Abdomen 9A Flashcards
Abdominal Cavity
A. Located between thoracic diaphragm & pelvic inlet
B. Lower ribs, muscular abdominal wall and pelvis protect viscera of abdomen
Two systems to describe location of structures in the Abdomen
9 Region System
Quadrant System
9 Region System
a. 2 horizontal planes
• transtubercular plane (level of iliac tubercles and body of L5)
• subcostal plane (level of inferior borders of 10th costal cartilage on each side)
b. 2 vertical planes
• R/L midclavicular plane
Naming the 9 Regions
• Center “column” (listed superior to inferior) (i) Epigastric (ii) Umbilical (iii) Hypogastric • Right and left lateral columns (listed superior to inferior) (i) Hypochondriac (R & L) (ii) Lumbar (R & L) (iii) Inguinal (R & L)
Quadrant System
a. horizontal plane
• transumbilical plane (level of umbilicus and L3-4 disc space)
b. vertical plane
• median plane
RUQ contains
(i) Liver/gallbladder,
(ii) pylorus of stomach, duodenum, large intestine – ascending & R ½ of transverse
(iii) head of pancreas
(iv) R kidney
LUQ contains
(i) L lobe of liver, jejunum & proximal ileum, large intestine – descending & L ½ of transverse
(ii) spleen
(iii) body & tail of pancreas
(iv) L kidney
RLQ contains
(i) Cecum, inferior portion of ascending LI, appendix
(ii) R ureter, bladder (if distended)
(iii) Some reproductive structures
1. Female: R ovary, R uterine tube, uterus if enlarged
2. Male: spermatic cord – abdominal part
LLQ contains
(i) Sigmoid colon, inferior portion of descending LI,
(ii) L ureter, bladder (if distended)
(iii) Some reproductive structures
1. Female: L ovary, L uterine tube, uterus if enlarged
2. Male: spermatic cord – abdominal part
Abdominal Wall
A. Technical divisions = anterior, lateral (flank) and posterior abdominal wall
B. However, for descriptive and functional purposes….anterolateral wall and posterior abdominal wall
Anterolateral Abdominal Wall (Clinical)
- patient presents with complaint of pain and noticeable bulge in the anterior groin region, increases with coughing and lifting …possible diagnosis?
a. Indirect inguinal hernia…bowel protrudes through inguinal canal into spermatic cord
b. Bowel pierces through weakened area of transverse fascia
2 Layers of Peritoneum
• Serous membrane that invests the abdominal structures
(i) Parietal layer - lines the wall of the abdominopelvic cavity
(ii) Visceral layer – covers the gastrointestinal structures
Transverse fascia
lines inner portion of the transverse abdominal muscle
• Continuous with linea alba
Superficial fascia composed of 2 layers of anterolateral wall
• Fatty layer = Camper’s fascia
• Membranous layer = Scarpa’s fascia….this is the inner layer & lacks fat
(i) This layer is continuous with other fascia layers in the perineum & reproductive organs (penis, clitoris & scrotum)
Multilayered wall of anterolateral wall of the abdomen
a. Skin
b. Superficial fascia composed of 2 layers
c. Deep fascia that invests the muscles of the abdominal wall
d. Muscles of the abdominal wall
e. Transverse fascia
f. Layer of extraperitoneal fat
g. 2 Layers of Peritoneum
external oblique (O,I,N,A)
(i) O: ribs 5-12 (external surfaces)
(ii) I: linea alba, pubic tubercle and anterior ½ of iliac crest
(iii) N: thoracic nerves (T5-12) Note: T12 is named the subcostal nerve
(iv) A: flex & rotate trunk, compress viscera (assists with expiration), support viscera/spine
(v) NOTE: inferior aponeuroses folds back on itself to form the inguinal ligament
Internal Oblique (O, I, N, A)
(i) O: thoracolumbar fascia, anterior 2/3 of iliac crest, lateral ½ of inguinal ligament
(ii) I: ribs 10- 12, linea alba, pectin pubis
(iii) N: thoracic nerves (T6-12) and first lumbar nerves
(iv) A: flex & rotate trunk, compress viscera (assists with expiration), support viscera/spine
transverse abdominal (O, I, N, A)
