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USAHS Anatomy 2 > Ch21: Posture > Flashcards

Ch21: Posture Flashcards

1
Q

Posture

A
  • The position of your body parts in relation to each other at any given time
  • Can be static, as in a stationary position such as standing, sitting, or lying ordynamic as the body moves from one position to another.
  • Deals with alignment of the various body segments which can be compared with blocks. (If you start stacking blocks, one directly on top of the other, the column will remain relatively stable. However, if you stack them off center from each other, the column will remain upright only if the block (or blocks) above offsets the block(s) below and remain(s) within the base of support.)
  • In the human body, each joint involved with weight-bearing can be considered a postural segment.
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2
Q

Vertebral Column

A

Can be compared with the column of blocks. It is not completely straight but has a serious of counterbalancing anterior-posterior curves. These curves, which must be maintained during rest and activity, act as shock absorbers and reduce the amount of injury. The thoracic and sacral curves offset the cervical and lumbar curves. The thoracic and sacral curves are concave anteriorly and convex posteriorly and are seen when viewed in the sagittal plane and the lumbar and cervical curves are just the opposite—convex anteriorly and concave posteriorly.

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3
Q

When one or more of these vertebral curves either increases or decreases significantly from what is considered good posture…

A

Poor Posture Results

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4
Q

Sway Back

A

An increased lumbar curve (In most cases, if there is an increased lumbar curve, there is also an increased thoracic curve. )

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5
Q

Flat Back

A

Decreased lumbar curve.

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5
Q

Flat Back

A

Decreased lumbar curve.

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6
Q

Scoliosis

A

Any lateral curvature of the spine

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7
Q

The four major curves of the vertebral column (lateral view).

A

.

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8
Q

At birth, the entire vertebral column is…

A

Flexed. When viewed from the sagittal plane, it is anteriorly concave.

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9
Q

Primary Curve

A

Concave curve (When viewed from the sagittal plane, it is anteriorly concave) The thoracic and sacral curves are considered primary curves for this reason.

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10
Q

Secondary Curves

A

Create by these two antigravity extension actions (when lying in a prone position, a 2- to 4-month-old infant begins to lift its head; at approximately 5 to 6 months of age, a prone infant begins bilateral lifting of its lower extremities)

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11
Q

Neutral Position of the Pelvis

A

The pelvis should maintain a neutral position.
(1) the anterior superior iliac spine (ASIS) and the posterior superior iliac spine (PSIS) are level with each other in the transverse plane
(2) the ASIS is in the same vertical plane as the symphysis pubis.
When the pelvis is in a neutral position, the lumbar curve has the desired amount of curvature.

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12
Q

Lordosis

A

When the pelvis tilts anteriorly, lumbar curvature increases

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13
Q

Flat Back

A

When the pelvis tilts posteriorly, lumbar curvature decreases

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14
Q

The primary curve of a newborn (lateral view).

A

.

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15
Q

With weight evenly distributed on both legs, the pelvis should…

A

Remain level from side to side, with both ASISs being at the same level.

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16
Q

During walking, the pelvis…

A

Dips from side to side as weight shifts from stance to swing phase.

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17
Q

Lateral Pelvic Tilt

A

Controlled by the hip abductors, mainly the gluteus medius and gluteus minimus, and by the trunk lateral benders, mainly the erector spinae and quadratus lumborum. If you bend your left knee and lift your foot off the ground, your pelvis on the left side becomes unsupported and will drop. Force couple action of the hip abductors and trunk lateral benders hold the pelvis level. The right hip abductors on the opposite side contract to pull the pelvis down on the right side, while trunk lateral benders on the left (same side) contract to pull the pelvis up on the left side

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18
Q

What can cause abnormal lateral pelvic tilt and what is the result of this?

A

An abnormal lateral pelvic tilt can also occur if both legs are not of equal length. This will result in a lateral curvature, or scoliosis.

