Surface anatomy and muscles of abdominal wall

Question 1

what are the 4 regions the abdomen can be divided into?

Answer 1

R & L upper quadrant

R & L lower quadrant

Question 2

What are the 9 regions the abdomen can be divided into?

Answer 2

L & R hypochondrium and epigastrium
L & R lumbar and periumbillical
L & R iliac fossa and hypogastrium

Question 3

what are the 2 imaginary lines used to divide the abdomen into 4 quadrants?

Answer 3

median line

transumbillical line

Question 4

what are the 4 imaginary lines used to divide the abdomen into 9 regions?

Answer 4

R & L midclavicular planes
transcostal plane
transtubercular plane

Question 5

what are the 3 flat muscles which constitute the anterior-lateral abdominal wall?

Answer 5

internal and external oblique

transversus abdominis

Question 6

in what orientation are the internal, external obliques and transverses abdomens arranged?

Answer 6

external oblique = superior to inferior medially
internal oblique = inferior to superior medically
transversus abdominis = transverse lines laterally

Question 7

what is the nerve innervation of the transverses abdomens?

Answer 7

thoracic abdominal nerves
subcostal nerve
1st lumbar nerves

Question 8

what is the nerve innervation of the oblique muscles?

Answer 8

both innervated by thoracic-abdominal nerves T7-T11 and subcostal nerves
internal also innervated by 1st lumbar nerves

Question 9

what is the action of the oblique muscles?

Answer 9

compresses and supports the abdominal viscera

flex and rotate the trunk

Question 10

what is the action of the transverses abdominis muscles?

Answer 10

compres and supports the abdominal viscera

Question 11

how is the rectus abdominis muscle arranged?

Answer 11

3 pairs of muscles arranged in a horizontal plane

Question 12

what is the action of the rectus abdominis?

Answer 12

compresses abdominal viscera
flexes trunk
stabilises and controls tilt of the pelvis

Question 13

what covers the rectus abdominis muscles?

Answer 13

the rectus sheath

Question 14

what is the rectus sheath?

Answer 14

an aponeurosis formed from the internal & external obliques and transverses abdominis muscles

Question 15

how does the rectus sheath differ above and below the umbilicus ?

Answer 15

above the umbilicus the anterior rectus sheath envelopes the rectus abdominis muscles therefore the muscle is covered by rectus sheath posteriorly.
below the umbilicus, all 3 muscles form the aponeurosis (rectus sheath) anterior to the rectus abominis therefore covering it posteriorly is the transversals fascia

Question 16

what thoracic spinal segments innervate the anterior abdominal wall?

Answer 16

T7-T11