Motor Control of Trunk, Lower Extremity

Question 1

What structure of the femur forms the angle of inclination?

What is a normal angle of inclination?

Answer 1

Formed by drawing an imaginary line through the center of the femoral shaft and the center of the femoral neck.

A normal angle is about 125 degrees in the frontal plane. This would orient the femoral shaft down and slightly toward the body.

Question 2

What are the potential consequences of altered angle of inclination of femur? Explain how the biomechanics may change all the way down the joint.

For example:

If the angle of inclination is <125

Answer 2

If the angle of inclination of the femur is oriented less than 125 degrees,

** lead to an increased Q-angle, leading in genu valgus (knock knees). The tibia will laterally slant.

** as such that the weight of the body gets distributed on the medial side of the foot.

** which loads the medial longitudinal arch (potentially stretchibg and flattening the foot)

*** leading to pes planus (flat feet)

Question 3

What is the Q angle?

Answer 3

The Q angle is an imaginary line made by connecting a point at the ASIS to the mid-point of the patella. Then draw another line through the center of the patella down to the tibia tubercle. In an aligned posture, the LOG acts through the center of the knee joint.

Question 4

What is femoral retroversion ?

What is an normal or abnormal angles?

Answer 4

The angle formed between the femoral neck and the shaft on the transverse plane.

Normal = ~ 14 degrees

> 14 deg = in excessive anterior rotation of the femoral neck and head – leads to the femur rotating inwards – and can lead to toes in stance.

Question 5

Coxa Vara

what lowerlimb structural deformity is coxa vara associated with?

Answer 5

Hip = A decreased angle of inclination of the femur < 125

Knee = Coxa Valgum and Increased Q angle > 15 degrees

Foot = pes planus

Longitudinal medial arch = decreased

-

Question 6

This bone is stronger than concrete and is the longest, strongest, and heaviest bone in your body.

Answer 6

Femur

Question 7

What is the orientation of the facet joints from C3 to T2 and what are the movements that is mostly predominant in this area?

Answer 7

The apophyseal joints are oriented 45 degrees in the transverse plane. This allow for greater movement of flexion/extension. With a smaller degree of rotation, and lateral flexion.

Question 8

What are the Motion the SI joints? What causes the motion?

Answer 8

Nutation occurs when the base of the sacrum moves anteriorly relative to the pelvis, AND when the pelvis rotates posteriorly (posterior pelvic tilt; ASIS moves upwards on the hip joint) relative to the sacrum (top picture).

Counternutation occurs when the base of the sacrum moves posteriorly relative to the pelvis AND when the pelvis rotates anteriorly (anterior pelvic tilt; ASIS moves downwards on the hip joint) relative to the sacrum (bottom picture).

Eg: bending backward, trunk extension, Hip flexion (open kinetic chain)

Sacral extension/ Counternutation - the base tilts posteriorly

Eg. trunk flexion, bending forward to touch toes, or thigh moves into extension, rising up from a squat position

Question 9

An excessive inward curvature of the spine is called

An excessive outward curvature of the spine is called

Answer 9

Lordosis (increased)

Kyphosis (increased)

Question 10

What function does the curvature of the spine perform? (lordosis/kyphosis)

Answer 10

The spine’s natural curves position the head over the pelvis and work as shock absorbers to distribute mechanical stress during movement.

Question 11

What is the orientation of the facet joints on the thoracic spine?

What happens at the thoracic spine during a movement of rotation to the left?

Answer 11

Thoracic spine

• T1-T12: less movement (ribcage, ribs)
• Rotation is always accompanied by lateral flexion
• Inferior facets face forward and medially
• Superior faces face backwards and laterally
• Oriented at a 60° angle on the transverse plan

Question 13

What movement occurs at the atlanto-occipital joint?

Movement at the atlantoaxial joint?

Answer 13

Cervical spine
• C0-C1 (atlanto-occipital): mostly flexion/extension

• C1-C2 (atlantoaxial): mostly rotation

Question 14

What is the action of the QL? attachment?

