Taken from clinical snell anatomy

1. C H A P
The Back
2

2. Vertebral coulumn
Typical vertebrae reigonal
chracteristics
CONTENTS
Atypical vertebrae chracteristics
Sacrum
Cocyx

3. PART
01

4. Vertebral Coulumn :
The vertebral column, also known as the spinal column or backbone, is a bony structure that
forms the central axis of the human body. It is composed of 33 individual bones called vertebrae
that are stacked on top of each other in a specific sequence.
The vertebral column has several important functions, including providing support and
protection for the spinal cord, which runs through a canal in the center of the vertebrae. It also
allows for movement and flexibility in the upper body and helps distribute the weight of the body.
There are five main regions of the vertebral column: cervical (neck), thoracic (upper back),
lumbar (lower back), sacral (pelvic), and coccygeal (tailbone). The cervical region has seven
vertebrae, the thoracic region has twelve, the lumbar region has five, and the sacral and
coccygeal regions are composed of fused bones.
Between each pair of vertebrae is an intervertebral disc, which acts as a shock absorber and
helps with movement. The vertebral column also has several important ligaments and muscles
that help support and stabilize the structure.
Problems with the vertebral column can result in a variety of conditions, including herniated
discs, spinal stenosis, scoliosis, and osteoporosis. Treatment options may include medication,
physical therapy, or surgery, depending on the specific condition and severity.

5. Composition of vetebral column :
The vertebral column is composed of 33 individual bones called vertebrae that are stacked on
top of each other. Each vertebra is a complex structure that consists of several different parts,
including:
• Body: The main mass of the vertebra, which bears the weight of the body.
• Arch: A bony ring that surrounds and protects the spinal cord, which runs through the vertebral
canal.
• Spinous process: A bony projection that extends from the back of the vertebra and serves as
an attachment point for muscles and ligaments.
• Transverse processes: Bony projections that extend from the sides of the vertebra and also
serve as attachment points for muscles and ligaments.
• Intervertebral discs: The discs that sit between each pair of vertebrae and act as shock
absorbers, helping to cushion the spine and allow for movement.
• The vertebral column is divided into five main regions, each with a different number and type
of vertebrae:
• Cervical region: The neck region, which contains seven cervical vertebrae.
• Thoracic region: The upper back region, which contains twelve thoracic vertebrae.

6. Lumbar region: The lower back region, which contains five lumbar vertebrae.
Sacral region: The pelvic region, which contains five fused vertebrae that make up the sacrum.
Coccygeal region: The tailbone region, which contains four fused vertebrae that make up the
coccyx.
In addition to the individual vertebrae, the vertebral column also includes various ligaments and
muscles that help suppo

7. PART
02

8. Typical vertebrae reigonal chracteristics:
Vertebrae are the individual bones that make up the spinal column, or backbone. There are 33
vertebrae in the human spine, divided into five regions: cervical, thoracic, lumbar, sacral, and
coccygeal. Each region has its own distinct characteristics that help to support the different
functions of the spine.
Here are some of the typical regional characteristics of vertebrae:
Cervical vertebrae (7 vertebrae) - These are the smallest and most delicate of the vertebrae.
They have small bodies and large vertebral foramina (openings) to allow passage of the spinal
cord. They also have transverse foramina, which allow for the passage of the vertebral arteries
that supply blood to the brain.
Thoracic vertebrae (12 vertebrae) - These are larger and more robust than cervical vertebrae.
They have long spinous processes (the bony projections on the back of the vertebrae) that
point downward, which help to attach muscles and ligaments. They also have facets for
articulation with the ribs, which help to form the ribcage.

9. Lumbar vertebrae (5 vertebrae) - These are the largest and strongest of the vertebrae. They
have thick bodies and short, blunt spinous processes that project straight back. They also have
large intervertebral discs, which provide cushioning between the vertebrae.
Sacral vertebrae (5 fused vertebrae) - These are fused together to form the sacrum, which is
located at the base of the spine. They are triangular in shape and have several sacral foramina,
which allow for the passage of nerves and blood vessels.
Coccygeal vertebrae (4 fused vertebrae) - These are fused together to form the coccyx, or
tailbone. They are small and have no real function in supporting the body.
Overall, the shape and size of the different vertebrae are adapted to their respective functions in
the spine, which include support, protection, and fle

10. PART
03

11. Atypical vertebrae chracteristics:
Atypical vertebrae are vertebral segments that differ from typical vertebrae in their structure and
function. Some of the characteristics of atypical vertebrae include:
Cervical Vertebrae: The cervical vertebrae (C1-C7) are atypical vertebrae due to their unique
structures that allow for greater flexibility and movement of the head and neck. The atlas (C1)
and axis (C2) are two of the most atypical cervical vertebrae.
Thoracic Vertebrae: The thoracic vertebrae (T1-T12) are atypical vertebrae due to the presence
of ribs that attach to them. The first thoracic vertebra (T1) has a full facet for the first rib, while
the remaining thoracic vertebrae have demi-facets for the attachment of the ribs.
Lumbar Vertebrae: The lumbar vertebrae (L1-L5) are atypical vertebrae due to their larger size
and weight-bearing function. They have thick, strong bodies and relatively short spinous
processes.
Sacral Vertebrae: The sacral vertebrae (S1-S5) are atypical vertebrae because they are fused
together to form the sacrum. They also have no intervertebral discs, and their spinous processes
are fused to form the median sacral crest.
Coccygeal Vertebrae: The coccygeal vertebrae (Co1-Co4) are atypical vertebrae because they are
vestigial and have no function in supporting the body. They are usually fused together to form
the coccyx.

12. PART
04

13. Sacrum:
The sacrum is a large, triangular bone located at the base of the spine, between the two hip
bones. It is made up of five fused vertebrae (S1-S5) and forms the posterior part of the pelvic
girdle, providing a strong foundation for the weight of the upper body to be transferred to the
lower extremities. The sacrum articulates with the ilium bones of the pelvis at the sacroiliac
joints.
The sacrum plays an important role in several bodily functions, including supporting the
weight of the upper body, transmitting loads from the spine to the pelvis and legs, and
providing attachment sites for muscles and ligaments. It also protects the sacral spinal nerves
that exit the spinal cord and travel through the sacral canal to the lower body.
In females, the sacrum is wider and shorter than in males to accommodate childbirth, and the
sacral promontory (the uppermost part of the sacrum) is less pronounced. The sacrum can
also be subject to various disorders, including fractures, infections, and tumors, which can
affect its normal function and cause pain and other symptoms.

14. Part
0 5

15. cocyx:
The coccyx, also known as the tailbone, is a small triangular bone located at the bottom of the
spine, below the sacrum. It is made up of three to five fused vertebrae and is considered a
vestigial structure, meaning that it has no function in supporting the body and is a remnant of
our evolutionary past.
Despite its lack of function, the coccyx plays a role in supporting the pelvic floor muscles and
provides attachment points for some muscles and ligaments. It can also be a source of pain if
injured or inflamed, such as from trauma, childbirth, or prolonged sitting.
Treatment for coccyx pain may include conservative measures such as rest, pain medications,
and physical therapy. In some cases, more invasive treatments such as coccyx injections or
surgical removal of the coccyx may be necessary to relieve symptoms. However, coccyx removal
is generally considered a last resort and is only recommended in cases where other treatments
have failed and the pain is severe and persistent.

16. C U T E
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