Question

Human skeleton altogether contains $213$ bones. Which of these are the $6$ bones?
(A) Neck vertebrae
(B) Ear ossicles
(C) Carpals
(D) Metacarpals

Answer 1

Hint: Try remembering the chapter skeletal system from Class eleventh. Now recall, option wise separately that how many bones/vertebrae are there in the neck and number of facial bones, both are the part of Axial Skeleton. Now for Carpals and Metacarpals recall the appendicular skeleton. Also remember that we have symmetry in the body. So, total bones in both hands are given as:
$\text{Total bones} = 2 \times \text{total number of bones in one hand}$

Complete answer:
Option A (Neck vertebrae): Also called the cervical spine is the most superior portion of the vertebral column, lying between the cranium and the thoracic vertebrae. It consists of seven distinct vertebrae \[\left( C1,\text{ }C2,\text{ }C3,\text{ }C4,\text{ }C5,\text{ }C6,\text{ }\!\!\And\!\!\text{ }C7 \right),\] two of which are given unique names: The first cervical vertebrae $(C1)$ is known as atlas and the second cervical vertebrae $(C2)$ is known as axis.
So option A is not correct.
Option B (Ear Ossicles): As our body is symmetrical, certain body parts are twice in number. For example: eyes, ears, hands, legs etc. The bones in the middle ear are the auditory ossicles- the malleus, incus and stapes. There are three bones in one ear so, total number of bones in both ear will be:
$\Rightarrow 2\times 3=6\text{ }bones$
So option B is correct.
Option C (Carpals): Part of Appendicular skeleton. On one hand, the carpal bones are a group of eight, irregularly shaped bones. They are organized in two rows: proximal and distal. Total metacarpals in both hands will be equal to $16$.
So option C is not correct.
Option D (Metacarpals): They are the part of the appendicular skeleton too. On one hand, there are five metacarpals each related to a digit. A total of $10$ metacarpals we have in our body.
So option D is not correct.

Therefore, Option B is correct.

Note:
There are typically around $270$ bones in human infants, which fuse to become $206$ to $213$ bones in the human adult. The reason for the variability in the number of bones is that some humans may have a varying number of ribs, vertebrae and digits. This consists of both the natural occurrences as well as deformities.