Upper Extremity Biomechanics BIO 455 week 7 day 2

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Upper Extremity BiomechanicsBIO 455 week 7 day 2

• Thought for the day
• "The main ingredient of stardom is the rest of
  the team."
• John Wooden

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Schedule

• Exams Back
• Human Assignment 2

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Critical Concepts

• In normal movement, there is synchronous movement
  between the components of the shoulder complex
• The movements are inter-dependent movement at
  one joint affects movements at the others
  (restriction or facilitation)
• Mechanical impairment in one joint can cause
  dysfunction at any or all the others

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The Shoulder Complex

• Some describe as 5 joints
• GH
• Super-humeral
• AC
• Sternoclavicular
• Scapulocostal

http//www-genome.wi.mit.edu/WWW/examples/Ch8/shou
lder.html
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The Shoulder Complex

• Sternoclavicular Joint
• unique feature
• Gliding/synovial with fibrocartilage disc
• Ligamentous support (3)
• Elevation/depression
• protraction/retraction
• rotate anterior/posterior

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The Shoulder Complex

• Acromioclavicular Joint (AC joint)
• Clavicle to scapula
• Gliding, synovial, fibrocart. Disc
• Scapula movements on Clavicle
• Elevation/depression
• Protraction/retraction
• Upward/downward rotation
• Scapulothoracic Joint (physiologic)
• Scapula rests on subscapularis and serratus
  anterior

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The Shoulder Complex

• Glenohumeral Joint
• Ball and socket, synovial
• Rotation, rolling, translating
• Lax capsule, minimal ligamentous support
• Shallow glenoid fossa, labrum deepens
• Reinforcements
• Anterior capsule, labrum, ligaments, subscap,
  pectoralis major muscles
• Posterior capsule, labrum, teres minor and
  infraspinatus
• Superior capsule, labrum, coaracohumeral lig,
  supraspinatus and long head biceps.

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The Shoulder Complex

• Glenohumeral Joint Movements
• Flexion/Extension
• Abduction/Adduction
• Effect of internal rotation
• Internal/External rotation
• Horizontal Flexion or Ab/Adduction

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The Shoulder Complex

• Combined Movements
• Scapulohumeral rhythm
• Flexion or abduction movements
• 180 degrees abduction 120 60 (initially GH
  motion, then 54 humeral/scapular)
• Humeral abduction and the greater tuberosity
• External rotation
• Internal rotation

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The Shoulder Complex

• Rotator Cuff Actions!
• Teres minor, subscapularis, infraspinatus,
  supraspinatus
• Humeral head stabilization
• Abduction 50
• Early Abduction teres minor depression, deltoid
  action (force couple)
• Late Abduction supraspinatus

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Internal/External Rotations

• Throwing preparatory phase, acceleration,
  follow-through
• Ext. Rotation infraspinatus and teres minor
• Int. Rotation subscapularis, lats, teres major,
  pects

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Shoulder Strength Sequence

• Adduction
• Extension
• Flexion
• Abduction
• Rotations
• Internal humerus in neutral
• External 90 degrees extension

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Shoulder Exercises

• Lat Pulldowns
• Abductions (dumbbells)
• Pushups, Military Presses
• Theraband or ext/int rotations on side
• Empty Can Exercise

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Shoulder Exercises

• Bent-over row
• Dumbbell Shrugs

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Shoulder Function in Activities

• Swimming
• Pull-through (internal rotation and adduction)
• Lats, teres major, pectoralis major
• Recovery (abduction and external rotation)
• Supraspinatus, infraspinatus, middle delt,
  serratus anterior (rotating scapula during lift)
• Serratus anterior!!

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Shoulder Function in Activities

• Throwing Pattern
• Step forward (creates?)
• Block step with lead foot. Transforming

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Shoulder Function in Activities

• Throwing Pattern
• Step forward (creates?)
• Block step with lead foot. Transforming
• Pelvic rotation
• Spinal rotation

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Shoulder Function in Activities

• Throwing Pattern
• Step forward (creates?)
• Block step with lead foot. Transforming
• Pelvic rotation
• Spinal rotation
• External rotation of humerus, horizontal
  abduction
• Arm left behind stretch

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Shoulder Function in Activities

• Throwing Pattern
• Step forward (creates?)
• Block step with lead foot. Transforming
• Pelvic rotation
• Spinal rotation
• External rotation of humerus, horizontal
  abduction
• Arm left behind stretch
• Acceleration follow through

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Shoulder Function in Activities

• Throwing
• Phase I cocking/preparation
• Abduction to 90 degrees, external rotation,
  scapular retraction, forearm flexion
• Ends at 90 deg abduction and max external
  rotation
• Huge muscular activity at end of phase
• Stretch Shorten Cycle Lats and pectorals at end
  of phase lengthen slowing arm movement and
  initiating forward movement
• Many muscles actively stabilizing
• Anterior capsule, ligaments also terminate
  movement

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Shoulder Function in Activities

• Throwing
• Phase II Acceleration
• Elbow extension, arm internal rotation with
  maintained 90 deg abduction, scapular protraction
  and horizontal flexion.
• Subscap, lats, teres major, pectoralis major,
  serratus anterior, triceps.
• Impingement compression during abduction and
  internal rotation

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Shoulder Function in Activities

• Throwing
• Phase III Follow-through/Deceleration
• Begins after ball release and after maximal
  internal rotation.
• Deltoids slow, lats stabilize and control
  internal rotation, traps stabile scapula,
  supraspinatus maintains arm in abduction and
  internal rotation.
• Posterior capsule stretch.