Week 10: Regional Anatomy: The Abdominopelvic Cavity Flashcards
The abdominopelvic region:
- The anterior region of the trunk between the thoracic diaphragm superiorly and the pelvic diaphragm inferiorly
- Limited by the abdominal wall anteriorly and the vertebral column and muscle posteriorly
- The superficial anterior structures of the abdominopelvic region are referred to as the abdominal wall
Composed of: Skeletal muscle, connective tissue
The abdominopelvic cavity:
- The abdominopelvic cavity is located deep to the abdominal wall
- It is the largest cavity in the body
- It is made up of two individual cavities: Abdominal cavity, pelvic cavity
- Contains organs and tissues that function within various body systems
Major body systems of the abdominopelvic cavity
Digestive
- Mechanical and chemical breakdown of food
- Absorption of digested products from GI tract into blood and lymph
Lymphatic
- Transport of proteins, lipids and fluid to blood
Urinary
- Produces, stores and eliminates wastes and regulates volume and chemical composition of blood
Reproductive
- Production of gametes
Hormone release for regulation of reproduction
Quadrants of the abdominopelvic region:
- One of two methods of categorizing the abdominopelvic region (the other divides into 9 segments)
- Theoretical divisions used to help clinicians to localize, identify and diagnose patient symptoms
- Four quadrants divided by theoretical anatomical lines
- A vertical line that follows the linea alba from the xiphoid process of the sternum down to the pubic symphysis of the pelvis
- Divides the abdominopelvic into left and right halves
- A horizonal line that runs at the level of the umbilicus
Divides the abdominopelvic cavity into an upper and lower hal
Organs of the Abdominopelvic quadrant: Right upper Quadrant
STRRAP GLD
Liver (right lobe), stomach (pylorus), transverse colon (right half), ascending colon (superior portion), duodenum, gallbladder, pancreas, right kidney, right adrenal gland
Left upper quadrant:
JILL PLSTD
Liver (left lobe), stomach, transverse colon (left half), Descending colon (superior portion), Jejunum, Illeum, pancreas (body and tail), left kidney, left adrenal gland, spleen
Right lower quadrant:
BAIRCARURU
Ascending colon (inferior portion), right ureter, bladder, cecum, Ileum appendix, right ovary and uterine tube (F), right ductus deferens (M), uterus (F)
Left Lower Quadrant:
(B)LUDSLULU
Descending colon (inferior portion), left ureter, bladder (when full), sigmoid colon, left ovary and uterine tube (females only), left ductus deferens (males only), Uterus (F)
The Peritoneum:
- A serous membrane that functions to support and protect the abdominopelvic organs
Contains two layers- Outer parietal peritoneum adheres to the anterior and posterior abdominal walls
- Inner visceral peritoneum lines the surface of the abdominopelvic organs
- Technically they are continuous with each other
- The space between the two layers is called the peritoneal cavity
Filled with lubricating fluid to reduce friction between layers during movement
Intraperitoneal and retroperitoneal organs:
- Organs within the abdominopelvic cavity are either located intraperitoneally or retroperitoneally
- Intraperitoneal organs are almost surrounded by visceral peritoneum
Retroperitoneal organs are located behind/posterior to the peritoneum (retro=behind)
- Intraperitoneal organs are almost surrounded by visceral peritoneum
Intraperitoneal organs:
SALT PRSSS
S: Stomach
A: Appendix
L: Liver
T: Transverse colon
P: Pancreas
R: Rectum (superior portion)
S: Small intestine (proximal portion of duodenum, jejunum, ileum)
S: Sigmoid colon
S: Spleen
Retroperitoneal organs:
SAD PUCKER
S: Suprarenal (adrenal) glands
A: Aorta
D: Duodenum (distal portion)
P: Pancreas (except the tail)
U: Ureters
C: Colon (ascending and descending only)
K: Kidneys
E: (O) Esophagus
R: Rectum (inferior portion)
The Mesentery:
- A double layered fold of peritoneum that wraps around and suspends visceral organs from the posterior wall
- Plays a major role in supporting the abdominopelvic organs by anchoring them to the posterior abdominal wall
- A store of fat for energy
- Allows organs to move more relative to one another
Contains the blood vessels, nerves and lymphatic supply of the abdominopelvic visceral organs
The Omenta:
- The omenta are also folds of peritoneum that serve to support organs, store fat and play a role in immune defense
- They are double-layered: Made up of two layers of visceral peritoneum
- They arise from the stomach (and proximal duodenum) and extend to neighboring organs
- There are two subdivision of the omentum depending on whether they extend from the greater or lesser curvature of the stomach
- The lesser omentum
The greater omentum
Lesser Omenta
- Attaches from the hilum of the liver to the lesser curvature of the stomach
Suspends the stomach from the inferior surface of the liver so that when the stomach fills, the force of gravity doesn’t cause the stomach to crush other visceral organs
Greater Omentum:
- Descends from the greater curvature of the stomach and covers the anterior surface of the intraperitoneal organs
Descends and then folds back on itself and ascends, forming a four-layered thick fold and attaches to the transverse colon
Anterior Abdominal Muscles:
- Skin: Anterior
- Lying deep is adipose tissue: Hyper dermis
- Deeper than hyper dermis is skeletal muscle which forms anterior abdominal wall and lateral abdominal wall
- Anterior skeletal muscles help to contain and protect abdominal visceral, they laterally flex and rotate vertebral column.
