Question

The vertebral formula for human beings is
(a) $C_5{T}_{12}{L}_7{S}_5{C}_{3-5}=33-35$
(b) $C_7{T}_{12}{L}_5{S}_5{C}_4=33$
(c) $C_5{T}_{10}{L}_5{S}_5{C}_3=33$
(d) $C_7{T}_{10}{L}_5{S}_5{C}_{3-5}=33$

Answer 1

Hint: The spinal column, also referred to as the backbone or spine, is a component of the skeletal structure. The vertebral column is the defining characteristic of a vertebrate during which the notochord (a flexible rod of uniform composition) found altogether chordates has been replaced by a segmented series of bone.

Complete answer:
In a human's vertebral column, there are normally thirty- three vertebrae, the upper twenty- four are articulating and separated from each other by intervertebral discs, and thus the lower nine are fused in adults, five within the sacrum and 4 within the coccyx, or tailbone. The articulating vertebrae are named consistent with their region of the spine. There are seven cervical vertebrae, twelve thoracic vertebrae, and five lumbar vertebrae.
Individual vertebrae are named consistent with their region and position. From top to bottom, the vertebrae are:
- Cervical spine: 7 vertebrae ($C_1-C_7$)
- Thoracic spine: 12 vertebrae ($T_1-T_{12}$)
- Lumbar spine: 5 vertebrae ($L_1-L_5$)
- Sacrum: 5 (fused) vertebrae ($S_1-S_5$)
- Coccyx: 4 (3–5) (fused) vertebrae (Tailbone)

So, the correct answer is ‘$C_7{T}_{12}{L}_5{S}_5{C}_4=33$’.

Note: The spinal cord is part of the central nervous system that supplies nerves and receives information from the peripheral nervous system within the body. There are about 50,000 species of animals that have a spinal column. The human spinal column is one of the most- studied examples.