Podcast
Questions and Answers
What is the primary function of the intervertebral disc?
What is the primary function of the intervertebral disc?
Which part of the intervertebral disc is responsible for distributing mechanical loads?
Which part of the intervertebral disc is responsible for distributing mechanical loads?
Why is the anterior wall of the annulus fibrosus thicker than the posterior wall?
Why is the anterior wall of the annulus fibrosus thicker than the posterior wall?
What effect does forward bending have on the annulus fibrosus?
What effect does forward bending have on the annulus fibrosus?
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How does the structural arrangement of fibers in the annulus fibrosus contribute to resistance against forces?
How does the structural arrangement of fibers in the annulus fibrosus contribute to resistance against forces?
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What characteristic of the annular wall contributes to spinal stability?
What characteristic of the annular wall contributes to spinal stability?
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Why are the posterior wall fibers of the annulus fibrosus more prone to herniation?
Why are the posterior wall fibers of the annulus fibrosus more prone to herniation?
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When twisting occurs, what happens to the annulus fibers aligned in the direction of the twist?
When twisting occurs, what happens to the annulus fibers aligned in the direction of the twist?
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What is the primary function of the lordotic curve in the spine?
What is the primary function of the lordotic curve in the spine?
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Which spinal region is characterized by relatively immobile vertebrae?
Which spinal region is characterized by relatively immobile vertebrae?
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What might occur as a result of chronic back pain?
What might occur as a result of chronic back pain?
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Which of the following components is NOT part of the functional spinal unit?
Which of the following components is NOT part of the functional spinal unit?
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What does a higher ratio between the vertebral body and disc indicate?
What does a higher ratio between the vertebral body and disc indicate?
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How does the structure of intervertebral discs contribute to their function?
How does the structure of intervertebral discs contribute to their function?
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What structural characteristic differentiates lumbar vertebrae from cervical vertebrae?
What structural characteristic differentiates lumbar vertebrae from cervical vertebrae?
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What is the role of the sacrum in the spinal column?
What is the role of the sacrum in the spinal column?
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What happens to the height of the vertebral column throughout the day?
What happens to the height of the vertebral column throughout the day?
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What primarily initiates side bending in the lumbar region?
What primarily initiates side bending in the lumbar region?
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Which lumbar vertebrae are commonly injured due to their anatomical structure?
Which lumbar vertebrae are commonly injured due to their anatomical structure?
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In lumbar extension, which muscle group is primarily responsible for extension?
In lumbar extension, which muscle group is primarily responsible for extension?
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Which of the following muscles is considered an efficient stabilizer for spinal stability?
Which of the following muscles is considered an efficient stabilizer for spinal stability?
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What type of contraction occurs on the opposite side during lateral flexion?
What type of contraction occurs on the opposite side during lateral flexion?
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Which action does the rectus abdominis primarily resist?
Which action does the rectus abdominis primarily resist?
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In which scenario does the psoas muscle facilitate hip flexion?
In which scenario does the psoas muscle facilitate hip flexion?
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Which muscle is primarily responsible for controlling the lumbar spine against extension forces?
Which muscle is primarily responsible for controlling the lumbar spine against extension forces?
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What is the primary role of the Transverse Abdominis?
What is the primary role of the Transverse Abdominis?
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Which statement accurately describes the Quadratus Lumborum's functions?
Which statement accurately describes the Quadratus Lumborum's functions?
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What typically occurs when the lumbosacral angle is increased?
What typically occurs when the lumbosacral angle is increased?
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Which muscle acts as an antagonist to the diaphragm?
Which muscle acts as an antagonist to the diaphragm?
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What measurement is considered a key indicator of major body systems' functionality?
What measurement is considered a key indicator of major body systems' functionality?
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What is the effect of degenerative disc disease on the discs over time?
What is the effect of degenerative disc disease on the discs over time?
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In terms of gait mechanics, which factor does NOT directly impact walking speed?
In terms of gait mechanics, which factor does NOT directly impact walking speed?
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What can high joint reaction forces (JRF) on the spine lead to?
What can high joint reaction forces (JRF) on the spine lead to?
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What is the typical lumbosacral angle for an adult?
What is the typical lumbosacral angle for an adult?
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What happens to intradiscal pressure in the sitting position with a forward lean?
