Method of Study for This Section Read assigned readings of text Use Thompson Manual and the Dynamic Human CD- ROM 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 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 to common injuries of the upper extremity.

Sh Jt & Girdle Ant Musculature

Sh Jt & Girdle Post Musculature

Upper Extremity – Chapter 7 Shoulder Girdle Structure:

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

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 accomodating action of the shoulder girdle. –If carrying something in arms, scapular elevators are involved –Arm elevation – scapular protraction and/or upward rotation (first 30°,1/5 th is scapular movement; then ½ scapular movement)

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. 5ap/fongemie.html –Website for Shoulder JointImpingement SyndromeWebsite for Shoulder JointImpingement 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 330Biomechanics

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 websiteEpicondylitis website

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 for prevention of repetitive stress injury at computer workstations: CUergo: Neutral Posture TypingCUergo: Neutral Posture Typing KIN 330Biomechanics

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 Wed October 13 –Introductory problems, p 217: # 8,9,10 –Additional problem, p 218: #10