Muscles: Test 3 Flashcards
external intercostal insertion
superior border of ribs below
External intercostal origin
inferior border of ribs
external intercostal innervation
intercostal nerve
external intercostal action
during forced inspiration: ELEVATE ribs
internal & innermost intercostal origin
inferior border of ribs
internal & innermost intercostals insertion
superior border of ribs below
internal & innermost intercostal innervation
intercostal nerve
internal & innermost intercostal action
during forced respiration:
interosseus part– DEPRESSES ribs
interchondral part– ELEVATES ribs
transversus thoracis origin
posterior surface of lower sternum
transversus thoracis insertion
internal surface of costal cartilages 2-6
transversus thoracis innervation
intercostal nerve
transversus thoracis action
weakly depresses ribs
external oblique origin
external surfaces of 5th-12th ribs
external oblique insertion
linea alba, pubic tubercle, and anterior half of iliac crest
external oblique innervation
thoraco-abdominal nerves (anterior rami of T7-T11)
subcostal nerve
external oblique action
compress and support abdominal viscera
flex and rotate trunk
internal oblique origin
thoracolumbar fascia
anterior 2/3 of iliac crest
connective tissue deep to inguinal ligament
internal oblique insertion
inferior borders of 10th-12th ribs
linea alba
pubis via conjoint tendon
internal oblique innervation
thoraco-abdominal nerves (anterior rami of T7-T11)
subcostal and first lumbar nerve
internal oblique action
compress and support abdominal viscera
flex and rotate trunk
transversus abdominis origin
internal surfaces of 7th-12th costal cartilages
thoraco-lumbar fascia
iliac crest
connective tissue deep to inguinal ligament
transversus abdominis insertion
linea alba with aponeurosis of internal oblique
pubic crest
pubis via conjoint tendon
transversus abdominis innervation
thoraco-abdominal nerves (anterior rami of T7-T11)
subcostal and first lumbar nerve
transversus abdominis action
compresses and supports abdominal viscera
rectus abdominis origin
pubis symphysis
pubic crest
rectus abdominis insertion
xiphoid process
5th-7th costal cartilages
rectus abdominis innervation
thoraco-abdominal and subcostal nerves
anterior rami of T7-T12 spinal nerves
rectus abdominis action
flexes trunk (lumbar vertebrae) compresses abdominal viscera stabilizes and controls tilt of pelvis (antilordosis)
Psoas Major origin
transverse processes of lumbar vertebrae
sides of bodies of T12-S1 vertebrae & intervening IV discs
Psoas major insertion
by a strong tendon to lesser trochanter of femur
Psoas major innervation
lumbar plexus via anterior branches of nerves L2-L4
Psoas major action
acting inferiorly with iliacus: flexes trunk with sitting and flexes thigh
acting superiorly: flexes vertebral column laterally to balance trunk
iliacus origin
superior 2/3 of iliac fossa
ala of sacrum
anterior sacro-iliac ligaments
iliacus insertion
lesser trochanter of femur shaft inferior to it
psoas major tendon
iliacus innervation
femoral nerve (L2-L4)
iliacus action
flexes thigh and stabilizes hip joint
acts with psoas major
quadratus lumborum origin
medial half of inferior border of 12th rib and tips lumbar transverse processes
quadratus lumborum insertion
iliolumbar ligament
internal lip of iliac crest
quadratus lumborum innervation
anterior branches of T12
L1-L4 nerves
quadratus lumborum action
extends and laterally flexes vertebral column
fixes 12th rib during inspiration
crura of the diaphragm
musculotendinous bundles that arise from the anterior surfaces of the bodies of the superior 3 lumbar vertebrae, the anterior longitudinal ligament and IV discs
Right- larger, arises from the L1-L3/L4 vertebrae
Left- arises from L1-L2/L3
Levator ani origin
body of pubis
tendinous arch of levator ani
ischial spine
levator ani insertion
perineal body coccyx anococcygeal ligament walls of prostate or vagina rectum anal canal
levator ani innervation
nerve to levator ani (branches of S4)
inferior anal nerve
coccygeal plexus
levator ani action
helps support pelvic viscera
resists increases in intra-abdominal pressure
coccygeus origin
ischial spine
coccygeus insertion
inferior end of sacrum and coccyx
coccygeus innervation
branches of S4 and S5 nerves
coccygeus action
forms small part of pelvic diaphragm that supports pelvic viscera
flexes coccyx
piriformis action
pelvic surface of 2nd-4th sacral segments
superior margin of greater sciatic notch
sacrotuberous ligament
piriformis insertion
greater trochanter of femur
piriformis innervation
anterior rami of S1 and S2
piriformis action
laterally rotates hip joint
abducts hip joint
assists in holding head of femur in acetabulum
obturator internus origin
pelvic surface of ilium and ischium
obturator membrane
obturator internus insertion
greater trochanter of femur
obturator internus innervation
nerve to obturator internus (L5,S1,S2)
obturator internus action
laterally rotates hip joint
assists in holding head of femur in acetabulum
tendinous arch of pelvic fascia
continuous bilateral band running from the pubis to the sacrum along the pelvic floor adjacent to the viscera
ischiocavernosus origin
lateral surface of ischiopubic ramus
ischial tuberosity
ischiocavernosus insertion
embraces crus of penis and clitoris, inserting onto inferior and medial aspects of crus and to perineal membrane medial to crus
ischiocavernosus innervation
muscular (deep) branch of perineal nerve
branch of pudendal nerve
ischiocavernosus action
maintains erection of penis or clitoris by compressing outflow veins and pushing blood from root of penis or clitoris into body
bulbospongiosus (male) origin
median raphe on ventral surface of bulb of penis and perineal body
bulbospongiosus (male) insertion
surrounds lateral aspects of bulb of penis and most proximal part of body of penis, inserting into perineal membrane.
dorsal aspect of corpora spongiosum and cavernosa
fascia of bulb of penis
bulbospongiosus (male) innervation
muscular (deep) branch of perineal nerve
branch of pudendal nerve (S2-S4)
bulbospongiosus (male) action
supports and fixes perineal body/pelvic floor
compresses bulb of penis to expel last drops of urine/semen
assists erection by compressing outflow via deep perineal vein and by pushing blood from bulb into body of penis
bulbospongiosus (female) origin
perineal body
bulbospongiosus (female) insertion
passes on each side of lower vagina, enclosing bulb and greater vestibular gland,
inserts onto pubic arch and fascia of corpora cavernosa of clitoris
bulbospongiosus (female) innervation
muscular (deep) branch of perineal nerve
branch of pudendal nerve (S2-S4)
bulbospongiosus (female) action
“sphincter” of vagina
assists in erection of clitoris
compresses greater vesticular gland
superficial transverse perineal body origin
internal surfaces of ischiopubic ramus & ischial tuberosity
compressor urethrea portion only
superficial transverse perineal body insertion
passes along superior posterior border of perineal membrane to perineal body
superficial transverse perineal body innervation
muscular (deep) branch of perineal nerve
terminal branch of pudendal nerve (S2-S4)
dorsal nerve of penis of clitoris
External anal sphincter origin
skin and fascia surrounding anus and coccyx via anococcygeal ligament
External anal sphincter insertion
passes around lateral aspects of anal canal
inserting into perineal body
External anal sphincter innervation
inferior anal nerve
branch of pudendal nerve (S2-S4)
External anal sphincter action
constructs anal canal during peristalsis
resists defecation
supports and fixes perineal body/pelvic floor
