Chapter 3Chapter 3

Kinesiology of the Kinesiology of the musculoskeletal systemmusculoskeletal system

OverviewOverview

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

Anatomical reference Anatomical reference pointpoint When describing movements it is When describing movements it is

necessary to have a starting position as necessary to have a starting position as the reference position. This starting the reference position. This starting position is referred to as the position is referred to as the anatomical anatomical reference positionreference position. .

The anatomical reference position for the The anatomical reference position for the human body is described as the erect human body is described as the erect standing position with the feet just standing position with the feet just slightly separated and the arms hanging slightly separated and the arms hanging by the side, the elbows straight and with by the side, the elbows straight and with the palms of the hand facing forward the palms of the hand facing forward

Directional TermsDirectional Terms

Superior or cranial – Closer to the headSuperior or cranial – Closer to the head Inferior or caudal – Closer to the feetInferior or caudal – Closer to the feet Anterior or ventral – Toward the front of Anterior or ventral – Toward the front of

the bodythe body Posterior or dorsal – Toward the back of Posterior or dorsal – Toward the back of

the bodythe body Medial – Toward the midline of the bodyMedial – Toward the midline of the body Lateral – Away from the midline of the Lateral – Away from the midline of the

bodybody

Directional TermsDirectional Terms

Proximal – Closer to the trunkProximal – Closer to the trunk Distal – Away from the trunkDistal – Away from the trunk Superficial – Toward the surface Superficial – Toward the surface

of the bodyof the body Deep – Away from the surface of Deep – Away from the surface of

the body in the direction of the the body in the direction of the inside of the bodyinside of the body

Planes of the BodyPlanes of the Body

There are three traditional planes of the body There are three traditional planes of the body corresponding to the three dimensions of corresponding to the three dimensions of space: sagittal, frontal, and transversespace: sagittal, frontal, and transverse

Sagittal plane. Also known as the anterior-Sagittal plane. Also known as the anterior-posterior or median plane. Divides the body posterior or median plane. Divides the body vertically into left and right halves of equal vertically into left and right halves of equal sizesize

Frontal plane. Also known as the lateral or Frontal plane. Also known as the lateral or coronal plane. Divides the body equally into coronal plane. Divides the body equally into front and back halvesfront and back halves

Transverse plane. Also known as the Transverse plane. Also known as the horizontal plane. Divides the body equally horizontal plane. Divides the body equally into top and bottom halvesinto top and bottom halves

The Center and Line of The Center and Line of GravityGravity The center of gravity may be The center of gravity may be

defined as ‘the point at which the defined as ‘the point at which the three planes of the body intersect three planes of the body intersect each other’each other’

The line of gravity is defined as The line of gravity is defined as ‘the vertical line at which the two ‘the vertical line at which the two vertical planes intersect each vertical planes intersect each other’ other’

Axes of the BodyAxes of the Body

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

Axes of the BodyAxes of the Body

Frontal. The frontal axis, also Frontal. The frontal axis, also known as the transverse axis, is known as the transverse axis, is perpendicular to the sagittal planeperpendicular to the sagittal plane

Sagittal. The sagittal axis is Sagittal. The sagittal axis is perpendicular to the frontal planeperpendicular to the frontal plane

Longitudinal. The longitudinal Longitudinal. The longitudinal axis, also known as the vertical axis, also known as the vertical axis is perpendicular to the axis is perpendicular to the transverse planetransverse plane

The planes and axes The planes and axes for common for common movementsmovements Flexion, extension, hyperextension, Flexion, extension, hyperextension,

dorsiflexion, and plantar flexion occur in dorsiflexion, and plantar flexion occur in the sagittal plane around a frontal-the sagittal plane around a frontal-horizontal axishorizontal axis

Abduction, adduction; side flexion of the Abduction, adduction; side flexion of the trunk; elevation and depression of the trunk; elevation and depression of the shoulder girdle; radial and ulnar shoulder girdle; radial and ulnar deviation of the wrist; eversion and deviation of the wrist; eversion and inversion of the foot occur in the frontal inversion of the foot occur in the frontal plane around a sagittal-horizontal axisplane around a sagittal-horizontal axis

The planes and axes The planes and axes for common for common movementsmovements Rotation of the head, neck and trunk; Rotation of the head, neck and trunk;

internal rotation and external rotation of internal rotation and external rotation of the arm or leg; horizontal adduction and the arm or leg; horizontal adduction and abduction of the arm or thigh; pronation abduction of the arm or thigh; pronation and supination of the forearm occur in the and supination of the forearm occur in the transverse plane around the longitudinal transverse plane around the longitudinal axisaxis

Circumduction involves an orderly Circumduction involves an orderly sequence of circular movements that occur sequence of circular movements that occur in the sagittal, frontal and intermediate in the sagittal, frontal and intermediate oblique planes, so that segment as a whole oblique planes, so that segment as a whole incorporates a combination of flexion, incorporates a combination of flexion, extension, abduction and adductionextension, abduction and adduction

