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
