Senior MESA Day

Overview of the Human Arm Anatomy◦ Bones, Joints, Muscles

Review Arm Motion◦ Kinematics: types of motion, location of motion, direction

of motion, magnitude of motion, and degrees of freedom◦ Kinetics: extrinsic forces, intrinsic forces, force vectors,

force of gravity, reaction forces, additional linear forces, and classes of levers

Overview of the Prosthetic Arm Building the Model Building the Display

Humerus◦ The longest and largest bone in the upper

extremity. Ulna

◦ A long bone in the forearm parallel with the radius; at the proximal is the elbow and the distal end is the wrist.

Radius◦ The other bone of the forearm, shorter than the

ulna.

Carpals◦ The wrist is composed of 8 separate

carpal bones. Metacarpals

◦ The intermediate part of the hand skeleton that is between the carpals and the phalanges (up to the knuckles); 5 metacarpal cylindrical bones

Phalanges◦ The fingers of the hand contain 14 digital

bones.

Elbow Joint/Complex◦ Humeroulnar Joint – simple hinge-joint◦ Humeroradial Joint – arthrodial joint allowing

gliding and sliding motions◦ Proximal Radioulnar Joint – pivot joint

Wrist Joint◦ Radiocarpal joint◦ Carpometacarpal joints◦ Intercarpal joints

intercarpal joints

carpometacarpal joint

midcarpal joint

radiocarpal joint

interphalangeal

joints

Metacarpophalangeal Joints Interphalangeal Joints

Flexion: decreasing joint angle such as bending

Extension: increased joint angle such as stretching

Abduction: movement that draws limb away from sagittal plane

Adduction: movement which brings limb closer to the sagittal plane

Supination: palm faces up

Pronation: palm faces down

Circumduction: combination of flexion, extension, abduction and adduction

Upper Arm◦ Biceps brachii, brachialis, coracobrachialis

Forearm◦ Flexor-pronator and extensor-supinator

Hand◦ Thenar, hypothenar, interosseous, lumbrical

Arm Muscles and Their Functions

Muscle Location FunctionBiceps brachii Anterior Arm (humerus) Flexion and supination of the elbow

Brachialis Anterior Arm (humerus) Flexion of elbow in all positions, but especially when the forearm is pronated

Triceps brachii Posterior Arm (humerus) Extension of the elbow

Brachioradialis Posterior/Anterior Forearm (superficial)

Flexion of elbow; also pronation and supination, depending on position of forearm

Pronator teres Anterior Forearm (superficial) Pronation of forearm; flexion of the elbow

Pronator quadratus Anterior Forearm (deep layer) Pronation of the forearm

Flexor carpi radialis Anterior Forearm (superficial) Flexion and abduction of the wrist

Palmaris longus Anterior Forearm (superficial) Flexion and abduction of the wrist

Flexor carpi ulnaris Anterior Forearm (superficial) Flexion and abduction of the wrist

Flexor digitorum superficialis Anterior Forearm (superficial) Flexion of the fingers

Flexor digitorum profundus Anterior Forearm (deep layer) Flexion of the fingers

Flexor pollicis longus Anterior Forearm (deep layer) Flexion of the thumb

Supinator Posterior Forearm (deep layer) Supination of forearm and wrist

Extensor carpi radialis longus Posterior Forearm (superficial) Extension and abduction of the wrist

Extensor carpi radialis brevis Posterior Forearm (superficial) Extension and abduction of the wrist

Extensor carpi ulnaris Posterior Forearm (superficial) Extension and adduction of the wrist

Extensor digitorum Posterior Forearm (superficial) Extension of the fingers

Extensor digiti minimi Posterior Forearm (superficial) Extension of the fingers

Extensor pollicis brevis Posterior Forearm (deep layer) Extension of the thumb

Extensor pollicis longus Posterior Forearm (deep layer) Extension of the thumb

Abductor pollicis longus Posterior Forearm (deep layer) Extension and abduction of the thumb

Anterior of forearm

Tough bands of fibrous connective tissue that connects muscles to bones.◦ Capable of withstanding tension◦ Function to transmit force◦ Function as springs

Purpose: To understand and demonstrate the bones, tendons and muscles of the handMaterials per group:

10 straws

10 beads

10 popsicle sticks

stringShared Tools:

Glue gun

Saw

Scissors

Tape

Bamboo skewers

Lesson plan courtesy of:Curt GabrielsonWatsonville Community Science Workshop

Cut a full length popsicle stick into 1/3 pieces Cut 3 pieces of straw slightly shorter than sticks Glue pieces of straw to stick pieces Glue all three segments onto a full straw; leave a

small space in between each segment, so that flexing is possible

Glue 3 segments with full straw end to a full length stick

Glue one more straw segment onto the top of the full length stick in line with other 3 segments

Tie a bead to the end of piece of string and thread other end through all 4 short straw segments

Tie bead to other end. Wrap each segment with tape.

Cut a paint paddle in half, then one half into two pieces, one about an inch shorter than the other

Glue the larger piece to the top of the full half to form a “T”. Glue smaller piece right underneath it.

