Shoulder Girdle

What are the three main functions of the shoulder girdle muscles?

1. Stabilize scapula 2. Contract to maintain scapula in static position 3. Contract to move shoulder girdle and enhance movement of upper extremity through extreme range of motion

What type of joint is the shoulder girdle?

Arthrodial

The shoulder girdle muscles primarily are innervated by the _______ and _______ plexus.

Cervical; brachial

If the shoulder joint carries out extension, what does the shoulder girdle do?

Depression/Downward rotation

List the movements of the shoulder girdle.

Depression/elevation; upward/downward rotation; retraction/protraction; upward/downward tilt

Depression

Downward or inferior movement, as in returning to normal position

If the shoulder joint carries out adduction, what does the shoulder girdle do?

Downward rotation

If the shoulder joint carries out flexion, what does the shoulder girdle do?

Elevation/Upward rotation

True or false: Some shoulder girdle muscles attach to humerus and cause shoulder joint action.

False. The shoulder girdle muscles do not attach to the humerus and do not cause shoulder joint action.

What muscle carries out the following movement: elevates the medial margin of the scapula

Levator scapula

The dorsal scapula nerve goes through what two muscles?

Levator scapula and rhomboid

What are the agonists of scapula depression?

Lower trapezius, pectoralis minor

The medial pectoral nerve originating from C8 and T1 runs through what muscle?

Pectoralis minor

What muscle carries out the following movements: Abduction: draws scapula forward and 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

Pectoralis minor

What are the agonists of protraction?

Pectoralis minor, serratus anterior

List the anterior shoulder girdle muscles.

Pectoralis minor, serratus anterior, subclavis

If the shoulder joint carries out horizontal adduction, what does the shoulder girdle do?

Protraction

If the shoulder joint carries out internal rotation, what does the shoulder girdle do?

Protraction

If the shoulder joint carries out diagonal adduction, what does the shoulder girdle do?

Protraction/Downward rotation/Depression

If the shoulder joint carries out external rotation, what does the shoulder girdle do?

Retraction

If the shoulder joint carries out horizontal abduction, what does the shoulder girdle do?

Retraction

If the shoulder joint carries out diagonal abduction, what does the shoulder girdle do?

Retraction/Upward rotation/Elevation

Downward rotation

Returning inferior angle inferomedially toward spinal column and glenoid fossa to normal position

What muscle carries out the following movements: (when working together) adduction: draw scapula toward spinal column; Downward rotation: from upward rotated position they draw scapula in downward rotation; Elevation: slight upward movement accompanying adduction

Rhomboid major and minor

What are the agonists of downward rotation?

Rhomboid, pectoralis minor

What are the agonists of elevation?

Rhomboid, trapezius, levator scapula

Protraction (abduction)

Scapula moves laterally away from spinal column

Retraction (adduction)

Scapula moves medially toward spinal column

What is the articulation of the shoulder girdle?

Scapula, sternum, and clavicle

The long thoracic nerve originating from C5, C6, and C7 runs through which muscle?

Serratus anterior

What muscle carries out the following movements: Abduction: 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

Serratus anterior

What muscle carries out the following movements: upper fibers: elevation of scapula, extension of head; middle fibers : elevation, upward rotation and adduction; lower fibers: depression, adduction, and upward rotation

Trapezius

What muscle does the spinal accessory nerve run through?

Trapezius

What muscles do branches C3 and C4 innervate?

Trapezius and levator scapula

What are the agonists of retraction?

Trapezius and rhomboids

List the posterior shoulder girdle muscles.

Trapezius, levator scapula, rhomboids (major and minor)

What are the agonists do upward rotation?

Trapezius, serratus anterior

True or False: Muscles involved in shoulder girdle movement all originate on axial skeleton and insert on scapula and/or clavicle

True

Upward rotation

Turning glenoid fossa upward and moving inferior angle superolaterally away from spinal column

Elevation

Upward or superior movement, as in shrugging shoulders

If the shoulder joint carries out abduction, what does the shoulder girdle do?

Upward rotation