GH Joint Flashcards
What kind of joint is the GH joint? How many DOF?
Synovial (diarthrosis), ball and socket, 3 DOF
How is the glenoid fossa positioned?
antero-laterally with slight upward rotation
How is the humeral head positioned?
Medial, posterior, superior
What is the closed packed position, the loose packed position, and the capsular pattern?
CPP: max ABD and ER
OPP: 55 ABD, 30 horiz. ADD, slight ER
CP: ER > ABD > IR
GH Flexion: what is allowed degree of movement and what muscles are being used?
120 degrees
Ant. Deltoid, Pec. Major (C) (0-60), coracobrachialis, long head of biceps
GH extension: what is allowed degree of movement and what muscles are being used?
65 degrees
Post. Delt., teres major, lat. dorsi, long head of triceps, pec major (S) (180-90)
GH abduction: what is allowed degree of movement and what muscles are being used?
120 degrees when in ER
Supraspinatus, lateral delt.
GH adduction: what is allowed degree of movement and what muscles are being used?
0 degrees pure add, 50-75 degrees in front of the body
Ant. delt., post. delt., lat. dorsi, pec. major, long head triceps, coracorachialis, teres major
GH ER: what is allowed degree of movement and what muscles are being used?
60-70 degrees pure ER, 90 degrees with shoulder abducted
Post. delt., teres minor, infraspinatus, supraspinatus (past neutral)
GH IR: what is allowed degree of movement and what muscles are being used?
75-85 degrees pure
Ant. delt., pec. major, teres major, lat. dorsi, subscapularis
GH flexion: what is the roll and glide?
Anterior roll posterior glide
GH extension: what is the roll and glide?
Posterior roll, anterior glide
GH abduction: what is the roll and glide? What happens without the glide?
Superior roll, inferior glide
Without glide, impingement under acromial arch
GH adduction: what is the roll and glide?
Inferior roll, superior glide
GH ER: what is the roll and glide? What would happen without the glide?
Posterior roll, anterior glide
without glide, humerus would roll posteriorly out of socket
GH IR: what is the roll and glide?
HH anterior roll, posterior glide
What are the stabilizing structures for GH?
RTC
GH ligaments
Capsule
Coracohumeral ligament
Coracoacromial arch
Long head of biceps
Glenoid labrum
Negative infra-articular pressure
Compressive forces
What are the RTC muscles? What do they do?
Supraspinatus, infraspinatus, teres minor, subscapular
reinforcement capsule, most dynamic GH stability
Inferior directed force of HH
Describe the GH capsule. What is it lined with?
Loose, expandable up to 2x the size
Lined with synovium
When is the superior GH ligament taut, and what movements does it control?
Taut with arm at side or inferior and posterior translation of humerus
Controls IR, flexion, ABD
What does the middle GH ligament control and where is it most effective?
Controls ER and anterior glide
Most effective with 45-60 ABD
What are the parts of the inferior GH ligament? Describe them.
Anterior band: prevents anterior glide with arm ABD to 90 degrees, strongest and thickest
Posterior band: prevent posterior glide with arm ABD to 90 degrees
Axillary pouch: taut in ABD > 90 degrees
What is the purpose of the coracohumeral ligament?
Limit inferior displacement with arm at side, watch extreme ER with shoulder in ADD
What structures make up the coracoarcomial arch? What does it do? What structures run underneath it?
Coracoid, acromion, coracoacriomal ligament
Prevents superior humeral dislocation
Structures under: RTC tendon, long head biceps, subacromial bursa, subdeltoid bursa
