3
MuscleTable
Table3-1
MUSCLE
PROXIMAL
ATTACHMENT
(ORIGIN)
DISTAL
ATTACHMENT
(INSERTION)
INNERVATION
MAIN ACTIONS
BLOOD SUPPLY
MUSCLE
GROUP
Diaphragm
Xiphoid process,
lower six costal
cartilages,
L1–L3 vertebrae
Converge into
central tendon
Phrenic nerve
Draws central
tendon down
and forward
during
inspiration
Pericardiacophrenic,
musculophrenic,
superior and inferior
phrenic arteries
Posterior
abdominal wall
External
intercostal
Lower border of ribs
Upper border of rib
below rib of
origin
Intercostal nerves
Supports intercostal
spaces in
inspiration and
expiration,
elevates ribs in
inspiration
Posterior intercostal arteries,
collateral branches of
posterior intercostal
arteries, costocervical
trunk, anterior
intercostal branches of
internal thoracic artery,
musculophrenic artery
Thoracic wall
Innermost
intercostal
Lower border of ribs
Upper border of rib
below rib of
origin
Intercostal nerves
Elevates ribs
Muscular branches of
anterior intercostal
arteries, muscular
branches of posterior
intercostal arteries,
intercostal branches of
internal thoracic and
musculophrenic arteries,
costocervical trunk
branches
Thoracic wall
Internal
intercostal
Lower border of ribs
Costal cartilage and
edge of costal
groove of rib
above rib of
origin
Intercostal nerves
Prevents pushing
out or drawing
in of intercostal
spaces in
inspiration and
expiration,
lowers ribs in
forced expiration
Muscular branches of
anterior intercostal
arteries, muscular
branches of posterior
intercostal arteries,
intercostal branches of
internal thoracic and
musculophrenic arteries,
costocervical trunk
branches
Thoracic wall
Levator
costarum
Transverse
processes of C7
and T1–T11
Subjacent ribs
between
tubercle and
angle
Dorsal ramus of
lower thoracic
nerves
Elevates ribs
Posterior intercostal arteries
Thoracic wall
Pectoralis major
Sternal half of
clavicle, sternum
to 7th rib,
cartilages of
true ribs,
aponeurosis of
external oblique
muscle
Lateral lip of
intertubercular
sulcus of
humerus
Medial and lateral
pectoral
nerves
Flexes and adducts
arm, rotates arm
medially
Pectoral branch of
thoraco-acromial artery,
perforating branches of
internal thoracic artery
Pectoral/axilla
region
Pectoralis minor
Outer surface of
upper margin of
ribs 3–5
Coracoid process of
scapula
Medial pectoral
nerve
Lowers lateral angle
of scapula and
protracts
scapula
Pectoral branch of
thoraco-acromial and
intercostal lateral
thoracic arteries
Pectoral/axilla
region
Serratus anterior
Lateral surfaces of
upper 8–9 ribs
Costal surface of
medial border of
scapula
Long thoracic
nerve
Protracts scapula
and holds it
against thoracic
wall
Lateral thoracic artery
Pectoral/axilla
region
Serratus
posterior
inferior
Spinous processes
of T11–L2
Inferior aspect of
ribs 9–12
Ventral rami of
lower thoracic
nerves
Depresses ribs
Posterior intercostal arteries
Superficial back
Serratus
posterior
superior
Ligamentum nuchae,
spinous
processes of
C7–T3
Superior aspect of
ribs 2–4
Ventral rami of
upper thoracic
nerves
Elevates ribs
Posterior intercostal arteries
Superficial back
Subcostal
Internal surface of
lower ribs near
their angles
Superior borders of
2nd or 3rd rib
below
Intercostal nerves
Depresses ribs
Posterior intercostal artery,
musculophrenic artery
Thoracic wall
Transversus
thoracis
Internal surface of
costal cartilages
2–6
Posterior surface of
lower sternum
Intercostal nerves
Depresses ribs and
costal cartilages
Anterior intercostal arteries,
internal thoracic artery
Thoracic wall
Variations in spinal nerve contributions to the innervation of muscles, their arterial supply, their attachments, and their actions are common themes in human
anatomy. Therefore, expect differences between texts and realize that anatomical variation is normal.
MuscleTable
