Muscles: Abdomen Flashcards
What are the muscles of the posterior wall of the abdomen?
- Psoas major
- Quadratus lumborum
Psoas Major
COURSE:
- Th. 12, L 1-4 side, L 1-5 cost. proc. > lesser trochanter
ACTION:
- flex and ext. rotate hip
INNERVATION:
- lumbar plexus
Quadratus Lumborum
COURSE:
- internal lip iliac crest & iliolumbal ligament > rib 12, L 1-4 costal processes
ACTION:
- expiration
- flexes spine
INNERVATION:
- lumbar plexus
What muscles form the lateral abdominal wall?
(in order from superficial to deep)
- external obliques
- internal obliques
- transverse abdominals
external obliques
COURSE:
- outside ribs 5-12 (interdigitated w/ serratus and latissimus) > iliac crest & inguinal ligament (via aponeurosis)
ACTION:
- ante/lateral trunk flexion
- lift pelvis
- abd. rotation (to opposite side)
- abd. pressure
INNERVATION:
- intercostal, iliohypogastric and ilioinguinal nerves
interal oblique
COURSE:
- int. line iliac crest, thoracolumbal fascia & inguinal lig. > 3 caudal ribs, linea alba
ACTION:
- ante/lateral flexion
- abd. rotation (own side)
- raise pelvis and abd. pressure
INNERVATION:
- intercostal, iliohypogastric and ilioinguinal nerves
Transverse Abdominis
(forms linea semicircularis (of Douglas))
COURSE:
- int. lip iliac crest & thoracolumbal fascia (direct), inguinal lig. & inside caudal 6 ribs (tendinously) > linea alba (via apo.)
ACTION:
- fixes abd. wall & provides pressure
INNERVATION:
- intercostal, iliohypogastric, ilioinguinal & genitofemoral nerves
What muscles form the medial (anterior group) of abdominal muscles?
- rectus abdominis
- pyramidalis
rectus abdominis
COURSE:
- outer surface costal cartilages 5-7, xipohoid process, interv. ligaments > pubic crest & symph.
ACTION:
- ante/lateral flexion
- raise pelvis
- expiration
INNERVATION:
- intercostal nerves
What is the small green muscle shown here?
Pyramidalis
(absent in 10%)
COURSE:
- pubic symph & crest > linea alba
ACTION:
- tense linea alba
INNERVATION:
- subcostal nerve
What is this line called?
What does it mark?
(Bonus: clinical significance)
Linea Semilunaris
- marks lateral border of rect. abd.
- formed by aponeurosis of int. oblique
(clinically, site of Spigelian hernia)
What is the line marked by the black pointer?
3 names
significance?
Arcuate Line
or Linea Semicircularis or Douglas’ line
- marks the lower limit of the posterior layer of the rectus sheath
(in other words, below this line the aponeuroses of the 3 lateral abdominal muscles only form an anterior sheath around the rectus abdominis)
What does this drawing represent?
Identify its labeled structures.
Rectus Sheath (above arcuate line)
- linea alba
- aponeurosis
- external oblique
- internal oblique
- transvere abominis
- transversalis fascia
- peritoneum
- round ligament of liver
- rectus abdominis
What does this drawing represent?
Identify its numbered structures.
Rectus Sheath (below arcuate line)
- urachus
- external oblique
- internal oblique
- transverse abdominis
- transversalis fascia
- peritoneum
- inferior epigastric artery and vein
- umbilical artery
- middle umbilical fold
- medial umbilical fold
- lateral umbilical fold
- skin
Identify the structures.
- tendinous intersections (of rect. abd.)
- external obliques
- internal obliques
- rectus abdominis
- linea alba
- transverse abdominis
- arcuate line
- semilunar line
- aponeurosis