Answer 14

12th rib to iliac crest bilaterally
Unilateral action: bending the trunk to same side or hike that hip up
Bilateral action: aids in trunk extension

Question 15

What function does the multifidus serve? attachments?

Answer 15

Multifidus:

• Stabilizes the spine, has deep and superficial layers, attach from the sacrum to lower 4 cervical vertebrae
• In the lumbar spine, the multifidus can cause spinal extension and increase compressive forces between vertebrae (and the disc)

Question 16

What are their function and attachments?

Abdominals are a group of muscles in the trunk

1. rectus abdominis
2. transverse abdominis
3. external and internal obliques

Answer 16

These muscles provide stability to the lumbar spine

Transverse abdominis:

strong stabilizer/flexor of the trunk and helps with posterior pelvic tilt

Internal & external obliques rotate and flex the trunk. Internal obliques rotate to the same side and is assisted by the external obliques of the opposite side

Combined actions: stabilize the spine and increase intro-abdominal pressure

Question 17

What happens to the intervertebral disc during movement of flexion of the spine?

… extension of the spine? …. movements of side flexion of the spine?

What would you expect to happen to the intervertebral disc during the movement of anterior pelvic tilt and posterior pelvic tilt?

Answer 17

Intervertebral disc alllows for movement such as bending and twisting to occur at the spine.

Extension: allows for greater compression of the posterior part of the disc, causing the nucleus pulposus to move anteriorly

Forward bending: compress the anterior part of the disc, likly for the nucleus pulposus to move anteriorly

Lateral bending: compresses the side of the disc that you’re bending toward

Question 18

Which segment of the spine (cervical, thoracic and lumbar) allows for the least amount of movement and why?

What happens at the thoracic spine during a movement of rotation to the left?

Answer 18

Thoracic spine, T1-T12: less movement (ribcage, ribs)

Because of the orientation of the facet joints and the orientation of the ribs there is less movement in the thoracic spine.

Characteristic:

• Rotation is always accompanied by lateral flexion in the same direction because
  1. Inferior facets face forward and medially
  2. Superior facets face backwards and laterally
  3. Oriented at a 60 degree angle on the transverse plane

Question 19

Where in the spine is the greatest ROM of rotation possible?

Where in the spine is the greatest ROM of extension possible?

33- Where in the spine is the greatest ROM of flexion possible?

Answer 19

Rotation: Cervical spine = especially C1/2

Extension movement: Cervical spine (Lumbar spine has slightly more extension than thoracic)

Flexion movement: Lumbar spine (L4/L5)

Side flexion occur about the same on every spinal level

Question 20

What is the orientation of the facet joints of the lumbar vertebrae? degrees and anatomical angle? Superior facets? Inferior facets?

What movement does it have least of?

Which movement is occupanied by another ?

Answer 20

Lumbar spine: The facet joints are oriented at 90 degrees angle on the transverse plan

• Lumbar spine
• L1-L5: large movement of flexion (L4-L5 greatest)
• Inferior facets laterally and forward
• Superior facets medially and backwards
• Least amount of movement is rotation
• Lateral flexion is accompanied by rotation
• Upper: lat flexion to the left – rotation to the right • Lower: lat flexion to the left – rotation to the left
• Orientation at 90° angle on the transverse plane

Question 21

Which segment of the spine (cervical, thoracic and lumbar) allows for the least amount of movement and why?

Answer 21

In addition to longer spinous processes, rib attachments add to the thoracic spine’s strength. These structures make the thoracic spine more stable than the cervical or lumbar regions. In addition, the rib cage and ligament system limit the thoracic spine’s range of motion and protects many vital organs.

The lumbar spine has more range of motion than the thoracic spine, but less than the cervical spine. The lumbar facet joints allow for significant flexion and extension movement but limits rotation.

Question 22

What function do the erector spinae muscles serve?