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19
Q

Muscle contractions are primarily responsible for keeping the body in the…

A

Upright position in both static and dynamic posture

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20
Q

Antigravity Muscles

A

Muscle contractions are primarily responsible for keeping the body in the upright position in both static and dynamic posture.
-These are hip and knee extensors andtrunk and neck extensors. Other muscles involved (perhaps to a lesser extent but also important in maintaining the upright position) are the trunk and neck flexors and lateral benders, the hip abductors and adductors, and the ankle pronators and supinators. If all of these muscles were to relax, the body would collapse.

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21
Q

The ankle plantar flexors and dorsiflexors are important in controlling…

A

Postural sway

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22
Q

Postural Sway

A

Anterior-posterior motion of the upright body caused by motion occurring primarily at the ankles. This sway is the result of constant displacement and correction of the center of gravity within the base of support.

23
Q

Antigravity muscles (lateral view).

A

.

24
Q

Postural Sway

A

.

25
Q

What increases the amount of postural sway?

A

High center of gravity and small base of support tend to

26
Q

Good Posture

A

Aka good alignment, is important because it decreases the amount of stress placed on bones, ligaments, muscles, and tendons. Also improves function and decreases the amount of muscle energy needed to keep the body upright.

27
Q

Static Standing Position/Posture

A

Posture is easier to describe in this position because, except for a slight amount of sway when standing, the body is not moving

28
Q

Standing Position, Lateral View- Plumb Line

A

Should be aligned so that it passes slightly in front of the lateral malleolus.

  • Head: Through the earlobe
  • Shoulder: Through the tip of the acromion process
  • Thoracic Spine: Anterior to the vertebral bodies
  • Lumbar Spine: Through the vertebral bodies
  • Pelvis: Level
  • Hip: Through the greater trochanter (slightly posterior to the hip joint axis)
  • Knee: Slightly posterior to the patella (slightly anterior to the knee joint axis) with the knees in extension
  • Ankle: Slightly anterior to the lateral malleolus, with the ankle joint in a neutral position between dorsiflexion and plantar flexion
29
Q

Posture (lateral view)

A

.

29
Q

Posture (lateral view)

A

.

30
Q

Because standing is a closed kinetic chain activity, the position or motion of one joint will…

A

Affect the positions or motions of other joints.

31
Q

Standing Position, Anterior View- Plumb Line

A

The plumb line should be aligned to pass through the midsagittal plane of the body, thus dividing the body into two equal halves

  • Head: Extended and level, not flexed or hyperextended
  • Shoulders: Level and not elevated or depressed
  • Sternum: Centered in the midline
  • Hips: Level, with both ASISs in the same plane
  • Legs: Slightly apart
  • Knees: Level and not bowed or knock-kneed
  • Ankles: Normal arch in feet; foot not inverted or pronated
  • Feet: Slight outward toeing
32
Q

Posture (anterior view)

A

.

33
Q

Standing Position, Posterior View Plumb Line

A

The plumb line should also be aligned to pass through the midsagittal plane of the body, dividing the body into two equal halves
Head: Extended, not flexed or hyperextended
Shoulders: Level and not elevated or depressed
Spinous Processes: Centered in the midline
Hips: Level, with both PSISs in the same plane
Legs: Slightly apart
Knees: Level and not bowed or knock-kneed
Ankles: Calcaneus should be straight.

34
Q

Posture (posterior view)

A

.

35
Q

Sitting Posture

A

Good postural alignment while sitting is important, because sitting can place a great deal of pressure on the intervertebral disks. Studies have shown that disk pressure in the sitting position increases by slightly less than half of the amount of disk pressure in the standing position. To state the obvious, shifting weight onto the front part of the vertebrae will increase the amount of pressure placed on the intervertebral disks. As the person leans forward, disk pressure increases. As a person reaches forward or picks up a weight, disk pressure further increases as the weight or length of the lever arm increases.

36
Q

When is disk pressure the least? When does it increase?

A

Disk pressure is least when you are lying supine. It increases as you stand and increases more as you sit. Leaning forward in these positions increases the disk pressure, and leaning forward with an object in your hand obviously increases it even more.

37
Q

If the lumbar curve decreases, as often happens when sitting with the back unsupported, the pressure on the intervertebral disks and posterior structures…

A

Increases.

