Shoulder Anatomy

Muscle Origin Insertion Action Innervation
Thoracodorsal Joint
Trapezius Occipital Bone, Ligamentum Nuchae, C7-T12 Vertebrae Spinous Processes Lateral Third of the Clavicle, Acromion & Medial End of the Spine of the Scapula Upper (descending part): Elevate Scapula & Extend Neck; Middle: Retract Scapula; Lower (ascending part): Depress Scapula; descending & ascending parts act together to rotate upward Spinal Accessory Nerve
Rhomboid Minor & Major Ligamentum Nuchae, C7-T1 & T2-T5 Spinous Processes Medial Border of the Scapula Retract & Elevate the Medial Border of Scapula & Rotate the Lateral Angle Downward Dorsal Scapular Nerve (C4 & C5)
Serratus Anterior Lateral Surfaces of the Upper Eight Ribs Medial Border of the Scapula Protract Scapula & Rotate Scapula Upward Long Thoracic Nerve
Levator Scapulae Transverse Processes of the C1-C4 Vertebrae Medial Border of the Scapula Elevate the Medial Border of Scapula; Rotate the Lateral Angle Downward; Laterally Flex Neck Dorsal Scapular Nerve (C5) & Ventral Primary Rami of C3 & C4
Pectoralis Minor Third, Fourth & Fifth Ribs Coracoid Process Draws the Scapula Forward and Downward Medial & Lateral Pectoral Nerves
Glenohumeral Joint
Pectoralis Major Sternum, Costal Cartilage Ribs 1-6, Medial Half of the Clavicle, Aponeurosis of Obliquus Externus Abdominis Lateral Lip of Intertubercular Groove Internally Rotate, Flex & Adduct Shoulder Medial & Lateral Pectoral Nerves
Deltoid Lateral Third of the Clavicle, Acromion & the Spine of the Scapula Deltoid Tubercle on the Lateral Surface of the Humerus Abduct Shoulder Axillary Nerve
Coraco-brachialis Coracoid Process Medial Mid-shaft Humerus Flex & Adduct Shoulder Musculocutaneous Nerve
Latissimus Dorsi Spinous Processes of Inferior 6 Thoracic Vertebrae, Iliac Crest, Sacrum, Thoracolumbar Fascia, Inferior 3 or 4 ribs Floor of Intertubercular Groove Extend, Internally Rotate & Adduct Shoulder Thoracodorsal Nerve
Teres Major Inferior Angle of Scapula Medial Lip of Intertubercular Groove Extend, Internally Rotate & Adduct Shoulder Lower Subscapular Nerve
Rotator Cuff
Supraspinatus Supraspinous Fossa Top of the Greater Tubercle of Humerus Abduct & Stabilize Shoulder Suprascapular Nerve
Infraspinatus Infraspinous Fossa Back of the Greater Tubercle of Humerus Externally Rotate & Stabilize Shoulder Suprascapular Nerve
Teres Minor Lateral Border Inferior of the Greater Tubercle of Humerus Externally Rotate & Stabilize Shoulder Axillary Nerve
Subscapularis Subscapular Fossa Lesser Tubercle of Humerus Internally Rotate, Depress & Stabilize Shoulder Subscapular Nerves
Shoulder Muscles
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