Answer 22

Erector Spinae:

is a group of muscles formed by the
Iliocostalis, Longissimus, and Spinalis
They form the superficial layer of the spinal muscles
Cause trunk extension from a flexed position
Eg, rising from a forward bend
Help with maintaining posture too

Question 23

The link between upper and lower extremity?

Answer 23

• Connects with the lower extremity via the pelvic girdle
• Movements at the lumbar spine will affect the sacrum and pelvis
• Connects with the upper extremity via the shoulder girdle
• Provides stability to the scapula for proper functioning of the upper extremity

Question 24

What is Lower crossed syndrome?

Characterized by?

Cause?

Answer 24

• Characterized by an Imbalance between anterior and posterior muscles of the abdominal wall and back
• Change the forces acting on the lumbar spine —> can cause pain, ligament/joint stress, postural changes, increase compression forces between vertebrae
  Shortened hip flexors and weak glutes cause an anterior shear and compression to the

Weak abdominal muscles & weak gluteus maximus

Tight hip flexors and tight thoracolumbar extensors

Weak abdominal muscles and increase lumbar lordosis. This increases the shearing forces between the ertebrae and disc sand can lead to disc degeneration. Also, the anterior shearing forces of L4 / L5 tends to push the disc backwards and facilitate protrusion

Question 25

What is Upper crossed syndrome ?

Answer 25

Weak cervical flexors and rhomboids, lower trapezius

Tight pectorals and tight suboccipitals upper trapezius and levator

• Imbalance between anterior and posterior muscles of the thoracic wall and back
• Change the forces acting on the thoracic and cervical spine
• Pain
• Ligament/joint stress • Change in posture

• Increase compression forces between vertebrae

Question 26

Muscles of the trunk act to provide _______ to the spine during upper and lower limb movements as well as to provide ____ ______to facilitate use of the limbs

Answer 26

stability

trunk movements

Question 27

• _____ ________ in the trunk can lead to change in forces acting on the spine and, therefore change in posture, increase stress in joints and ligaments and pain

Answer 27

Muscle imbalance

Question 28

Bilateral movements of the lower extremity will cause which movements on the pelvis? Unilateral movements? Examples?

Answer 28

There is a strong relationship between the lower extremity and the trunk. Because trunk and pelvis movement often occurs in combination.

Bilateral movements of the lower extremity will cause movements (flexion/extension) on the pelvis on the sagittal plane.

Example: When we are in an open kinetic chain and when we flex the hip, the pelvis would move into a posterior pelvic tilt at the end range of hip flexion. Abdominal exercises: Lying supine and we bring our knee to chest;

Example: When in a closed kinetic chain, contraction of the hip flexors will tend to pull the pelvis in an anterior pelvic tilt position. Exercises: lowering down into a squat

Unilateral movements of the lower extremity will cause movements on the pelvis on the transverse plane (creating rotation at the pelvis). Could you give same examples of this?

Example: Walking —> step foot forward, the pelvis will rotate to the left side

Remember —> sacrum transfer forces from one side to the other; Sacral iliac joint allows for the rotation of the pelvis

Question 29

Describe the movement of nutation and counternutation of the sacrum.

Discuss sacroiliac movements with pelvic movements.

What goes on when you move the hip (thigh) compared to the trunk?

Answer 29

True sacral nutation/counternutation refers to movements of the sacrum relative to the ilium (pelvis), so in order to identify what is happening on the sacrum we should also look at what is happening with the pelvis.

Nutation occurs when the base of the sacrum moves anteriorly relative to the pelvis, AND when the pelvis rotates posteriorly (posterior pelvic tilt; ASIS moves upwards on the hip joint) relative to the sacrum (top picture).

Counternutation occurs when the base of the sacrum moves posteriorly relative to the pelvis AND when the pelvis rotates anteriorly (anterior pelvic tilt; ASIS moves downwards on the hip joint) relative to the sacrum (bottom picture).

