Muscles of the Back and Scapular Regions

Latissimus Dorsi

C6-C8

Attachment of Latissimus Dorsi

From: Spinous processes of lower thoracic vertebrae, Thoracolumbar Fascia, Iliac Crest
To: Floor of Intertubercular Sulcus of Humerus

Action of Latissimus Dorsi

Extension, Adduction, Medial Rotation of Humerus

Innervation of Latissimus Dorsi

Thoracodorsal Nerve (C6-C8)

Levator Scapulae

C4-C5

Attachment of Levator Scapulae

From: Transverse Processes of C1-C4

To: Superior angle, superiomedial border of scapula

Action of Levator Scapulae

Elevation, Downward Rotation of Scapula

Innervation of Levator Scapulae

Dorsal Scapular Nerve (C4-C5), Sensory: direct branches of C3-4

Pectoralis Major

Clavicular Head - C5-C7, Sternocostal Head - C8-T1

Attachment of Pectoralis Major

From: Anterior Border of Clavicle, Costal cartilages, Sternum, Aponeurosis of External Oblique

To: Lateral Lip of Intertubercular Sulcus of Humerus

Action of Pectoralis Major

Flexion, Adduction, Medial Rotation of Humerus (Sternocostal portion assists with extension of the flexed arm)

Innervation of Pectoralis Major

Lateral (C5-C7) and Medial Pectoral (C8-T1) Nerves

Pectoralis Minor

C5-T1

Attachment of Pectoralis Minor

From: Outer surfaces of Ribs 3-5

To: Coracoid Process of Scapula

Action of Pectoralis Minor

Anterior tilt of scapula; assists with depression of shoulder and forced inspiration

Innervation of Pectoralis Minor

Lateral (C5-C7) and Medial Pectoral (C8-T1) Nerves

Rhomboids

C4-C5

Attachment of Rhomboids

From: Major - Spinous Processes of T2-T5, Minor - Spinous Processes of C7-T1, Nuchal Ligament

To: Medial Border of Scapula

Action of Rhomboids

Retraction, Elevation (upper), Downward Rotation of Scapula

Innervation of Rhomboids

Dorsal Scapular Nerve (C4-C5); Sensory: Direct branches of C3-C4

Serratus Anterior

C5-C7

Attachment of Serratus Anterior

From: Outer surfaces and Superior borders of upper 8-10 ribs

To: Costal Surface of Medial border of Scapula

Action of Serratus Anterior

Protraction, Upward Rotation of Scapula

Innervation of Serratus Anterior

Long Thoracic Nerve (C5-C7)

Subclavius

C5-C6

Attachment of Subclavius

From: 1st rib and cartilage

To: Undersurface of clavicle

Action of Subclavius

Depression, Stabilization of Clavicle

Innervation of Subclavius

Subclavian Nerve (C5-C6)

Trapezius

Motor: Cranial Nerve XI - Accessory Nerve, Sensory: C3-C4

Attachment of Trapezius

From: Superior nuchal line, External occipital protuberance, Nuchal ligament, Spinous processes of cervical and thoracic vertebrae

To: Posterior border of Clavicle, Acromion, Crest of Spine of Scapula

Action of Trapezius

Upper - Elevation of Scapula, Middle - Retraction of Scapula, Lower - Depression of Scapula, Upper/Lower - Upward Rotation of Scapula

Innervation of Trapezius

Motor: Cranial Nerve XI - Accessory Nerve, Sensory: C3-C4

Deltoid

C5-C6

Attachment of Deltoid

From: Anterior Border of Clavicle, Acromion, Spine of Scapula

To: Deltoid Tuberosity of Humerus

Actions of Deltoid

Anterior: Flexion, Internal Rotation of Humerus, Middle: Abduction of Humerus, Posterior: Extension, External Rotation, Horizontal Extension of Humerus

Innervation of Deltoid

Axillary Nerve (C5-C6)

Supraspinatus

C4-C6

Attachment of Supraspinatus

From: Medial 2/3 of the Supraspinous Fossa

To: Superior Facet of Greater Tubercle of Humerus, Shoulder Joint Capsule

Action of Supraspinatus

Initiates humeral abduction, lateral rotation of humerus; stabilizes glenohumeral joint (reinforces superior aspect of joint capsule)

Innervation of Supraspinatus

Suprascapular Nerve (C4-C6)

Infraspinatus

C5-C6

Attachment of Infraspinatus

From: Medial 2/3 of Infraspinous fossa

To: Middle Facet of Greater Tubercle of Humerus, Shoulder Joint Capsule

Action of Infraspinatus

Lateral Rotation of Humerus, stabilizes Glenohumeral Joint

Innervation of Infraspinatus

Suprascapular Nerve (C5-C6)

Teres Minor

C5-C6

Attachment of Teres Minor

From: Upper 2/3 of the Dorsal surface of the Lateral Border of Scapula

To: Inferior Facet of the Greater Tubercle of Humerus, Shoulder Joint Capsule

Action of Teres Minor

Lateral Rotation of Humerus, Stabilizes glenohumeral joint

Innervation of Teres Minor

Axillary Nerve (C5-C6)

Subscapularis

C5-C6

Attachment of Subscapularis

From: Subscapular Fossa

To: Lesser Tubercle of Humerus

Action of Subscapularis

Medial Rotation of Humerus, Stabilize Glenohumeral Joint

Innervation of Subscapularis

Upper and Lower Subscapular Nerves (C5-C6)

Teres Major

C5-C6

Attachment of Teres Major

From: Dorsal Surface of the Inferior Angle of Scapula, Lower 1/3 of the Lateral Border of Scapula

To: Medial Lip of Intertuburcular Sulcus of Humerus

Action of Teres Major

Extension, Adduction, Medial Rotation of Humerus

Innervation of Teres Major

Lower Subscapular Nerve (C5-C6)