Shoulder Muscles Flashcards
Trapezius (Upper)
Origin: External occipital protuberance
Ligmentum nuchae
Insertion: Posterior lateral 1/3rd clavicle
Actions: Elevation scapula
Extension/rotation head
Innervation: Accessory Nerve (CN XI)
Trapezius (Middle)
Origin: Spinous C7-T3
Insertion: Medial border acromion
Upper border scapular spine
Actions: Elevation scapula
Retraction scapula
Upward rotation scapula
Innervation: Accessory nerve (CN XI)
Trapezius (Lower)
Origin: Spinous T4-T12
Insertion: Triangular space base scapular spine
Actions: Depression scapula
Upward rotation scapula
Retraction scapula
Innervation: Accessory nerve (CN XI)
Latissimus dorsi
Origin: Spinous T7-T12
Lumbar/sacral vertebrae
Posterior iliac crest
Insertion: Medial lip (crest of lesser tubercle)
Floor intertubercle groove of humerus
Actions: Extension of arm
Adduction of arm
Internal rotation glenohumeral
horizontal abduction glenohumeral
Innervation: Thoracodorsal nerve (C6-C8)
Brachial plexus: posterior
Levator scapulae
Origin: Transverse process C1-C4
Insertion: Medial border scaupla above base of spine (superior angle)
Actions: Elevation scapula
Downward rotate of scapula
adduction
Innervation: Dorsal scapular nerve (C5), (C3,C4)
Rhomboid minor
Origin: Lower ligamentum nuchae
Spinous C7-T1
Insertion: Medial border of scapula base of spine
Actions: Elevation of scapula
Retraction of scapula
Downward rotate glenohumeral
Innervation: Dorsal scapular nerve (C5)
Rhomboid major
Origin: Spinous T2-T5
Insertion: Medial border scapula below rhomboid minor
Actions: Elevation of scapula
Retraction of scapula
Downward rotate glenohumeral
Innervation: Dorsal scapular nerve (C5)
Serratus anterior
Origin: Surface Ribs 1-8 anteriolateral thoracic wall
Insertion: Anterior medial border scapula (Inferior angle)
Actions: Upward rotation of glenoid cavity
Protraction scapula
Holds medial border scapula against thoracic wall
Innervation: Long thoracic nerve (C5-C7)
Deltoid (Anterior)
Origin: Anterior lateral 1/3 clavicle
Insertion: Deltoid tuberosity
Actions: Flexion of arm
Adduction of arm
Internal rotation of humerus
Horizontal/Diagonal adduction
Innervation: Axillary nerve (C5,C6)
Brachial plexus: posterior
Deltoid (Middle)
Origin: Lateral aspect of acromion
Insertion: Deltoid tuberosity on humerus
Actions: Abduction
horiz abduction
Innervation: Axillary nerve (C5,C6)
Brachial plexus: posterior
Deltoid (Posterior)
Origin: Inferior scapula spine
Insertion: Deltoid tuberosity
Actions: Extension of arm
External rotation of humerus
Adduction of arm
horiz/diag abduction
Innervation: Axillary Nerve (C5,C6)
Brachial plexus: posterior
Pectoralis major (upper-clavicular fibers)
Origin: Medial anterior 1/3 clavicle
Insertion: Lateral lip intertubercular groove (crest greater tubercle)
Actions: Flexion of arm
Adduction of arm
Internal rotation
horizontal/diagonal adduction
Innervation: Medial pectoral nerve (C8,T1): Medial
Lateral pectoral nerve (C5-C7): Lateral
Pectoralis major (lower-sternocostal fibers)
Origins: Anterior costal cartialge Ribs 1-6
Sternum
Insertion: Lateral lip intertubercular groove (crest greater tubercle)
Actions: Extension of arm
Adduction of arm
Internal rotation
horizontal/diagonal adduction
Innervation: Medial pectoral nerve (C8,T1): Medial
Lateral pectoral nerve: (C5-C7): Lateral
Pectoralis minor
Origin: Anterior Ribs 3-5
Insertion: Coracoid process scapula
Actions: Depression shoulder
Downward rotation scapula
Innervation: Medial pectoral nerve (C8, T1)
Brachial plexus: Medial
Sternocleidomastoid
Origin: Tendinous head- sternum
Muscular head- medial 1/3 clavicle
Insertion: Mastoid of skull
Actions: Head flexion same side
Head internal rotation
Innervation: Accessory nerve (CN XI)
Subclavius
Origin: Rib 1
Insertion: Undersurface clavicle
Actions: Depress clavicle
Maintain sternoclavicular joint
Innervation: Nerve to subclavius (C5,C6)
Supraspinatus
Origin: Medial 2/3 supraspinous fossa
Insertion: Superior greater tubercle humerus
(superior facet)
Actions: Abduction arm
Innervation: Suprascapular nerve (C5, C6)
Brachial plexus: Upper
Infraspinatus
Origin: Medial infraspinous fossa
Insertion: Superior greater tubercle below supraspinatus
(Middle facet)
Actions: External rotation of humerus
Extension of arm
horizontal/diagonal abduction
Innervation: Suprascapular nerve (C5,C6)
Brachial plexus: Upper
Teres minor
Origin: Upper 2/3 lateral border scapula
Insertion: Posterior greater tubercle below infraspinatus
(Inferior facet)
Actions: External rotation of humerus
Extension of arm
horizontal/diagonal abduction
Actions: Axilary nerve (C5,C6)
Brachial plexus: posterior
Teres major
Origin: Posterior inferior angle scapula
Insertion: Medial lip intertubecular groove
(crest of lesser tubercle)
Actions: Internal rotation of humerus
Adduction of arm
Extension of arm
Innervation: Lower subscapular nerve (C5,C6)
Brachial plexus: Posterior
Subscapularis
Origin: Subscapular fossa of anterior scapula
Insertion: Lesser tubercle and crest of humerus
Actions: Internal rotation of humerus
Extension/Adduction of arm
Innervation: Upper/lower subscapular nerve (C5,C6)
Brachial plexus: Posterior
