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The sacral promontory    is the anterior lip of the superior base of the sacrum. Lateral to this is the roughened auricular surface, which joins with the ilium portion of the hipbone to form the immobile sacroiliac joints of the pelvis. Passing inferiorly through the sacrum is a bony tunnel called the sacral canal    , which terminates at the sacral hiatus    near the inferior tip of the sacrum. The anterior and posterior surfaces of the sacrum have a series of paired openings called sacral foramina    (singular = foramen) that connect to the sacral canal. Each of these openings is called a posterior (dorsal) sacral foramen    or anterior (ventral) sacral foramen    . These openings allow for the anterior and posterior branches of the sacral spinal nerves to exit the sacrum. The superior articular process of the sacrum    , one of which is found on either side of the superior opening of the sacral canal, articulates with the inferior articular processes from the L5 vertebra.

The coccyx, or tailbone, is derived from the fusion of four very small coccygeal vertebrae (see [link] ). It articulates with the inferior tip of the sacrum. It is not weight bearing in the standing position, but may receive some body weight when sitting.

Sacrum and coccyx

This figure shows the structure of the sacrum and coccyx. The left panel shows the vertebral column with the sacrum and coccyx highlighted in pink. The middle panel shows the anterior view and the right panel shows the posterior view of the sacrum and coccyx.
The sacrum is formed from the fusion of five sacral vertebrae, whose lines of fusion are indicated by the transverse ridges. The fused spinous processes form the median sacral crest, while the lateral sacral crest arises from the fused transverse processes. The coccyx is formed by the fusion of four small coccygeal vertebrae.

Intervertebral discs and ligaments of the vertebral column

The bodies of adjacent vertebrae are strongly anchored to each other by an intervertebral disc. This structure provides padding between the bones during weight bearing, and because it can change shape, also allows for movement between the vertebrae. Although the total amount of movement available between any two adjacent vertebrae is small, when these movements are summed together along the entire length of the vertebral column, large body movements can be produced. Ligaments that extend along the length of the vertebral column also contribute to its overall support and stability.

Intervertebral disc

An intervertebral disc    is a fibrocartilaginous pad that fills the gap between adjacent vertebral bodies (see [link] ). Each disc is anchored to the bodies of its adjacent vertebrae, thus strongly uniting these. The discs also provide padding between vertebrae during weight bearing. Because of this, intervertebral discs are thin in the cervical region and thickest in the lumbar region, which carries the most body weight. In total, the intervertebral discs account for approximately 25 percent of your body height between the top of the pelvis and the base of the skull. Intervertebral discs are also flexible and can change shape to allow for movements of the vertebral column.

Each intervertebral disc consists of two parts. The anulus fibrosus    is the tough, fibrous outer layer of the disc. It forms a circle (anulus = “ring” or “circle”) and is firmly anchored to the outer margins of the adjacent vertebral bodies. Inside is the nucleus pulposus    , consisting of a softer, more gel-like material. It has a high water content that serves to resist compression and thus is important for weight bearing. With increasing age, the water content of the nucleus pulposus gradually declines. This causes the disc to become thinner, decreasing total body height somewhat, and reduces the flexibility and range of motion of the disc, making bending more difficult.

Questions & Answers

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mahamed Reply
Yeah, when there is a blockage in the bilary system( bile ducts) which lead to obstruction of the bile pigments called bilirubin leading to a characteristically yellowish appearance of the eyes.
ibrahim
hi pls what causes jaundice
Umar Reply
where the love feelings emotions and hate lies in the body?
Loving Reply
what is Regional anatomy
Sharon Reply
Please information on dialysis
Agbo Reply
what is the relationship between Clinical officer general, unqualified professionals and traditional healers?
Purity Reply
is that how the microscopic anatomy is
Elizabeth Reply
to understand the structures of the body. to understand how the structures of the body work . To understand how the structures of the body work and support the functions of life.
Dora Reply
procedures that removes waste from body when kidneys dont function properly..
maribel Reply
Want to join
Ordeal
dialysis
kimunya
dialysis is a process to remove extra fluid , impurities and waste product from the blood and to correct electrolytes imbalance such as sodium, potassium and calcium with the help of dialysis machine. when the kidneys can't do their job.
Kishan
what will lead a person to dialysis
Agbo
what's metabolic acidosis
Nana
A condition in which too much acid accumulates in the body. Causes of metabolic acidosis can include buildup of body toxins, kidney failure, and ingestion of certain drugs or toxins, such as methanol or large doses of aspirin. It can be a rare complication of diabetes.
Loving
What is dialisis
Friday Reply
When kidney is not functioning properly than with the help of dialysis blood filtration is occur Or we can say that it is a process through which filtration of blood is done
sonugora
dialysis is a process of removing wastes, excess fluid ,impurities from the blood and to correct electrolytes imbalance such as sodium, potassium and calcium etc with the help of dialysis machine.when the kidney can't do their job.
Kishan
describe anatomical position
Getrude Reply
The erect position of the body with the face directed forward, the arms at the side, and the palms of the hands facing forward, used as a reference in describing the relation of body parts to one another
Jean
Somebody to explain for me the duties of specialist obstetrician
Irene
Definition of an anatomy
Oppong Reply
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b pharmacy all subject complete notes
Sayed
the study of the body's structures scientifically
Dora
what is regional anatomy ?
Jharana Reply
regional anatomy - the study of anatomy based on regions or divisions of the body and emphasizing the relations between various structures (muscles and nerves and arteries etc.) in that region.
Noor
it's the scientific study of the body's structures in a particular region of the body, to study and understand how the body's structures in that region work together and the relations between them.
Dora
Regional anatomy is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen. Studying regional anatomy helps us appreciate the interrelationships of body structures, such as how muscles, nerves, blood vessels, and other structures work together to
Loving
together to serve a particular body region
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what is joint
ISHQ Reply
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Noor
what is gross anatomy ?
Jharana Reply
what is pharynx
Kishan
membrane behind the nose
Oloruntoba
Gross anatomy is the study of anatomy at the visible or (macroscopic) level
Noor
how does blood gets into the heart
Kity
through the inferior and superior vena cava
Oloruntoba
it's the anatomy of complex body structures that can be seen without the aid of a microspe.
Dora
it is the study of large body structures that can be observed without the aid of a microscope
Purity
state factors that affect sterilization (10marks)
Bright
Gross anatomy is the study of anatomy at the visible or (macroscopic) level. The counterpart to gross anatomy is the field of histology, which studies microscopic anatomy.
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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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