Muscles of the superficial back

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supraspinatus: insertion

- superior facet on the greater tubercle of humerus

trapzeius-upper actions

-Bilaterally (using both muscles) extend the head and neck -Unilaterally (using one muscle) laterally flex the head and neck to the same side -rotate the head and neck to the opposite side -elevate the scapula (scapulothoracic joint) -upwardly rotate the scapulathoracic joint

trapezius nerve supply

-Cranial nerve XI (11)-spinal accessory nerve (branches from ventral rami C2-C4)

Rhomboid major and minor-action

-aDDuction (retraction) of scapula -elevates the scapulothoracic joint -downward rotates the scapula

8) latissimus dorsi

-broadest muscle of the back -originates at the low back, ascend the side of the trunk, and merge into a thick bundle at the axilla (armpit)

7) teres major

-complete syngergist with the latissimus dorsi -located along the scapula's lateral border between the latissimus dorsi and teres minor -rotates arm medially

levator scapula: nerve supply

-dorsal scapular (branches from C5) -the dorsal scapular nerve also innervates the rhomboids

rhomboid major and minor-nerve supply

-dorsal scapular nerve (C5)

latissimus dorsi: action

-extend the shoulder (glenohumeral joint) -aDDuct the shoulder -medially rotate the shoulder -if the humerus is fixed, it will elevate the pelvis

teres major: action

-extend the shoulder (glenohumeral joint) -aDDuct the shoulder -medially rotate the shoulder (glenohumeral joint) -stabilizes head in glenoid cavity during ABduction

1) trapezius-upper fibers origin

-external occipital protuberance -superior nuchal line -ligamentum nuchae

teres major: origin

-inferior angle and lower 1/3 of lateral border of the scapula

latissimus dorsi: origin

-inferior angle of the scapula -spinous processes of the last 6 thoracic vertebrae -last 3-4 ribs -posterior crest of the ilium -all the lumbar and sacral spines via thoracolumbar fascia

infraspinatus: origin

-infraspinous (below spine) fossa of the scapula

5) infraspinatus

-is a synergist with teres minor in lateral rotation of the shoulder -part of rotator cuff muscles

teres minor: action

-laterally rotate the shoulder (glenohumeral joint) -aDDuct the shoulder -stablize the head of humerus in glenoid cavity -horizontal aBduction -extends the shoulder

infraspinatus: action

-laterally rotate the shoulder (glenohumeral joint) -extend the shoulder -aDDuct the shoulder -stablize the head of humerus in glenoid cavity

Rhomboid minor and major-origin

-lower ligamentum nuchae and spinous processes of C7-T5

6) teres minor

-part of rotator cuff muscles -located on the anterior surface of the scapula -sandwhiched between the subscapular fossa and serratus anteior muscle

4) supraspinatus

-part of the rotator cuff muscles -attaches to the humers' greater tubercle -assists the with deltoid with abduction of the shoulder and is the only muscle of the rotator cuff group not involved in shoulder rotation

trapezius- middle fibers origin

-spinous processes of lower cervical and upper thoracic vertebrae

levator scapula: insertion

-superior angle of the scapula

supraspinatus: nerve supply

-suprascapular nerve (C5 and C6)

supraspinatus: origin

-supraspinous fossa (above spine) of scapula

3) Levator Scapula

-the brachial plexus, a large group of nerves which innervates the arm, exits from the transverse processes of the cervical vertebrae

Levator scapula: origin

-transverse processes of cervical vertebrae C1-C4

Trapezius

-upper fibers, middle fibers, lower fibers -the lower fibers and the upper fibers act together to rotate the glenoid cavity upward-a neccessary position in raising the arm greater than 90 degrees. this motion is based on the supraglenoid tubercle of the scapula

latissimus dorsi: insertion

1) floor of the intertubercular (bicipital) groove of the humerus 2) crest of the lesser tubercle of the humerus

rotator cuff muscles

1) supraspinatus 2) infraspinatus 3) teres minor 4) subscapularis (SITS acronym)

Muscles of the superficial back

1) trapezius 2) thomboid minor and major 3) levator scapula 4) supraspinatus 5) infraspinatus 6) teres minor 7) teres major 8) latissimus dorsi

levator scapula: actions

Unilaterally (using only 1 levator scapula muscle) elevate the scapula (scapulothoracic joint) -downwardly rotate the scapula -laterally flex the head and neck -rotate the head and neck to the same side Bilaterally (using both levator scapula muscles): -extend the head and neck

supraspinatus: action

aBduct the shoulder (glenohumeral joint) -stablize the head of the humerus in glenoid cavity

trapezius-middle fibers insertion

acromion process and the spine of the scapula

teres minor: nerve supply

axillary nerve- C5,6 -is a nerve of the brachial plexus -also innervates the deltoid

teres major: blood supply

circumflex scalpular artery

teres minor: blood supply

circumflex scalpular artery

teres major: insertion

crest of the lesser tubercle of the humerus

trapzeius-lower fibers action

depresses scapula, upward rotates scapula

levator scapula: blood supply

dorsal scapular artery

rhomboid major and minor-blood supply

dorsal scapular artery

trapzeius-upper fibers insertion

lateral 1/3rd of the clavicle

teres major: nerve supply

lower subscapular nerve- C5, 6 -is a nerve of the brachial plexus -also innervates the subscapularis muscle

teres minor: insertion

lowest facet on the greater tubercle of the humerus

Rhomboid major and minor- insertion

medial (vertebral) border of scapula from the base of the spine to the inferior angle

trapezius-lower fibers insertion

medial end (base) of the spine of the scapula

infraspinatus: insertion

middle facet on the greater tubercle of the humerus

trapezius-lower fibers origin

spinous process of lower thoracic vertebrae

trapzeius-middle fibers action

stabilizes scapula, aDDucts scapula

infraspinatus: nerve supply

suprascapular (C5, 6) -also innervates supraspinatus

infraspinatus: blood supply

suprascapular artery

supraspinatus: blood supply

suprascapular artery

latissimus dorsi: blood supply

thoracodorsal artery

latissimus dorsi: nerve supply

thoracodorsal nerve- C6,7,8 -part of the brachial plexus

trapezius blood supply

transverse cervical artery

teres minor: origin

upper (superior) 2/3 of the lateral border of the scapula


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