L5: Axial Pt. 2 Flashcards
What is sinusitis?
Sinusitis is an inflammation of the mucous membrane of one or more paranasal sinuses.
What may cause sinusitis?
Sinusitis may be caused by a microbial infection (virus, bacterium, or fungus), allergic reactions, nasal polyps, or a severely deviated nasal septum.
What happens if the inflammation or an obstruction blocks the drainage of mucus into the nasal cavity?
If the inflammation or an obstruction blocks the drainage of mucus into the nasal cavity, fluid pressure builds up in the paranasal sinuses, and a sinus headache may develop.
What are other signs and symptoms of sinusitis?
Other signs and symptoms of sinusitis may include nasal congestion, inability to smell, fever, sore throat, pressure or pain in the ears and teeth, postnasal drainage, and cough.
What are the treatment options for sinusitis?
Treatment options for sinusitis include saline nasal irrigation, decongestant sprays or drops, oral decongestants, nasal corticosteroids, antibiotics, analgesics to relieve pain, warm compresses, and surgery.
What does the skull of a developing embryo consist of?
The skull of a developing embryo consists of cartilage and mesenchyme arranged in thin plates around the developing brain.
What happens gradually as ossification occurs?
Gradually, ossification occurs, and bone slowly replaces most of the cartilage and mesenchyme.
What happens at birth when bone ossification is incomplete?
At birth, bone ossification is incomplete, and the mesenchyme-filled spaces become dense connective tissue regions between incompletely developed cranial bones called fontanels.
What are fontanels commonly called?
Fontanels are commonly called “soft spots”.
What are fontanels?
Fontanels are areas where unossified mesenchyme develops into the dense connective tissues of the skull.
What happens to fontanels as bone formation continues after birth?
As bone formation continues after birth, the fontanels are eventually replaced with bone by intramembranous ossification, and the thin collagenous connective tissue junctions that remain between neighboring bones become the sutures.
What is the function of fontanels?
Functionally, the fontanels serve as spacers for the growth of neighboring skull bones and provide some flexibility to the fetal skull, allowing the skull to change shape as it passes through the birth canal and later permitting rapid growth of the brain during infancy.
How many fontanels are fairly constant at birth?
Although an infant may have many fontanels at birth, the form and location of six are fairly constant.
Where is the anterior fontanel located?
The unpaired anterior fontanel, the largest fontanel, is located at the midline among the two parietal bones and the frontal bone, and is roughly diamond-shaped.
When does the anterior fontanel usually close?
The anterior fontanel usually closes 18 to 24 months after birth.
Where is the posterior fontanel located?
The unpaired posterior fontanel is located at the midline among the two parietal bones and the occipital bone.
How does the posterior fontanel compare in size to the anterior fontanel?
The posterior fontanel is much smaller than the anterior fontanel.
When does the posterior fontanel generally close?
The posterior fontanel generally closes about 2 months after birth.
Where are the anterolateral fontanels located?
The paired anterolateral fontanels are located laterally among the frontal, parietal, temporal, and sphenoid bones, and are small and irregular in shape.
When do the anterolateral fontanels normally close?
The anterolateral fontanels normally close about 3 months after birth.
Where are the posterolateral fontanels located?
The paired posterolateral fontanels are located laterally among the parietal, occipital, and temporal bones, and are irregularly shaped.
When do the posterolateral fontanels begin to close and when is closure generally complete?
The posterolateral fontanels begin to close 1 to 2 months after birth, but closure is generally not complete until 12 months.
What does the amount of closure in fontanels help a physician gauge?
The amount of closure in fontanels helps a physician gauge the degree of brain development.
What does the anterior fontanel serve as a landmark for?
The anterior fontanel serves as a landmark for withdrawal of blood for analysis from the superior sagittal sinus.
are mesenchyme-filled spaces between cranial cavity bones that are present at birth.
Fontanels
What is a unique component of the axial skeleton because it does not articulate with any other bone?
The single hyoid bone is a unique component of the axial skeleton because it does not articulate with any other bone.
How is the hyoid bone suspended?
The hyoid bone is suspended from the styloid processes of the temporal bones by ligaments and muscles.
Where is the hyoid bone located?
The hyoid bone is located in the anterior neck between the mandible and larynx.
What does the hyoid bone support?
The hyoid bone supports the tongue.
What does the hyoid bone provide attachment sites for?
The hyoid bone provides attachment sites for some tongue muscles and for muscles of the neck and pharynx.
What are the parts of the hyoid bone?
The hyoid bone consists of a horizontal body and paired projections called the lesser horns and the greater horns.
What attaches to the body and paired projections of the hyoid bone?
Muscles and ligaments attach to the body and these paired projections.
What structures are often fractured during strangulation?
The hyoid bone and the cartilages of the larynx and trachea are often fractured during strangulation.
Why are the hyoid bone and cartilages of the larynx and trachea carefully examined at autopsy?
The hyoid bone and cartilages of the larynx and trachea are carefully examined at autopsy when manual strangulation is a suspected cause of death.
supports the tongue, providing attachment sites for muscles of the tongue, neck, and pharynx.
Hyoid bone
What is another name for the vertebral column?
The vertebral column is also called the spine, backbone, or spinal column.
How much of your total height does the vertebral column make up?
The vertebral column makes up about two-fifths of your total height.
What is the vertebral column composed of?
The vertebral column is composed of a series of bones called vertebrae.
What forms the skeleton of the trunk of the body?
The vertebral column, the sternum, and the ribs form the skeleton of the trunk of the body.
What does the vertebral column consist of?
