Prehension and Ballistic Skills Flashcards
What body part is involved in fine motor development of prehension?
Hand
What is prehension?
Process of reaching and grasping - ability to use the hands and the UE effectively
What are the primary components of prehension?
Visual regard, reach (approach), grasp, manipulation, and release
How does stabilization factor into prehension?
Trunk and UE require varied degrees of stabilization to afford us the ability to reach and grasp objects
What is visual regard?
Visual attention of the object
What are the two factors of visual regard?
- Visual regard - accommodation (focus) and convergence
2. Visual perception - ability to use visual information to recognize, recall, discriminate, and understand what we see
What does visual regard require?
Eye-head-trunk coordination
What is approach (reaching)?
Directing or adjusting of the hand toward an object
What does approaching require?
Visual-motor control - eye-hand coordination
What does reaching involve?
Movement of all joints of the UE - vision initially important followed by tactile and proprioceptive input
What are postural adjustments associated with reaching?
Arms play a role with balance and hand can be used to form a new BOS
What does movement beyond arm’s length entail?
Movement of the trunk and the hips
What are the three stages of development of reaching?
- Prereaching - birth to 4 months
- Visually guided reaching - 4 to 8 months
- Visual elicited reaching - 9+ months
What is prereaching?
Excited thrashing of the limbs and no correction of reach once initiated
What is visually guided reaching?
Increased use of vision to guide hands and make corrections as they reach
What is visually elicited reaching?
No longer needs to see hand to guide reach and infant shapes hand correctly for the object
What are the two types of grip?
Power and precision
What is the power grip?
Forcible activities of the fingers and thumb that act against the palm to transmit a force to an object
What are three examples of power grips?
Cylindrical, spherical, and hook
What is precision grip?
Forces are directed between the thumb and fingers without contacting the palm
What are three examples of precision grip?
Pad to pad prehension, tip to tip prehension, and pad to side (lateral) prehension
What percentage does the thumb contribute to total hand function?
40-70%
What is opposition?
Movement by which the pad surface of the thumb is placed diametrically opposite the terminal par of one or all of the digits
What is the second most important finger?
Index finger
Which finger is the longest and the strongest?
Middle finger
What percentage does the index finger play in lateral pinch and power grip (supinated and pronated)?
Lateral pinch - 20% Power grip (supinated) - 20% Power grip (pronated) - 50%
What two digits are the most anatomically stable?
Index and middle finger
What two digits are the most mobile and weakest?
Ring and pinky finger
What are the three development grasps?
- Reflexive grasp - traction response and grasp reflex
- Transitional reaction - orienting response and instinctive grasp
- Purposeful grasp - squeeze grasp (palmar grasp) and radial palmar grasp (radial digital grasp)
What is the goal of catching?
Retain possession of object that is caught
How is catching developed?
Master ability to move left or right/forward or backward and point fingers up or down when catching a high or low ball
What is throwing?
Ability to project an object accurately and with sufficient force through space
How does throwing develop?
6 months - crude unrefined throwing
2 years - immature, stiff, and jerky throw
What is a fundamental movement used in a number of child and adult games?
Ball-bouncing
What is striking?
Propulsion skill - object or body part is used to project an object
What are characteristics of early sidearm striking?
Chopping motion (elbow extension) and little leg and trunk movement
How does striking progress?
Sideways preparatory stance, arm extended before contact, and swing through a large ROM
