Biomech MS System (cont'd), Upper Extremity

Report
Method of Study for This Section
(Applied Anatomy of the
Musculoskeletal System)
• Read assigned readings of text
• Use the Dynamic Human CD-ROM and models and
illustrations of the musculoskeletal system to help review
structure of bones, joints, and muscles as necessary. This is
the purpose of lab.
• Complete labs conscientiously and study models of
articulated skeleton, shoulder, spine, and knee
• Lecture will only provide a selective review of structure,
muscles & movements, and movement-related issues
• For exams, review lecture notes and understanding
questions in both lecture and labs
Objectives of Upper Ext Unit
• Explain how anatomical structure affects
movement capabilities on upper extremity
articulations.
• Identify factors influencing the relative mobility
and stability of upper extremity movements
• Identify muscles that are active during specific
upper extremity movements
• Describe the biomechanical contributions,
specific structures, and movement-related causes
of common injuries of the upper extremity.
Sh Jt & Girdle Ant Musculature
Sh Jt & Girdle Post Musculature
Upper Extremity – Chapter 7
Shoulder
Girdle
Structure:
Normal Rom of Shoulder girdle
• Sternoclavicular joint
– Protraction 15 deg, retraction 15 deg
– Elevation 45 deg, depression 15 deg
• Acromioclavicular joint
– All directions 20-30 deg
Muscles and Movement of Shoulder Girdle
• Illustrations on next three slides
• Trapezius (large, superficial medial and sup to scapulae)
– Upper portion - elevation, upward rotation
– Middle portion - adduction, or retraction
– Lower portion - depression, upward rotation
• Rhomboids – elevation, downward rotation, adduction, or retraction
• Serratus anterior (underneath scapulae)
– abduction, upward rotation
• Pectoralis minor (underneath pectoralis major)
– downward rotation, abduction, or protraction
• Levator Scapulae (underneath upper trapezius)
– elevation, downward rotation
Elevation and Depression
Upward & Downward Rotation
Protraction & Retraction
Shoulder Joint Structure
Normal ROM of arm movements
• Flexion – (arm at side is 0 deg) 180 deg,
hyperextension 60 deg
• Transverse flex (arm in front of chest is 0
deg) – 40 deg, transverse ext 90 deg
• Rotation(arm abducted, elbow bent to 90
deg, arm at right angles to trunk is 0 deg)
– Internal 90 deg, external 90 deg
• Abduction 180 deg
Shoulder Joint Stabilizers
• Stabilizers and rotators - Rotator cuff muscles –
–
–
–
–
Teres minor - external rotation
Infraspinatus - external rotation
Supraspinatus - abduction
Subscapularis - internal rotation
Shoulder Joint Primary Movers
• Anterior movers – Anterior deltoid, pectoralis
major
• Superior movers - middle deltoid
• Posterior movers - posterior deltoid
• Inferior movers - latissimus dorsi, teres major,
lower pectoralis m.
• Force vectors of muscles (see next slide)
Shoulder Jt Muscles
Movements of Shoulder Complex
• Every movement of upper extremity involves
either stabilizing or accommodating action of the
shoulder girdle.
– If carrying something in arms, scapular elevators are
involved
– Arm elevation – scapular protraction and/or upward
rotation (first 30°,1/5th is scapular movement; then
1/3rd scapular movement after that)
Shoulder Joint Impingement Syndrome
• What is it? Pain from shoulder area resulting from impingement of
structures between humeral head, acromion, and coracromial arch. Three
stages:
– Stage I - edema and hemorrhage of subacromial structures
– Stage II - tendon fibrosis and bursal thickening
– Stage III - rotator cuff tears, biceps tendon ruptures, and bone spurs
I:
II:
III:
Causes of Sh Jt Impingement
• Primary impingement:
– Repeated movements requiring elevated and/or medially
rotated humerus, compounded by weak rotator cuff
muscles, causing: impingement of long head of biceps,
supraspinatus
• Secondary Impingement:
– Decreased volume of subacromial space due to
glenohumeral joint instability, and perhaps joint capsular
tightness
• Structural abnormalities:
– hooked or curved acromion, calcium deposits, bone
spurs, thickened bursa, thickened ligaments
Shoulder Jt Impingement (3)
• Treatment:
– Related to the cause - may
involve surgery, rotator cuff
strengthening, and flexibility
exercises.
– Later, avoid humeral
elevation and rotation
movements.
– Website for Shoulder Joint
Impingement Syndrome
(click on “view eorthopod”,
then “shoulder”, then
“impingement syndrome”)
Elbow Joint Structure
Elbow and Wrist Joint Muscles
•
•
•
•
True Flexor - Brachialis
Flexor-Supinator - Biceps brachii
Extensor - Triceps brachii
Wrist flexors (medial epicondyle of humerus)
– Flexor carpi ulnaris and flexor carpi radialis
• Wrist extensors (lateral epicondyle of humerus)
– Extensor carpi ulnaris & extensor carpi radialis
• Force vectors of muscles on next slide
KIN 330
Biomechanics
• Muscles of
elbow joint:
Muscles and Movements of Radioulnar Joint
• Elbow Flexion – Forearm Supination - Biceps Brachii
– Forearm Pronation - Pronator Teres
• Elbow Extension – Forearm Supination - Supinator
– Forearm Pronation -Pronator Quadratus
• Muscle force vectors on next slide
• Epicondylitis
– The most common cumulative trauma disorder (CTD), repetitive
stress injury (RSI), repetitive motion disorder (RMD), or overuse
syndrome (OS) is epicondylitis
– Epicondylitis website (click on “view eorthopod”, then “elbow”,
then “medial epicondylitis” or “lateral epicondylitis”
Normal ROM for forearm and
wrist movements
• Forearm
– Flexion 150 deg
– Supination 80-90 deg
– Pronation 80-90 deg
• Wrist
–
–
–
–
Flexion 80 deg
Extension 70 deg
Radial flex 20 deg
Ulnar flex 30 deg
Radioulnar Jt Muscles
Bones of Wrist and Hand
Carpal Tunnel Syndrome
• Background
Carpal tunnel includes
median nerve and
9 flexor tendons
( 4 flex dig sup,
4 flex dig prof,
1 fl pol l)
Carpal Tunnel Syndrome (cont’d)
• Symptoms
– Pain in wrist area, or referred proximally or distally
– Tingling of thumb, fingers, or palmar side of hand
– Loss of control of muscles affected by median nerve blockage
• Causes
– Enlargement of tissues within tunnel
– Decreased size of tunnel
– Extraneous tissue in tunnel
• Treatment
– Related to cause
• Website on carpal tunnel syndrome (Click on “view
eorthopod”, then “hand”, then “carpal tunnel syndrome”
–
KIN 330
Biomechanics
Review & Homework Problems
for Chapter 7
• Review problems:
– Torque at shoulder with elbow flexed vs extended
• Fig 7-15, 7-16
– Compressive force at shoulder jt
• Fig 7-17, sample problem 1 p 197
– Elbow flexion force
• Figure 7-25, sample problem 2 p 206
• Homework – Due Tuesday, March 7
– Introductory problems, p 217: # 8,9,10
– Additional problem, p 218: #10

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