The vertebral column consists of bone and connective tissue.
What does the spinal cord consist of?
The spinal cord consists of nervous and connective tissues.
What is the average length of the vertebral column in an adult male?
The vertebral column is about 71 cm (28 in.) in an average adult male.
What is the average length of the vertebral column in an adult female?
The vertebral column is about 61 cm (24 in.) in an average adult female.
How does the vertebral column function?
The vertebral column functions as a strong, flexible rod with elements that can move forward, backward, and sideways, and rotate.
What are the functions of the vertebral column?
The vertebral column encloses and protects the spinal cord, supports the head, and serves as a point of attachment for the ribs, pelvic girdle, and muscles of the back and upper limbs.
How many vertebrae are present during early development?
The total number of vertebrae during early development is 33.
Why does the number of vertebrae decrease as a child grows?
As a child grows, several vertebrae in the sacral and coccygeal regions fuse.
How many vertebrae does the adult vertebral column typically contain?
The adult vertebral column typically contains 26 vertebrae.
How many cervical vertebrae are in the neck region?
There are 7 cervical vertebrae in the neck region.
How many thoracic vertebrae are posterior to the thoracic cavity?
There are 12 thoracic vertebrae posterior to the thoracic cavity.
How many lumbar vertebrae support the lower back?
There are 5 lumbar vertebrae supporting the lower back.
What does the sacrum consist of?
The sacrum consists of five fused sacral vertebrae.
What does the coccyx usually consist of?
The coccyx usually consists of four fused coccygeal vertebrae.
Which vertebrae are movable?
The cervical, thoracic, and lumbar vertebrae are movable.
Which parts of the vertebral column are not movable?
The sacrum and coccyx are not movable.
The adult vertebral column typically contains __ vertebrae
26
How does a normal adult vertebral column appear when viewed from the anterior or posterior?
A normal adult vertebral column appears straight when viewed from the anterior or posterior.
How does a normal adult vertebral column appear when viewed from the side?
When viewed from the side, a normal adult vertebral column shows four slight bends called normal curves.
What are the primary curves of the vertebral column?
The thoracic and sacral curves are the primary curves.
What are the primary curves of the vertebral column described as?
The primary curves are concave (cupping in) when viewed from the front of the body.
What are the secondary curves of the vertebral column?
The cervical and lumbar curves are the secondary curves.
What are the secondary curves of the vertebral column described as?
The secondary curves are convex (bulging out) when viewed from the front of the body.
What are the functions of the curves of the vertebral column?
The curves of the vertebral column increase its strength, help maintain balance in the upright position, absorb shocks during walking, and help protect the vertebrae from fracture.
How does the fetus appear in terms of vertebral curvature?
The fetus has a single anteriorly concave curve throughout the length of the entire vertebral column.
When does the anteriorly convex cervical curve develop?
The anteriorly convex cervical curve develops at about the third month after birth, when an infant begins to hold its head erect.
When does the anteriorly convex lumbar curve develop?
The anteriorly convex lumbar curve develops later, when the child sits up, stands, and walks.
Why are the thoracic and sacral curves called primary curves?
The thoracic and sacral curves are called primary curves because they retain the original curvature of the embryonic vertebral column.
Why are the cervical and lumbar curves known as secondary curves?
The cervical and lumbar curves are known as secondary curves because they begin to form later, several months after birth.
At what age are all curves fully developed?
All curves are fully developed by age 10.
What may happen to secondary curves in old age?
Secondary curves may be progressively lost in old age.
What may happen if the normal curves of the vertebral column are exaggerated or if a lateral bend occurs?
If the normal curves of the vertebral column are exaggerated or if a lateral bend occurs, it results in abnormal curves of the vertebral column.
What are the three abnormal curves of the vertebral column?
The three abnormal curves of the vertebral column are kyphosis, lordosis, and scoliosis.
Where are intervertebral discs found?
Intervertebral discs are found between the bodies of adjacent vertebrae from the second cervical vertebra to the sacrum.
What percentage of the height of the vertebral column do intervertebral discs account for?
Intervertebral discs account for about 25% of the height of the vertebral column.
What is the outer fibrous ring of an intervertebral disc called?
The outer fibrous ring of an intervertebral disc is called the annulus fibrosus.
What type of cartilage is found in the annulus fibrosus?
The annulus fibrosus consists of fibrous cartilage.
What is the inner soft, pulpy, highly elastic substance of an intervertebral disc called?
The inner soft, pulpy, highly elastic substance of an intervertebral disc is called the nucleus pulposus.
What do the superior and inferior surfaces of an intervertebral disc consist of?
The superior and inferior surfaces of an intervertebral disc consist of a thin plate of hyaline cartilage.
What are the three functions of intervertebral discs?
Intervertebral discs form strong joints, permit various movements of the vertebral column, and absorb vertical shock.
What happens to intervertebral discs under compression?
Under compression, intervertebral discs flatten and broaden.
Why are we shorter at night?
We are shorter at night because during the course of a day, the discs compress and lose water from their cartilage.
Why are we taller in the morning?
We are taller in the morning because while we are sleeping, there is less compression and rehydration occurs.
What happens to the nucleus pulposus with age?
With age, the nucleus pulposus hardens and becomes less elastic.
What causes a decrease in vertebral height with age?
A decrease in vertebral height with age results from bone loss in the vertebral bodies and not a decrease in thickness of the intervertebral discs.
Why do intervertebral discs rely on blood vessels from the bodies of vertebrae?
Intervertebral discs rely on blood vessels from the bodies of vertebrae to obtain oxygen and nutrients and remove wastes because they are avascular.
