manual dexterity

Question 1

professions where manual dexterity is a requirement

Answer 1

dentistry

surgery

Question 2

what can result in mobility limitations?

Answer 2

neuromuscular and orthopedic disabilities - produce wide variations in the nature and extent of the remaining physical functions

Question 3

causes of mobility limitations

Answer 3

wrist sprain or fractured arm;

dyspraxia;

arthritis;

muscular dystrophy;

multiple sclerosis;

cerebral palsy;

partial or total paralysis;

Question 4

treatment to improve dexterity or recover dexterity

Answer 4

hand exercises

splints

Question 5

what bones make up the human hand and wrist?

Answer 5

14 phalanges
5 metacarpals
8 carpals
distal carpal row
second and third metacarpals
phalanges
thumb

Question 6

what are the fixed elements of the hand and wrist?

Answer 6

distal carpal row

second and third metacarpals

Question 7

what are the mobile elements of the hands and wrists?

Answer 7

phalanges

thumb

Question 8

what is the basis of precision?

Answer 8

basis of precision

Question 9

what allows for an opposable thumb?

Answer 9

• the first metacarpal makes an angle of 45 degrees with the second metacarpal in the sagitattal plane and is independent
• this allows the thumb ray to oppose the other four digital rays
• the thumb can be moved independently of the rest of the fingers - rotary movemnt in which the thumb swings about its own axis
• helps to grasps things more easily, picking up small objects and eating with one hand

Question 10

is the opposable thumb specific to humans?

Answer 10

• no
• chimps, gorillas orangutans, old world monkeys as well as some other animals such as opossums and giant pandas
• their thumbs are usually small, weak and relatively immobile
• apes and old world monkeys are the only ones that have hands that are capable of grasping objects
• opposable thumbs help monkeys and apes climbe trees as well as gather and eat their food

Question 11

describe the fingers of chimps

Answer 11

-Elongated metacarpal and phalanges.
-Third and fourth metacarpals which absorb
the highest compression during knuckle
walking are especially robust
-short thumb
-Both proximal and middle phalanges are curved towards the palm to withstand
stress from gripping limbs during arboreal locomotion.
-The finger tips are cone-shaped and lack broad apical tufts.
-Thumb phalanges and metacarpals are
slender and the intrinsic muscles of the thumb, underlying the thenar region
of the palm are small.
-Thumb is week and relatively immobile.

Question 12

describe the fingers of humans

Answer 12

-Relatively short metacarpals and phalanges
-Apart from the thickening of the fifth metacarpal and enlargement of its base,
the balance of strength and robusticity has shifted radially to the thumb, second
and third fingers.
-longer thumb
-Fingers have lost their curvature.
-The distal phalanges have gained large apical tufts to facilitate gripping with the finger ends.
-The intrinsic thumb muscles are largerand three additional muscles add strength and
control to thumb movements.
-The thumb metacarpal articulates with the
carpals in a saddle joint which in combination with remodelling in the
metacarapal-phalangeal joint allows full opposability.

Question 13

differences in the thumb muscles in humans:

Answer 13

added:
- flexor pollicis brevis
- fist volar interosseous of henie

just longer in humans:
flexor pollicis longus

Question 14

what are the two prehensile actions that come with the opposable thumb

Answer 14

power and precision grips

Question 15

what is the precision grip?

Answer 15

throwing grip, writing, - tip of the thumb comes into play

Question 16

what is the power grip?

Answer 16

clubbing grip

Question 17

what neuroanatomical specialisation facilitates manual dexterity?

Answer 17

• primary motor cortex is divided into two distinct regions
• one region is evolutionary more recent and is essential for the highly skilled movements
• this region is highly developed in humans as compared to other primates

Question 18

what is the primary motor cortex?

Answer 18

the region of the brain that controls voluntary movement in higher primates

Question 19

the earliest tool makers

Answer 19

likely has no archeological record - wood or bone

chimps use tools and leave little trace of behavior

Question 20

what was the earliest stone tool age

Answer 20

oldowan - just a core and then flakes chipped off

Question 21

when and were were the oldest stone tools found? - timeline format

Answer 21

Gona, Afar Ethiopia 2.6 Ma
Omo River, Ethiopia 2.3 Ma
West Turkana, Kenya 2.3 Ma
Hadar, Afar Ethiopia, 2.3 Ma
Kanjera, Kenya, 2.1 Ma
Koobi Fora, Kenya, 1.9 Ma

Question 22

what is a sign that earlier hominins knew their landscape

Answer 22

there was evidence that they transported raw resources from one area to another and carried these resources from one area back to where they stayed - they knew where to look for raw and natural resources

Question 23

are chimps efficient tool makers?

Answer 23

• no, even despite years of training
• even aus garhi was better
• chimps have a relatively short thumb and immobile wrist
• prevents them from using the same precision grip as our ancestors - difficult to control their blows to produce flakes of specific sizes and shapes

Question 24

cut marks on bones from 3.39 mya?

Answer 24

No

bones were buried and the sediment impacted them while being trampled on by other creatures