Make three more fingers and a thumb Glue the fingers to the paint paddle frame Glue on the thumb more towards the side of the

side of the hand Each finger should move when pulling on its

string

Types of Motion◦ Translatory: all parts move toward same direction◦ Rotatory/Angular: around a fixed axis◦ General: combination of translation and rotation

Location of Motion◦ Transverse or Horizontal Plane

Superior and Inferior◦ Coronal or Frontal Plane

Anterior and Posterior◦ Sagittal plane

Medial and Lateral

y - vertical axis

z –sagittal axis

x - coronal axis

Axis of rotation Direction of motion

Perpendicular to

Sagittal axis(anterior posterior axis)

Horizontally from front to back

Coronal plane

Coronal axis(frontal axis)

Horizontally from side to side

Sagittal plane

Vertical axis Perpendicular to ground

Transverse plane

Magnitude of Translatory Motion◦ Displacement: change of position

that an object moves from the reference point

◦ Velocity: rate of change in displacement v = dx / dt

◦ Acceleration: rate of change in velocity over time A = dv / dt

C

3.6 m

3 m

2 m B A

Magnitude of Rotatory Motion◦ Angular displacement: rotation of an object about

an axis in radians

Δθ = Δθ2 − Δθ1

◦ Angular velocity: time rate at which an object rotates about an axis, or at which angular displacement between two bodies changes

◦ Angular acceleration: change of angular velocity over time

Degrees of Freedom◦ 3 translatory motions along the x, y, and z axes

and 3 rotatory motions around the x, y, and z axes

◦ 6 DOF of a rigid body Moving up and down Moving left and right Moving forward and backward Tilting forward and backward (pitch) Turning left and right (yaw) Tilting side to side (roll)

Purpose: to understand degrees of freedom in biomechanics

Materials:

Standard coffee mug

Water

Bucket

Fill standard coffee mug with water ¾ full Place empty bucket on table. Using your hand,

grab and lift the cup and pour the water into the bucket◦ How many different positions can you pour the water

without spilling? Restricting a DOF at the shoulder joint, grab and

lift the cup and pour the water Restricting a DOF at the elbow joint, grab and lift

the cup and pour the water Restricting a DOF at the wrist joint, grab and lift

the cup and pour the water Record observations on Activity Sheet (page 41 of

curriculum)

Purpose: to build a paper robot arm and demonstrate the degrees of freedom

Materials:

Card stock paper Push pins

Foam board Scissors

String Tape

Fasteners Glue

Paper clips protractors

Activity developed by Pre College Programs,

USC Viterbi School of Engineering

Carefully cut out humerus, radius/ulna, and carpal Bend along lines to form arm segments Using push pin, poke holes where indicated Line up holes of humerus with holes of radius/ulna

and insert fastener through both sides Line up holes of radius/ulna with holes of carpal

and insert fastener through both sides Cut one strip of foam board 4" x 2", one strip 3" x

2", and two small pieces 1" x 2" Create standing post Tape free side of humerus to top of standing post Tape a string to the proximal end of radius/ulna Insert paper clip through top of standing post and

bring free end of humerus string through clip

Questions for Analysis◦ How many degrees of freedom does your paper

robot arm possess?

◦ Using a protractor, determine the actual degrees of movement.

◦ Determine the angular displacement

Part II:◦ Using what you learned in Part I, design and create

another paper robot are that has three or more degrees of freedom. You can modify the existing paper robot arm or you can create a new paper robot arm

◦ Questions for Analysis: How many DOF does your new paper robot arm have? Describe the DOF. Using a protractor, determine the actual degrees of

each movement. Determine the angular displacement for each DOF. What was different in design of your new paper robot

arm that allowed for additional DOF?

Extrinsic Forces◦ Gravitation force◦ Fluid force◦ Contact forces

Intrinsic Forces◦ Include muscles, ligaments, and bones◦ Friction between articular surfaces◦ Tension of antagonistic muscles, ligament,

fasciae, and capsules◦ Atmospheric pressure within the join capsule

Concepts to Consider:◦ Force Vectors

Point of application, action line and direction and magnitude

◦ Force of Gravity Gives an object weight, the magnitude of force that

must be applied to an object in order to support it in a gravitational force Weight = mass x 9.8 m/s2 or 32.2 ft/s2

Center of mass: the point where all of the mass of an object is concentrated

◦ Equilibrium Law of Inertia: every object persists in its state of

rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed on it

∑ F = 0 Law of Acceleration: acceleration is produced when a

force acts on a mass; directly proportional to force and inversely proportional to mass

a = F/ m◦ Reaction Forces

Law of Reaction: for every action, there is an equal and opposite reaction

◦ Additional Linear Forces Tension: pulling force exerted when an object is

being stretched or elongated Compression: force applied to an object tending to

cause a decrease in volume Shear: force that moves or attempts to move on

another object Torque: the tendency of a force to rotate an object

about an axis

or τ = (F) (moment arm)

Moment Arm = ⊥dIn A, what is the moment arm?In B, what is the moment arm?