How do certain stretching exercises like yoga affect intervertebral discs?
Certain stretching exercises like yoga decompress discs and increase general blood circulation, which speeds up the uptake of oxygen and nutrients by discs and the removal of wastes.
How do vertebrae in different regions of the spinal column vary?
Vertebrae in different regions of the spinal column vary in size, shape, and detail.
How are vertebrae similar despite their differences?
Vertebrae are similar enough that we can discuss the structures (and the functions) of a typical vertebra.
What are the three main components that vertebrae typically consist of?
Vertebrae typically consist of a vertebral body, a vertebral arch, and several processes.
What is the vertebral body?
The vertebral body is the thick, disc-shaped anterior portion and is the weight-bearing part of a vertebra.
What are the superior and inferior surfaces of the vertebral body roughened for?
The superior and inferior surfaces of the vertebral body are roughened for the attachment of cartilaginous intervertebral discs.
What do the anterior and lateral surfaces of the vertebral body contain?
The anterior and lateral surfaces of the vertebral body contain nutrient foramina.
What are nutrient foramina?
Nutrient foramina are openings through which blood vessels deliver nutrients and oxygen and remove carbon dioxide and wastes from bone tissue.
What are the pedicles?
Pedicles are two short, thick processes that project posteriorly from the vertebral body.
What do the pedicles unite with to form the vertebral arch?
The pedicles unite with the flat laminae to form the vertebral arch.
What does the vertebral arch extend from?
The vertebral arch extends posteriorly from the body of the vertebra.
What do the vertebral body and vertebral arch surround?
The vertebral body and vertebral arch surround the spinal cord by forming the vertebral foramen.
What does the vertebral foramen contain?
The vertebral foramen contains the spinal cord, adipose tissue, areolar connective tissue, and blood vessels.
What do the vertebral foramina of all vertebrae collectively form?
The vertebral foramina of all vertebrae collectively form the vertebral canal.
What are the vertebral notches?
The vertebral notches are superior and inferior indentations of the pedicles.
What do stacked vertebral notches form?
Stacked vertebral notches form an opening between adjoining vertebrae on both sides of the column.
What is an intervertebral foramen?
An intervertebral foramen is an opening formed by stacked vertebral notches that permits the passage of a single spinal nerve carrying information to and from the spinal cord.
A vertebra consists of a
vertebral body, a vertebral arch, and several processes.
How many processes arise from the vertebral arch?
Seven processes arise from the vertebral arch.
What extends laterally on each side at the point where a lamina and pedicle join?
A transverse process extends laterally on each side at the point where a lamina and pedicle join.
What projects posteriorly from the junction of the laminae?
A single spinous process projects posteriorly from the junction of the laminae.
What is the function of the transverse process and spinous process?
These three processes serve as points of attachment for muscles.
How many processes form joints with other vertebrae above or below?
The remaining four processes form joints with other vertebrae above or below.
What do the two superior articular processes of a vertebra articulate with?
The two superior articular processes of a vertebra articulate with the two inferior articular processes of the vertebra immediately above them.
What do the two inferior articular processes of a vertebra articulate with?
The two inferior articular processes of a vertebra articulate with the two superior articular processes of the vertebra immediately below them.
What are the articulating surfaces of the articular processes referred to as?
The articulating surfaces of the articular processes are referred to as facets.
What are the facets covered with?
The facets are covered with hyaline cartilage.
What are the articulations formed between the vertebral bodies and articular facets of successive vertebrae termed?
The articulations formed between the vertebral bodies and articular facets of successive vertebrae are termed intervertebral joints.
How many regions does Section 7.10 present in the vertebral column?
Section 7.10 presents five regions in the vertebral column.
What are the five regions of the vertebral column?
The five regions of the vertebral column are the cervical, thoracic, lumbar, sacral, and coccygeal.
How are vertebrae in each region numbered?
Vertebrae in each region are numbered in sequence, from superior to inferior.
What do you notice when actually viewing the bones of the vertebral column?
When actually viewing the bones of the vertebral column, you will notice that the transition from one region to the next is not abrupt but gradual.
What is the significance of the gradual transition between regions of the vertebral column?
The gradual transition helps the vertebrae fit together.
What happens to the vertebral column with advancing age?
With advancing age, the vertebral column undergoes changes characteristic of the skeletal system in general.
What are the changes in the vertebral column due to aging?
The changes include reduction in the mass and density of the bone along with a reduction in the collagen-to-mineral content within the bone.
What effect do these changes have on the bones?
These changes make the bones more brittle and susceptible to damage.
What happens to the articular surfaces as they age?
The articular surfaces lose their covering cartilage, and rough bony growths form in their place, leading to arthritic conditions.
What are osteophytes in the vertebral column?
Osteophytes are bony growths around the intervertebral discs.
What can osteophytes lead to?
Osteophytes can lead to a narrowing (stenosis) of the vertebral canal.
What is the consequence of vertebral canal stenosis?
Vertebral canal stenosis can lead to compression of spinal nerves and the spinal cord.
How can compression of spinal nerves and the spinal cord manifest?
Compression of spinal nerves and the spinal cord can manifest as pain and decreased muscle function in the back and lower limbs.
The cervical vertebrae are found in the
neck region
Which vertebrae are smaller than all other vertebrae except those that form the coccyx?
Cervical vertebrae (C1–C7)
How do the vertebral arches of cervical vertebrae compare to others?
The vertebral arches of cervical vertebrae are larger.
How many foramina do all cervical vertebrae have?
All cervical vertebrae have three foramina: one vertebral foramen and two transverse foramina.
