80 Questions
What is the natural curve of the lumbar spine called?
lordotic
Where does the spinal cord terminate?
L1-L2
Which part of the lumbar spine is most commonly injured in back injuries?
intervertebral disks
What are the characteristics of the body of lumbar vertebrae?
- deeper anteriorly than posteriorly - flattened superior and inferior surfaces
Describe the characteristics of the laminae of lumbar vertebrae.
thicker than cervical or thoracic vertebrae
What is the function of the mamillary process of lumbar vertebrae?
smooth rounded projection on the back of each superior articular process
Where are the accessory processes of lumbar vertebrae located?
located at the back of the root of the transverse process
What is the pars interarticularis?
part of the lamina between the superior and inferior articular processes
What are the characteristics of the transverse process of lumbar vertebrae?
- smaller than those of the thoracic spine - L1-L3 are directed laterally whereas L4-L5 are directed slightly superiorly
What is the function of the pedicles of lumbar vertebrae?
strong and directed posteriorly
What are the unique characteristics of the L5 vertebrae in terms of its shape and processes?
Wedge-shaped body, smaller spinous process, thickest transverse process
How are the zygapophyseal joints of the lumbar spine typically demonstrated?
Majority are demonstrated in a 45 degree oblique position
What is the orientation of the intervertebral foramina in the lumbar spine, and what is the exception?
Majority are situated at right angles to the midsagittal plane, except L5 which is slightly anteriorly turned
How is the sacrum formed and what is its shape?
Formed by fusion of 5 sacral vertebrae, curved triangular-shaped bone
Where is the sacrum located and what joints does it articulate with?
Located between the iliac bones of the pelvis, articulates with the sacroiliac joints
What distinguishes the female sacrum from the male sacrum?
Female sacrum is more acutely curved, resulting in a sharper angle at the junction of lumbar and pelvic curves
Where is the sacral promontory located and what is its significance?
Prominent ridge on the superior surface of the sacrum
What structures are contained within the sacral canal and where is it located?
Continuation of the vertebral (spinal) cord, transmits sacral nerves, located behind the bodies of the sacral segments
What is the composition of the coccyx and how many vertebrae does it typically have?
Composed of 4 rudimentary vertebrae fused into one bone, by adulthood
How does the coccyx curve and what projects superiorly from its first segment?
Curves inferiorly and anteriorly, coccygeal cornua
What is the unique shape of the body of the L5 vertebra?
Wedge-shaped
In what position are the majority of zygapophyseal joints in the lumbar spine demonstrated?
45 degree oblique position
What is the orientation of the intervertebral foramina in the lumbar spine, and what is the exception?
Right angles to the Midsagittal plane, except L5 which is turned slightly anteriorly
What is the composition of the coccyx?
4 rudimentary vertebrae fused into one bone by adulthood
Where is the sacral canal located and what does it transmit?
Behind the bodies of the sacral segments; transmits sacral nerves
What is the shape of the sacrum and where is it located in the body?
Curved, triangular-shaped bone located between the iliac bones of the pelvis
What is the function of the sacral foramina?
Passage for sacral nerves and blood vessels
What is the significance of the sacral promontory?
Prominent ridge on the base of the sacrum
What projects superiorly from the first coccygeal segment to join the sacral cornua?
Coccygeal cornua
Where are the sacral cornua located?
Posterior lateral aspect of the last sacral segment
Describe the characteristics of the mamillary process of lumbar vertebrae.
Smooth rounded projection on the back of each superior articular process
What is the orientation of the transverse processes in L4-L5 lumbar vertebrae?
Slightly superiorly
Explain the characteristics of the pars interarticularis of lumbar vertebrae.
Part of the lamina between the superior and inferior articular processes
Where are the accessory processes of lumbar vertebrae located?
At the back of the root of the transverse process
What is the main function of the laminae in lumbar vertebrae?
They are thicker than cervical or thoracic vertebrae
Explain the characteristics of the spinous process of lumbar vertebrae.
Large, thick, and blunt projecting posteriorly and horizontally
What distinguishes the lumbar vertebrae from thoracic vertebrae in terms of the pedicles?
Pedicles in lumbar vertebrae are stronger and directed posteriorly
Describe the characteristics of the body of lumbar vertebrae.
Deeper anteriorly than posteriorly, with flattened superior and inferior surfaces
What is the natural curve of the lumbar spine called?
Lordotic curve
Where does the spinal cord terminate?
L1-L2
What are the unique characteristics of the L5 vertebra?
Wedge-shaped body, wedge-shaped intervertebral disk, shorter spinous process, thickest transverse process
Where is the sacral promontory located?
On the base of the sacrum
What is the composition of the coccyx?
4 rudimentary vertebrae fused into one bone
What is the shape of the sacrum and where is it located?
Curved, triangular-shaped bone located between the iliac bones of the pelvis
Where are the sacral cornua located?
On the posterolateral aspect of the last sacral segment
What is the function of the sacral canal?
Location of the continuation of the vertebral (spinal) cord and transmission of sacral nerves
What projects superiorly from the first coccygeal segment to join sacral cornua?
Coccygeal cornua
How is the female sacrum different from the male sacrum?
Female sacrum is more acutely curved, resulting in a sharper angle at the lumbar-pelvic junction
Describe the anatomy of the sacral ala.
Wing-like lateral mass on each side of the sacral base containing articular surface for the iliac bones
What is the orientation of the intervertebral foramina in the lumbar spine?