◦ Classes of Levers First-class levers: effort force and resistance force

located on opposite sides of axis of rotation

Second-class levers: effort force located at the end of bar and fulcrum located at other end, with the resistance force at a point between these two forces

Third-class levers: effort force is applied between the resistance force on one end the fulcrum on the opposite end

Law of the Lever: Effort Arm x Effort Force =Resistance Arm x Resistance Force

EA = distance effort force lies from axis of rotationRA = distance resistance force lies from axis of rotation

◦ Mechanical Advantage (MA) Factor by which a mechanism multiplies the force or

torque put into it; Ratio of effort arm (EA) to the resistance arm (RA) A second-class lever will always have a MA > 1

because EA > RA A third-class lever will always have a MA < 1

because EA < RA common in the body and the MA is poor; however, the

speed of rotation created is high because the origin of the resistance force is located farther from the axis rotation than the origin of the effort force, it must travel a greater distance in the same time

A first-class lever can have a MA <, =, or > than 1, depending on the locations of the effort force and resistance force versus the axis of rotation

Purpose: To create a wooden robot arm with three degrees of freedom that uses hydraulics for motionMaterials and Tools:

Plywood Electrical tape

1” bolts with hex nuts Sandpaper

Syringes Scissors

Plastic tubing Hot glue gun

Film canister tops Drill with drill bits

Scotch or masking tape

Saw

Safety Procedure:Use extreme caution with using sharp tools, drills, and hot glue gun

Activity developed by Pre College Programs,

USC Viterbi School of Engineering

Cut two 6”x3” plywood long rectangles, a 4”x2½ “ plywood medium rectangle, and a 2½”x 2½” plywood square

Round off corners of each piece w/sandpaper Humerus: in the middle of one of the long

rectangles, drill three holes Radius/ulna: in the middle of the other long

rectangle, drill two holes Carpal: in the middle of the medium rectangle,

drill one hole and one large hole in the center Line up single hole of humerus with hole of

radius/ulna and insert bolt and nut Line up remaining hole of radius/ulna with small

hole of carpal and insert bolt and nut

Platform

Standing Post

Cut a strip of plywood 10”x3” and two small pieces of plywood 1”x3”

On the large strip, drill two holes Create the standing post by gluing the two small

pieces on both bottom sides of the large plywood Line up holes of standing post with holes of

humerus and insert bolts and nuts Using the center of mass, determine the

dimensions of the platform in order to balance the standing post and the arm structures with nuts and bolts

Cut plywood to determined dimensions above Glue standing post vertically to platform

Three DOF◦ Determine the best manner in attaching the

syringes, plastic tubing, and film canister tops in order to create 3 DOF, taking into consideration the center of mass, torque and classes of levers. You may use additional materials if needed.

Questions for Analysis◦ Calculate the work done by lifting a 147.87 ml (5

oz) dixie cup filled with 100 ml of water to a height of 10 cm. Hint:

◦ Calculate the torque using the above parameters. Hint: use

◦ What class of lever is the wooden hydraulic robot arm? What are the advantages/disadvantages?

Artificial limb is a type of prosthesis, an artificial substitute, that replaces a missing extremity such as an arm

Needed for a various reasons, including disease, accidents, and congenital defects

History◦ Roman Capua Leg, found in a tomb in Capua, Italy

dating to 300 BC, was made of cooper and wood◦ Armorers in the 15th and 16th centuries made

artificial limbs out of iron for soldiers who lost limbs

Types◦ Transradial prosthesis: artificial limb that replaces

an arm missing below the elbow◦ Transhumeral prosthesis: one that replaces an

arm above the elbow Current Technology

◦ New plastics and other materials, such as carbon fiber, have allowed artificial limbs to be stronger and lighter

◦ Additional materials allow for a more realistic look◦ Myoelectric limbs allow more direct control

Emerging Technology◦ Robotic limbs

Purpose: to learn design concepts, teamwork, problem solving techniques and about simple machines

Goal: must be 18 inches in length and be able to pick up an empty Styrofoam cup

Resources/Materials for each group

5 strips of cardboard 15 paper clips

8 binder clips 4 pencils

10 Brads 15 rubber bands

6 clothespins Clear and masking tape

15 craft sticks 4 feet twine

4 feet fishing line Scraps of cardboard

2 hangers

Developed by IEEE as part of TryEngineering

Model MUST perform 3 tasks: grab, lift, and pour 50ml graduated cylinder with 50ml of sand

Model MUST be operated by push of button(s), pull of string(s), push or pull of syringe(s), etc. May NOT perform actual function of grabbing, lifting, or pouring

Entire base of model MUST fit within a 1.5 foot square. Any part of model that may be in contact with the table MUST be within the 1.5 foot square.

Use materials found around the house or school, taking into consideration cost and weight efficiency (max points awarded for low cost and low weight)

Dimensions: 3 ft x 3 ft x 2 ft deep Freestanding Synopsis of project, 200 to 250 words

◦ Include purpose of project, explanation of model, and scientific and engineering ideas involved

Scaled plan rendering◦ Three separate 8 ½ x 11 scaled drawings (front, side, and

top views) with dimensions Materials Table

◦ Table of all materials used in the model including retail price, price per unit, quantity used, total cost, and how each material was acquired (see rules for sample)