38
Q

A chair with the seat inclined anteriorly, such as the kneeling stool, can decrease disk pressure by…

A

Tilting the pelvis forward slightly. This helps to maintain the lumbar curve. However, because the back is unsupported, increased and sustained muscle contraction is required to keep the body upright.

39
Q

Shifting weight onto the front part of the vertebra is not always a problem.

A

Although disk pressure increases in this position, the stresses placed on the posterior part of the vertebra (the facet joints) decreases. Therefore, if a person has a facet joint problem, a flexed position is generally more desirable. Conversely, if a person has a disk problem, an extended position is usually more desirable.

40
Q

Disk pressures in various positions.

A

.

41
Q

Slouched posture increases disk pressure.

A

.

42
Q

Kneeling stool posture reduces disk pressure.

A

.

43
Q

In sitting postures, a chair with lumbar support and/or a slight forward angle to the seat helps maintain…

A

Lumbar lordosis and minimize pressure on the disks.

44
Q

Maintaining the vertebral curves, keeping the feet flat on the floor, having the low back supported, and keeping the upper body in good alignment are key elements of…

A

Good sitting posture.

45
Q

Supine Posture

A

Lying down is considered a resting position. The least amount of intervertebral disk pressure occurs while lying supine. If you could run a plumb line horizontally, it would intersect many of the same landmarks as in the standing position. Good alignment in this position is also important. Good resting surface should be firm enough to avoid loss of the lumbar curve, yet soft enough to conform and give support to the normal curves of the body. In the side-lying position, the bottom leg is extended and the top leg is flexed. Placing a pillow between the legs can increase comfort by keeping the hips in good alignment. Lying prone is usually not recommended because of the increased pressure placed on the neck. In this position, using a pillow only increases the stresses on the neck.

46
Q

Most principles of good body mechanics involve…

A

Avoiding stress to the trunk and maintaining the spinal curves, which involve maintaining good posture.

47
Q

Text Neck

A

Smart phones are wonderful inventions but may come at a musculoskeletal price. Looking at and using them for long periods of time throughout the day puts a great deal of stress on the neck, hence the common name “text neck.” The typical posture while texting or looking at our smart phones is one of extreme neck flexion. The problem is that the more the neck is flexed, the more weight is placed on the cervical spine. When you are in good postural alignment, the line of gravity passes through the earlobe (see Fig. 21-6). In that position, the weight on the cervical spine is approximately 10 pounds. Flexing the neck to 45 degrees (Fig. A) can increase the stress on the cervical spine five times to approximately 50 pounds. If you use your phone 2 to 3 hours per day, that is a lot a strain on the cervical disks, extensor muscles, and posterior ligaments. A simple change of holding the phone higher and looking down with your eyes can significantly decrease the stress on the neck

48
Q

Text neck. (A) Flexed neck - greater stress. (B) Extended neck - less stress.

A

.

49
Q

Deviation from “good” posture is considered…

A

“Poor” or “bad” posture

50
Q

Causes of poor posture can be the result of…

A

Structural problems. These structural problems may result from a congenital malformation such as a hemivertebra. The deviation may be an acquired deformity caused by trauma such as a compression fracture. Postural deviations also may result from neurological conditions that cause paralysis or spasticity. In addition, postural problems may be functional, or nonstructural, in nature. A person who sits or stands for long periods of time will tend to slouch. This can result in muscle imbalance.

51
Q

if a person tends to maintain a posture in which a curve is increased, the muscles on the concave side will…

A

Tend to tighten (adaptive shortening) while the muscles on the convex side tend to weaken (adaptive lengthening).

52
Q

You would expect a person with a lumbar lordosis to have tight…

A

Back extensors and weak abdominal muscles. Also, postures that tend to increase the lordotic curves (cervical and lumbar) will increase pressure on the more posterior facet joints and decrease pressure on the more anterior intervertebral disks.

53
Q

An increase in the kyphotic curves (thoracic and sacral) will increase the…

A

Pressure on the intervertebral disks while decreasing the pressure on the facet joints.

USAHS Anatomy 2 (7 decks)

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