What happens to intradiscal pressure in the sitting position with a forward lean?
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What characterizes the terminal stance phase of the gait cycle?
What characterizes the terminal stance phase of the gait cycle?
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During which phase of the gait cycle does the weight transfer primarily occur?
During which phase of the gait cycle does the weight transfer primarily occur?
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What is the knee flexion angle during the initial swing phase?
What is the knee flexion angle during the initial swing phase?
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Which of the following describes the ankle position during the mid stance phase?
Which of the following describes the ankle position during the mid stance phase?
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What is the total range of motion (ROM) of the foot in the frontal plane?
What is the total range of motion (ROM) of the foot in the frontal plane?
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What is the position of the thigh during the terminal swing phase?
What is the position of the thigh during the terminal swing phase?
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Which phase indicates the end of the pre-swing and the start of the swing phase?
Which phase indicates the end of the pre-swing and the start of the swing phase?
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During which phase of the gait cycle is the ankle at 5° dorsiflexion?
During which phase of the gait cycle is the ankle at 5° dorsiflexion?
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What is the relationship between hip flexion and toe clearance during the initial swing phase?
What is the relationship between hip flexion and toe clearance during the initial swing phase?
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What is the ankle position at the loading response phase?
What is the ankle position at the loading response phase?
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Which statement best describes the primary motion of the thoracic spine?
Which statement best describes the primary motion of the thoracic spine?
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What is the primary function of the cervical spine?
What is the primary function of the cervical spine?
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Which joint is responsible for the 'YES' nodding motion?
Which joint is responsible for the 'YES' nodding motion?
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What is the primary role of the multifidi muscles?
What is the primary role of the multifidi muscles?
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Which anatomical structure stabilizes the C1-C2 joint?
Which anatomical structure stabilizes the C1-C2 joint?
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Which motion is primarily accounted for by the C1-C2 joint?
Which motion is primarily accounted for by the C1-C2 joint?
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What is the classification of true ribs?
What is the classification of true ribs?
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What motion do the muscles of the rectus capitis group primarily facilitate?
What motion do the muscles of the rectus capitis group primarily facilitate?
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What is the curvature of the thoracic spine described as?
What is the curvature of the thoracic spine described as?
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Which of the following best describes lumbar motion?
Which of the following best describes lumbar motion?
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How does the thoracic spine's structure aid in stability?
How does the thoracic spine's structure aid in stability?
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What do the Alar ligaments connect?
What do the Alar ligaments connect?
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What muscle group primarily assists with cervical extension?
What muscle group primarily assists with cervical extension?
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What happens to the lower thoracic vertebral bodies as you move downward?
What happens to the lower thoracic vertebral bodies as you move downward?
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Study Notes
Normal Spine Curves
- Lordotic: Inward curvature of the spine
- Located in the cervical (neck) and lumbar (lower back) regions
- Normal function: Helps distribute weight and absorb shock
- Excessive curve: May lead to lordosis (swayback)
- Kyphotic: Outward curvature of the spine
- Located in the thoracic (upper back) and sacral (pelvic) regions
- Normal function: Provides stability and supports the body's upright posture
- Excessive curve: May lead to kyphosis (hunchback)
Spine Segments
- 7 cervical, 12 thoracic, 5 lumbar, 5 sacrum (fused), 4 coccygeal (fused)
- Cervical (C1-C7)
- More flexible, supporting the head
- Wide range of motion
- Flexion: 45-50°
- Extension: 60-70°
- Lateral flexion (side bending): 40-45°
- Rotation: 70-90°
- Thoracic (T1-T12)
- Relatively immobile
- Ribs attach
- Plays with the balance of mobility vs. stability
- Lumbar (L1-L5)
Sacrum and Coccyx
- Sacrum: Triangle base of spine connects spine to pelvis
- Coccyx: Delivers nerves to pelvic organs, few small bones, remnant of tail
Mobility and Stability
- 3 aspects
- Neurological control
- Bone structure (passive)
- Muscle (active)
- Body is great at compensating, making it difficult to diagnose chronic back pain.
- Recruiting bigger muscles instead of smaller stabilizers sacrifices mobility.
