Final Part 1 Spinal Biomechanics Flashcards
Which Thoracic Vertebrae are Atypical?
What makes them different from Typical Thoracic Vertebrae?
- T1 and T9-12
- T1 resembles C7 and has one facet which articulates with the first rib (whereas usually it’s two vertebra per rib
- T9-T12 have variations on the location of the facets on the body and transverse process for articulation w the ribs (T11, T12 start to look like lumbar vertebra)
Out of the vertebrae, which type has the biggest body?
- Lumbar
Which type of vertebrae has transverse foramen?
- Cervical
Which part of the Thoracic vertebrae articulate with the rib head? the rib tubercle? joint name?
- costovertebral joint on side of body to rib head
- costotransverse joint on transverse process to rib tubercle
(inferior costal facet on the body of top vertebra, superior costal facet [of body] and transverse process facet of bottom vertebra articulate with a rib)
What about the anatomy of C1, the atlas, allow it to compliment the Occipital Condyles?
- concave surface of facets which face superiorly and medially allow condyles to rock
Which group of vertebrae make up Kyphosis of the spine? Lordosis? degree range? Random facts?
How many of each vertebrae are there?
- Lordosis: Cervical 20-50 degrees (45 deg ave) facet and disc planes determine curve. secondary curve. develops in response to upright posture.
- Kyphosis: Thoracic 20-50 degrees (45 deg ave) apex at T6-T7. primary curve at birth. flattening causes 1. cervical curve to decrease. 2. cervical curve to shift forward. 3. lumbar curve to increase.
- Lordosis: Lumbar 20-60 degrees (35 deg ave) extends to sacrum. apex at L3-L4. develops in response to standing. Anterior pelvic tilt increases lordosis while posterior pelvic tilt decreases lordosis.
- (think breakfast lunch and dinner) 7 cervical, 12 thoracic, 5 lumbar
When Flexing the entire spine, which vertebrae account for the most ROM? When Extending?
- Lumbar, then cervical, then thoracic
- Cervical, then lumbar, then thoracic
- cervical spine by far has the most ROM when flexing and extending.
When laterally flexing the entire spine, which vertebrae have the most ROM?
Cervical, then equally thoracic and lumbar
In rotation of the entire spine, which vertebrae have the most ROM?
- Cervical, then thoracic, then a little in lumbar
Which vertebrae have thick and broad spinous processes and which have long and slender ones?
Which have thick, strong and long transverse processes and which have slender and long ones?
- thick, broad spinous processes with long slender transverse processes are lumbar vertebrae
- long, slender spinous processes with thick, strong and long transverse processes are thoracic vertebrae. (just remember thoracic vertebrae are more even in shape)
In the lumbar region, greatest mobility is in what type of movement?
Facet orientation limits what type of movement? How are the facets oriented?
- greatest mobility in flexion-extension
- face orientation limits rotational movement. articular facets are primarily in sagittal plane but become more coronal at the lumbosacral junction (facets at 90 degree angle to the body of vertebra vs. thoracic at 60 degree angle and lower cervicals at 45 degrees)
Where is the greatest ROM?
C0-C1 condyles and atlas
Which ways do the condyles face?
- laterally and inferiorly
- form convex rockers that sit in concave surface of superior articular facet of C1
In Flexion, the occiput moves how? In Extension? Lateral Flexion? Rotation? (rotation limited by?)
- in Flexion, the occiput Glides posteriorly (10 degrees)
- In Extension, the occiput Rolls anteriorly (25 degrees)
- In Lateral Flexion, the occiput Rolls ipsilaterally and Glides contralaterally (5 degrees)
- In Rotation, the occiput Glides posteriorly ipsilaterally and Glides anteriorly contralaterally (rotation limited by the alar ligament on opposite side - 5 degrees ROM)
In Flexion, how does C1 move in relation to C2? Extension? Lateral Flexion? Rotation?
- In Flexion, C1 articular surfaces Glide posteriorly (minimal) < same as occiput
- In Extension, C1 articular surfaces Glide anteriorly (minimal) < the occiput rolls
- In Lateral Flexion, C1 articular surfaces Glide ipsilaterally (5 degrees) < occiput rolls (ips.) and glides
- In Rotation, C1 articular surfaces Glides posterior ipsilaterally and anterior contralaterally and C1 rotates around odontoid in horizontal plane (40 degree ROM, but first 25 deg occur exclusively at C1-C2) < same as occiput
How many joints does C1-C2 have with each other? Describe the inferior facet of C1 and superior facet of C2 (this is where they articulate).
- 3: two facet joints plus atlas-odontoid joint
- inferior facets of C1 are slightly convex and face inferior and medially
- superior facets of C2 are slightly convex and face superiorly and laterally
What kind of joint is the Atlas-Odontoid Joint? Which ligament courses around the posterior aspect of the odontoid? What ligament connects the odontoid to the occiput?
- synovial joint (between odontoid and Anterior arch of atlas)
- transverse ligament
- alar ligament (the one that limits rotation)
Design of Lower Cervicals C3 to C7 is consistent. The articular facets are parallel to each other (in frontal plane). The Joints of _____ limit what type of movement to only a few degrees and serve as guides to couple ________ with ________ (coupled motion).
- Joints of Luschka limit lateral flexion and serve as guides to couple lateral flexion with rotation.
- these joints are inter body joints (completed by age 18)
What does Degrees of Freedom mean?
the number of ways in which a body can move
- one degree of freedom is translation or rotation about one axis
- spinal segments exhibit 6 degrees of freedom: 3 translations & 3 rotations
Define Axis. X, Y, Z. Movement around the X-axis is in what plane? What about Y and Z?
a line around which rotary movement takes place or along which translation occurs
X-axis
- a line passing horizontally from side to side
- referred to as the “frontal” or “coronal” axis
- movement around the X-axis is in the sagittal plane
Y-axis
- perpendicular to the ground
- referred to as the “longitudinal” or “vertical” axis
- movement around the Y-axis is in the transverse or axial plane
Z-axis
- passing horizontally back to front
- referred to as the “sagittal” axis
- movement around the Z-axis is in the frontal or coronal plane
Motion occurring in sagittal plane is? Frontal? Transverse?
- In Sagittal Plane, motion is flexion and extension.
- In Frontal/Coronal Plane, motion is R or L lateral flexion
- In transverse/axial plane, motion is rotation.
What is Out of Plane Motion?
motion in which all points of a rigid body do not move in a single plane (3D movement)
What does Instantaneous Axis of Rotation mean?
- when a rigid body moves in a plane, at every instant there is a point in the body or some hypothetical extension of it that does not move
- an axis perpendicular to the plane of motion and passing through that point is the instantaneous axis (center) of rotation for that motion at that instant
- used to describe any vertebral motion in a 2D plane
- as diff force vectors are applied to a vertebra, they may cause a shift in the IAR which will dictate the pattern of deformation for that motion segment
- the IAR is different fro cervical, thoracic, and lumbar
The functional unit of the spine is referred to as? What does this mean?
- Motion Segment - smallest spinal segment exhibiting biomechanical characteristics similar to those of the entire spine
- two adjacent vertebrae and their interconnecting disc, joints, capsule, and ligaments
- six degrees of freedom