Why are the vertebral foramina of cervical vertebrae the largest in the spinal column?
Because they house the cervical enlargement of the spinal cord.
What does each cervical transverse process contain?
Each cervical transverse process contains a transverse foramen.
What passes through the transverse foramen?
The vertebral artery, its accompanying vein, and nerve fibers pass through the transverse foramen.
What feature is unique to cervical vertebrae?
The presence of a transverse foramen is unique to cervical vertebrae.
What is special about the spinous processes of C2 through C6?
The spinous processes of C2 through C6 are often bifid (branch into two small projections at the tips).
What is the first cervical vertebra called?
The first cervical vertebra is called the atlas (C1).
What is the atlas (C1) named after?
The atlas (C1) is named after the mythological Atlas who supported the world on his shoulders.
Where is the atlas (C1) located?
The atlas (C1) is the first cervical vertebra inferior to the skull.
What does the atlas (C1) lack?
The atlas (C1) lacks a body and a spinous process.
What are the superior articular facets of the atlas?
The superior articular facets are concave surfaces on the lateral masses.
What do the superior articular facets articulate with?
The superior articular facets articulate with the occipital condyles of the occipital bone.
What movement do the atlanto-occipital joints permit?
The atlanto-occipital joints permit movement of the head to signify “yes”.
What do the inferior articular facets of the atlas articulate with?
The inferior articular facets articulate with the second cervical vertebra.
Which cervical vertebra is known as the axis (C2)?
The second cervical vertebra (C2) is called the axis.
What process does the axis (C2) have?
The axis (C2) has a dens (odontoid process).
Where does the dens (odontoid process) project?
The dens projects superiorly through the anterior portion of the vertebral foramen of the atlas.
What function does the dens (odontoid process) serve?
The dens makes a pivot on which the atlas and head rotate, allowing side-to-side movement.
What movement does the atlanto-axial joint permit?
The atlanto-axial joint permits movement of the head to signify “no”.
What can happen to the dens in cases of trauma?
In some cases of trauma, the dens may be driven into the medulla oblongata of the brain.
What is the usual cause of death from whiplash injuries?
The usual cause of death from whiplash injuries is injury to the medulla oblongata by the dens of the axis.
Which cervical vertebrae correspond to the typical cervical vertebra structure?
The third through sixth cervical vertebrae (C3–C6) correspond to the typical cervical vertebra structure.
What is the seventh cervical vertebra (C7) called?
The seventh cervical vertebra (C7) is called the vertebra prominens.
How is the vertebra prominens (C7) different from the other cervical vertebrae?
The vertebra prominens (C7) has a large, nonbifid spinous process.
Where can the spinous process of C7 be seen and felt?
The spinous process of C7 can be seen and felt at the base of the neck.
What is the overuse syndrome that results from the forward placement of the head more than one inch past the atlas?
Forward head posture (FHP)
What are other names for forward head posture (FHP)?
Texting neck, computer neck, reader’s neck, and sofa neck
What is the first cervical vertebra on which the skull rests?
Atlas
What are some possible causes of forward head posture (FHP)?
Neck injuries, poor sleeping habits, rotational athletics (baseball, golf, tennis, and hockey), and certain occupations (massage therapists, hair stylists, painters, and writers)
What activities most commonly lead to forward head posture (FHP)?
Repetitive use of texting, using a computer, playing video games, and carrying heavy backpacks
What does forward head posture (FHP) cause in the body?
A shift in the body’s center of gravity
What is the effect of forward head posture (FHP) on the cervical spine?
Increased pressure on the cervical spine
How much heavier does the head feel to the neck muscles for every inch the head moves past the shoulders?
Ten pounds heavier
What are some signs and symptoms of forward head posture (FHP)?
Chronic pain in the neck, shoulders, and back; muscle spasms; forward tilting of the head; chronic headaches; increased curvature of the spine; early onset of arthritis; intervertebral disc compression and herniation; temporomandibular (TMJ) dysfunction; fatigue; insomnia or poor sleep; decreased lung capacity; and numbness and tingling in the upper limbs
What are some treatment options for forward head posture (FHP)?
Assuming proper posture, setting up an ergonomic workstation to adopt and maintain a neutral position, visiting a physical therapist to begin and maintain corrective exercises, avoiding carrying heavy backpacks, and using a pillow that supports the neutral curve of the neck
are found in the chest region and articulate with the ribs.
thoracic vertebrae
Which vertebrae are considerably larger and stronger than cervical vertebrae?
Thoracic vertebrae (T1–T12)
How are the spinous processes of T1 through T10 described?
Long, laterally flattened, and directed inferiorly
How are the spinous processes of T11 and T12 different from those of T1 through T10?
Shorter, broader, and directed more posteriorly
Compared to cervical vertebrae, how do the transverse processes of thoracic vertebrae differ?
They are longer and larger
What feature easily identifies thoracic vertebrae?
Costal facets
What is the function of costal facets on thoracic vertebrae?
They are articular surfaces for the ribs
What feature distinguishes thoracic vertebrae from other vertebrae?
They articulate with the ribs
What do the transverse processes of thoracic vertebrae, except for T11 and T12, have?
Transverse costal facets
What do transverse costal facets articulate with?
Tubercles of the ribs
What do the vertebral bodies of thoracic vertebrae have that form articulations with the heads of the ribs?
Costal facets
What does the superior costal facet of T1 articulate with?
The first rib
What does the inferior costal facet of T1 articulate with?
The second rib
What costal facets do T2–T8 have on each side of the vertebral body?
