Question

In man the axial skeleton is made up of
A. 80 bones
B. 100 bones
C. 103 bones
D. 106 bones

Answer 1

Hint: Axial skeleton comprises the bones that lies along the central axis of human body.
It is constituted by skull bones, ribs, vertebral column, etc.

Complete answer:
Skull is made up of two sets of bones: Cranial & Facial, constituting a total of 22 bones.
Out of 22 skull bones, 8 are cranial bones while 14 are facial bones.
> CRANIAL BONES (8): Constitutes Frontal bone (1), Parietal bones(2), temporal bones(2), Occipital bone(1), Ethmoid bone(1) and Sphenoid bone(1).

> FACIAL BONES (14): Facial bones are constituted by Maxilla (2), Palatine (2), Zygomatic (2) Nasal (2), Lacrymal (2), Inferior Turbinals (2), Mandible (1) and Vomer (1).

> There is one Sternum lateral to which ribs are arranged.

> 12 pairs of ribs are present in the human body. Out of these 12 pairs, 7 pairs are true ribs i.e. they are attached to the sternum on the ventral side as well as attached to vertebrae on the dorsal side. The 8th, 9th and 10th pair of ribs are called false ribs as they are merged into one another and then attached to the sternum as a single rib. The 11th & 12th pair of ribs is called floating rib as it is only connected to vertebrae on its dorsal side, there is no attaching surface on ventral side for these ribs.

> Vertebral column: Formed by 26 linearly attached units called vertebrae, lying dorsally to the body. They are classified as follows:
- Cervical: 7
- Thoracic: 12
- Lumbar: 5
- Sacral: 5 (Fused into 1)
- Lumbar: 4 (Fused into 1)

> Associated skull bones: 7
Hyoid bone: 1 (Only bone that do not attach to any other bone)
Ear ossicles: 2*3 (Malleus, Incus, Stapes)

Thus, the correct option is (A) 80 bones.

Note:
 Bones in the body that are formed by ossification of tendons are called sesamoid bones.
Longest and strongest bone of the human body is femur.
Smallest bone of the human body is stapes.
Rabbit - axial skeleton 132 bones, appendicular skeleton 128 bones.