Abdominal muscles Flashcards
external oblique - proximal and distal attachments
proximal: external surface of ribs 5-12
distal: aponeurosis attaches to linea alba, iliac crest, pubic tubercle, folds to form inguinal ligament
external oblique - function
compression of abdominal cavity stabilization of pelvis ipsilateral side bending contralateral rotation trunk flexion
external oblique - innervation
intercostal nerves T7-T12
what direction do the external oblique muscle fibers run?
superolateral to medio-inferior
“hands in pockets”
internal oblique - proximal and distal attachments
proximal: inferior border ribs 10-12 & thoracolumbar fascia
distal: aponeurosis attaches to linea alba, anterior 2/3 iliac crest, continue in the inguinal ligament (cremaster muscle)
internal oblique - function
core to support abdominal contents and stabilize pelvis
ipsilateral side bending and rotation
trunk flexion
elevate testes
internal oblique - innervation
intercostal nerves T7-T12
2 branches of L1
- iliohypogatric: internal oblique
- ilioinguinal: cremaster part
which way do the internal oblique muscle fibers run?
opposite external oblique
oh my direction
transversus abdominis - proximal and distal attachments
proximal: thoracolumbar fascia
inner surface ribs 7-12
distal: aponeurosis attaches to linea alba, iliac crest, pubic tubercle, folds to inguinal ligament
- slip of muscle fibers interdigit with diaphragm
transversus abdominis - function
increase intrabdominal pressure (compression)
rotate spine
transversus abdominis - innervation
intercostal nerves T7-T12
2 branches of L1:
- iliohypogatric
- ilioinguinal
between which muscle layers do the intercostal nerves run?
between transversus abdominis and internal oblique
rectus abdominis (6 pack) - proximal and distal attachment
proximal: xiphoid process
5-7 costal cartilage
distal: pubic crest
tubercle
pubic symphysis
rectus abdominis - function
compression and stabilizes the pelvis
trunk flexion
rectus abdominis - innervation
intercostal nerves T7-T12
what is the pyramidalis?
small triangular muscle in the distal anterior rectus abdominis
- doesn’t exist in all people
- isn’t on both sides all the time
quadratus lumborum - proximal and distal attachments
proximal: inferior border of 12th rib
lateral transverse process of L1-L4
distal: posterior iliac crest
iliolumbar ligament
quadratus lumborum - function
ipsilateral lumbar side bending (closed chain)
hip lift (open chain)
depress 12th rib to facilitate respiration
quadratus lumborum - innervation
T12-L4 lumbar spinal nerves (ventral rami)
psoas major - proximal and distal attachments
proximal: transverse process, body and discs of T12-L5
distal: lesser trochanter
psoas major - function
hip flexion, external rotation, adduction (open chain)
trunk flexion, side bending (closed chain)
psoas major - innervation
femoral nerve (L2-L4)