Spinal Column
- Stability
- Protect spinal cord
- Maintain upright posture
- Transmit weight to lower limbs
- Mobility
- Provide motion for head and trunk
- Absorb force
- Provide space for muscle attachments
- Functional spinal unit
- Allows for movement
- 2 adjacent vertebrae, Intervertebral disc, Intervening disc, Intervening ligaments
- Allows for movement
Vertebrae Motion
- 6 degrees of freedom
- Distraction, Compression, Translation, Extension, Side flexion
Intervertebral Joints
- Allow for small motion between segments
- Separated by fibrous-cartilaginous discs
- Ratio between vertebral body and disc dictates mobility
- Higher ratios = thicker discs = more motion, especially in cervical regions
- Lower ratios = thinner discs = limited motion, especially in thoracic regions
- Also, motion can vary during the day
Vertebral Disc
- Fluid-filled (jelly donut)
- Outer layer: annulus fibrosus (fibrous ring)
- Inner layer: nucleus pulposus (gel)
- Shock absorption: maintains space between vertebrae and maintains height
- Avascular (nutrition via endplate) = thin cartilage layer between vertebral body and intervertebral disc
Disc Anatomy
- Spongy center = nucleus pulposus
- Fibrous ring = annulus fibrosus
- Annulus = whole thing
- Annulus Fibrosus: entire outer fibrous ring
- Concentric layers of collagen and fibrocartilage
- Annular Wall: outer layer
- 12-14 layers altering obliquities of about 30°
- Annulus Fibrosus: entire outer fibrous ring
Disc Under Compressive Loads
- Nucleus pulposus absorbs water and expands
- Hydration decreases with increased load, increasing internal pressure
- Compressive stress on disc causes tensile stress in annulus fibrosis
- Increased stiffness = stability but sacrifices mobility
- Laterally against annulus, and against end vertebrae
- Increased stiffness superiorly/inferiorly
Disc Kinematics
- Nucleuses flatten under axial compression
- Forces are distributed throughout the layers.
- Protects the spine from localized damage
Intradiscal Pressure
- Rises with annular stress increases and uneven loading
- Nuclei are driven away from closure of space to allow material to distribute evenly
Anterior Longitudinal Ligament
- Resists extension forces, limits excessive lordosis
- Fiber span: several segments (superficial) and single segment (deep)
Posterior Longitudinal Ligament
- Resists flexion
Atlanto-occipital Joint & C1-C2
- “Yes” nodding motion
- Condyles of occipital bone (convex)
- Facets of atlas (concave)
- “No” head joint- rotation
- Atlas = bony ring without body, pivot joint
- 50% rotation of transverse plane
Cervical Motion
- Most flexible region
- Anatomical position: approximately 80° extension, 50° flexion, 30-35° lordosis, and 20-25° sagittal plane motion
Lateral Flexion
- Down and back slide = same side we're going to
- Rotation is still down and back
Cervical Coupling
- Combines all motions
- C1-C2 not involved
Cervical Flexion Muscles
- Rectus capitis anterior, Rectus capitis lateralis, Longus capitis, Longus colli, Sternocleidomastoid, Scalenes
Cervical Extension Muscles
- Rotators, Splenius capitis, Splenius cervicis, Rectus capitis posterior major/minor, Obliquus capitis superior/inferior
Thoracic Spine
- Least mobile due to ribs
- Sacrifices mobility for stability
- Articulates with ribs
Thoracic Spine Curve
- 40° kyphotic curve
- Curve from wedge-shaped vertebral bodies
- T1 similar to C7
- Disc to height ratio highest
- Decreases in tensile forces
- Decreases possibility of disc injury as you move to lower regions of spine
Rib Anatomy
- Three classifications (12 pairs)
- True ribs
- Direct connection
- False ribs
- Cartilage connection
- Floating ribs
- No connection
- True ribs
- Costotransverse joint: Takes a lot of effort to displace
Thoracic Motion
- Extension is primarily caused by lumbar extensors
- Muscles:
- Erector spinae group
- Quadratus lumborum
Axial Rotation
- Abdominal muscles and trunk rotators
- Abs are farther away from spine than rotators, increase the arm's moment
- Rotators have high sensory cells
- Side bending is initiated by ipsilateral abs + erectors and continued by gravity.