KinematicsKinematics

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

Osteokinematic MotionOsteokinematic Motion

Osteokinematic motion occurs Osteokinematic motion occurs when any object forms the radius when any object forms the radius of an imaginary circle about a of an imaginary circle about a fixed pointfixed point

The axis of rotation for The axis of rotation for osteokinematic motions is osteokinematic motions is oriented perpendicular to the oriented perpendicular to the plane in which the rotation occurs plane in which the rotation occurs

Osteokinematic motionOsteokinematic motion

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

Arthrokinematic Arthrokinematic MotionMotion Arthrokinematic movements are Arthrokinematic movements are

the motions occurring at the joint the motions occurring at the joint surfacessurfaces

Direction of movement based on Direction of movement based on the shape of the joint surfacesthe shape of the joint surfaces

Generally, joint surfaces can be Generally, joint surfaces can be either concave (female) or convex either concave (female) or convex (male) in shape (ovoid), or a (male) in shape (ovoid), or a combination of both shapes (sellar)combination of both shapes (sellar)

Arthrokinematic Arthrokinematic MotionMotion The three types of movement The three types of movement

occur at the articulating surfaces:occur at the articulating surfaces:– RollRoll– SlideSlide– SpinSpin

Motion relationshipsMotion relationships

Osteokinematic and Osteokinematic and arthrokinematic motions are arthrokinematic motions are directly proportional to each other directly proportional to each other and one cannot occur completely and one cannot occur completely without the otherwithout the other

Thus, if motion is reduced, one, or Thus, if motion is reduced, one, or both, of these motions is at fault both, of these motions is at fault

Degrees of FreedomDegrees of Freedom

The number of independent modes of The number of independent modes of motion at a joint is called the motion at a joint is called the degrees degrees of freedom (DOF)of freedom (DOF)– A joint that can swing in one direction or A joint that can swing in one direction or

can only spin, it is said to have 1 DOF. can only spin, it is said to have 1 DOF. Example: PIP jointExample: PIP joint

– A joint that can spin and swing in one way A joint that can spin and swing in one way only only oror it can swing in two completely it can swing in two completely distinct ways, but not spin, it is said to distinct ways, but not spin, it is said to have 2 DOF. Example: Tibiofemoral joint have 2 DOF. Example: Tibiofemoral joint

Degrees of FreedomDegrees of Freedom

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

Conjunct RotationConjunct Rotation

The rotation at a joint that The rotation at a joint that accompanies the prime motion. accompanies the prime motion. Example: supination of the Example: supination of the forearm during elbow extensionforearm during elbow extension

Conjunct rotation is only under Conjunct rotation is only under volitional control in joints with 3 volitional control in joints with 3 DOF DOF

Conjunct rotationConjunct rotation

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

Kinematic chainsKinematic chains

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

Kinematic chainsKinematic chains

Closed kinematic chainClosed kinematic chain– Various definitionsVarious definitions– Fixation of the distal segment so Fixation of the distal segment so

that joint motion takes place in that joint motion takes place in multiple planes and the limb is multiple planes and the limb is supporting weightsupporting weight

Kinematic chainsKinematic chains

Open kinematic chainOpen kinematic chain– All activities that involve the end All activities that involve the end

segment of an extremity moving segment of an extremity moving freely through spacefreely through space

Close-packed PositionClose-packed Position

The position of maximum The position of maximum congruity of the opposing joint congruity of the opposing joint surfaces is termed the surfaces is termed the close-close-packedpacked position of the joint position of the joint

Movements toward the close-Movements toward the close-packed position of a joint involve packed position of a joint involve an element of joint compression an element of joint compression

Position of maximum joint stabilityPosition of maximum joint stability

Open-packed PositionOpen-packed Position

The position of least joint The position of least joint congruity is termed the congruity is termed the open-open-packedpacked position position

Movements away from the close-Movements away from the close-packed position involve an packed position involve an element of joint distractionelement of joint distraction

Position of least joint stability Position of least joint stability

Available Joint MotionAvailable Joint Motion

If a joint moves less than what is If a joint moves less than what is considered normal, or when compared considered normal, or when compared to the same joint on the opposite to the same joint on the opposite extremity, it may be deemed extremity, it may be deemed hypomobilehypomobile

A joint that moves more than considered A joint that moves more than considered normal, or when compared to the same normal, or when compared to the same joint on the opposite extremity, may be joint on the opposite extremity, may be deemed deemed hypermobilehypermobile. .

Available Joint MotionAvailable Joint Motion

Instability of a joint involves a Instability of a joint involves a disruption of the osseous and disruption of the osseous and ligamentous structures of that ligamentous structures of that joint, resulting in a loss of joint, resulting in a loss of functionfunction

Factor of joint integrity, elastic Factor of joint integrity, elastic energy, passive stiffness, and energy, passive stiffness, and muscle activation muscle activation