A superior costal facet and an inferior costal facet
Why do ribs 2–9 articulate with two vertebrae?
Because T2–T8 have both superior and inferior costal facets
What kind of costal facets do T10–T12 have on each side of the vertebral body?
A single costal facet
What are the articulations between the thoracic vertebrae and ribs called?
Vertebrocostal joints
What limits the movements of the thoracic region?
The attachment of the ribs to the sternum
Which vertebrae are the largest and strongest of the unfused bones in the vertebral column?
Lumbar vertebrae (L1–L5)
Why are the lumbar vertebrae the largest and strongest?
Because the amount of body weight supported by the vertebrae increases toward the inferior end of the backbone
How are the various projections of the lumbar vertebrae described?
Short and thick
How are the superior articular processes of lumbar vertebrae directed?
Medially instead of superiorly
How are the inferior articular processes of lumbar vertebrae directed?
Laterally instead of inferiorly
What shape are the spinous processes of lumbar vertebrae?
Quadrilateral
How are the spinous processes of lumbar vertebrae described?
Thick and broad
In what direction do the spinous processes of lumbar vertebrae project?
Nearly straight posteriorly
Why are the spinous processes of lumbar vertebrae well adapted?
For the attachment of the large back muscles
What is the sacrum?
A triangular bone formed by the union of five sacral vertebrae (S1–S5)
When do the sacral vertebrae begin to fuse?
Between 16 and 18 years of age
When is the fusion of the sacral vertebrae usually completed?
By age 30
Where is the sacrum positioned?
At the posterior portion of the pelvic cavity medial to the two hip bones
What does the sacrum serve as?
A strong foundation for the pelvic girdle
How does the female sacrum differ from the male sacrum?
It is shorter, wider, and more curved between S2 and S3
What does the concave anterior side of the sacrum face?
The pelvic cavity
What does the concave anterior side of the sacrum contain?
Four transverse lines (ridges) that mark the joining of the sacral vertebral bodies
What is found at the ends of the transverse lines?
Four pairs of anterior sacral foramina
What is the sacral ala?
A smooth surface on the lateral portion of the superior surface of the sacrum
What forms the sacral ala?
The fused transverse processes of the first sacral vertebra (S1)
What does the convex posterior surface of the sacrum contain?
A median sacral crest, a lateral sacral crest, and four pairs of posterior sacral foramina
What is the median sacral crest?
The fused spinous processes of the upper sacral vertebrae
What is the lateral sacral crest?
The fused transverse processes of the sacral vertebrae
What do the posterior sacral foramina connect with?
Anterior sacral foramina
What is the function of the sacral foramina?
To allow passage of nerves and blood vessels
What is the sacral canal?
A continuation of the vertebral canal
What happens when the laminae of the fifth sacral vertebra, and sometimes the fourth, fail to meet?
It leaves an inferior entrance to the vertebral canal called the sacral hiatus
What is the sacral hiatus?
An inferior entrance to the vertebral canal
What is on either side of the sacral hiatus?
A sacral cornu
What is the sacral cornu?
An inferior articular process of the fifth sacral vertebra
What are the sacral cornua connected to?
The coccyx by ligaments
What is the narrow inferior portion of the sacrum called?
The apex
What is the broad superior portion of the sacrum called?
The base
What is the sacral promontory?
The anteriorly projecting border of the base
What is the sacral promontory used for?
Measurements of the pelvis
What is the auricular surface of the sacrum?
A large ear-shaped surface on both lateral surfaces of the sacrum
What does the auricular surface articulate with?
The ilium of each hip bone
What joint is formed by the articulation between the auricular surface and the ilium?
The sacroiliac joint
What is posterior to the auricular surface?
A roughened surface called the sacral tuberosity
What does the sacral tuberosity contain?
Depressions for the attachment of ligaments
What does the sacral tuberosity unite with?
The hip bones to form the sacroiliac joints
What do the superior articular processes of the sacrum articulate with?
The inferior articular processes of the fifth lumbar vertebra
What does the base of the sacrum articulate with?
The body of the fifth lumbar vertebra
What joint is formed between the base of the sacrum and the fifth lumbar vertebra?
The lumbosacral joint
are found in the lower back.
lumbar vertebrae
is formed by the union of five sacral vertebrae, and the coccyx is formed by the union of usually four coccygeal vertebrae.
Sacrum
What is the size of cervical vertebrae?
Small
What is the size of thoracic vertebrae?
Larger
What is the size of lumbar vertebrae?
Largest
How many foramina do cervical vertebrae have?
One vertebral and two transverse
How many foramina do thoracic vertebrae have?
One vertebral
How many foramina do lumbar vertebrae have?
One vertebral
What is the structure of the spinous processes in cervical vertebrae?
Slender, often bifid (C2–C6)
What is the structure of the spinous processes in thoracic vertebrae?
Long, fairly thick (most project inferiorly)
What is the structure of the spinous processes in lumbar vertebrae?
Short, blunt (project posteriorly rather than inferiorly)
What is the size of the transverse processes in cervical vertebrae?
Small
What is the size of the transverse processes in thoracic vertebrae?
Fairly large
What is the size of the transverse processes in lumbar vertebrae?
Large and blunt
Are costal facets present in cervical vertebrae?
Absent
Are costal facets present in thoracic vertebrae?
Present
Are costal facets present in lumbar vertebrae?
Absent
What is the direction of the superior articular facets in cervical vertebrae?
Posterosuperior
What is the direction of the superior articular facets in thoracic vertebrae?
Posterolateral
What is the direction of the superior articular facets in lumbar vertebrae?
