Kines Chap1

7/31/2019 Kines Chap1

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Prepared By: Floriza P. de Leon, PTRP

MECHANICAL PRINCIPLES:KINEMATICS


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Introduction Kinesiology study of motion

Combining theories of and principles from anatomy, physiology, psychology, anthropology, andmechanics

Biomechanics application of mechanics to the living human body Statics concerned with bodies at rest or in uniform motion

Dynamics treats bodies that are accelerating or decelerating

Note: Since most of the motion with which physical and occupational therapists deal

therapeutically is slow and lacks rapid accelerations, the concepts from mechanicsapplicable to clinical practice using principles from statics.

Note: The purpose of studying clinical kinesiology is to understand the forces actingon the human body and to manipulate these forces in treatment procedures so thathuman performance may be improved and further injury may be prevented.

Kinematics science of motion of bodies in space Movement of a single point in the body (COG)

Position of several segments (UE) Position of a single joint or motions that occur between adjacent joint surfaces

Subdivisions of kinematics Osteokinematics concerned with the movements of the bones

Arthrokinematics addresses the movements occurring between joint surfaces


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Anatomic Body Position

Defined as standing erect with the head, toes, and palms of thehands facing forward and with the fingers extended.

3 imaginary planes are arranged perpendicular to each otherthrough the body, with their axes intersecting at the COG of thebody (slightly anterior to the S2). These planes are called cardinalplanes of the body.


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Frontal Plane

AKA Coronal plane (XY plane) Parallel to the frontal bones and divides the body into front and

back parts

Movement that occurs: abduction and adduction

Abduction is a position or motion of the segment away from themidline, regardless of which segment moves.

Adduction is position or motion toward the midline

Motion of abduction and adduction occur around the Z axis


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Sagittal Plane

AKA midsagittal plane (YZ plane) It is vertical and divides the body into right and left sides

Joint motions occurring in the sagittal plane are flexion andextension

Flexion indicates two segments approach each other Extension occurs when two segments move away from each other

Hyperextension is an extension that goes beyond the anatomicreference position

Motions of flexion and extension occurs around the x axis


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Horizontal Plane

AKA transverse plane (XZ plane) Divides the body into upper and lower parts

Rotation occurs in this plane around the vertical y axis

Internal rotation (inward or medial rotation) is a transverse

rotation oriented to the anterior surface of the body. Pronation is the term used for IR of the forearm

External Rotation(outward or lateral rotation) is in the oppositedirection and is oriented to the posterior surface of the body

Supination is the term used at the forearm


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Special Cases

Secondary Planes sagitttal, frontal and horizontal planes may belaid through points other than the COG of the body

In the hand, the sagittal plane is centered through the 3 rd segment

In the foot, the sagittal plane is centered through the 2nd segment

At the wrist, the motion of abduction is called radial deviation andadduction is called ulnar deviation

Movement of the dorsum of the foot toward the tibia is calleddorsiflexion, and the movement of the sole of the foot away fromthe tibia is called plantarflexion

The thumb is also a special case because it is rotated 90 deg fromthe plane of the hand. Thus flexion/extension occurs in the frontalplane and abduction/adduction in the sagittal plane


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Goniometry

It is an application of the coordinate system to a joint to measurethe degrees of motion present in each plane of a joint.

Two systems of recording exist:

1st uses zero deg as reference point for the standard anatomic position

2nd uses 180 deg as the reference point for the standard anatomic position

Normal individual ranges of motion vary with bony structure,muscular, development, body fat, ligamentous integrity, genderand age


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Normal End Feel

AKA Physiologic end feel The resistance that is felt by the examiner to further motion at the

end of its ROM (felt when the joint is moved passively)

Described as hard, firm or soft

Hard/bony felt when motion is stopped by contact of bone on bone

Firm/springy limitation is from ligamentous, capsular, or muscle structures.

Soft occurs with contact of adjacent soft tissues

Pathologic End feel occur at a different place in the ROM or havean end feel that is not characteristic of the joint

Empty end feel pathologic type denoting pain on motion butabsence of resistance


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Rotary and Translatory Motion

Rotary/angular/rotation Movements occurring around an axis or a pivot point

Takes place about a fixed or relatively fixed axis

These motions are called rotary because every point on a segment adjacent to thejoint follows the arc of a circle, the center of which is the joint axis

Translatory

Movements of a body in which all of its parts move in the same direction withequal velocity

It can be either be in a straight line (linear) or follow a curve (curvilinear)


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Degrees of Freedom One degree of freedom

Joints that move in one plane possess one axis and have one degree of freedom

Two degrees of freedom If a joint has two axes, the segments can move in two planes

Three degrees of freedom Movements take place about three main axes, all of which pass through the joints center of

rotation

Maximum number that a single joint can possess in planar motion

Circumduction Performed during which the moving segment follows the surface of a cone and the tip of the

segment traces a circular path Circumduction is characteristic of joints with two and three degrees of freedom but cannot take

place in joints with one degree of freedom

There are actually six degrees of freedom


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Kinematic chains

Combination of several joints uniting successive segmentsconstitutes a kinematic chain.

The more distal segments can have higher degrees of freedom thando proximal ones


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Open and Closed Kinematic Chains

Open Kinematic Chains Distal segment of the chain moves in space

Segments can move independently or not at all

Proximal segment is fixed and the distal segment moves

Ex: UE reaching or bringing the hand to the mouth

Closed Kinematic Chains

Distal segment is fixed, and proximal parts move

Ex: Crutch walking, Elevating the body using an ovebed trapeze


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