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