shoulder complex biomechanics.ppt

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SHOULDER COMPLEX

BIOMECHANICS

 Dr BF MtshaliDr BF Mtshali

(2)

Shoulder Complex

Articulations

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(4)

Bony articulations

 Glenohumeral jointGlenohumeral joint

(5)

Functional joints

 Scapulothoracic articulationScapulothoracic articulation  Suprahumeral (subacromial) Suprahumeral (subacromial)

articulation

 Bicipital groove betw. Greater and Bicipital groove betw. Greater and lesser tuberosity

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Glenohumeral joint G/H

 Glenoid cavity articulates with head Glenoid cavity articulates with head of humerus

(7)

Glenohumeral joint

Proximal component

- Concave glenoid – glenoid labrum

Fibocartilage to deepen glenoid cavity

Distal component

Convex compont

Retroversion of humeral 30

Retroversion of humeral 3000 to ML axis at _{to ML axis at}

elbow joint

Joint type ball and socket

(8)

Glenohumeral cont’

 Motion- Convex on concaveMotion- Convex on concave

- Sh F/E with post/ anterior glide of Sh F/E with post/ anterior glide of

humeral head

- Sh Abd/Add with inf/superior glide of Sh Abd/Add with inf/superior glide of

humeral head

- Sh I/E rotation with posterior/ Sh I/E rotation with posterior/

anterior glide of humeral head

- 3 DOF- Closed pack pos Sh abd & 3 DOF- Closed pack pos Sh abd &

full ER

(9)

Arthrokinematics

 Sh F –posterolateral glide of head of Sh F –posterolateral glide of head of

humerus on glenoid cavity

 Limiting factor – inferior glenohumeral Limiting factor – inferior glenohumeral

ligament and tightness of posterior joint

capsule

 Sh E- anteromedial glide of head of Sh E- anteromedial glide of head of

humerus

 Limit- tightness of superior and middle Limit- tightness of superior and middle

glenohumeral ligaments

(10)

Arthrokinematics cont’

 Sh abd- inferior glide of humeral Sh abd- inferior glide of humeral head on glenoid cavity

head on glenoid cavity

 Limit tightness of inferior Limit tightness of inferior

glenohumeral ligament and inferior

joint capsule

 Sh add- superior glide of humeral Sh add- superior glide of humeral head on glenoid cavity

head on glenoid cavity

(11)

Internal and external

rotation

 90900 0 of sh abd and 90of sh abd and 9000 of elb flexion of elb flexion

 Internal rot- posterolateral glide of Internal rot- posterolateral glide of humeral head on glenoid cavity

humeral head on glenoid cavity

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(14)

Shoulder horizontal add/

abd

 Sh F/E at 90Sh F/E at 9000 of sh abd of sh abd

(15)

Sternoclavicular joint /

(16)

SC joint

 Proximal component – sternumProximal component – sternum

- Saddle shaped manubrium sterniSaddle shaped manubrium sterni

- Distal component - clavicleDistal component - clavicle

- - Saddle shaped medial end- Saddle shaped medial end

- Articular disc between 2 articular surfacesArticular disc between 2 articular surfaces

- Joint type -saddle jointJoint type -saddle joint

- Movements- shoulder girgle motionMovements- shoulder girgle motion

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Clavicle

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Clavicle

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Clavicle posterior

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Clavicle

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Acromioclavicular joint

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AC Joint

 Proximal componentProximal component

- Convex lat end of clavicleConvex lat end of clavicle

- Concave acromion process of scapulaConcave acromion process of scapula - Joint type- nearly plane_{Joint type- nearly plane}

- MovementsMovements

- Upward/downward rotUpward/downward rot

- Winging (horizontal plane adjustment)_{Winging (horizontal plane adjustment)} - Tipping (sagittal plane adjustment)Tipping (sagittal plane adjustment)

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Scapulothoracic

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ST articulation

-Proximal component -Proximal component - Convex rib cageConvex rib cage

- Distal componentDistal component

- Concave anterior surface of scapulaConcave anterior surface of scapula - Not real anatomical jointNot real anatomical joint

- Movements are the result of mvts occuring at SC Movements are the result of mvts occuring at SC & AC joints

& AC joints

- Elevation/depressionElevation/depression - Protraction/retractionProtraction/retraction

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Downward/upward

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Manual stretch of scapula

into ER

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Manual strecth in 90-90

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Self stretch of pect

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Impingement of

supraspinatus tendon

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Painful Arc

Rotator Cuff Injury

• Drop Arm Test: Unable to resist pressure at 90°

abduction • Painful Arc:

