating ribs because one end of the rib is attached to the vertebral column and the other end is free.
They are dorsally attached to the thoracic vertebrae and are ventrally connected to the sternum with help of hyaline cartilage.	They are only attached on one side to the vertebral column, the other end is free.
They protect the lungs.	These ribs play an important role in protecting the kidneys.

Additional information:
False ribs : The three pairs of ribs i.e., 8th, 9th and 10th pair do not directly articulate with the sternum rather it joins the 7th pair of ribs and hence are called false ribs because ribs generally articulate with both thoracic vertebrae and sternum but these ribs do not articulate with the sternum directly.

Note:
i) With every breath we take our Rib cage expands by 3 to 5cm.
ii) The rib cage being an endoskeleton protects our heart and lungs.
iii) Ribs if damaged can take longer time to heal.
iv) They are very significant as they protect the lungs and heart from any sort of shock or damage.