03-05: The Shoulder Joint

Question 1

Description of Shoulder Joint (3)

Answer 1

1. Ball-and-socket joint
2. One of the most movable joints
3. One of the least stable joints

Question 2

Labrum

Answer 2

Cartilagenous disk between head of humerus and glenoid fossa; helps with joint congruency

Question 3

Plane of Scapula

Answer 3

Lateral, Anterior, Superior (somewhat upward elevation); ROM at 45˚

Question 4

Joint Motion - Flexion/Abduction

Answer 4

0-180˚

Question 5

Joint Motion - Medial Rotation (Internal)

Answer 5

0-70˚ (Any further is scapular tilt)

Question 6

Joint Motion - Lateral Rotation (External)

Answer 6

0-90˚

Question 7

Joint Motion - Horizontal Adduction

Answer 7

0-30˚

Question 8

Joint Motion - Horizontal Abduction

Answer 8

0-120˚

Question 9

Glenohumeral Ligament - Superior

Answer 9

Resists external rotation in neutral ABD

Question 10

Glenohumeral Ligament - Middle

Answer 10

Resists external rotation in 45˚ ABD

Question 11

Glenohumeral Ligament - Inferior

Answer 11

Resists external rotation in 90˚ ABD

Question 12

Elements of Glenohumeral Joint

Answer 12

• Glenohumeral Ligaments (3)
• Coracohumeral Ligament
• Axillary Recess
• Tranverse Ligament

Question 13

Coracohumeral Ligament

Answer 13

Resists excessive external rotation, excessive extension, excessive depression of head of humerus; Limits flexion

Question 14

Axillary Recess

Answer 14

An excess tissue of joint capsule (inferior to glenohumeral capsule)

• “Pleats” allow humeral head to descend; slides into pleats and allow for motion
• Must free up before muscle control

Question 15

Transverse Ligament

Answer 15

Synovial sheath that prevents friction of bicipital tendon - crosses over bicipital groove and holds tendon in groove

Question 16

GH Kinematics

Answer 16

Flexion/Extension (120˚/45˚) - Sagittal Plane/Frontal Axis
Abduction/Adduction (120˚) - Frontal Plane/Sagittal Axis
Internal/External Rotation (80˚/70˚) - Tranverse Plane/Vertical Axis

Question 17

Glenohumeral Scapulothoracic Rhythm (GHST)

Answer 17

2:1 Ratio - For every 2 degrees of shoulder abduction at GH joint, 1 degree occurs at ST joint (SC, AC)

Question 18

Scapulothoracic Rhythm (ST)

Answer 18

First 30˚ of shoulder joint = pure shoulder motion

After first 30˚, 2:1 ratio = 2˚ of shoulder flexion/abduction accompanied by 1˚ of upward rotation of scapula

Question 19

Muscles of the Shoulder Joint (12)

Answer 19

Deltoid (3), Supraspinatus, Pectoralis Major (2), Latissimus Dorsi, Teres Major, Infraspinatus, Teres Minor, Subscapularis, Coracobrachialis

Question 20

Rotator Cuff Muscles (SITS)

Answer 20

Supraspinatus, Infraspinatus, Teres Minor = Posterior

Subscapularis = Anterior

Question 21

Supraspinatus

Answer 21

O: Supraspinous fossa
I: Superior facet of greater tubercle of humerus
A: Initiates “roll”
N: Suprascapular Nerve (Superior Trunk)

• Travels under acromion
• No roll = arm doesn’t move overhead

Question 22

Infraspinatus

Answer 22

O: Infraspinous fossa
I: Middle facet of greater tubercle of humerus
A: Lateral/External Rotation, Horizontal Abduction
N: Suprascapular Nerve (Superior Trunk)

Question 23

Teres Minor

Answer 23

O: Axillary border of scapula
I: Inferior facet of greater tubercle of humerus
A: Lateral/External Rotation, Horizontal Abduction
N: Axillary Nerve (Posterior Cord)

Question 24

Subscapularis

Answer 24

O: Subscapular fossa
I: Lesser tubercle of humerus
A: Medial/Internal Rotation
N: Subscapular Nerve (Posterior Cord)

Question 25

Quadrangular Space

Answer 25

Common site of impingement - hypertrophy, trauma to shoulder - Border of teres minor (superior), teres major (inferior), long head of triceps (medial), and lateral lip of humerus (lateral)

Question 26

Anterior Deltoid

Answer 26

O: Inferior aspect of lateral 1/3 of clavicle I: Deltoid tuberosity A: Shoulder abduction, flexion, medial rotation, horizontal abduction N: Axillary Nerve (Posterior Cord)

