Shoulder Muscles Flashcards
Trapezius Descending part
O: Occipital bone; SP of C1-C7
I: Lateral third of clavicle
A: elevation of scapula; ipsilateral inclination and extension of the head
In: Accessory n.
Trapezius transverse part
O: SP of T1-T4
I: Acromion
A: Retraction of the scapula
In: Accessory n.
Trapezius ascending part
O: SP of T5-T12
I: scapular spine
A: Retraction, depression, upward rotation of the scapula
In: accessory n.
Rhomboids major
O: SP of T1-T4
I: Medial border (margin) of the scapula (under minor)
A: Retraction, elevation, downward rotation of the scapula
In: Dorsal scapular n.
Rhomboids minor
O: SP of C6-C7
I: Medial border of the scapula (above major)
A: Retraction, elevation, downward rotation of the scapula
In: Dorsal scapular n.
Levator scapulae
O: TP of C1-C4
I: Superior angle of the scapula
A:
Proximal insertion fixed: elevation, downward rotation of the scapula
Distal insertion fixed : extension and ipsilateral inclination of cervical spine
In: dorsal scapular n.
Serratus anterior
O: 1st-9th ribs
I: superior angle and medial margin of the scapula
A: Protraction and upward rotation of scapula
In: Long thoracic n.
Subclavius
O: 1st rib
I: lateral third of inferior face of clavicle
A: Stabilization of the sternoclavicular joint and resisting elevation of the lateral end of the clavicle
In: Subclavius n.
Pectoralis minor
O: 3rd-5th ribs
I: Coracoid process
A:
Proximal insertion fixed : scapula depression, protraction, and downward rotation
Distal insertion fixed : elevation of ribs –> accessory inspiration
In: Medial pectoral n.
Supraspinatus
O: Supraspinous fossa
I: Greater tubercle of the humerus
A: Initiate shoulder abduction
In: Suprascapular n.
Infraspinatus
O: Infraspinous fossa
I: Greater tubercle of the humerus
A: Shoulder external rotation
In: Suprascapular n.
Teres minor
O: Superior 2/3 of lateral border of the scapula
I: Greater tubercle of the humerus
A: Shoulder external rotation, adduction
In: Axillary n.
Subscapularis
O: subscapular fossa
I: Lesser tubercle of the humerus
A: Shoulder internal rotation
In: subscapular n.
Teres major
O: Inferior angle of the scapula
I: Medial side of the bicipital groove
A: Shoulder: adduction, extension, internal rotation
In: Lower subscapular n.
Deltoid clavicular (anterior) fibers
O: lateral third of the clavicle
I: Deltoid tuberosity
A: Shoulder flexion, abduction, internal rotation, horizontal ADD
In: Axillary n.
Deltoid acromial (lateral) fibers
O: Acromion
I: Deltoid tuberosity
A: Abduction
In: Axillary n.
Deltoid Spinal (posterior) fibers
O: Spine of the scapula
I: Deltoid tuberosity
A: Shoulder extension, external rotation, horizontal abduction, and all muscles abduction
In: Axillary n.
Latissimus dorsi
O: Spinous process T7-S5 (via thoracolumbar fascia), iliac crest, 9-12th ribs, inferior angle of the scapula
I: Medial side of bicipital groove
A: Shoulder extension, adduction, internal rotation
In: Thoracodorsal n.
Coracobrachialis
O: Coracoid process
I: Middle third of medial margin of the humerus
A: Shoulder flexion, adduction
In: Musculocutaneous n.
Pectoralis major
O:
Clavicular fibers: Medial half of the clavicle
Sternocostal fibers: Sternum, 2nd-6th costal cartilages
I: Lateral margin of the bicipital groove
A: Shoulder adduction, horizontal adduction, internal rotation (entire muscle)
Flexion (clavicular fibers)
In: Medial and lateral pectoral nn.
