Exam 2 Flashcards
Biomechanics (Lec 3), Kinesiology + Spine
What does the henneman’s principle state? What is the benefit of it?
Motor units are recruited from smallest to largest (this helps preserve energy)
Differentiate between the two types of bone
Cortical Bone: Dense and forms the outer layer of a bone segment
Trabecular Bone: Low density and fills the inside of a bone segment
What are the 6 types of bone fractures?
- Compression Fracture (caused by compression)
- Tension Fracture (caused by pulling at both ends of the bone segment)
- Bending Fracture (caused by bending of the bone segment)
- Shear Fracture (caused by two forces going opposite directions… one force moves the upper part of the bone one way and one force moves the lower part of the bone the other way)
- Torsion Fracture (caused by twisting of the bone segment)
- Combined Loading Fracture [caused by compression and torsion (twisting) of a bone segment]
How do you strengthen a bone?
Weight bearing exercises
(Supported by Wolff’s Law: “If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading)
How is “stiffness” determined?
- The force that acts on an object (stress)
- The shape of the object (strain)
ex: An object is considered stiff if a large amount of force can only cause a small change of shape
What are the 3 types of joints?
Synarthrosis: Joints that can barely move (skull)
Amphiarthrosis: Joints that can slightly move
Diarthrosis: Joints that can move freely with a certain amount of “degrees of freedom”
Degrees of Freedom (DOF): The number of axis that the joint can move around
What are the 6 types of joints? describe and provide an an example for each
- Plane Joint: Allows for gliding motion only (ex: intercarpal joint)
- Hinge Joint: Allows for 1 degree of freedom and moves like a door hinge (ex: humeroulnar joint)
- Pivot Joint: Allows for 1 degree of freedom and described as a “ring like” bone rotating on another bone (ex: atlantoaxial joint)
- Saddle Joint: Allows for 2 degrees of freedom and has a convex and concave configuration (ex: CMC joint)
- Condyloid Joint: Allows for 2 degrees of freedom and described as an oval head sitting on an elliptical cavity (ex: radiocarpal joint)
- Ball and Socket Joint: Allows for 3 degrees of freedom (ex: hip and shoulder joints)
Differentiate between a close-packed and loose-packed joint position?
Closed-packed: Joint space is minimized
Loose-packed: Joint space is maximized
What are the 3 types of muscle fibers and their function?
Type I: Slow-twitch oxidative fibers
- High endurance, low power
Type IIa: Fast-twitch oxidative fibers
- Intermediate power and endurance
Type IIb: Fast-twitch gylcolytic fibers
- High power, low endurance
T or F? Posture muscles are more type I whereas power muscles are more type II
True
T or F? Atrophy is greater in type II muscle fibers than it is in type I
True
How do muscle neuromechanics work? provide an example
Alpha motor neurons send a signal to an axon, and the axon carries the signal to innervate muscle fibers
ex: flicking a light switch on, the current traveling through the wires, then eventually turning the lights on
T or F? Small size motor units control type I muscle fibers, medium size motor units control type IIa, large size motor units control type IIb muscle fibers
True
Fill in the blank…
_________ arranged muscles allow for greater ROM, while _________ arranged muscles allow for greater force
Parallel, Pennate
The point that marks the end of a stretch, and beginning of permanent muscle strain is called the…
Yield point
Differentiate between active and passive insufficiency
Active Insufficiency (muscle weakness): A position in which a muscle is weak due to extreme shortening or lengthening of a muscle
Passive Insufficiency (muscle tightness): A position in which joint mobility is restricted due to a muscle not being long enough (tight muscle) to allow full ROM
What is considered to be the ideal standing posture? where does the line of gravity go through?
Line of gravity goes through mastoid process, anterior to 2nd sacral segment, posterior to the hip joint, anterior to knee joint, anterior to ankle joint
What is the primary purpose of having a curvature in the spine?
Convert vertical compression into slight horizontal force (disperses the force better)
Which motions do they anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), and ligamentum flavum limit?
Anterior Longitudinal Ligament (ALL): Limits lordosis and extension
Posterior Longitudinal Ligament (PLL): Limits kyphosis and flexion (located posterior to vertebral body, anterior to spinal cord)
Ligamentum Flavum: Limits kyphosis and flexion (Located posterior to spinal cord)
Which ligaments support the spine and it’s curve?