Question 27

Middle Deltoid

Answer 27

O: Acromion I: Deltoid tuberosity A: Shoulder abduction N: Axillary Nerve (Posterior Cord)

Question 28

Posterior Deltoid

Answer 28

O: Inferior aspect of spine of scapula I: Deltoid tuberosity A: Shoulder abduction, extension, lateral rotation, horizontal abduction N; Axillary Nerve (Posterior Cord) - Actions are opposite of anterior deltoid

Question 29

Pectoralis Major (Clavicular portion)

Answer 29

O: Inferior aspect of medial 2/3 of clavicle I: Lateral lip of bicipital groove of humerus A: Shoulder flexion (0-60˚)

Question 30

Pectoralis Major (Sternal portion)

Answer 30

O: Sternum, Costal cartilage of ribs 1-6 I: Lateral lip of bicipital groove of humerus A: Shoulder extension from full flexion (180˚-120˚)

Question 31

Pectoralis Major (Sternal AND Clavicular)

Answer 31

A: Shoulder adduction, medial rotation, horizontal adduction N: Lateral pectoral (Lateral Cord), Medial Pectoral (Medial Cord) - Primary medial rotator - Restricted shoulder adduction to muscle test - Also abdominal head of pec major

Question 32

Latissimus Dorsi

Answer 32

O: Spinous process of T7-L5, posterior surface of sacrum, iliac crest, lower 3 ribs, thoracolumbar fascia I: Floor of the bicipital groove of humerus, inferior angle of scapula A: Prime shoulder extension, medial rotation of humerus, also contributes to scapular depression N: Thoracodorsal (Posterior Cord) - Largest muscle in body (surface area)

Question 33

Teres Major

Answer 33

O: Inferior angle of scapula I: Medial lip of bicipital groove of humerus A: Medial/Internal rotation, Shoulder adduction, Extension N: Subscapular Nerve (Posterior Cord)

Question 34

"Lady that sits between the two majors"

Answer 34

Teres Major - Medial lip of bicipital groove Latissimus Dorsi - Middle floor of bicipital groove Pectoralis Major - Lateral lip of bicipital groove

Question 35

Coracobrachialis

Answer 35

O: Coracoid process of the scapula I: Medial aspect of the mid-shaft of the humerus A: Assists with shoulder flexion, shoulder adduction N: Musculocutaneous Nerve (Lateral Cord) - Adjacent to insertion of deltoid (lateral aspect)

Question 36

Glenohumeral Movement (Arthorkinematic motions)

Answer 36

Shoulder ABD 1. Supraspinatus initiates roll, gives deltoid mechanical advantage for ABD 2. "ITS" pulls down humeral head posterior and inferior 3. Deltoid ABD shoulder 4. Scapula must rotate (upper/lower trap, serratus anterior) to complete ABD Rotation of Humerus Must be performed to move bony landmarks (greater tubercle, acromion) out of the way during movement

Question 37

Traction ischemia of rotator cuff musculature, especially supraspinatus

Answer 37

- Blood cut off when arm is by side | - Need to angle arm at 55˚ to loosen up blood flow

Question 38

Coracoacromical Arch & Bursa

Answer 38

1 cm of space between acromion process and humeral head Arch contains supraspinatus, subacromial bursa, long head of the biceps, superior joint capsule Site of shoulder impingement

Question 39

Muscle Action - Flexion

Answer 39

``` Anterior deltoid Pectoralis major (clavicular) ```

Question 40

Muscle Action - Extension

Answer 40

``` Posterior deltoid Latissimus dorsi Teres major Pectoralis major (sternal) ```

Question 41

Muscle Action - Hyperextension

Answer 41

Latissimus dorsi | Posterior deltoid

Question 42

Muscle Action - Abduction

Answer 42

Deltoid | Supraspinatus

Question 43

Muscle Action - Adduction

Answer 43

Pectoralis major Teres major Latissimus dorsi

Question 44

Muscle Action - Horizontal Abduction

Answer 44

Posterior deltoid Infraspinatus Teres minor

Question 45

Muscle Action - Horizontal Adduction

Answer 45

Pectoralis major | Anterior deltoid

Question 46

Muscle Action - External Rotation

Answer 46

Infraspinatus Teres minor Posterior deltoid

Question 47

Muscle Action - Internal Rotation

Answer 47

``` Latissimus dorsi Teres major Subscapularis Pectoralis major Anterior deltoid ```