Just the muscles of Superficial Back and Pectoral Region

trapezius

PA: external occipital protuberance, medial third of superior nuchal ligament, nuchal ligament, spinous processes of C7-T12

DA: lateral 1/3 of clavicle, spine of scapula, acromion

Inn: spinal accessory n (CN XI) and C3, C4 for sensory

A: elevates the scapular (upper/descending), retracts the scapula (middle), depresses the scapular (lower/ascending), rotates glenoid cavity superiorly when upper and lower work together

latissimus dorsi

PA: spinous processes of T7-T12, thoracolumbar fascia, iliac crest, inferior 3-4 ribs

DA: floor of bicipital groove of humerus

Inn: thoracodorsal n (C6, C7, C8)

A: extends arm, medially rotates arm, helps to pull body upwards

levator scapulae

PA: transverse processes of C1-C4

DA: medial border of scapula above spine

Inn: dorsal scapular n (C4, C5) and cervical nerves (C3, C4)

A: elevates scapula, rotates glenoid cavity inferiorly

rhomboid major

PA: spinous processes of T2-T5

DA: medial border of scapular below scapular spine to inferior angle

Inn: dorsal scapular n (C4, C5)

A: retracts scapula and rotates glenoid cavity inferiorly

rhomboid minor

PA: nuchal ligament, spinous processes of C7-T1

DA: smooth triangular area at medial end of scapular spine

Inn: dorsal scapular n (C4, C5)

A: retracts scapula and rotates glenoid cavity inferiorly

serratus posterior superior and inferior

thin muscles deep to rhomboids adn latissimus dorsi, involved in respiration, contribute little to movement or stability of the trunk

splenius muscles

superfical layer of intrinsic back, fibers run medial to lateral

erector spinae (spinalis, longissimus, iliocostalis)

intermediate layer of intrinsic back, fibers run mostly vertical, create bulges on either side of furrow on posterior back, align with rib angles, form shallow grooves

transversospinalis

deep layer of intrinsic back muscles, fibers run lateral to medial

function of the intrinsic back muscles

act on the vertebral column, maintain posture and enable movement

pectoralis major

PA: clavicular head: medial ½ of clavicle, sternocostal head: anterior surface of sternum, superior 6 costal cartilages, aponeurosis of external oblique

DA: lateral lip of bicipital groove of humerus

Inn: lateral and medial pectoral n (C5, C6) and (C7, C8, T1)

A: adducts and medially rotates humerus, clavicular head flexes, sternocostal head extends from flexed position

pectoralis minor

PA: ribs 3-5 near costal cartilages

DA: medial border and superior surface of coracoid process of scapula

Inn: medial pectoral n (C8, T1) and lateral pectoral n (variable)

A: stabilizes scapula by drawing inferiorly and anteriorly against thoracic wall

subclavius

PA: junction of first rib and costal cartilage

DA: middle 1/3 of inferior clavicle

Inn: nerve to subclavius (C5, C6)

A: anchors and depresses clavicle

serratus anterior

PA: external surfaces of lateral parts of ribs 1-8

DA: anterior surface of medial border of scapula

Inn: long thoracic n (C5, C6, C7)

A: protracts scapula, stabilizes by holding against thoracic wall, rotates scapula