Movement of the hip (thigh)

When there is bilateral flexion of the hip/thigh when the distal end of the lower extremity kinematic chain is free to move (in other words, open chain kinematics) there is a posterior pelvic tilt (ilium rotates posteriorly). Therefore, relative to the pelvis, the sacrum performs nutation.

When there is bilateral extension of the hip (thighs), there is an anterior pelvic tilt (ilium rotates anteriorly). Therefore, relatively to the pelvis, the sacrum performs counternutation.

Movements of the trunk

With trunk flexion, the pelvis (ilium) will rotate anteriorly on the hip joint (as you can see in the picture below). Therefore, if the ilium rotates anteriorly, the sacrum will perform relative counternutation.

With trunk extension (which is not the same as increased lumbar lordosis), the pelvis will rotate posteriorly on the hip joint as you can see in the image below. Therefore, the sacrum will nutate in relation to the posterior movement of the pelvis.

Question 30

Give me an example of how Change in the normal biomechanical functioning on one joint will tend to affect the biomechanics of another joint.

Answer 30

Example 1: contraction of hip flexors muscles in a closed kinetic chain leads to anterior pelvic tilt and lordosis

Example 2: contract your hip flexors in an open kinetic chain —> lead to hip flexion

Question 31

Define anteversion

Answer 31

Anteversion - “leaning forward” femoral ante version means the femoral neck is leaning forward

Question 32

Define Hypotonicity and how does it cause shoulder subluxation in stroke patients

Define Hypertonicity

Answer 32

Hypotonicity - decrease in tone initially, therefore less muscle activity on that UE —> less muscle to increase the coaptation of the GHJ, therefore, during the recovery from a stroke —> subluxation of the shoulder could occur (separation btw the head of the humerus and the glenoid fossa)

Hypertonicity - increase in tone, elbow is in flexion at rest, increase in the flexor muscles of the shoulder —> note an internal rotation at the shoulder and the shoulder is held slightly in front of the body.

Question 33

What functions does the pelvic girdle serve?

Answer 33

Support the body during weight bearing and posture

Allow for locomotion

Mostly works in a closed kinetic chain

Question 34

Closed Kinetic Chain:

Answer 34

refers to movements where the distal segment is fixed and the proximal segment is moving

Question 35

pelvic girdle is formed by 3 joints? List the joints and describe their function

Answer 35

The pubis symphysis

Hip joint

Sacroiliac joint

Pubis Symphysis - joins the anterior aspect of the right and left ilium bone.

Cartilaginous joint (amphiarthroses) and supported by strong ligaments. Provides little or no movements.

Sacroiliac Joint (SI) - connects the pelvis to the trunk via the sacrum. Synovial joint. Reinforced by strong ligaments. Transmits the weight of the body to the lower extremity (load). It absorbs impact during gait.

Question 36

Which muscles provide dynamic stability to the GH joint and control accessory movements of the humeral head?

Answer 36

Glenohumeral joint - muscles

• Provide mobility and stability
• Rotator cuff: muscles that provide dynamic stability to the joint and control accessory movements of the humeral head
• Subscapularis • Infraspinatus • Supraspinatus • Teres minor

Question 37

What function does the shoulder girdle serve

Answer 37

• Provide stability to allow function of the upper limb

Question 38

What are the joints of the shoulder girdle?

Answer 38

The shoulder girdle • Joint • Acromioclavicular joint • Sternoclavicular (SC) joint • Scapulothoracic joint • Glenohumeral joint

Question 39

The relationship between upper extremity and trunk

Answer 39

Movements in the glenohumeral joint do not occur in isolation • For proper movement to occur all muscles and joints need to work together • Joints and muscles are responsible for attaching the upper extremity to the trunk

Question 40

Squatting is a closed kinetic chain exercise as the distal end of the extremity (the feet) is fixed to the ground. As the knee bends, the hips moves back, the trunk moves forward due to hip flexion.

Bilateral hip flexion promotes which pelvic and sacral movement?

Answer 40

The sacrum nutates and the base of the sacrum moves anteriorly.

Therefore, the pelvis tilts back?

