[Biology Class Notes] on Vertebral Column Pdf for Exam

Vertebrae in Human Body: The axial skeleton comprises the vertebral column, often regarded as the backbone skeleton or spine. The notochord (an elastic rod of similar thickness present in all chordates) has been substituted by either a segmented set of bone: vertebrae in human body divided by intervertebral discs.

The spinal canal (backbone skeleton), a cavity that encircles and protects the spinal cord, is housed within the vertebral column. A vertebral column is found in about 50,000 animal species. Of the most well-studied examples is the human vertebral column.

Vertebral Column Function

Vertebral column function: The spinal cord passes inside the spinal canal, which is created by a central hole inside each vertebra, that is surrounded by the vertebral column. The central nervous system, which generates nerves and collects input from the peripheral nervous system, includes the spinal cord.

The white and grey matter of the spinal cord, as well as a circular cavity, is known as the central canal, which makes up the spinal cord. Spinal nerves arise from each vertebra. The sympathetic trunk and the splanchnic nerves emerge from the spinal nerves, providing sympathetic nervous support to the body.

The spinal canal follows the curves of the spine; it is long and triangular in the areas of the spine that have the most mobility freedom, including the lumbar and cervical regions, and narrow and circular in the thoracic area, whereby motion is restricted. The conus medullaris and cauda equina are the ends of the spinal cord.

Since we have learnt about the spinal cord and vertebral column, let us take a look at the diagram of the human spine.

Human Skeleton Spine Diagram

Below given is the Human skeleton spine diagram:

Structure

There are usually thirty-three vertebrae in a human’s vertebral column; the top twenty-four articulate and are divided from one another by intervertebral discs, while the bottom nine become united in adults, five throughout the sacrum and four throughout the coccyx, or tailbone. The articulating vertebrae are named after the regions of the spine where they are located.

The cervical vertebrae are seven, the thoracic vertebrae are twelve, and the lumbar vertebrae are five in number. The number of vertebrae in a region may differ, however, the total number of vertebrae remains constant. The number of those in the cervical region, on the other hand, varies very little, whereas the amount in the coccygeal region differs even more.

Ligaments connect the transverse processes, spinous processes, and vertebral laminae and run the length of the column in front and backwards.

Vertebral Body Function:

The Vertebrae in human body throughout the human vertebral column was divided into regions that correspond to the spinal column’s curves. The articulating vertebrae are called after the regions of the spine where they are located. The vertebrae in such areas are the same, with slight differences. The sacrum, cervical spine, lumbar spine, thoracic spine, and coccyx are all parts of the spine.

The cervical vertebrae are seven, the lumbar vertebrae are five and the thoracic vertebrae are twelve. The count of vertebrae in a region might vary, yet the total number of vertebrae stays unchanged. Nevertheless, the number of those within the cervical region is frequently altered.

The vertebrae of the thoracic, cervical, and lumbar spines are separate but somewhat common bones. The sacrum and coccyx vertebrae are normally fused and therefore unable to act independently. The atlas and axis, upon which the head lies, are 2 main vertebrae.

The vertebral body and the vertebral arch are the two components of a typical vertebra. The vertebral arch is lateral, which means it faces backwards. The vertebral foramen, which houses the spinal cord, is encased by these structures. The sacrum and coccyx do not have a centralized foramen since the spinal cord finishes in the lumbar spine, as well as the sacrum and coccyx, are connected.

The vertebrae are listed in order from top to bottom:

• Cervical spine: 7 vertebrae (C1–C7)

• Lumbar spine: 5 vertebrae (L1–L5)

• Sacrum: 5 (fused) vertebrae (S1–S5)

• Thoracic spine: 12 vertebrae (T1–T12)

• Coccyx: 4 (3–5) (fused) vertebrae (Tailbone)

Shape:

As a product of Human bipedal evolution, the vertebral column is bent in many ways. The curves in the human spine help to keep the body in a more standing posture.

The convex forward curve of the upper cervical spine starts at the axis (second cervical vertebra) at the apex of the odontoid process or dens and ends at the centre of the second thoracic vertebra; it is the lowest described of all the curves. A lordotic curve is a type of inward curve.

Surfaces

Anterior Surface: 

The width of the bodies of the vertebrae increases from the second cervical to the first thoracic whenever seen from the front; the next three vertebrae have a slight diminution. Below this, a steady and incremental rise in width continues down to the sacrovertebral angle. From here, the coccyx gradually shrinks until it reaches the apex.

Posterior Surface: 

The spinous processes are visible in the median line of the vertebral column when viewed from behind. These are low, longitudinal, and bifid in the cervical region (except for the second and seventh vertebrae). They have been targeted disingenuously downward in the upper portion of the thoracic region, more or less vertical in the centre, and almost horizontal in the bottom section.

Lateral Surfaces: 

The articular processes throughout the cervical and thoracic regions, as well as the transverse processes within the lumbar region, distinguish the ends of the vertebral column from that of the posterior surface. The faces of the bodies of the vertebrae were identified in the posterior through facets for articulation mostly with rib’s heads in the thoracic region.