(i) O: costal cartilage of ribs 7 –12, thoracolumbar fascia, iliac crest, lateral 1/3 of inguinal ligament
(ii) I: linea alba, pectin pubis, pubic crest
(iii) N: thoracic nerves (T6-12) and first lumbar nerves
(iv) A: compress viscera (assists with expiration), support viscera/spine
rectus abdominis (O, I, N, A)
(i) O: costal cartilage of ribs 5 - 7, xiphoid process
(ii) I: pubic symphysis and pubic crest
(iii) N: thoracic nerves (T6-12)
(iv) A: flexes trunk, compress viscera (assists with expiration), support viscera/spine
3 Muscles of the Abdominal Wall
anterolateral wall
rectus sheath
linea alba
5 muscles of the Anterolateral wall
rectus abdominis transverse abdominal internal oblique external oblique pyramidalis
Rectus Sheath
• formed aponeuroses by the external oblique, internal oblique & transverse abdominal
• encloses rectus abdominis
• arcuate line (located between the level of the umbilicus & the pubic symphysis)
(i) above – posterior portion of rectus sheath covers the rectus abdominis
(ii) below – the rectus sheath travels anterior to rectus abdominis
Linea Alba
- Fibrous band of connective tissue located between the R/L rectus abdominis muscles
- Attachment for the oblique and transverse abdominal muscles
Inguinal Ligament
a. extends between ASIS (anterior superior iliac spine) and pubic tubercle
b. formed by the folded aponeurosis of external oblique
Clinical Implications of the Inguinal Canal
• Indirect inguinal hernia
(i) Bowel protrudes through deep ring and descends through canal
• Direct inguinal hernia
(i) Bowel protrudes through defect in anterior abdominal wall
(ii) Most common site of defect is Hesselbach’s triangle
(iii) Where is Hesselbach’s triangle?
1. Lateral border of rectus abdominis
2. Inguinal ligament
3. Inferior epigastric artery and vein
2 Openings to the Inguinal Canal
- Superficial (external) ring: formed by an arch in the external oblique aponeurosis
- Deep (internal) ring: formed by transverse fascia
Canal is formed by the connective tissue of the abdominal wall (4)
- Anterior: aponeurosis of external & internal oblique
- Posterior: transverse fascia
- Superior: fibers of the transverse abdominal and internal oblique arch over
- Inferior: inguinal ligament (remember formed by the inferior fold of external oblique)
Contents of the Inguinal Canal depending on Gender
- Males: spermatic cord and ilioinguinal nerve
* Female: round ligament of uterus and ilioinguinal nerve
Peritoneal cavity
- thin potential space between the visceral and parietal peritoneum
- NOTE: the peritoneal cavity is NOT same as the abdominal cavity the peritoneal cavity is within the abdominal cavity
Mesentery
- double layered fold of peritoneum d/t the organ invaginating on the peritoneum (again…visualize the pressing in on a balloon)
- “suspends” or connects the organ to the posterior abdominal wall
- Contains blood vessels, lymphatic vessels and nerves that supply structure suspended by the mesentery
Greater omentum
peritoneal fold that hangs down from the greater curvature of the abdomen and loops back up to attach to the transverse colon
Lesser omentum
double layer of peritoneum that attaches to the stomach (and proximal duodenum) and then attaches to the liver
Peritoneal ligament
doubled layer of peritoneum that attaches an organ to the abdominal wall or another organ…two examples are….
• Falciform ligament…attaches liver to anterior abdominal wall
• Gastrosplenic ligament…attaches spleen to the stomach
Peritoneum and Peritoneal Cavity
a. Parietal layer – lines internal walls of abdominopelvic cavity
b. Visceral layer – lines the abdominal viscera
c. Mesentery
d. Greater omentum
e. Lesser omentum
f. Peritoneal ligament
g. Peritoneal cavity
h. Retroperitoneal vs intraperitoneal space
3 Divisions of the Abdominal Viscera
Foregut
Hindgut
Midgut
Hindgut
a. distal 1/3 of transverse colon to anus
b. Blood supply - inferior mesenteric artery