sternocleidomastoid
origin- manubrium, medial clavical
insertion- mastoid process
action- unilateral-oppositional rotation, bilateral-flexes the neck
semispinalis (group)
origin- T-processes of C7-T12
insertion- occiput, s-processes of C1-T4
action- extension of head and neck
erector spinae (group)
origin- illiac crest; T processes and ribs
insertion- ribs, T-processes (above origins)
action- extension and lateral flexion of torso and neck
splenius (group)
origin- nuchal ligament; s-processes of C7-T6
insertion- mastoid process; occiput; T-processes of L-vert
action- extension, rotation and lateral flexion of neck and head
rectus abdominus
origin- pubic bone (symphasis)
insertion- xiphoid process; costal cartilage 5-7
action- flexion of vertebral column (torso)
external oblique
origin- anterior lower 8 ribs
insertion- linea alba; pubic crest; illiac crest
action- compresses abdominal wall; flexes, rotates and lateral
flexion of trunk
internal oblique
origin- lumbar fascia; illiac crest; inguinal ligament
insertion- linea alba; last 3 ribs
action- compresses abdominal wall; flexes, rotates and lateral
flexion of trunk
transverse abdominus
origin- inguinal ligament; illiac crest; coastal cartilage 5 and 6
insertion- line alba; pubic crest
action- compresses abdominal wall; lateral rotation of trunk
scalenes
origin- t-processes of C-vert
insertion- ribs 1/2 anteriorlaterally
action- aid inspiration (lift ribs 1/2)
diaphram
action- inhalation
external intercostals
origin-rib above
insertion- rib below
action- aids inspiration
internal intercostals
origin- rib below
insertion- rib above
action- aids experation