Muscles of the shoulders and torso

sternocleidomastoid

O: sternum and clavicle

I: mastoid process

Action: flexes and laterally rotates head

Accessory nerve

external intercostals

O: inferior border of rib above

I: superior border of rib below

Action: elevate rib cage

Intercostal nerves

internal intercostals

o: superior border of rib below

i: inferior border of rib above

action: compress and depress ribcage

intercostal nerves

diaphragm

o: xiphoid process, lower costal cartilages, lumbar vertebrae

i: central tendon

action: flattens during inhalation

phrenic nerve

rectus abdominis

o: pubic crest and symphysis

i: xiphoid process and lower costal cartilages

action: flex and rotate vertebral column

intercostal nerves

external oblique

o: lower eight ribs

i: linea alba, pubic tubercle, iliac crest

action: rotates and flexes vertebral column laterally, compresses abdomen

intercostal nerves

internal oblique

o: lumbar fascia, iliac crest

i: linea alba, pubis, lower ribs

action: rotates and flexes vertebral column to same side, compresses abdomen

intercostal nerves

transversus abdominis

o: lower costal cartilages, lumbar fascia, iliac crest

i: linea alba, pubic crest

action: compresses abdominal

intercostal nerves

pectoralis major

o: clavicle, sternum, costal cartilages

i: humerus

action: adducts, medially rotates, flexes arm

lateral and medial pectoral nerves

deltoid

o: lateral clavicle; acromion, spine of scapula

i: deltoid tuberosity

action: arm abduction

axillary nerve

pectoralis minor

o: ribs 3-5

i: coracoid process

action: depresses scapula

medial and lateral pectoral nerve

serratus anterior

o: ribs 1-8

i: vertebral border of scapula

action: rotates scapula

long thoracic nerve

trapezius

o: occipital bone, vertebral column

i: acromion, spine of scapula, clavicle

action: stabilizes, elevates, retracts, and rotates scapula

accessory nerve

latissimus dorsi

o: vertebrae, ribs, iliac crest, inferior angle of scapula

i: humerus

action: arm extension, arm adductor, medially rotates arm

thoracodorsal nerve

subscapularis

o: subscapular fossa

i: lesser tubercle

action: rotates arm medially

subscapular nerve

supraspinatus

o: supraspinous fossa

i: greater tubercle

action: abduction of arm

suprascapular nerve

infraspinatus

o: infraspinous fossa

i: greater tubercle

action: rotates arm laterally

suprascapular nerve

teres minor

o: lateral border of scapular

i: greater tubercle

action: rotates arm laterally

axillary nerve