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°,1/5th 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.

http://www.aafp.org/afp/980215ap/fongemie.html

– Website 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 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

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 Typing

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