Lumbar Flexion
- Muscles:
- Rectus abdominis
- Internal obliques
- External obliques
Lumbar Extension
- Layering effect of muscles
- 2 classes of muscles
- Erector spinae (spinae, longissimus, iliocostalis)
- Middle (semispinalis) connects adjacent
- Erector spinae (spinae, longissimus, iliocostalis)
- Deep spinal muscles; connects adjacent muscles, Multifidus, Rotatores, and some other muscles that aren't the primary
Lateral Flexion
- Involved quadratus lumborum, psoas major, and unilateral flexors / extensors
- The opposite side of the motion is involved in eccentric contraction, holding a position
Lumbar Stability
- Efficient stabilizers
- Obliques, Transverse abdominis, Multifidus, Quadratus lumborum
- Inefficient stabilizers
- Rectus abdominis, Longissimus, Latissimus dorsi
Rectus Abdominis
- Isometric contraction increases abdominal pressure
- Resist extension forces
- Controls against hyperextension
- Stabilizes spine; holding breath during squatting increases intra-abdominal pressure
Psoas
- Function depends on the position of the lumbar spine
- Hip flexion/external rotation
- Unilateral contraction = side bending
- Bilateral contraction = flexes trunk toward hip & arches lower back
External Oblique
- Stabilizer vs. neutralizer
- Pulls chest down, compresses abdominal cavity, increases intra-abdominal pressure
- Involved in flexion and rotation (opposite side) working against each other.
Internal Oblique
- Antagonist to the diaphragm, compresses organs and produces trunk rotation
- Works with opposite side external oblique
Quadratus Lumborum
- Unilateral = laterally flexes vertebral column; Bilateral = extends lumbar column
- Provides lateral stability
Sacrum
- 1-3° motion relative to ilium
- Supports weight of spine and entire upper body
- Acts as a keystone
Loads on the Spine
- Body weight acts anterior to the spine
- Creates forward bending loads
- Erectors & spine extensors are always active to some level
Disc Failure
- Pressure elevated by bending, coughing, sneezing, straining
- Intradiscal pressure
- Sitting (forward lean)
- Standing
- Side lying
- Supine lying
- Order of most to least pressure
Disc Injuries
- Degenerative disc disease: flattening over time, fissures
- Herniated discs: nucleus pulposus migration, can apply pressure on nerves
Walking Speed
- 6th major vital sign
- Cardiorespiratory,
- Musculoskeletal,
- Neurological
- Scores in any major deficits will likely show up in walking speed
- Reliability: consistency of a measurement
- Validity: if the test is measuring what it is intended to assess
Cadence, Stride Length, Gait Rhythm, and ONE STRIDE
- Cadence: number of steps per minute (men: ~108, women: ~118)
- Stride length: foot-to-foot
- Men: ~1.51 m, Women: ~1.32 m
- One stride is 1 complete gait cycle
- Step: initial contact of one foot to the other
- Stride: 2 steps (initial contact of one limb to the next contact of the same limb)
Gait Cycle Phases
- Stages of the stride cycle
- Double support
- Single support
- Double support (again)
- Initial contact
- Loading Response
- Single support - Mid Stance
- Terminal stance
- Pre-swing
- Double Support
- Initial, Mid, and Terminal swing
Sagittal Plane Kinematics
- Initial contact
- Thigh - 25° flexion, knee - 0-5°flexion, Ankle - neutral
- Mid-stance
- Thigh - 0°, knee - 0°, Ankle- 5° dorsiflexion
- Terminal stance
- Thigh - 15° extension, knee - 0°, Ankle- 10° dorsiflexion
- Initial swing
- Thigh -15° flexion, kneee-60°flexion
- Ankle - 5° plantar flexion
- Mid swing
- Thigh + knee- 25° flexion, Ankle-neutral
- Terminal swing
- Thigh -25° flexion, knee -0°, Ankle- 15° plantar flexion
Frontal Plane Kinematics
- Total motion:
- 7° eversion, 6° inversion, 13° total ROM
- Pronated = more flexion
- Supinated = more rigid
- Initial Contact (rigid supinated)
- Loading response (flex pronate)
- Walking GRFs peak eversion is 7°during mid-stance
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Description
Explore the normal spine curves and segments in this quiz. Learn about lordotic and kyphotic curves, their functions, and the anatomy of cervical, thoracic, lumbar, sacral, and coccygeal regions. Test your knowledge on spinal structure and function.
