Shoulder Girdle

© McGraw-Hill Higher Education. All rights reserved.

Test 1

4-1

Breakdown

• A – 5

• B – 18

• C – 21

• D – 9

• F – 2

• Max – 94; Min – 58; Mean – 77


4-2

Thoughts

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4-3

Chapter 4

The Shoulder Girdle


4-4

• Bones

– Landmarks

• Joints

• Movements

• Muscles

Outline


4-5

• The picture of Konstantinos Gastioudis

(right) shows us the forces the shoulder girdle generates/supports. As you can see, his left shoulder (the left side of the top of the “I”) is dropping downward, while at the same time, trying to brace the left side (in conjunction with the left him). You can also see the tremendous importance of latissimus dorsi to the javelin thrower. In this photo, you can nearly see the attachment site of latissimus on his humerus! Not only is latisimus dorsi being used, so is serratus anterior and pectoralis major. We see that these three muscles are primarily responsible for transferring the power generated in the core into the throwing arm.

Of course we cannot forget that the shoulder is a very free moving and complex joint that sees a great connection to the scapula. The second integral point of this particular article deals with the movement of the thrower’s scapula. It is the opinion of the author that the movement of the scapula is one of the most integral components of a successful javelin thrower. First, the throwing scapula needs to drop down the back in order to allow the throwing shoulder to roll into position. Proper throwing position requires the armpit area to open. This can be seen in the picture of Backley and Gastioudis.

Second the scapula on the block side needs to drop down in order to cause the scapula on the throwing side to drive up and into the throw. Now the key in this scenario is the fact that there must be a delay between the block scapula’s movement and the movement of the throwing scapula. This creates the stretch-reflex through the chest.


4-6


4-7

Bones

• Scapula & clavicle

– Move as a unit

– Clavicle’s articulation with sternum is only bony link to axial skeleton


4-8

Bones

• Key bony landmarks

– Manubrium

– Clavicle

– Coracoid process

– Acromion process

– Glenoid fossa

– Lateral border

– Inferior angle

– Medial border


4-9

Bones

• Key bony landmarks

– Acromion process

– Glenoid fossa

– Lateral border

– Inferior angle

– Medial border

– Superior angle

– Spine of the scapula

From Seeley RR, Stephens TD, Tate P; anatomy and physiology , ed 7,

New York, 2006, McGraw-Hill

4-10



4-11


4-12

Joints

• Shoulder girdle (scapulothoracic)

– scapula moves on the rib cage

– joint motion occurs at sternoclavicular joint

& to a lesser amount at the acromioclavicular joint


4-13

Joints

• Sternoclavicular (SC)

– (multiaxial) arthrodial classification

– Movements

• anteriorly 15 degrees with protraction

• posteriorly 15 degrees with retraction

• superiorly 45 degrees with elevation

• inferiorly 5 degrees with depression


4-14

Joints

• Sternoclavicular (SC)

– Ligamentous support

• anteriorly by the anterior SC ligament

• posteriorly by the posterior SC ligament

• costoclavicular & interclavicular ligaments provide stability against superior displacement


4-15

Joints

• Acromioclavicular (AC)

– arthrodial classification

– 20- to 30-degree total gliding & rotational motion accompanying other shoulder girdle & shoulder joint motions

– supported by

• Coracoclavicular ligaments

• Superior acromioclavicular ligament

• Inferior acromioclavicular ligament

– often injured


4-16

Joints

• Scapulothoracic

– not a true synovial joint

– does not have regular synovial features

– movement depends on SC & AC joints which allows the scapula to move

• 25-degrees abduction-adduction

• 60-degrees upward-downward rotation

• 55-degrees elevation-depression

– supported dynamically by its muscles

– no ligamentous support


4-17

Movements

• Focus on specific bony landmarks

– inferior angle

– glenoid fossa

– acromion process

• Shoulder girdle movements = scapula movements


4-18

Movements

• Abduction

(protraction)

– scapula moves laterally away from spinal column

• Adduction (retraction)

– scapula moves medially toward spinal column


4-19

Movements

• Downward rotation

– returning inferior angle inferomedially toward spinal column & glenoid fossa to normal position

• Upward rotation

– turning glenoid fossa upward & moving inferior angle superolaterally away from spinal column


4-20

Movements

• Depression

– downward or inferior movement, as in returning to normal position

• Elevation

– upward or superior movement, as in shrugging shoulders


4-21

Movements

• Shoulder joint & shoulder girdle work together in carrying out upper extremity activities

• Shoulder girdle movement is not dependent upon the shoulder joint & its muscles


4-22

Movements

• Shoulder girdle muscles

– Stabilize scapula so the shoulder joint muscles will have a stable base from which to exert force for moving the humerus

– Contract to maintain scapula in a relatively static position during shoulder joint actions

– Contract to move shoulder girdle & to enhance movement of upper extremity when shoulder goes through extreme ranges of motion


4-23

Movements

• For some shoulder girdle movements, scapula must rotate or tilt on its axis

• Lateral tilt (outward tilt)

– during abduction

– scapula rotates about its vertical axis resulting in posterior movement of medial border & anterior movement of lateral border

• Medial tilt (return from lateral tilt, inward tilt)

– during extreme adduction

– scapula rotates about its vertical axis resulting in anterior movement of medial border & posterior movement of lateral border


4-24

Movements

• Anterior tilt (upward tilt)

– rotational movement of scapula about frontal axis occurring during glenohumeral hyperextension

– superior border moving anteroinferiorly & inferior angle moving posterosuperiorly

