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43. Rectus abdominis
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
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44. External oblique
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
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45. Internal oblique
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
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46. Transverse abdominis
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
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Serratus posterior superior
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)
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Serratus posterior inferior
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
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Erector spinae
38-A Iliocostalis
38-B Longissimus
38-C Spinalis
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)
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mm. Multifidi
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)
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Diaphragm
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)
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39. Quadratus lumborum
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)
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47 Levator ani
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
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48 Coccygeus
Origin: Ischial spine
Insertion: coccyx
Function: Supports pelvic viscera, part of the diaphragm of pelvis
Nerve: sacral plexus S3 - S4
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