Muscles of the superficial back
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