Question 41

The biomechanics of the upper extremity • Stop and think: • How is gravity acting on the upper extremity? • What are the challenges of a joint that is very mobile? • How does the limb and shoulder girdle work together?

Answer 41

The biomechanics of the upper extremity • Stop and think: • How is gravity acting on the upper extremity? • What are the challenges of a joint that is very mobile? • How does the limb and shoulder girdle work together?

Question 42

What is the effect of gravity on the shoulder joint?

Answer 42

The challenges of gravity • Gravity tends to “pull down” on the humeral head. Therefore, continuous muscle action is essential for coaptation of the joint • Muscles of the rotator cuff provide coaptation of the glenohumeral joint

Question 43

Scapulohumeral rhythm

Answer 43

is used to describe the coordinated activity of muscles acting on the scapula and the glenohumeral joint.

Question 44

What region of the shoulder area is most susceptible to injury ? Why? What could contribute to it?

Answer 44

is the subacromial space (between the acromion and the head of the humerus), particularly during movements of flexion and abduction • The bursa, capsule and tendons of muscles are located in this region • Any impairment of movement (particularly the scapulohumeral rhythm) may result in structures moving and rubbing against each other, leading to injuries http://www.physio-pedia.com/File:Subacromial_structures.jpg • I

Question 45

Describe the relationship among the trunk and lower extremity during trunk extension.

Which structures are contracted, stretched, compressed?

Postures:

* Standing with hands placed on the tops of the pelvis and leaning back into a slight backbend. (hyperextension)

* extend the trunk from a flexed position (extension)

Answer 45

Raising the trunk from a flexed position to a slight backbend,

Pelvis: the pelvis starts to tilt backward as the ASIS moves upward while the PSIS moves downward.

Sacrum: as the base of the sacrum moves forward - nutates

Back extensors: contract to extend the trunk from a flexed position. Iliocostalis, Longissimus, spinalis

Hip flexors: stretching/eccentric contraction of the Iliopsoas & quadriceps

Question 46

What is hip flexion and describe the position that causes hip to flex

Answer 46

Decreasing the angle between the femur (thigh) and pelvis. This occurs from a standing position when a person elevates their knee toward their abdomen (femoral-on-pelvic hip rotation) or when bending forward from the trunk, as if touching their toes (pelvic-on-femoral rotation).

Question 47

Explain Knee Flexion and how does it occur

Answer 47

Decreasing the angle between the lower leg (tibia, fibula) and femur. This occurs when a person bends their knee, bringing their heel closer to their thigh or butt.

Question 48

In an open kinetic chain, working bilaterally, concentric contraction of the iliosposas muscle will cause what type of chain occurences on the pelvis, sacrum, spine & spinal muscles.

Provide a couple of examples.

On the other hand, bilaterally hip extension, while eccentrically contracting the ilipsoas causes the oppsosite reaction

Answer 48

In an open kinetic chain, concentric contraction of the iliosposas muscle will cause a posterior pelvic tilt as the hips flex, the base of the sacrum nutates, lumbar lordosis decreases, the erector spinae muscle lengthens

Lying supine while hugging the knees toward the chest; leg raises

Question 49

True or False

Activity of the psoas muscles increases the lumbar intradiscal pressure on the spine - because it pulls the lumbar spine into lordosis. Indirectly, this could cause anterior shear and posterior disc protrusion

Answer 49

True

Question 50

Relationship between the lower extremity and the trunk.

Eg, lowering down into a squat

In an closed kinetic chain, bilateral concentric contraction of the iliosposas muscle will cause what type of chain occurences on the pelvis, sacrum, spine & spinal muscles.

Answer 50

The action of the psoas muscles increases lumbar lordosis.

1. Pull the lumbar spine anteriorly and down
2. The hip flexes, and the pelvis draw closer to the femur bone
3. Flexion at the hip creates an anterior pelvic tilt
4. Counternutation - The base of the sacrum moves posteriorly relative to the pelvis
5. The back extensor muscles shortens (trunk)

Question 51

What movement occurs at the pelvis and sacrum when performing a supine knee to chest crunch?