Medial
What is the direction of the inferior articular facets in cervical vertebrae?
Anteroinferior
What is the direction of the inferior articular facets in thoracic vertebrae?
Anteromedial
What is the direction of the inferior articular facets in lumbar vertebrae?
Lateral
What is the size of intervertebral discs in cervical vertebrae?
Thick relative to size of vertebral bodies
What is the size of intervertebral discs in thoracic vertebrae?
Thin relative to size of vertebral bodies
What is the size of intervertebral discs in lumbar vertebrae?
Thickest
Through what structure are anesthetic agents injected to act on the sacral and coccygeal nerves?
Sacral hiatus
What is the procedure called when anesthetic agents are injected through the sacral hiatus?
Caudal anesthesia
How does caudal anesthesia compare to a lumbar epidural block in terms of frequency?
Not as common
When is caudal anesthesia preferred over a lumbar epidural block?
When sacral nerve spread of the anesthetics is preferred over lumbar nerve spread
What anatomical structures are important bony landmarks for locating the sacral hiatus?
Sacral cornua
Through what other structure may anesthetic agents be injected besides the sacral hiatus?
Posterior sacral foramina
Why is there little danger of damaging the spinal cord when injecting anesthetics through the hiatal and foraminal sites?
Because the hiatal and foraminal injection sites are inferior to the lowest portion of the spinal cord
Why is the lumbar approach preferred over the sacral hiatus approach?
Because there is considerable variability in the anatomy of the sacral hiatus
What happens to the dorsal ligaments and cornua with advancing age?
They thicken, making it difficult to identify the hiatal margins
What shape is the coccyx, like the sacrum?
Triangular
How is the coccyx formed?
By the fusion of usually four coccygeal vertebrae
What vertebrae make up the coccyx?
Co1–Co4
When do the coccygeal vertebrae fuse?
Between the ages of 20 and 30
What does the dorsal surface of the body of the coccyx contain?
Two long coccygeal cornua
What are the coccygeal cornua connected to?
The sacral cornua
What are the coccygeal cornua?
The pedicles and superior articular processes of the first coccygeal vertebra
What structures are on the lateral surfaces of the coccyx?
A series of transverse processes
Which pair of transverse processes on the coccyx are the largest?
The first pair
With what structure does the coccyx articulate superiorly?
The apex of the sacrum
In females, where does the coccyx point, and why?
Inferiorly, to allow the passage of a baby during birth
In males, where does the coccyx point?
Anteriorly
What does the term thorax refer to?
The entire chest region
What is the skeletal part of the thorax called?
The thoracic cage
What forms the thoracic cage?
The sternum, ribs and their costal cartilages, and the bodies of the thoracic vertebrae
What do the costal cartilages attach?
The ribs to the sternum
How is the thoracic cage shaped?
Narrower at its superior end and broader at its inferior end, flattened from front to back
What does the thoracic cage enclose and protect?
The organs in the thoracic and superior abdominal cavities
What does the thoracic cage provide support for?
The bones of the upper limbs
What role does the thoracic cage play in?
Breathing
What is the sternum also called?
Breastbone
What type of bone is the sternum?
A flat, narrow bone
Where is the sternum located?
In the center of the anterior thoracic wall
How long is the sternum?
About 15 cm (6 in.) in length
How many parts does the sternum consist of?
Three
What is the superior part of the sternum called?
Manubrium
What is the middle and largest part of the sternum called?
Body
What is the inferior, smallest part of the sternum called?
Xiphoid process
When do the segments of the sternum typically fuse?
By age 25
What marks the points of fusion in the sternum?
Transverse ridges
What does the junction of the manubrium and body form?
Sternal angle
What is the depression on the superior surface of the manubrium called?
Jugular notch
What articulates with the medial ends of the clavicles to form the sternoclavicular joints?
Clavicular notches
What does the manubrium articulate with?
The costal cartilages of the first and second ribs
What does the body of the sternum articulate with?
The costal cartilages of the second through tenth ribs
What is the xiphoid process made of during infancy and childhood?
Hyaline cartilage
When does the xiphoid process completely ossify?
About age 40
Are ribs attached to the xiphoid process?
No
What does the xiphoid process provide attachment for?
Some abdominal muscles
What may happen if the hands of a rescuer are incorrectly positioned during CPR?
The xiphoid process may fracture and be driven into internal organs
Why may the sternum be split along the midline during thoracic surgery?
To allow surgeons access to structures in the thoracic cavity
What structures does splitting the sternum allow access to?
The thymus, heart, and great vessels of the heart
How are the halves of the sternum held together after surgery?
With wire sutures
The bones of the ___ enclose and protect organs in the thoracic cavity and in the superior abdominal cavity.
thorax
Each rib articulates posteriorly with its corresponding
thoracic vertebra
How many pairs of ribs are there?
Twelve pairs
How are the ribs numbered?
1–12 from superior to inferior
What do the ribs provide structural support to?
The sides of the thoracic cavity
How does the length of the ribs change?
They increase in length from the first through seventh, then decrease to rib 12
Where does each rib articulate posteriorly?
With its corresponding thoracic vertebra
What do the first through seventh pairs of ribs have?
A direct anterior attachment to the sternum by costal cartilage
What is the costal cartilage made of?
Hyaline cartilage
What do the costal cartilages contribute to?
The elasticity of the thoracic cage
What do the costal cartilages help prevent?
Fracturing of the sternum and/or ribs
What are true (vertebrosternal) ribs?
Ribs that have costal cartilages and attach directly to the sternum
What are the articulations formed between the true ribs and the sternum called?