At right angles (90 degrees) to the Midsagittal plane, except for L5 which is slightly turned anteriorly
What is the natural curve of the lumbar spine called?
lordotic
Where does the spinal cord terminate?
L1-L2
Which part of the lumbar spine is most likely to be injured in back injuries?
intervertebral disks
What are the characteristics of the laminae of lumbar vertebrae?
thicker than cervical or thoracic vertebrae
What is the function of the pedicles of lumbar vertebrae?
strong and directed posteriorly
What is the shape of the mamillary process of lumbar vertebrae?
smooth rounded projection
Where are the accessory processes of lumbar vertebrae located?
back of the root of the transverse process
What is the part of the lamina between the superior and inferior articular processes called?
pars interarticularis
Describe the characteristics of the spinous process of lumbar vertebrae.
large, thick, blunt, project posteriorly and horizontally
What are the characteristics of the transverse process of lumbar vertebrae?
smaller than those of the thoracic spine, L1-L3 directed laterally, L4-L5 slightly superiorly
Which part of the lumbar spine is most commonly injured in back injuries?
the intervertebral disks
What is the unique shape of the mamillary process of lumbar vertebrae?
smooth rounded projection
Describe the characteristics of the transverse process of lumbar vertebrae.
smaller than those of the thoracic spine; L1-L3 are directed laterally whereas L4-L5 are directed slightly superiorly
Where are the accessory processes of lumbar vertebrae located?
at the back of the root of the transverse process
What is the function of the pedicles of lumbar vertebrae?
strong and directed posteriorly
What are the characteristics of the laminae of lumbar vertebrae?
thicker than cervical or thoracic vertebrae
What are the unique characteristics of the L5 vertebra?
The transverse processes are directed slightly superiorly; The body is deeper anteriorly than posteriorly
Where is the sacrum located and what joints does it articulate with?
located at the base of the spine; articulates with the ilium of the pelvis
What is the composition of the coccyx?
formed by fusion of 3-5 rudimentary vertebrae
What is the orientation of the intervertebral foramina in the lumbar spine?
oriented more vertically
What is the orientation of the majority of zygapophyseal joints in the lumbar spine demonstrated?
45 degree oblique position
Where are the sacral foramina located?
On anterior and posterior walls of sacral canal
What is the shape of the sacrum and where is it located?
Curved, triangular-shaped bone located between the iliac bones of the pelvis
What projects superiorly from the first coccygeal segment to join the sacral cornua?
Coccygeal cornua
Where is the sacral canal located and what does it transmit?
Behind the bodies of the sacral segments; transmits sacral nerves
What is the composition of the coccyx and how many vertebrae are fused into one bone by adulthood?
4 rudimentary vertebrae fused into one bone
Where does the spinal cord terminate in relation to the sacrum?
Sacral canal; behind the bodies of the sacral segments
What is the function of the sacral promontory and where is it located?
Prominent ridge on the base of the sacrum; marks the sacral hiatus
What is the unique shape of the L5 vertebra compared to other lumbar vertebrae?
Wedge-shaped body
What is the significance of the female sacrum being more acutely curved?
Results in a sharper angle at the junction of the lumbar and pelvic curves
Study Notes
Lumbar Spine
- The natural curve of the lumbar spine is called lordosis.
- The spinal cord terminates at the level of the L1 or L2 vertebra.
- The pars interarticularis is the most commonly injured part of the lumbar spine in back injuries.
Lumbar Vertebrae
- The body of lumbar vertebrae is kidney-shaped and has a larger size compared to thoracic vertebrae.
- The laminae are broad and flat, forming the posterior wall of the vertebral foramen.
- The pedicles are stout and directed posteriorly.
- The transverse process is long and slender, and its orientation changes from L1 to L5.
- The mamillary process is a small, rounded projection located at the tip of the transverse process.
- The accessory processes are small, located at the base of the transverse process.
- The pars interarticularis is the region between the superior and inferior articular processes.
- The zygapophyseal joints are demonstrated in a sagittal or near-sagittal plane.
- The intervertebral foramina are oriented in a coronal plane, except for L5-S1, which is oriented in a sagittal plane.
L5 Vertebra
- The L5 vertebra has a unique shape, with a larger body and a more horizontal transverse process compared to other lumbar vertebrae.
Sacrum
- The sacrum is formed by the fusion of five vertebrae and is located at the base of the spine.
- It is shaped like a triangular wedge, with a broad base and a narrow apex.
- The sacrum articulates with the two iliac bones to form the sacroiliac joints.
- The sacral canal is located within the sacrum and transmits the sacral nerve roots.
- The sacral promontory is located at the anterior tip of the sacrum and serves as an attachment point for ligaments.
- The sacral foramina are located on the anterior and posterior surfaces of the sacrum.
- The female sacrum is more acutely curved than the male sacrum.
Coccyx
- The coccyx is composed of 3-5 fused vertebrae and is located at the end of the spine.
- It curves downward and forward, with a projection from the first coccygeal segment that joins the sacral cornua.
- The sacral cornua are located at the posterolateral tip of the sacrum.
Test your knowledge about the lumbar spine anatomy with this quiz. Questions cover the number of lumbar vertebrae, size variations, weight-bearing capacity, natural curve, termination of the spinal cord, common injuries, and characteristics of the lumbar vertebrae.
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