- Interspinous ligament
- Supraspinous ligament
- Apophyseal ligament
- Anterior longitudinal ligament
- Posterior longitudinal ligament
- Ligamentum Flavum
Describe the intervertebral discs
Contains the nucleus pulposus and annulus fibrosus
Nucleus Pulposus:
- Inner layer
- 70-90% water
Annulus Fibrosus:
- Outer layer
- Protects nucleus pulposus
- Fiber orientation goes several directions
What is a herniated disc?
When the nucleus pulposus protrudes out beyond the damaged annulus fibrosus
During Extension: Compresses the posterior disc, nucleus pulposus moves forward
During Flexion: Compresses the anterior disc, nucleus pulposus moves backward
What is the “end plate”?
A thin, porous plate that separates the disc and vertebrae that allows fluid inflow and outflow
- End plates are the “weak link” of the spinal column
Describe the curvature and movement norms of the atlanto-occipital joint. Which structures are concave/convex?
Occipital Condyle: Convex
Atlas: Concave
Flexion: 5 degrees
Extension: 10 degrees
Lateral Flexion: 5 degrees
Axial Rotation: Limited
During _________, the occipital condyles slide backward against the superior articular surface. During __________, the occipital condyles slide forward against the superior articular surface. During ___________, the occipital condyles slide against superior articular facet towards opposite side
Flexion, Extension, Lateral Flexion
T or F? The transverse ligament keeps the dens in contact with the anterior arch of atlas while the alar ligament checks the rotation of the head and atlas on axis
True
Which ligament restricts humans from excessive rotation of the head like an owl?
Alar ligament
What does the lower cervical spine consist of?
Intervertebral joints, uncovertebral joints, facet joints
What is the uncovertebral joint?
The articulation between uncinate process and adjacent vertebral body
(Note: The uncinate process is a hook shaped process on the lateral borders of the vertebral bodies… only in lower cervical vertebrae)
T or F? The uncovertebral joint guides anterior-posterior sliding (flexion and extension), but restricts lateral sliding and rotation
True
What is the angle of inclination of lower c-spine (C3-C7) facet joints? What are the ROM norms?
45 degrees
Extension: 55-60 degrees
Flexion: 35-40 degrees
Axial rotation: 30-35 degrees
Lateral Flexion: 30-35 degrees
Explain the arthrokinematics of the vertebral facet joints
During flexion, the inferior facet slides upward and forward
During extension, the inferior facet slides downward and backward
During lateral flexion and rotation, the ipsilateral inferior facet slides backward and downward
During head protraction, the lower cervical spine is _________ while the upper cervical spine is _________. During head retraction, lower cervical spine is _________ while the upper cervical spine is _________
flexed, extended
extended, flexed
The longus capitis and longus colli can perform which actions?
Flexion and lateral flexion
The splenius capitis and cervicis can perform which actions?
Bilateral:
- Cervical extension
Unilateral:
- Lateral flexion to the ipsilateral side
- Ipsilateral rotation
The anterior scalene can perform which actions?
Bilateral:
- Cervical flexion
Unilateral:
- Contralateral rotation
- Ipsilateral lateral flexion
The obliquus capitis inferior can perform which actions?
Ipsilateral rotation and extension
The sternocleidomastoid can perform which actions?
Bilateral:
- Extension of the upper cervical spine
- Flexion of the lower cervical spine
Unilateral:
- Ipsilateral lateral flexion
- Contralateral rotation
The scalene medius can perform which actions?
Unilateral:
- Lateral flexion to the ipsilateral side
Describe the sternocostal joints
The articulation between the sternum and costal cartilage
List the ROM norms for the thoracic region
Flexion: 30-40 degrees
Extension: 20-25 degrees
Transverse Rotation: 30-35 degrees
Lateral Flexion: 25-30 degrees
Why is t-spine motion limited?
- Restriction of the rib cage
- The space between the spinous processes is limited
- Facet joint configuration
What is the angle of inclination of T1-T8 facet joints?
75 degrees
T or F? The lower thoracic region (T9-T12) has a sagittal plane bias
True
Which analogy is used when referring to the joints of inspiration and expiration? Explain it
Bucket handle analogy
During inspiration, the handle rotates upwards (rib cage elevation)
Which muscles perform inspiration? expiration?
Inspiration Muscles:
- External intercostals
- Parasternal fibers (of internal intercostals)
Expiration Muscles:
- Interosseus fibers (of internal intercostal)
What is the most important muscle of inspiration?
Diaphragm (dome shaped muscle)
The transversus thoracis can perform which actions?
Rib cage depression, forced expiration
What does Boyle’s law state?
