The Abdomen

Question 1

Where are lines drawn that separate the four quadrants of the abdomen?

Answer 1

mid-sagittal plane and transumbilical plane (the transverse plane passing through the umbilicus)

Question 2

What are the anterior muscles of the abdomen?

Answer 2

-external oblique -internal oblique -rectus abdominis -transversus abdominis

Question 3

What are the posterior muscles of the abdomen?

Answer 3

-psoas major -quadratus lumborum

Question 4

What are the attachment points of rectus abdominis?

Answer 4

S: costal cartilages of ribs 5-7, xiphoid process I: pubic symphysis and pubic crest

Question 5

What are the actions of rectus abdominis?

Answer 5

-flexes the vertebral column (trunk) -stabilizes the pelvis during leg-lowering -compresses viscera

Question 6

What are the attachments of external oblique?

Answer 6

S/L: ribs 5-12 -upper fibres interdigitate with serratus anterior and lower fibres interdigitate with latissimus dorsi I/M: linea alba (via abdominal aponeurosis), pubic tubercle, anterior 1/2 of iliac crest

Question 7

What’s the fibre direction of external oblique?

Answer 7

anteriorly and inferomedially

Question 8

What are the actions of external oblique?

Answer 8

-(unilateral contraction): rotates column to contralateral side -(unilateral contraction): ipsilateral lateral flexion -(bilateral contraction): trunk flexion -(bilateral contraction): stabilizes the pelvis during leg-lowering -(bilateral contraction): compress and support viscera

Question 9

What are the attachments of internal oblique?

Answer 9

I/L: anterior 1/2 of the iliac crest S/M: linea alba (via abdominal aponeurosis), ribs 10-12 (inferior borders)

Question 10

What’s the fibre direction of internal obliques?

Answer 10

anteriorly and superomedially

Question 11

What are the actions of internal obliques?

Answer 11

-(unilateral contraction): rotates column to ipsilateral side -(unilateral contraction): ipsilateral lateral flexion -(bilateral contraction): trunk flexion -(bilateral contraction): compress and support viscera

Question 12

What are the attachments of transversus abdominis?

Answer 12

L: inner iliac crest, lower 6 costal cartilages, thoracolumbar fascia M: linea alba (via abdominal aponeurosis)

Question 13

What’s the fibre direction of transversus abdominis?

Answer 13

medially

Question 14

What’s the action of transversus abdominis?

Answer 14

compress and support viscera

Question 15

What’s a description of the rectus sheath?

Answer 15

part of the fascia of the abdomen: the aponeurotic attachments of the external oblique, internal oblique and transversus abdominis form a sheath of connective tissue which encases the rectus abdominis muscle; medially, they reconnect to form the linea alba

Question 16

Where does the linea alba run and what does it separate?

Answer 16

part of the fascia of the abdomen: runs vertically from the xiphoid process to the symphysis pubis; separates 2 rectus abdominis muscles

Question 17

Where is the linea semilunaris?

Answer 17

the lateral border of the rectus abdominis and its sheath

Question 18

What are the attachment points of psoas major?

Answer 18

S/P: sides of T12-L5 vertebrae and the associated intervertebral discs I/D: lesser trochanter of the femur

Question 19

What are the actions of psoas major?

Answer 19

-works with iliacus to flex the hip joint -flexes the lumbar spine when you’re already somewhat forward flexed

Question 20

What are the attachment points of quadratus lumborum (QL)?

Answer 20

S: medial 1/2 of rib 12, TVPs of lumbar vertebrae I: iliac crest, iliolumbar ligament

Question 21

What are the actions of quadratus lumborum?

Answer 21

-(bilateral contraction): extends the lumbar spine -(bilateral contraction): fixes 12th rib during forced expiration -(bilateral contraction): stabilizes lumbar spine -(unilateral contraction): if inferior attachment is fixed, ipsilateral lateral flexion; if 12th rib is fixed, hip hike

Question 22

What are the muscles of the posterior wall of the abdomen?

Answer 22

-psoas major -quadratus lumborum (QL)