Between 45 ° and

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Subacromial Space

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Suprahumeral

articulation

- Subacromial jointSubacromial joint

- Coracoacromial arch- composed of Coracoacromial arch- composed of

coracoacromial ligament

- Supraspinatus tendon passing underneath Supraspinatus tendon passing underneath

arch

- Homework – Tabulate contents of the Homework – Tabulate contents of the

subacromial space

- Shoulder impingement occurs if space is Shoulder impingement occurs if space is

insufficient

(43)

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Plane of scapula

- Not parallel to frontal planeNot parallel to frontal plane

- Plane at an angle of 30Plane at an angle of 3000 anterior to _{anterior to}

frontal plane

- No impingement in the No impingement in the

suprahumeral joint if shoulder

motion occurs in scapular plane

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Stability of shoulder

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Stability cont’

 Dependant onDependant on

 Static stabilisersStatic stabilisers – bony – bony configuration

configuration

- capsule - capsule

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Relationship of glenoid

cavity to head of humerus

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Superior GH

 Superior glenohumeral ligament Superior glenohumeral ligament resists inferior translation of the

resists inferior translation of the

head of humerus on glenoid cavity

(52)

Middle Glenohumeral

Ligament

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Middle GH

 It resists anterior translation of head It resists anterior translation of head of humerus on glenoid cavity at 45

of humerus on glenoid cavity at 450 0

of abduction

(54)

Inferior glenohumeral

ligament

 It has 2 bands – anterior & posteriorIt has 2 bands – anterior & posterior  IGH ligament resists anterior IGH ligament resists anterior

translation of head of humerus at

90

900 0 of abduction_{of abduction}

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Inferior glenohumeral

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Inferior GH

 Posterior band resists posterior Posterior band resists posterior translation in IR/FE

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Serratus Anterior

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Pectoralis Anterior

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Stages of scapulohumeral

rythym

 Stage 1Stage 1

 000 0 – 30_{– 30}0 0 glenohumeral movement alone_{glenohumeral movement alone}

 Scapular shouldn’t moveScapular shouldn’t move  Stage 2Stage 2

 303000- 90_{- 90}0 0 scapular elevation and upward _{scapular elevation and upward} rotation points glenoid towards ceiling rotation points glenoid towards ceiling

 Humeral head glides inferiorly by 90Humeral head glides inferiorly by 9000 revealing sulcus

(67)

Stages of scapulohumeral

rythym

 Stage 3Stage 3

 Scapula slides around ribcage and Scapula slides around ribcage and thoracic spine flattens

thoracic spine flattens

 Inferior angle of scapula should not Inferior angle of scapula should not protrude further than 1cm from

protrude further than 1cm from

chest wall

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Force couples in arm

elevation A

 In the first 60In the first 6000, the axis of rotation of _{, the axis of rotation of}

the scapula is situated at the root of

the spine of the scapula

 Primary muscles involved in upward Primary muscles involved in upward rotation are lower fibres of serratus

rotation are lower fibres of serratus

anterior and upper trapezius

 Lower and middle traps function Lower and middle traps function eccentrically to control movement

(79)

60

(80)

Force couples in B

 In the next 60In the next 6000 the axis of rotation the axis of rotation

begins to move along the spine of

the scapula towards the

acromioclavicular joint

 Lower trapezius becomes more Lower trapezius becomes more

actively involved in upward rotation

along with lower serratus anterior

and upper trapezius

(81)

120

(82)

120

00

of arm elevation

 The axis of rotation is at the The axis of rotation is at the acromioclavicular joint

acromioclavicular joint

 Upper traps is no longer positioned Upper traps is no longer positioned to be able to function in upward rot

to be able to function in upward rot

of scapula

 Lower traps and lower serratus are Lower traps and lower serratus are ideally positioned for upward

ideally positioned for upward

rotation of scapula

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Final stage of arm

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Final stage

 Lower traps and lower serratus Lower traps and lower serratus

anterior are the primary rotators of

the scapula

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Early wind-up Phase

 Early Windup Phase: Front hip Early Windup Phase: Front hip

flexed, horizontally adducted,

internally rotated.

(90)

Early Wind-up Phase

 Common Fault: Thigh cannot Common Fault: Thigh cannot

pass midline

 Common compensation – Test Common compensation – Test

Pitcher’s Prayer Position. IR right

hip and subtalar in/eversion

(91)

Late Wind-up Phase

 Late Windup Phase: Stand Tall, Late Windup Phase: Stand Tall,

Butt Tucked In Tight

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Late Wind –up Phase

 Common Fault: Weight back on Common Fault: Weight back on

heel or forward torso.