Pressure and volume are negatively related
T or F? Contraction of the inspiration muscles expands the intra-thoracic volume while contraction of the expiration muscles reduces the intra-thoracic volume
True
T or F? L1-L4 have a sagittal and vertical bias
True
T or F? L5-S1 are similar to the upper thoracic region
True
List the ROM norms of the lumbar region
Flexion: 40-50 degrees
Extension: 15-20 degrees
Lateral Flexion: 20 degrees
Transverse Rotation: 5-7 degrees
Describe the sacrohorizontal angle
The angle of the superior margin of the sacrum from horizontal orientation
Normal Range: 30-40 degrees (increases during pelvic tilt)
What is spondylolisthesis?
Spondylolisthesis is when the disc protrudes away from the spinal column
Describe the SI joint
- Fibrotic and not very movable
- Supported by strong ligaments
What is pelvic nutation and counternutation?
Pelvic Nutation:
- Anterior tilt of the sacrum in relation to the ilium
- Posterior tilt of the ilium relative to the sacrum
- Both close the SI joint
Pelvic Counternutation:
- Opposite of nutation
- Opens the SI joint
Which ligaments limit pelvic nutation?
- Interosseus ligament
- Sacrospinous ligament
- Sacrotuberous ligament
Which ligaments limit counternutation?
- Short posterior sacroiliac ligament
- Long posterior sacroiliac ligament
Which muscles generate nutation torque actively?
Erector spinae, Rectus abdominis, Biceps femoris
The rectus abdominis can perform which actions?
Bilateral:
- Flexion
Unilateral:
- Side flexion
The external oblique can perform which actions?
Bilateral:
- Flexion
Unilateral:
- Lateral flexion
- Contralateral rotation
The internal oblique can perform which actions?
Bilateral:
- Flexion
Unilateral:
- Lateral flexion
- Ipsilateral rotation
T or F? 70% of oblique strains occur in the external oblique opposite of the dominant arm
False
70% of oblique strains occur in the INTERNAL oblique opposite to the dominant arm
The iliopsoas can perform which actions?
- Hip flexion
- Lumbar flexion
- Lateral lumbar flexion
The transverse abdominis (TA) does what?
Compresses the abdominal contents
The quadratus lumborum can perform which actions?
Bilateral:
- Lumbar extension
Unilateral:
- Lateral flexion of the lumbar spine
- Hip hiking
Which actions can the lumbar extensors (erector spinae and transversospinal muscles) perfom?
Erector Spinae:
- Lumbar extension
- Lumbar lateral flexion
Transversospinal muscles:
- Lumbar extension
- Contralateral rotation
- Lumbar lateral flexion
What does the AO joint look like?
Cup on a saucer
Describe the thoracolumbar fascia
Anterior Layer:
- anterior to QL
Middle Layer:
- posterior to QL
Posterior Layer:
- posterior to back extensors
- attach to spinous processes
All 3 layers blend together at the lateral raphe
Describe the lumbopelvic rythym
Lumbar: 40 degrees of flexion
Hip: 70 degrees of flexion
T or F? The upper thoracic region has a frontal plane bias?
True
Which of the following muscles CANNOT achieve cervical flexion when working bilaterally?
a. Scalenus Anterior
b. Scalenus Medius
c. Sternocleidomastoid
b. Scalenus Medius
T or F? The upper thoracic facets are more vertically oriented than the lower cervical facets
True
During flexion of the atlanto-occipital joint, the occipital condyle slides ________ on the superior articular facet of the atlas
a. anteriorly
b. posteriorly
c. to the right
d. to the left
b. posteriorly
Which of the following muscles, when contracting concentrically, can assist in generating nutation toque at the SI joint?
a. Quadriceps
b. Erector Spinae
c. Rectus Abdominis
d. b and c
e. a, b, and c
d. b and c
Based on the mechanical principles that we have learned in class, a spinal extension could make which of the following conditions worse:
a. Spondylolisthesis at L5-S1 region
b. Posterior protrusion of an intervertebral disc between L4 and L5
c. Facet joint syndrome
a and c
a, b, and c
a and c
T or F? When extending the trunk, hip extensors fire first then lumbar extensors fire next
True
T or F? When seated, leaning forward will cause the most pressure
True
Which muscles cannot achieve cervical rotation?
Scalenus medius + Longus colli
T or F? An anterior tilt of the sacrum increases sacrohorizontal angle
True
T or F? Increasing sacrohorizontal angle can worsen L5-S1 spondylolisthesis
True
During concentric contraction, a muscle can generate _______ force with _______ velocity.
True