Sternocostal joints
How many pairs of false ribs are there?
Five pairs
Why are they called false ribs?
Because their costal cartilages either attach indirectly to the sternum or do not attach at all
What are vertebrochondral ribs?
The eighth, ninth, and tenth pairs of false ribs
What are floating (vertebral) ribs?
The eleventh and twelfth pairs of false ribs
Why are floating ribs called that?
Because their costal cartilages do not attach to the sternum at all
Where do floating ribs attach?
Only posteriorly to the thoracic vertebrae
What is costochondritis?
Inflammation of one or more costal cartilages
What are the symptoms of costochondritis?
Local tenderness and pain in the anterior chest wall that may radiate
What can the symptoms of costochondritis mimic?
Chest pain (angina pectoris) associated with a heart attack
What is the head of the rib?
A projection at the posterior end of the rib that contains a pair of articular facets
What do the articular facets of the head of the rib fit into?
A costal facet on the body of a single vertebra or the costal facets of two adjoining vertebrae
What is the neck of the rib?
A constricted portion of a rib just lateral to the head
What is the tubercle of the rib?
A knoblike structure on the posterior surface where the neck joins the body
What does the nonarticular part of the tubercle attach to?
The transverse process of a vertebra by a ligament (lateral costotransverse ligament)
What does the articular part of the tubercle articulate with?
The facet of a transverse costal facet of a vertebra
What is the body (shaft) of the rib?
The main part of the rib
What is the costal angle?
The abrupt change in curvature of the shaft
What is the costal groove?
A groove on the inner surface of the rib that protects intercostal blood vessels and a small nerve
What are intercostal spaces?
Spaces between ribs
What do intercostal spaces contain?
Intercostal muscles, blood vessels, and nerves
How is surgical access to the lungs or thoracic structures commonly obtained?
Through an intercostal space
What is used to create a wide separation between ribs during surgery?
Special rib retractors
Why can costal cartilages bend without breaking in younger individuals?
Because they are sufficiently elastic
How does the posterior portion of the rib connect to a thoracic vertebra?
By its head and the articular part of a tubercle
What does the facet of the head of the rib fit into?
A costal facet on the body of one vertebra or the superior and inferior costal facets of two adjoining vertebrae
What does the articular facet of the tubercle articulate with?
The facet of the transverse costal facet
What are the most common chest injuries?
Rib fractures
What usually causes rib fractures?
Direct blows, most often from impact with a steering wheel, falls, or crushing injuries to the chest
Where do ribs tend to break?
At the point where the greatest force is applied
Where else may ribs break?
At their weakest point—the site of greatest curvature, just anterior to the costal angle
Which ribs are the most commonly fractured?
The middle ribs
What can fractured ribs puncture?
The heart, great vessels of the heart, lungs, trachea, bronchi, esophagus, spleen, liver, and kidneys
Are rib fractures usually painful?
Yes, rib fractures are usually quite painful
Why are rib fractures no longer bound with bandages?
Because of the pneumonia that would result from lack of proper lung ventilation
What are dislocated ribs?
Displacement of a costal cartilage from the sternum
When are dislocated ribs common?
In body contact sports
What symptom results from dislocated ribs?
Pain, especially during deep inhalations
What are separated ribs?
Displacement of a rib and its costal cartilage
What happens when a rib is separated?
A rib may move superiorly, overriding the rib above and causing severe pain
What function do intervertebral discs serve?
Shock absorbers
What happens to intervertebral discs as they function?
They are constantly being compressed
What happens if the anterior and posterior ligaments of the discs become injured or weakened?
The pressure developed in the nucleus pulposus may be great enough to rupture the surrounding fibrous cartilage (annulus fibrosus)
What may occur if the annulus fibrosus ruptures?
The nucleus pulposus may herniate (protrude) posteriorly or into one of the adjacent vertebral bodies
What is the condition called when the nucleus pulposus herniates?
A herniated (slipped) disc
In which region do herniated discs most often occur?
The lumbar area
Why do herniated discs most often occur in the lumbar area?
Because the lumbar region bears much of the weight of the body and is the region of the most flexing and bending
Where does the nucleus pulposus frequently slip?
Posteriorly toward the spinal cord and spinal nerves
What does the movement of the nucleus pulposus exert pressure on?
The spinal nerves
What symptoms can pressure on the spinal nerves cause?
Local weakness and acute pain
What happens if the roots of the sciatic nerve are compressed?
The pain radiates down the posterior thigh, through the calf, and occasionally into the foot
What can occur if pressure is exerted on the spinal cord itself?
Some of its neurons may be destroyed
What are some treatment options for a herniated disc?
Bed rest, medications for pain, physical therapy and exercises, and percutaneous endoscopic discectomy (removal of disc material using a laser)
What surgical procedure may a person with a herniated disc undergo?
A laminectomy
What is a laminectomy?
A procedure in which parts of the laminae of the vertebra and intervertebral disc are removed to relieve pressure on the nerves
Most often the nucleus pulposus herniates
posteriorly
is the result of the exaggeration of a normal curve.
abnormal curve
What may exaggerate the normal curves of the vertebral column or cause the column to acquire a lateral bend?
Abnormal curves of the vertebral column
What is the most common of the abnormal curves?
Scoliosis
What is scoliosis?
A lateral bending of the vertebral column, usually in the thoracic region
What may cause scoliosis?
Congenitally (present at birth) malformed vertebrae, chronic sciatica (pain in the lower back and lower limb), paralysis of muscles on one side of the vertebral column, poor posture, or one leg being shorter than the other
What are signs of scoliosis?
