lecture 1

Question 1

body landmarks of abdomen and pelvis

Answer 1

sternum and xiphoid process; costal margin, costal cartilages and lower ribs; iliac crest, iliac fossa and anterior superior iliac spine (ASIS); pubic symphysis, pubic tubercle and superior pubic ramus; thoracic and lumbar verterbae, sacrum and pelvic bones

Question 2

abdominopelvic cavity: sagittal plane

Answer 2

anteriorly, abdominal and pelvic cavities are continuous; diaphragm separates thoracic and abdominal cavities (upper part of abdominal cavity extends beneath thoracic cage); pelvic inlet (brim) arbitarily separates abdominal cavity from pelvic cavity

Question 3

visceral structures

Answer 3

stomach, duodenum, small and large intestines; liver, pancreas and spleen; kidneys, ureters and urinary bladder; reproductive organs; abdominal vessels

Question 4

what lines mark the 9 regions of abdomen (anterior abdomen wall)

Answer 4

vertical lines from mid-clavicular lines; horizontal lines from subcostal (L2) and intertubercular plane (iliac regions - L5)

Question 5

4 quadrants; what lies in each area

Answer 5

midline through sagital plane; horizontal through umbilical plane

Question 6

antero-lateral abdominal wall surface anatomy

Answer 6

costal margin, xiphoid process, ilial crest, ASIS, pubic symphysis and tubercle; umbilicus, epigastric fossa; rectus abdominis, linea alba (line down sagittal plane in middle of rectus abdominis), linea semilunaris (grooves either side of rectus abdmonis); abdominal wall muscle sheets

Question 7

abdominal wall muscles

Answer 7

anterior wall (rectus abdominis in rectus sheath); lateral wall (3 flat sheet layered muscles: external oblique, internal oblique, transversus abdominis); posterior wall (vertebral column and adjacent muscles, behind which lie erecto spinae muscles, and in front of which lie psoas major muscles of lower limb, quadratus lumborum and iliacus muscles)

Question 8

structure of sheet muscles

Answer 8

separate in flanks (lumbar regions); continue anteriorly as aponeurotic sheets (fibrous) to anterior-midline (linea alba), forming rectus sheath

Question 9

function of three muscles

Answer 9

compress abdomen and increase intra-abdominal pressure to aid expiration, evacuation of urine, faeces, parturition, heavy lifting; supports viscera guarding mainly intestines; flex and rotate trunk in different angles

Question 10

external oblique attachments

Answer 10

external surface at lower 8 ribs; free posterior border (area muscle not attached to anything, posterior are erecto spinae muscles); fans out to attach to xiphoid process, linea alba, pubic crest and tubercle, anterior half of iliac crest; muscle fibres directed downward and forward

Question 11

external oblique and inguinal ligament

Answer 11

fleshy muscle fibre cannot attach directly to bone, so attach by a tendon; aponeurosis tendon fuse medially with rectus sheath at midline, formin linea alba; lower aponeurotic edge rolled inwards to form inguinal ligament: ASIS to pubic tubercle gap connected by inguinal ligament

Question 12

internal oblique attachments

Answer 12

lateral: thoracolumbar fascia, iliac crest (anterior 2/3rd), inguinal ligament (lateral half); medial: lower 3 ribs and costal cartilages, xiphoid process, rectus sheath, conjoint tendon; muscle fibres directed downward and backward

Question 13

transversus abdominis attachments

Answer 13

lateral: lower 6 costal cartilages, thoracolumbar fascia, iliac crest (anterior 2/3rd), inguinal ligament (lateral 1/3rd); medial: xiphoid process, linea alba (rectus sheath), symphysis pubis, conjoint tendon; horizonal layer of muscle fibres; neurovascular structres run between internal oblique and transversus abdominis

