GH Joint Flashcards
Resting position of GH joint
55 ABD
30 Horiz ADD
Slight ER
CPP of GH jt
Max ABD and ER
Capsular pattern of GH jt
ER>ABD>IR
During Flexion the GH joint works for how many degrees?
120 degrees of movement
Prime Flexion movers
Ant delt
Pec major (clavicular head)
Coracobrachialis
Biceps brachii
Extension of GH degrees
65 degrees
Prime extension movers of GH
Post delt
Teres major
Lat Dorsi
Long head of triceps
Pec major (sternocostal part)
Abduction GH joint
(When in ER) 120 degrees
Abduction prime movers
Supraspinatus
lat delt
Adduction GH joint
0 pure adduction at side
50-75 degrees in front of body
Adduction prime movers
Post delt
Ant delt
Pec major
Long head of triceps
Coracobrachialis
Teres major
Lat dorsi
Extemal rotation In GH joint
60-70° of pure ER
ER increases to 90 when shoulder is ABD
External rotation prime movers
Post delt
Teres minor
Infraspinatus
Supraspinatus (between neutral and full ER)
Internal rotation of GH
75° - 85° of pure IR
Internal rotation prime movers
Anterior deltoid
Pectoral major
Teres major
lat dorsi
Subscapularis
Variables that determine the pattern of movements within the fossa
Articular geometry
Capsuloligamentous influences
Positional influences
Muscle dynamics
Stabilizing structures of the GH
Rotator cuff muscle
Capsule
GH ligaments
Coracohumeral ligament
Coracoacromial arch
Long head of biceps
Glenoid labrum
Negative intra-articular pressure
Compressive forces
Rotator cuff muscles
Provide static stability through reinforcement of the capsule
Provide most of the dynamic GH stability
Supra
Infra
Teres minor
Subscap
Capsule
It’s loose and expandable
The space was in the capsule. It can be twice the size of the humeral head.
It is lined with synovium
Superior GH ligament
Becomes taut when the arm is at the side or with inferior and posterior translation of the humerus
Middle GH ligament
Restricts an interior translation of the GH and resists ER
Most effective at 45 to 60° of abduction
Inferior GH ligament
Anterior band: prevent interior translation of the GH with the arm abducted to 90° or greater.
-Strongest and thickest part of the entire capsule
Posterior band: prevent posterior translation of the GH with the arm abducted to 90° or greater
Auxiliary pouch: TAUT in abduction more than 90 degrees
Coracohumeral ligament
Limits inferior displacement of the GH with arm at the side
Extremes of external rotation, when shoulder is in Adduction
Coracoacromial Arch
Consist of the coracoid the acromion and the coracoacromial ligament
Prevent the humerus from dislocating superiorly
Structures under the coracoacromial arch
Rotator cuff tendons
Long head of biceps
Subacromial bursa
Sub deltoid bursa
Long head of the biceps
An important attachment to the labrum
Role in humeral head, depression
Limiting excessive anterior translation
Glenoid labrum
Deepens the Glenoid fossa providing increased stability
Negative intra-articular pressure
Can be lost if the capsule is punctured
Compressive forces
These forces hold the humeral head in the glenoid fossa
Due to the upward orientation of the scapula, the force of vectors of gravity and the superior GH restraints.
Scapular plane
The scapula is not fully in the frontal plane. It is 30 to 45° toward the sagittal plane.
Scapulohumeral rhythm
Rhythm between the GH abduction and scapulothoracic upward is relatively constant and has a ratio of 2 to 1
For every 3° of shoulder abduction 2° occur at the GH while one degree occurs at the ST joint
Role of scapular movement
Maintains glenoid fossa in optimal position
Allows muscles to maintain good length – tension relationship
Allows for increased ROM
SC and AC involvement
In the early phase of shoulder abduction, less than 90 degrees, 60% of abduction at the Gleno humeral joint and 30° of scapular rotation.
Of the 30° of scapular rotation:
20 to 25° of clavicular elevation at the SC joint and 5 to 10° of upward rotation of the acromion at the AC joint.
SC and AC Involvment in the late phase shoulder ABD more than 90 degrees
Of 30 degrees of scap rotation and 60 degrees of ABD at GH
5 degrees clavicular elevation at the SC
20-25 upward rotation at the acromion at the AC joint
40 degrees posterior rotation of clavicle
Deltoid anterior
Origin: outer 1/3 of the clavicle
Insertion: deltoid tuberosity
Innervation: axillary nerve
Action: ABD, FLEX, MEDROT,HORIZ ABD
Lateral deltoid
Origin: lateral acromion
Insertion: deltoid tuberosity
Innervation: axillary nerve
Action: ABD
Posterior deltoid
Origin: spine of scap
Insertion: deltoid tuberosity
Innervation: axillary nerve
Action: ABD, EXT,HORIZ ABD, EXT ROT
Pec major clavicular portion
Origin: medial 1/3 clavicle
Insertion: lat lip of bicipital groove of humerus
Innervation: lateral and medial pec nerve C5-T1
Action: Flex to 60 deg
Pec major sternocostal part
Origin: sternum, coral cartilage 1-6
Insertion: lateral lip of bicipital groove of humerus
Innervation: medial and lateral pectoral nerve C5-T1
Action: Ext 180-120 putting arm down from full extension
Lat dorsi
Origin: T7-L5 spinous processes by dorsilumbar fascia, posterior sacrum, iliac crest and last 3 ribs
Insertion: medial floor of bicipital groove
Innervation: thoracodorsal nerve C6-C8
Action: ADD, MED ROT, EXT
Teres major
Origin: axillary border, inferior angle of scap, dorsal surface
Insertion: crest lesser tubercle
Innervation: lower subscapular nerve C5-C7
Action: ADD,MED ROT, EXT
Supraspinatus
Origin: Supraspinous fossa
Insertion: greater tubercle
Innervation: suprascspular nerve C5-C6
Action: ABD, ER
Infraspinatus
Origin: Infraspinous fossa
Insertion:greater tubercle
Innervation: suprascapular nerve C5-C6
Action : LAT ROT, HORIS ABD
Teres minor
Origin: axillary border of scap or lateral margin of infraspinous fossa
Insertion: greater tubercle
Innervation axillary nerve
Action: LAT ROT, HORIZ ABD
Subscapularis
Origin: subscapular fossa
Insertion: lesser tubercle
Innervation: upper and lower subscapular nerve
Action: MED ROT, ADD
Coracobrachialis
Origin: coracoid process of the scap
Insert: medial surface of humerus
Innervation: musculocutaneous nerve C6-C7
Action: FLEX, ADD
Biceps brachii
Origin: Long head- supraglenoid tubercle. Short head- coracoid process
Insertion: radial tuberosity
Innervation: musculocutaneous nerve C5-C6
Action: FLEX
Triceps brachii
Origin: long head- infraglenoid tubercle
Insertion: olecranon process of the ulna
Innervation: radial nerve
Action: EXT
