| Chest and trunk |
|
|
|
|
| Muscle |
Origin |
Insertion |
Action |
Notes |
| Intercostals |
Inferior
border of the rib above |
Superior
border of the rib below |
External
Intercostals: draw the ventral part of the ribs upward, increasing thoracic
cavity space
Internal Intercostals: draw
the ventral part of the ribs downward, decreasing the space of the thoracic
cavity |
Stabilize
the rib cage and assist in respiration.
Meat of spare ribs. |
| Pectoralis
major |
Sternal
½ of clavicle, sternum to 7th rib, aponeurosis of external
oblique muscle. |
Crest
of greater tubercle of humerus: Lateral lip of bicipital grove. |
Clavicular
(upper) fibers- flexion of humerus
Sternocostal (middle and
lower) fibers- extension of humerus returning from flexion
Adduction, medial rotation |
Forms
the anterior wall of axilla.
Upper and lower fibers are
work in opposite actions making it an antagonist to itself.
Triggerpoints may cause pain,
swelling and congestion of lymphatic fluids in breast tissue. |
| Pectoralis
minor |
Third,
fourth and fifth ribs |
Coracoid
process of scapula |
Tilts
scapula forward, depresses and abducts scapula, |
Pulls
shoulder forward when rhomboids are weak |
| Diaphragm |
Sternal:
inner part of ziphoid process
Coastal- inner surface of
lower 6 ribs
Lumbar- upper 2-3 lumbar
vertebrae |
Central
tendon |
Draws
central tendon down during inspiration, increases volume of thoracic cavity
(increases diameters) |
Forms
floor of thoracic cavity. |
| Rectus
abdominis |
Crest
of the pubis, pubic symphysis |
Cartilage
of the 5th, 6th and 7th ribs and ziphoid
process |
Flexes
the vertebral column |
Sometimes
origin and insertion are reversed |
| External
obliques |
Lower
eight ribs (5-12) |
Anterior
part of iliac crest, abdominal aponeurosis to linea alba |
Bilaterally-
flexes thorax and compresses abdominal contents
Unilaterally- laterally flexes
spine and rotates spine to opposite side |
Interdigitates
with serratus anterior. Place hands on hips as if you were reaching into
pants pockets to follow directions of fibers (obliquely downward and medialward) |
| Internal
obliques |
Lateral
inguinal ligament, anterior iliac crest, thoracolumbar aponeurosis |
Cartilage
of lower 3-5 ribs (7-12), abdominal aponeurosis to linea alba |
Bilaterally-
flexes the thorax, compresses abdominal contents
Unilaterally- laterally flexes
spine and rotates trunk to same side |
Place
hands over abdomen with fingertips on the anterior-superior iliac spine,
your fingertips will follow the direction of the fibers (obliquely upward
and medialward) |
| Transverse
abdominis |
Lateral
inguinal ligament, anterior iliac crest, thoracolumbar fascia, cartilage
of lower 6 ribs (7-12) |
Abdominal
aponeurosis to linea alba |
Compresses
abdominal contents |
Deepest
layer of abdominals: runs horizontally medialward |
| Quadratus
lumborum |
Posterior
iliac crest, iliolumbar ligament |
Last
rib, transverse processes of L1-L4 |
Bilaterally-
extends the spine
Unilaterally- lateral flexion
of lumbar spine
With spine fixed-elevates
hip (hikes hip up).
Holds 12th rib
against the pull of the diaphragm
Accessory breathing muscle.
Spinal stabilizer |
Composed
of three groups of fibers: Iliocostal fibers run from medial upper crest
of ilium and iliolumbar ligament upward to 12th rib (vertical)
Iliolumbar fibers run from the ilium to the transverse processes of L1-L4
Lumbocostal fibers fun from
the 12th rib to transverse processes of lumbar vertebrae |
