Trunk and Pelvic Floor Muscles

Origin: pubic crest & symphysis

Insertion: xyphoid process &  ribs 5-7

Function: flex and rotate lumbar region of vertebral column, fix & depress ribs, stabilize pelvis during walking, increase inta-abdominal pressure

Nerve: Intercostals T7-T11, Subcostal T12

Origin: outer surface of lower 8 ribs

Insertion: linea alba via aponeurosis, ilac crest (external part)

Function: when togetherm synergist to rectus abdomis, flex bertebral column & compress abdominal wall, when alone, synergist to muscles of back, rotate & lateral flexion of trunk

Nerve: Intercostals T7-T11, Subcostals T12

Origin: thoracolumbar fascia, iliac crest & inguinal ligament 

Insertion: linea alba, last 3 or 4 ribs, lower margin of aponeurosis with tranverse abdominis = falx inguinalis

Function: when together, synergist to rectus abdominis, flex vertebral column & compress abdominal wall, when alones, synergist to muscles of back, rotate & lateral flexion of trunk

Nerve: Intercostals T8-T11, Subcostal T12, Iliohypogastric T12, Ilioinguinalis L1

Origin: inguinal ligament, lumbar fascia, cartilages of last 6 ribs, iliac crest

Insertion: linea alba, pubic crest

Function: compresses abdominal contents

Nerve: Intercostal T7-T11, Subcostal T12, Iliohypogastric, Ilioinguinal

Origin: ligamentum nuchae, spinous process C6-Th2, supraspinal ligaments

Insertion: angle of ribs 2 - 5

Function: raises ribs; accesory respiratory muscle

Nerve: intercostal (2 - 5)

Origin: spinous process Th11-L2, supraspinal ligaments

Insertion: angle of rib 9-12

Function: antagonist - draws in the lower ribs (helps with exhalation), fixes lower ribs for more action from diaphragm (helps with breathing)

Nerve: intercostal nerves 9-12

Origin: [iliocostalis] iliac crests (lumborum), inferior 6 ribs (thoracic), ribs 3-6 (cervicis), [longissimus] transverse process of lumbar through cervical vertebrae, [spinalis] spines of upper lumbar & lower thoracic vertebrae

Insertion: [iliocostalis] angle of ribs, cervical vertebrae, [longissimus] transeverse process of thoracic or cervical vertebrae, ribs, mastoid process, [spinalis] spines of upper thoracic & cervical vertebrae

Function: [iliocostalis] extend vertebral column, bend vertebral column side to side when act on one side [longissimus] extend vertebral column, act on one side (bend it laterally), extends head + turns face toward same side [spinalis] extends vertebral column

Nerve: Spinal nerves, posterior branch (dorsal rami)

Origin: superior articulations of C4 - C7 (cervicis), transverse processes of thoracic vertebrae (thoracis), mamillary process of lumbar vertebrae, sacrum (lumborum)

Insertion: spinous processes of vertebrae

Function: Bilateral contraction: Extension of spineUnilateral contraction: Lateral flexion of spine (ipsilateral), rotation of spine (contralateral)

Nerve: Spinal nerves (dorsal rami)

Origin: (sternal part) inner surface of sternum (xiphoid process) + inner side of rectus abdominis, (costal part) rib cartilages 7 - 12, (lumbal part) Medial and lateral arcuate ligaments (lumbocostal arches), bodies of vertebrae L1-L3 (+intervertebral discs), anterior longitudinal ligamentInsertion: central tendonFunction: Depresses costal cartilages, primary muscle of breathing (inspiration)Nerve: Phrenic nerve (cervical plexus, C3, C4, C5)

Origin: posterior boarder of iliac crest + lumbar fascia

Insertion: transverse process of L1 - L5 + lower margin of  12th rib

Function: flexes vertebral column + laterally, extends lumbar spine

Nerve: T12 + 1st - 4th anterior lumbar spinal nerves, anterior branch (L1-L4)

Origin: 

Puborectalis: Posterior surface of bodies of pubic bones

Pubococcygeus: Posterior surface of bodies of pubic bones (lateral to puborectalis)

Iliococcygeus: Tendinous arch of interal obturator fascia, Ischial spine

Insertion: 

Puborectalis: None (forms 'puborectal sling' posterior to rectum)

Pubococcygeus: Anococcygeal ligament, Coccyx, Perineal body and musculature of prostate/ vagina

Iliococcygeus: Anococcygeal ligament, Coccyx

Function: Stability and support of the abdominal and pelvic organs, resistance against increased intra-abdominal pressure, opening and closing of the levator hiatus

Nerve: sacral plexus S3, S4

Origin: Ischial spine

Insertion: coccyx

Function: Supports pelvic viscera, part of the diaphragm of pelvis

Nerve: sacral plexus S3 - S4