Chapter 4
The Shoulder Girdle

Manual of Structural Kinesiology

PE 3320

Texas State University

Bones

•Scapula & clavicle

–Move as a unit

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

Bones

•Key bony landmarks

–______________________

–______________________

–______________________

–______________________

–______________________

–______________________

–______________________

–______________________

Joints

•Shoulder girdle (scapulothoracic)

•scapula moves on the ______________________

–joint motion occurs at ______________________ joint & to a lesser amount at the ______________________ joint

Joints

Sternoclavicular (SC)

(multiaxial) arthrodial classification

Movements

anteriorly 15 degrees with ______________________

posteriorly 15 degrees with ______________________

superiorly 45 degrees with ______________________

inferiorly 5 degrees with ______________________

Joints

Sternoclavicular (SC)

______________________ support

anteriorly by the anterior _____ ligament

posteriorly by the posterior _____ ligament

costoclavicular & interclavicular ligaments provide stability against superior displacement

Joints

______________________ (AC)

arthrodial classification

20- to 30-degree total ______________________& ______________________

motion accompanying other shoulder girdle & shoulder joint motions

supported by

Costoclavicular ligaments

Superior acromioclavicular ligament

Inferior acromioclavicular ligament

often injured

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 ______________________

–60-degrees ______________________

–55-degrees ______________________

supported dynamically by its muscles

no ligamentous support

______________________ (protraction)

scapula moves laterally away from spinal column

______________________ (retraction)

scapula moves medially toward spinal column

Downward rotation

–returning inferior angle ______________________ ______________________& ______________________

to normal position

Upward rotation

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

Depression ______________________ or inferior movement, as in returning to normal position

Elevation

______________________ or superior movement, as in shrugging shoulders

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

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

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

Shoulder Girdle MovementsMuscles

5 muscles primarily involved in shoulder girdle movements

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

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

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

Shoulder Girdle Muscles

•5 muscles primarily involved in shoulder girdle movements

_________________ – 3 Parts (some authors indicate 4 parts (upper, middle, lower)

–_________________ - deep

–_________________

–________________

–

Actions :

Trapezius muscle

Upper fibers: elevation of scapula, extension of head

Levator scapulae muscle

Elevates the medial margin of the scapula

Rhomboid muscles - major & minor

Serratus anterior muscle

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

Pectoralis minor muscle

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

Scapula Abduction

Scapula move laterally away from spinous processes without rotation

EX. _________________

Agonists

Pectoralis
minor

Serratus
anterior

Scapula Adduction

Return from abduction

Occurs with retractions

Agonists

Middle Trapezius

Rhomboids

Scapula Upward Rotation

Lateral & upward movement

Agonists

Middle Trapezius

Lower Trapezius

Serratus anterior

Scapula Downward Rotation

Downward & Medial Movement

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

Scapula Elevation

Lifting scapula without rotation in anatomic position

Shoulder Shrug

Scapula Depression

EX. _________________

Agonists

Lower Trapezius

Pectoralis Minor