Uneven shoulders and waist, one shoulder blade more prominent than the other, one hip higher than the other, and leaning to one side
What can severe scoliosis (a curve greater than 70 degrees) cause?
Breathing is more difficult and the pumping action of the heart is less efficient
What other complications may arise from scoliosis?
Chronic back pain and arthritis of the vertebral column
What are the treatment options for scoliosis?
Wearing a back brace, physical therapy, chiropractic care, and surgery (fusion of vertebrae and insertion of metal rods, hooks, and wires to reinforce the surgery)
What is kyphosis?
An increase in the thoracic curve of the vertebral column that produces a “hunchback” look
What can cause kyphosis?
Tuberculosis of the spine, degeneration of the intervertebral discs in the elderly, rickets, poor posture, and advanced osteoporosis in females
What happens in tuberculosis of the spine that leads to kyphosis?
Vertebral bodies may partially collapse, causing an acute angular bending of the vertebral column
What leads to kyphosis in the elderly?
Degeneration of the intervertebral discs
What is another name for lordosis?
Hollow back
What is lordosis?
An increase in the lumbar curve of the vertebral column
What may cause lordosis?
Increased weight of the abdomen as in pregnancy or extreme obesity, poor posture, rickets, osteoporosis, or tuberculosis of the spine
is caused by a failure of laminae to unite at the midline.
Spina bifida
What is spina bifida?
A congenital defect of the vertebral column in which laminae of L5 and/or S1 fail to develop normally and unite at the midline
What is the least serious form of spina bifida?
Spina bifida occulta
Where does spina bifida occulta occur?
L5 or S1
What symptoms does spina bifida occulta produce?
No symptoms
What is the only evidence of spina bifida occulta?
A small dimple with a tuft of hair in the overlying skin
What are several types of spina bifida that involve protrusion of meninges and/or spinal cord called?
Spina bifida cystica
Why is spina bifida cystica called that?
Because of the presence of a cyst-like sac protruding from the backbone
What is the condition called when the sac contains the meninges from the spinal cord and cerebrospinal fluid?
Spina bifida with meningocele
What is the condition called when the sac contains the spinal cord and/or its nerve roots?
Spina bifida with meningomyelocele
What factors make spina bifida cystica more serious?
The larger the cyst and the number of neural structures it contains
What are severe complications of spina bifida?
Partial or complete paralysis, partial or complete loss of urinary bladder and bowel control, and the absence of normal reflexes
What vitamin deficiency is associated with an increased risk of spina bifida?
Folic acid
How can spina bifida be diagnosed prenatally?
By a test of the mother’s blood for a substance produced by the fetus called alpha-fetoprotein, by sonography, or by amniocentesis
What is alpha-fetoprotein?
A substance produced by the fetus
What is amniocentesis?
Withdrawal of amniotic fluid for analysis
Which vertebrae are often involved in fractures of the vertebral column?
C1, C2, C4–T7, and T12–L2
What type of injury usually causes cervical or lumbar fractures?
A flexion–compression type of injury
What are examples of situations that may cause cervical or lumbar fractures?
Landing on the feet or buttocks after a fall or having a weight fall on the shoulders
How may cervical vertebrae be fractured or dislodged?
By a fall on the head with acute flexion of the neck
What are examples of incidents that may cause a fall on the head with acute flexion of the neck?
Diving into shallow water or being thrown from a horse
What may occur as a result of fractures of the vertebral column?
Spinal cord or spinal nerve damage
When does spinal cord or spinal nerve damage occur due to fractures?
If the fractures compromise the foramina
A holistic health-care discipline that focuses on nerves, muscles, and bones. A chiropractor is a health-care professional who is con cerned with the diagnoses, treatment, and prevention of mechani cal disorders of the musculoskeletal system and the effects of these disorders on the nervous system and health in general. Treatment involves using the hands to apply specific force to adjust joints of the body (manual adjustment), especially the vertebral column. Chiro practors may also use massage, heat therapy, ultrasound, electrical stimulation, and acupuncture. Chiropractors often provide informa tion about diet, exercise, changes in lifestyle, and stress manage ment. Chiropractors do not prescribe drugs or perform surgery.
Chiropractic
Premature closure of one or more cranial sutures dur ing the first 18 to 20 months of life, resulting in a distorted skull. Premature closure of the sagittal suture produces a long narrow skull; premature closure of the coronal suture results in a broad skull. Premature closure of all sutures restricts brain growth and development; surgery is necessary to prevent brain damage
Craniostenosis
Sur gical procedure in which part of the cranium is removed. It may be performed to remove a blood clot, a brain tumor, or a sample of brain tissue for biopsy.
Craniotomy
Surgical proce dure to remove a vertebral lamina. It may be performed to access the vertebral cavity and relieve the symptoms of a herniated disc.
Laminectomy
Narrowing of the spi nal canal in the lumbar part of the vertebral column, due to hyper trophy of surrounding bone or soft tissues. It may be caused by arthritic changes in the intervertebral discs and is a common cause of back and leg pain.
Lumbar spine stenosis
Surgical procedure in which two or more vertebrae of the vertebral column are stabilized with a bone graft or synthetic device. It may be performed to treat a fracture of a ver tebra or following removal of a herniated disc.
Spinal fusion
Injury to the neck region due to severe hyper extension (backward tilting) of the head followed by severe hyperflexion (forward tilting) of the head, usually associated with a rear-end automobile collision. Symptoms are related to stretch ing and tearing of ligaments and muscles, vertebral fractures, and herniated vertebral discs.
Whiplash injury
