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Muscles of the Back and Upper Arm
Muscles of the rotator cuff: supraspinatus, infraspinatus,
subscapularis, and to a smaller degree, the teres minor.
Supraspinatus:
origin: supraspinatus fossa of
scapula
insertion: greater tubercle of
humerus
action: holds head of humerus
in glenoid cavity
(Lateral view)
Subscapularis:
origin: subscapularis fossa
insertion: lesser tubercle of
humerus
action: holds head of humerus
in glenoid cavity
Serratus anterior
origin: ribs 1-8
insertion: vertebral boarder of scapula
action: protracts shoulder and snugs scapula chest wall
Trapezius
origin: occipital bone, lig.
Nuchae, and spinous
processes of thoracic
vertebrae
insertion: acromion and spine
of scapula
action: stabilizes, elevates,
depresses, adducts scapula.
Rhomboids (major and minor):
origin: spinous processes of
thoracic vertebrae
insertion: vertebral boarder of
scapula
action: stabilizing and
adducting scapula
Levator scapulae:
origin: transverse
processes of cervical
vertebrae 1 thru 4
insertion: vertebral
boarder of scapula near
superior angle
action: elevates scapula
Pectoralis major
origin: sternum, clavicle, and ribs 1-7
Insertion: greater tubercle of humerus
action: prime mover of shoulder
flexion
Latissimus dorsi:
origin: spinous process of
lower thoracic and lumbar
vertebrae
insertion: bicepital groove of
humerus
action: extension and
adduction of humerus
Teres major:
origin: inferior angle of
scapula
insertion: bicepital groove of
humerus
action: synergist to “Lats”
Deltoid
origin: clavicle, acromion and spine of scapula
insertion: deltoid tuberosity of humerus
action: abduction of humerus (whole muscle)
Biceps brachii
origin: coracoid process and
glenoid of scapula
insertion: radial tuberosity
action: flexion of elbow
Triceps brachii
origin: scapula and posterior
of humerus
insertion: olecranon of ulna
action: extension of elbow
Brachioradialis
origin: lateral epicondyle of
Humerus
insertion: styloid of radius
action: flexion of elbow
Muscle compartments of the upper arm. Note the larger extensor compartment.