 Common Compensation- Test Common Compensation- Test

Knee, ankle excursion with

overhead reach

(93)

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Cock- up Phase

 Stride Phase, Arm Cocking: Stride Phase, Arm Cocking:

Shoulders level, “heavy” on

support leg

(95)

Cock-up Phase

 Common Faults: High Lead Common Faults: High Lead

shoulder, backward lean to torso,

pushing off of support leg.

Incorrect: Backward lean to

 torso, high lead shoulder. torso, high lead shoulder. Bad Bad

(96)

Cock-up Phase

 Incorrect: Incorrect: Pushing off the rubberPushing off the rubber

 Incorrect Test Frontal Plane R Incorrect Test Frontal Plane R

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Acceleration Phase

(100)

Acceleration Phase

 Incorrect: Poor hip extension & Incorrect: Poor hip extension &

rotation, compensates c/

lumbosacral flexion. Stress

to ant. capsule

(101)

Acceleration Phase

 Incorrect:Incorrect:

 Same as above, but stress at Same as above, but stress at

medial elbow due to low arm

angle

(102)

Acceleration Phase

 Test: Frontal plane balance c/ R. Test: Frontal plane balance c/ R.

leg medial reach

(103)

Late Acceleration Phase

 Common Compensations:Common Compensations:

 1. Short Step (lack of hip extension).1. Short Step (lack of hip extension).

 2. Long Step, but compensates with 2. Long Step, but compensates with hyperlordosis (look for the

hyperlordosis (look for the

 ““bowstring” effect in the rectus bowstring” effect in the rectus abdominus).

abdominus).

 3. Flexing at the waist ( sacroiliac, 3. Flexing at the waist ( sacroiliac, iliosacral dysfunction).

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Late Acceleration Phase

 4. Arm(s) & Elbow(s) drop and/or 4. Arm(s) & Elbow(s) drop and/or

move forward in the sagittal

plane (tight pectoralis minor

and/or latissimus dorsi, kyphotic

thoracic spine).

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Late Acceleration Phase

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(107)

(108)

Follow through Phase

 Are the Clutch & Brake working Are the Clutch & Brake working

correctly? correctly?

 Who Will Rescue the Posterior Who Will Rescue the Posterior

Capsule, infraspinatus,Teres Capsule, infraspinatus,Teres

(109)

Improper Follow

Through

Neutral Torso, Poor “Relative”

Internal Rotation, Foot Still in

Pronation of Femur

(110)

Link Sequencing (Kibler

1998)

 ““The scapula is pivotal in The scapula is pivotal in

transferring the large forces and

high energy from the major

source for force and energy—the

legs, back, and trunk—to the

actual delivery mechanism of the

energy and force—the arm and

the

hand.”

(111)

Link Sequencing (Kibler

1998)

 Forces that are generated in the Forces that are generated in the

proximal segments have to be proximal segments have to be

transferred efficiently and must transferred efficiently and must

be regulated as they go through be regulated as they go through

(112)

Link Sequencing (Kibler

1998)

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Objective Evaluation

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Anterior and posterior

drawer

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(143)

Hawkins &Kennedy test

 Humerus placed in 90Humerus placed in 9000F and then F and then

internally rotated.

 Physio exerts force through the Physio exerts force through the forearm to bring G/H into IR

forearm to bring G/H into IR

 Pain implicates supraspinatus Pain implicates supraspinatus tendon impingement

(144)

(145)

Neer’ test

 Patient seated while examiner standsPatient seated while examiner stands

 Scapular ER is blocked with one handScapular ER is blocked with one hand

 Other hand raises arm in forced F, Other hand raises arm in forced F,

causing approximation of greater

tuberosity and the acromion.

 Pain implicates impingement of Pain implicates impingement of

supraspinatus and biceps tendon

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(147)

(148)

(149)

Shoulder stretch

 Do abdominal bracing to decrease Do abdominal bracing to decrease lumbar lordosis

(150)

Shoulder stretch

(151)

Seated shoulder stretch

(152)

Shoulder stretch

(153)

Shoulder tapping

(154)

Retract and upwardly rotate

scapula

(155)

Concavity-compression

retraining

(156)

Pect major stretching

(157)

(158)

(159)

(160)

Closed Kinetic Chain

(161)

CKC Exercise

(162)

(163)

Trampoline exercise/

plyometrics

(164)

(165)

(166)

Scapular stabilising

(167)

(168)

(169)

Facilitation of scapular

upward rotation

(170)

(171)

(172)

Scapular Balance and

Stabilisation

(173)