• Posterior tilt (downward tilt)

– rotational movement of scapula about frontal axis occurring during glenohumeral hyperflexion

– superior border moving posteroinferiorly & inferior angle moving anterosuperiorly


4-25

Movements

• Synergy with muscles of glenohumeral joint

– As shoulder joint goes through more extreme ranges of motion, scapular muscles contract to move shoulder girdle so that its glenoid fossa will be in a more appropriate position from which the humerus can move

– Without the accompanying scapula movement humerus can only be raised into approximately 90 degrees of total shoulder abduction & flexion


4-26

Movements

• Synergy with muscles of glenohumeral joint

– This works through the appropriate muscles of both joints working in synergy to accomplish the desired action of the entire upper extremity

– Ex. to raise our hand out to the side laterally as high as possible, the serratus anterior & trapezius

(middle & lower fibers) muscles upwardly rotate scapula as supraspinatus & deltoid initiate glenohumeral abduction

– This synergy between scapula & shoulder joint muscles enhances movement of entire upper extremity


4-27

Shoulder

Girdle

Movements

Elevation

Adduction Abduction


Depression

4-28

Muscles

• 5 muscles primarily involved in shoulder girdle movements

– All originate on axial skeleton & insert on scapula and/or clavicle

– Do not attach to humerus & do not cause shoulder joint actions

– Essential in providing dynamic stability of the scapula so it can serve as a relative base of support for shoulder joint activities such as throwing, batting, & blocking


4-29

Shoulder Girdle Muscles

• 5 muscles primarily involved in shoulder girdle movements

– Trapezius - upper, middle, lower

– Rhomboid - deep

– Levator scapula

– Serratus anterior

– Pectoralis minor deep


4-30


• Location & action

– Anterior

• Pectoralis minor – abduction, downward rotation, & depression

• Subclavius – depression

– Posterior & laterally

• Serratus anterior – abduction & upward rotation

4-31



• Location & action

– Posterior

• Trapezius

• Upper fibers – elevation & extension of the head

• Middle fibers – elevation, adduction, & upper rotation

• Lower fibers – adduction, depression, & upper rotation

• Rhomboid – adduction, downward rotation, & elevation

• Levator scapulae – elevation


4-32

Trapezius muscle

Upper fibers: elevation of scapula, extension

& rotation of head

Middle fibers: elevation, upward rotation, & adduction

Lower fibers: depression, adduction, & upward rotation


4-33

Levator scapulae muscle

Elevates the medial margin of the scapula


4-34

Rhomboid muscles - major & minor

Rhomboid major & minor muscles work together

Adduction (retraction): draw scapula toward spinal column

Downward rotation: from upward rotated position they draw scapula in downward rotation

Elevation: slight upward movement accompanying adduction


4-35


4-36


4-37

Serratus anterior muscle

Abduction (protraction): draws medial border of scapula away from vertebrae

Upward rotation: longer, lower fibers tend to draw inferior angle of scapula farther away from vertebrae, thus rotating scapula upward slightly


4-38

Pectoralis minor muscle

Abduction (protraction): draws scapula forward & tends to tilt lower border away from ribs

Downward rotation: as it abducts, it draws scapula downward

Depression: when scapula is rotated upward, it assists in depression


4-39

Subclavius muscle

Stabilization & protection of sternoclavicular joint

Depression

Abduction


4-40

Scapula Abduction

• Scapula move laterally away from spinous processes without rotation

• EX. Push-up & bench press

• Agonists

– Pectoralis minor



4-41

Scapula Adduction

• Return from abduction

• Occurs with retractions

• Agonists

– Middle Trapezius

– Rhomboids


4-42

Scapula Upward Rotation

• Lateral & upward movement

• Agonists

– Middle

Trapezius

– Lower

Trapezius



4-43

Scapula Downward Rotation

• Downward & Medial Movement

• Glenoid Fossa is rotated downward when downward movement of shoulder joint occurs

• EX. Lat Pulls pulling wt. down

• Agonists

– Pectoralis Minor

– Rhomboid

4-44


Scapula Elevation

• Lifting scapula without rotation in anatomic position

• Shoulder Shrug

• Agonists

– Levator

Scapula

– Upper

Trapezius

– Rhomboid


4-45

Scapula Depression

• EX. Dip

• Agonists

– Lower

Trapezius

– Pectoralis

Minor


4-46

Nerves

• Shoulder girdle muscles primarily innervated by

cervical

& brachial plexus

From Seeley RR, Stephens TD, Tate P: Anatomy and physiology , ed 6,

Dubuque, IA, 2003, McGraw-Hill


4-47

Nerves

• Shoulder girdle muscles primarily innervated by cervical &

brachial

plexus

From Seeley RR, Stephens TD, Tate P: Anatomy and physiology , ed 6,

Dubuque, IA, 2003, McGraw-Hill


4-48

Nerves

• Branches of C3 & C4

– Trapezius

– Levator scapula

• Spinal accessory nerve

– Trapezius


4-49

Nerves

• Dorsal scapula nerve

– Levator scapula

– Rhomboid

• Long thoracic nerve originating from C5,

C6, & C7


• Medial pectoral nerve originating from

C8 & T1

– Pectoralis minor


4-50

Shoulder Girdle

Test 1

Breakdown

Thoughts

Chapter 4

The Shoulder Girdle

Outline

cervical

brachial

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Shoulder Girdle

Test 1

Breakdown

Thoughts

Chapter 4

The Shoulder Girdle

Outline

cervical

brachial

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