Kinesiology of the musculoskeletal system

1
Chapter 3

• Kinesiology of the musculoskeletal system

2
Overview

• A fundamental skill of the physical therapist is
  to identify, analyze and solve problems related
  to human movement

3
Anatomical reference point

• When describing movements it is necessary to have
  a starting position as the reference position.
  This starting position is referred to as the
  anatomical reference position.
• The anatomical reference position for the human
  body is described as the erect standing position
  with the feet just slightly separated and the
  arms hanging by the side, the elbows straight and
  with the palms of the hand facing forward

4
Directional Terms

• Superior or cranial Closer to the head
• Inferior or caudal Closer to the feet
• Anterior or ventral Toward the front of the
  body
• Posterior or dorsal Toward the back of the body
• Medial Toward the midline of the body
• Lateral Away from the midline of the body

5
Directional Terms

• Proximal Closer to the trunk
• Distal Away from the trunk
• Superficial Toward the surface of the body
• Deep Away from the surface of the body in the
  direction of the inside of the body

6
Planes of the Body

• There are three traditional planes of the body
  corresponding to the three dimensions of space
  sagittal, frontal, and transverse
• Sagittal plane. Also known as the
  anterior-posterior or median plane. Divides the
  body vertically into left and right halves of
  equal size
• Frontal plane. Also known as the lateral or
  coronal plane. Divides the body equally into
  front and back halves
• Transverse plane. Also known as the horizontal
  plane. Divides the body equally into top and
  bottom halves

7
The Center and Line of Gravity

• The center of gravity may be defined as the
  point at which the three planes of the body
  intersect each other
• The line of gravity is defined as the vertical
  line at which the two vertical planes intersect
  each other

8
Axes of the Body

• Three reference axes are used to describe human
  motion frontal, sagittal, and longitudinal. The
  axis around which the movement takes place is
  always perpendicular to the plane in which it
  occurs.

9
Axes of the Body

• Frontal. The frontal axis, also known as the
  transverse axis, is perpendicular to the sagittal
  plane
• Sagittal. The sagittal axis is perpendicular to
  the frontal plane
• Longitudinal. The longitudinal axis, also known
  as the vertical axis is perpendicular to the
  transverse plane

10
The planes and axes for common movements

• Flexion, extension, hyperextension, dorsiflexion,
  and plantar flexion occur in the sagittal plane
  around a frontal-horizontal axis
• Abduction, adduction side flexion of the trunk
  elevation and depression of the shoulder girdle
  radial and ulnar deviation of the wrist eversion
  and inversion of the foot occur in the frontal
  plane around a sagittal-horizontal axis

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The planes and axes for common movements

• Rotation of the head, neck and trunk internal
  rotation and external rotation of the arm or leg
  horizontal adduction and abduction of the arm or
  thigh pronation and supination of the forearm
  occur in the transverse plane around the
  longitudinal axis
• Circumduction involves an orderly sequence of
  circular movements that occur in the sagittal,
  frontal and intermediate oblique planes, so that
  segment as a whole incorporates a combination of
  flexion, extension, abduction and adduction

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Kinematics

• Kinematics is the study of motion. In studying
  joint kinematics, two major types of motion are
  involved
• The osteokinematic
• The arthrokinematic

13
Osteokinematic Motion

• Osteokinematic motion occurs when any object
  forms the radius of an imaginary circle about a
  fixed point
• The axis of rotation for osteokinematic motions
  is oriented perpendicular to the plane in which
  the rotation occurs

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Osteokinematic motion

• Examples of osteokinematic motion include
  abduction or adduction of the arm, flexion of the
  hip or knee, and side flexion of the trunk

15
Arthrokinematic Motion

• Arthrokinematic movements are the motions
  occurring at the joint surfaces
• Direction of movement based on the shape of the
  joint surfaces
• Generally, joint surfaces can be either concave
  (female) or convex (male) in shape (ovoid), or a
  combination of both shapes (sellar)

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Arthrokinematic Motion

• The three types of movement occur at the
  articulating surfaces
• Roll
• Slide
• Spin

17
Motion relationships

• Osteokinematic and arthrokinematic motions are
  directly proportional to each other and one
  cannot occur completely without the other
• Thus, if motion is reduced, one, or both, of
  these motions is at fault

18
Degrees of Freedom

• The number of independent modes of motion at a
  joint is called the degrees of freedom (DOF)
• A joint that can swing in one direction or can
  only spin, it is said to have 1 DOF. Example PIP
  joint
• A joint that can spin and swing in one way only
  or it can swing in two completely distinct ways,
  but not spin, it is said to have 2 DOF. Example
  Tibiofemoral joint

19
Degrees of Freedom

• If the joint can spin and also swing in two
  distinct directions then it is said to have 3 DOF
  . Example Glenohumeral joint

20
Conjunct Rotation

• The rotation at a joint that accompanies the
  prime motion. Example supination of the forearm
  during elbow extension
• Conjunct rotation is only under volitional
  control in joints with 3 DOF

21
Conjunct rotation

• Where appropriate, mobilizing techniques must
  take into consideration both the relative shapes
  of the articulating surfaces, in addition to the
  conjunct rotation that is associated with a
  particular motion

22
Kinematic chains

• The expression kinematic chain is used in
  rehabilitation to describe the function or
  activity of an extremity or trunk in terms of a
  series of linked chains

23
Kinematic chains

• Closed kinematic chain
• Various definitions
• Fixation of the distal segment so that joint
  motion takes place in multiple planes and the
  limb is supporting weight

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Kinematic chains

• Open kinematic chain
• All activities that involve the end segment of an
  extremity moving freely through space

25
Close-packed Position

• The position of maximum congruity of the opposing
  joint surfaces is termed the close-packed
  position of the joint
• Movements toward the close-packed position of a
  joint involve an element of joint compression
• Position of maximum joint stability

26
Open-packed Position

• The position of least joint congruity is termed
  the open-packed position
• Movements away from the close-packed position
  involve an element of joint distraction
• Position of least joint stability

27
Available Joint Motion

• If a joint moves less than what is considered
  normal, or when compared to the same joint on the
  opposite extremity, it may be deemed hypomobile
• A joint that moves more than considered normal,
  or when compared to the same joint on the
  opposite extremity, may be deemed hypermobile.

28
Available Joint Motion

• Instability of a joint involves a disruption of
  the osseous and ligamentous structures of that
  joint, resulting in a loss of function
• Factor of joint integrity, elastic energy,
  passive stiffness, and muscle activation