Answer 51

Posterior pelvic tilt and nutation

Question 52

What does it measure?

Answer 52

What does it measure?

Increased in Q angle is thought to increase the lateral force on the patella, therefore, increase the compression of the lateral patella on the lateral lip of the femoral sulcus. (increase risk for sublux or dislocate of the patella when the quadriceps muscle pulls on the knee)

Question 53

What is associated with an increased in Q angle?

Why is the increased in force perceived as harmful?

Answer 53

1. increases the pull of the quadriceps relative to the patella tendon.
2. This increased lateral force could increased in the lateral compression of the patella on the lateral lip of the femoral condyle.
3. Risk of subluxation and dislocation when the quadriceps contracts

Question 54

What is associated with an Increased angle of anteversion?

Answer 54

Increase in angle of anteversion tend to lead the toes to point in, thus decreasing mechanical advantage of gluetus.

Question 55

Is the cervical spine concave or convex?

Answer 55

Concave is where the surface curves outward

Convex is where the surface curves inward

The cervical spine and lumbar spine is convex anteriorly

The thoracic spine is convex posteriorly

Question 56

Coxa Valga (describe how this might present visually)

Answer 56

the femur points straight up and down — this would lead to a great increase in the angle between the neck of the femur and the femur shaft. Coxa Valga is the term used for this increased in femoral neck angle that is greater than 125 degrees.

Question 57

Coxa Vara

Answer 57

coxa vara is a term referring to an angle created by the neck and the shaft less than 125 degrees.

• femoral shaft shifts closer to the body

Question 58

Coxa Vara is known as the angle of inclination less than 125 degrees. Is this associated with genu valga or genu varum

Answer 58

Coxa varum is referred to an angle less than 125 degrees.

The neck and the shaft femur forms the angle of inclination. When the angle between the neck and the shaft of the femur is less than 125 degrees, the patella also shifts medially –> increasing the Q angle. ( widening the angle between the ASIS and through the center of the patella)

genu valgum = angle greater than 15 degrees.

If the angle of inclination of the femur increases to over 125 degrees, term coxa valga is given, and this angle is associated with a decreased in Q angle at the knee. This is known medically as Genu Varum if angle is less than 15 degrees.Normal = 15 deg (women tend to have greater Q angle)

< 15 = Genu Varum

> 15 = Genu Valgum

Question 59

What angle is a normal Q angle?

Answer 59

10-15 degrees (women tend to have greater Q angle)

Question 60

When extending your trunk from flexion, what movement does this cause at the pelvis and sacrum ?

Answer 60

Posterior pelvic tilt and nutation of the sacrum

Question 61

What movement occurs at the pelvis and sacrum when performing a closed chain forward bend?

Answer 61

Anterior pelvic tilt, counternutation of the sacrum (flexion of the trunk)

Question 62

What are potential issues with a Decreased Angle of Inclination?

Answer 62

A decrease angle of inclination can cause knock knee or genu valgus, this increase stress on medial structures of the knee. As well as resulting in excessive pronation due to a drop in the medial arch

Question 63

What is the role of the SI joint?

Answer 63

1. Connects the pelvis to the trunk via the sacrum
2. Transmits the weight of the body to the lower extremity (load)
3. Absorbs impact during gait

Question 64

Describe the biomechanical changes that occur in the lower extremity as a result of changes to the angle of inclination of the femur.

Question 65

When rising up from a chair? What do you need to consider?

Answer 65

Forward displacement of the COG

Knees flexed (90-115 deg)

Feed under or behind the knee joint

Hip flexion 120 deg

Question 66

An increased angle of inclination of the femur

Changes to hip, knee, foot, arch…

Answer 66

Hip = Coxa valga

Knee = Coxa varus, decreased Q angle < 15 degrees

Foot = pes cavus

Longitudinal medial arch = increased