The Shoulder

Anatomy and Injuries

PSK 4U Unit 3, Day 4

Shoulder Girdle

Shoulder Complex is the most mobile joint in the body.

Scapula

Clavicle

Sternum

Humerus

Rib cage/Thorax

Shoulder Girdle

It also includes

Sternoclavicular joint

Acromicoclaviulcar joint

Glenohumeral joint

Scapulothoracic articulation

Shoulder joint is attached to axial skeleton

via the clavicle at sternoclavicular joint

The Shoulder Joint

Wide range of motion of the shoulder joint in

many different planes requires a significant

amount of laxity

Common to have instability problems

Rotator cuff impingement

Subluxations & dislocations

The price of mobility is reduced stability

The more mobile a joint is, the less stable it

is & the more stable it is, the less mobile

McGraw-Hill Higher Education. All rights reserved.

5-4

Shoulder Girdle Ligaments

Sternoclaviular Joint-Joint connecting the sternum to the clavicle on each side of the body.

Shoulder Girdle Ligaments

Acromioclavicular Joint- joint connecting the acromion process to the clavicle at the distal end of the clavicle.

Shoulder Girdle Joints

Glenohumeral joint- joint where the humerus fits into the glenoid fossa of the scapula.

Shoulder Girdle Ligaments

Scapulothoracic joint- joint where the scapula slides over the thorax or rib cage.

Bones

Scapula, clavicle, & humerus serve as attachments for shoulder joint muscles Scapular landmarks

supraspinatus fossa

infraspinatus fossa

subscapular fossa

spine of the scapula

glenoid cavity

coracoid process

acromion process

inferior angle

McGraw-Hill Higher Education. All rights reserved.

5-9 From Seeley RR, Stephens TD, Tate P: Anatomy and physiology, ed 7, New York, 2006, McGraw-Hill

Bones

Scapula, clavicle, & humerus serve as

attachments for shoulder joint muscles

Humeral landmarks

Head

Greater tubercle

Lesser tubercle

Intertubercular groove

Deltoid tuberosity

McGraw-Hill Higher Education. All rights reserved.

5-10

Glenohumeral Joint

multiaxial ball-&-socket

McGraw-Hill Higher Education. All rights reserved.

5-11

Bones of Shoulder Joint

Acromion Process

Clavicle

Posterior Anterior

Glenoid

McGraw-Hill Higher Education. All rights reserved.

5-13

Glenohumeral Joint

Glenoid labrum slightly enhances stability

McGraw-Hill Higher Education. All rights reserved.

5-14

GLENOID LABRUM

Cartilage ring around the glenoid fossa. Deepens the socket of the G-H Joint.

Glenohumeral Joint

Glenohumeral ligaments provide stability

especially anteriorly & inferiorly

inferior glenohumeral ligament

McGraw-Hill Higher Education. All rights reserved.

5-16

Superior, Middle and Inferior Glenohumeral Ligament

Coracoclavicular Acromioclavicular

Coraco-acromial Lig.

Glenohumeral Joint

Ligaments are quite lax until extreme ranges of motion reached due to wide range of motion involved

Stability is sacrificed to gain mobility

McGraw-Hill Higher Education. All rights reserved.

5-18

Glenohumeral Joint

Frequently injured due to anatomical design

shallowness of glenoid fossa

laxity of ligamentous structures

lack of strength & endurance in muscles

anterior or anteroinferior glenohumeral subluxations & dislocations common

posterior dislocations rare

posterior instability problems somewhat common

McGraw-Hill Higher Education. All rights reserved.

5-19

Glenohumeral Joint

Rotator cuff is frequently injured Subscapularis, supraspinatus, infraspinatus, & teres minor

muscles

attach to the front, top, & rear of humeral head

point of insertion enables humeral rotation

vital in maintaining humeral head in correct approximation within glenoid fossa while more powerful muscles move humerus through its wide range of motion

McGraw-Hill Higher Education. All rights reserved.

5-20

Movements

Abduction upward lateral

movement of humerus out to the side, away from body

Adduction downward movement of

humerus medially toward body from abduction

McGraw-Hill Higher Education. All rights reserved.

5-21

Movements

Flexion movement of

humerus straight anteriorly

Extension movement of

humerus straight posteriorly

McGraw-Hill Higher Education. All rights reserved.

5-22

Movements

Horizontal adduction (transverse flexion) movement of humerus in a

horizontal or transverse plane toward & across chest

Horizontal abduction (transverse extension) movement of humerus in a

horizontal or transverse plane away from chest

McGraw-Hill Higher Education. All rights reserved.

5-23

Movements

External rotation movement of humerus

laterally around its long axis away from midline

Internal rotation movement of humerus

medially around its long axis toward midline

McGraw-Hill Higher Education. All rights reserved.

5-24

Movements

Diagonal abduction

movement of humerus in a diagonal plane away from midline of body

Diagonal adduction

movement of humerus in a diagonal plane toward midline of body

McGraw-Hill Higher Education. All rights reserved.

5-25

Glenohumeral Joint Scapula movement

usually occurs with movement of humerus: Humeral flexion & abduction

require scapula elevation, rotation upward, & abduction

Humeral adduction & extension results in scapula depression, rotation downward, & adduction

Scapula abduction occurs with humeral internal rotation & horizontal adduction

Scapula adduction occurs with humeral external rotation & horizontal abduction

McGraw-Hill Higher Education. All rights reserved.

5-26

Glenohumeral Joint

Determining exact range of each movement at the glenohumeral joint is difficult due to accompanying shoulder girdle movement (movement at the scapula)

McGraw-Hill Higher Education. All rights reserved.

5-27

Shoulder

Flexion

Extension

Hyperextension

Adduction

Abduction

Medial rotation

Lateral rotation

Shoulder girdle

Up rotation

Down rotation

Scapular tilt

Down rotation

Up rotation

Protraction

Retraction

Scapulohumeral rhythm

The first 30 degrees of motion is shoulder.

After that the for every 2 degrees the humerus moves the scapula upwardly rotates 1 degree.

Lets try it

Stand next to a partner that you are comfortable touching on their back.

Person in anatomical position, place your hand on the axillary border of the scapula. Ask them to abduction and see what happens when they get above 30 degrees.

The scapula will start rotating upward

Shoulder Injuries

Shoulder Separation

Separation: occurs when bones held together by fibrous ligaments tear and separate from each other.

There are several grades of separation depen-ding on the severity of the torn ligaments

Grades of Shoulder Separation

Healthy Shoulder Separated Shoulder

Shoulder Dislocation

Dislocation occurs when a bone is displaced from its original location

Usually involves damage to the joint capsule and the ligaments that hold the joint together

Signs and symptoms include:

Joint looks awkward or deformed

Joint is painful

Joint is not useable

Healthy Shoulder Dislocated Shoulder

Shoulder bursitis Occurs from trauma or overuse or direct impact

Signs and symptoms are: pain with movement; tenderness to palpation in area just under acromion

Shoulder Impingement

Cause: mechanical compression of supraspinatus tendon, the subacromial

bursa, and long head of biceps tendon; most common in overhead activities

Signs and symptoms: diffuse pain around the acromion in overhead position; external rotators weaker than internal; tightness in posterior and inferior capsules;

First Aid Care

The first aid care for the majority of these shoulder injuries is PIER.

After PIER and further monitoring, further medical attention may be required.