prehension patterns of the hand

Question 1

prehension

Answer 1

involves grasping of an object b/w any 2 surfaces in the hand

type of grip used depends on the size and the shape

Question 2

2 broad categories

Answer 2

power grip

precision grip

Question 3

power grip

Answer 3

a forceful act

fibers are flexed around an object with counter pressure from the palm

thumb may or may not participate

grip employs the whole hand

Question 4

the power grip the most powerful group at

Answer 4

most powerful grip attained w/ wrist in about 30 degrees of extension

optimal length tension relationship

Question 5

3 patterns of power group

Answer 5

cylindrical grip

spherical grip

hook grip

Question 6

cylindrical grip

Answer 6

employed when holding a cylindrical objects such as a cup or a can of soda

ball provides base for prehension

Question 7

joint position for cylindrical grip

Answer 7

thumb opposition and flexion

fingers flexed

varying degrees of ulnar deviation - this position optimizes the force of the long finger flexors

the heavier the object –> the more likely there is UD at the wrist

Question 8

muscles for cylindrical grip

Answer 8

FDP

wrist extensors

FPL

ADD pollicis

Question 9

spherical grip

Answer 9

employed when holding a round object (ex: ball or an orange)

ball provides base for prehension and the arches must adject to accommodate the size of the object

Question 10

joint position spherical grip

Answer 10

MCP extension - depending on object size
-larger –> extension
-smaller –> flexion

MCP ABD or ADD
-smaller –> ABD
-larger –> ADD

ABD and opposition of thumb

Question 11

muscles involved in spherical grip

Answer 11

FDP

FDS

OP

FPL

APL

Question 12

hook grip

Answer 12

employed when carrying a suitcase or carrying books

Question 13

hook grip joint position

Answer 13

thumb does not need to be used

MCP joints are extended

PIP and DIP joints are flexed

Question 14

muscles involved w/ hook grip

Answer 14

FDP and FDS depending on load and where we hold the load

Question 15

precision grip

Answer 15

the placement of an object between fingers or finger and thumb

skillful grip that is used for manipulating objects

develops after power grip

3 types

Question 16

3 types of precision grip

Answer 16

palmar pinch (3 jaw chuck or pad to pad)

lateral pinch

tip prehension

Question 17

palmar pinch (3 jaw chuck or pad to pad)

Answer 17

the palmar pad of the thumb is in contract w/ the palmar pad of the index and middle fingers

employed when holding a pen

Question 18

joint position palmar pinch

Answer 18

MCP and PIP joints of the index and middle finger are flexed

DIP of index and middle finger are extended and sometimes hyperextended

IP of the thumb is slightly flexed or extended

Question 19

muscles involved palmar pinch

Answer 19

FDP

FDS

FPB

OP

ABD pollicis brevis

Question 20

lateral pinch

Answer 20

employed when grasping an object b/w the thumb and the side of the index finger

no contact with the middle finger, but it acts as support for the index finger as the thumb pushed against the index fingers

Ex: holding a piece of paper or to hold and turn keys

Question 21

joint position lateral pinch

Answer 21

no thumb opposition

thumb ADD

MCP and PIP of index finger are flexed

Question 22

muscles involved lateral pinch

Answer 22

FBP places the thumb against the side of the index finger and holds it there

first dorsal interosseous stabilizes and ABD the index finger

Question 23

clinical note lateral pinch

Answer 23

pts who have a median nerve injury (lose ability to oppose thumb), will be able to ADD and will employ this grip for grasping and holding small objects

(ADD pollicis in innervated by the ulnar nerve)

Question 24

tip prehension

Answer 24

tip to tip

employed to pick up small objects

the tip of the thumb is used against the top of the other fingers most often the index finger

Question 25

joint motion tip prehension

Answer 25

same as palmar pinch

except more finger flexion

Question 26

muscles involved tip prehension

Answer 26

same as palmar pinch

but DIP used FDP for more flexion while thumb uses FPL for ore flexion at the IP joint