Question 14

rectus abdominis attachments

Answer 14

is a long strap muscle of anterior wall enclosed in rectus sheath (most powerful flexer of vertebral column); inferior margin of rib cage; superior attachment: 5-7 costal cartilages, xiphoid process; inferior attachments: pubic crest and symphysis pubis; divided into 4 segments by tendinous intersections (3 on each side), attached to anterior wall of rectus sheath

Question 15

rectus sheath

Answer 15

formed by aponeurosis of 3 muscles; above umbilicus: internal oblique aponeurosis split and encloses rectus abdominis, the aponeuroses of external oblique is in front an transversus abdominis behind rectus muscle; below umbilicus: all 3 aponeurotic layers are anterior to rectus muscle - only transversalis fascia present so weak (C-section here so chance of hernia as weak); rectus sheaths meet in linea alba midline; anterior wall of sheath complete from xiphoid process and costal cartilages to pubic crest and symphysis; posterior wall of sheath is incomplete, stopping short below umbilicus at arcuate line (below is rectus abdominis in contact with transversalis fascia)

Question 16

posterior abdominal muscles

Answer 16

diaphragm above and transversus abdominis laterally; iliacus muscle (in greater pelvis), quadratus lumborum (attached at lower border of 12th rib and transverse process of 5th lumbar vertebra and adjacent iliac crest; stabilises 12th rib and lateral flexor of trunk), psoas major (attached at bodies and discs of all 5 lumbar vertebrae and lesser trochanter of femur; flexor of hip and trunk), lumbo-sacral plexus of nerves (lower limb)

Question 17

blood supply to abdominal wall

Answer 17

nerve supply same as from same segments up to T12; segmental blood supply to flank: intercostal arteries T6-T12 and L1: 7-11, subcostal artery, lumbar arteries, deep circumflex iliac arteries; blood supply of rectus muscle: superior (terminal branch of internal thoracic from pelvic region) and inferior (branch of external iliac from lower limbs) epigastric arteries, entering rectus sheath and anastomose forming potential by-pass to abdominal aorta - if abdominal aorta blocked blood shunts through epigastrics, but not enough to support whole of lower limbs; venous drainage: deep veins with same name as accompanying arteries

Question 18

nerve supply of abdominal wall

Answer 18

segmental innervation T7-T12 and L1, external oblique by T7-T11, internal oblique and transversus abdominis by T7-T12 and L1, rectus by T7-T12; dermatomes: T7 - epigastrium, T10 - umbilicus, L1 - inguinal ligament; same segmental nerves of body wall provide somatic sensory supply to underlying parietal peritoneum; visceral peritoneum has no somatic innervation

Question 19

3 posterior abdominal wall nerves supplying antero-lateral abdominal wall

Answer 19

subcostal nerve - T12, iliohypogastric nerve - L1, ilio-inguinal nerve - L1; motor supply to quadratus lumborum (T12 and L1-L4), psoas major (L2-L4) and iliacus (femoral nerve L2-L4); lumbar plexus (L1-L4) has motos and sensory (lower limbs), with sensory branches to parietal petioneum of posterior abdominal wall

Question 20

lymphatic drainage of abdominal wall

Answer 20

superficial tissues: above umbilicus all drain to axillary lymph nodes (thorax); below umbilicus all drain to superficial inguanal lymph nodes (lower limb); deeper tissues: above umbilicus to mediastinal lymph nodes; below umbilicus to external iliac and para-aortic lymph nodes; no lymph nodes in abdominal wall

Question 21

angle of abdominal cavity

Answer 21

straight down laterally

Question 22

angle of pelvic cavity

Answer 22

angled laterally

Question 23

diagram of abdominopelvic cavity (sagittal plane)

Answer 23

diagram

Question 24

what are the 9 regions of the abdomen (top left to bottom right)

Answer 24

right hypochondrium, epigastric, left hypochondrium, right lumbar, umbilical, left lumbar, right iliac, hypogastric/supra pubic, left iliac

Question 25

what structures lie under each area

Answer 25

living anatomy