- They produce force to remove contents from the body e.g. urination, defecation, child birth
- Each external, internal oblique and transverse muscles contains tendons which are referred to aponeurosis: Include rectus abdominus muscle
These meet in the midline to form a tough fibrous band extending from the xiphoid process to the pubic symphysis
External oblique:
- Largest and most superficial of the anterolateral abdominal muscles
- 5-12th ribs, inserts into linea alba and iliac crest
The main function of this muscle is to compress the abdomen and flex vertebral column
- 5-12th ribs, inserts into linea alba and iliac crest
Internal obliques:
- Thin muscle sheet fanning out anteromedially
- Fibers run perpendicular to external oblique
- Origin is the iliac crest, inguinal ligament and the thoracolumbar fascia
- Insertion is cartilage of ribs 7-10 and linea alba
Key function: Compress abdomen and flex the vertebral column
Transverse abdominis:
- Inner most of the three flat abdominal muscles and the fiber orientation are ideal for compressing the abdominal contents and increasing abdominal pressure and its origins are the iliac crests, the inguinal ligaments, lumbar fascia and the cartilages of ribs 5-10 with insertion in the xiphoid process, linea alba and pupas
Main function: To compress the abdomen
Rectus abdominis:
- Main vertical muscles of the anterior abdominal wall
- The origins are the pubic crest and pubic symphysis and insertion is the cartilage of ribs 5-7 and xiphoid process
Main function: Flex the vertebral column, compress abdomen to aid in expulsion from the body (defecation, urination, child birth)
- The origins are the pubic crest and pubic symphysis and insertion is the cartilage of ribs 5-7 and xiphoid process
Abdominal aorta:
- Enters into abdominal cavity by piercing abdominal diaphragm
- AA arises from the descending aorta is the major artery in the abdominal cavity and lies left of VC and against posterior body wall
- It begins at aortic hiatus in diaphragm and ends at level of 4th lumbar vertebrae
- Gives rise to visceral and parietal branches the unpaired visceral branches arise from the anterior surface of aorta and include the celiac trunk, superior mesenteric and inferior mesenteric arteries
- These unpaired arteries supply the visceral organs of the digestive system
Developmentally, these digestive system is divided into 3 sections: Fore gut, mid gut, hind gut. Give rise to organs of the digestive system
Celiac trunk: SPLEDS
Supplies the foregut organs: Lower end of esophagus, stomach, duodenum, liver, pancreas, spleen
Superior mesenteric artery: JICAAT
- Supplies the midgut
Jejunum, ileum, caecum, appendix, ascending colon, proximal 2/3 of transverse colon
Inferior mesenteric artery: RASDT
- Supplies the hindgut
- Rectum, sigmoid colon, descending colon, distal 1/3 of transverse colon
- Supplies proximal part of anus
- Small intestine is not all derived from same embryological structure
- 1st part: Duodenum from the foregut and supplies celiac trunk
- The rest of the small intestine: Jejunum and ileum being derived from the midgut
Being supplied by superior mesenteric artery
Large intestine:
- Two embryological structures from both midgut and hind gut
Therefore being supplied by both superior and inferior mesenteric artery
Blood supply to upper organs of abdominopelvic cavity
- Inferior phrenic arteries: underside of the thoracic diaphragm and the adrenal glands
- Suprarenal arteries: Suprarenal glands or adrenal glands
- Large renal arteries: Kidneys
- Gonadal arteries: Gonads-ovaries or testes
Lumbar Arteries: posterior abdominal wall
Blood drainage of abdomen:
Portal Venous system:
- All blood from lower limbs, pelvis and abdomen needs to get back to the heart and is done by heaps of different branches that converge into the inferior vena cava
- The inferior vena cava will leave the abdominal cavity through the thoracic diaphragm and take blood back to the heart
- First though it needs to be taken to the liver for processing and sorting before going back into circulation
- Inferior mesenteric vein: Drains blood from transverse colon, descending colon, sigmoid colon and rectum
- Superior mesenteric vein: Drains blood from the Jejunum, ileum, the caecum and appendix, the ascending colon as well as most of the transverse colon
- Large splenic vein: Spleen as well as receiving smaller veins draining blood from the duodenum, the gall bladder parts of the stomach and parts of the pancreas
- Portal venous system drains into large Hepatic portal vein then to the liver and then to the inferior cava to the heart
- Blood goes from liver to inferior vena cava which pierces the diaphragm to go back into the thoracic cavity and deliver blood to the heart
Mesentery:
- Double sheet of peritoneum that helps suspend visceral organs
- Support: Anchor viscera to abdominal wall e.g. small intestine (usually posterior) and allow movement of viscera, stores fat
Plumbing and wiring: Conveys neurovascular structures to/from viscera
- Support: Anchor viscera to abdominal wall e.g. small intestine (usually posterior) and allow movement of viscera, stores fat
Omenta:
- Double layers fold (apron) of peritoneum
- Arise from stomach or proximal duodenum
- Greater and lesser Omentum
- Lesser attaches from the hilum of the liver to the lesser curvature of the stomach, it is a double fold of the peritoneum, one layer of visceral peritoneum squashed to another, suspends stomach from inferior surface of the liver so when the stomach fills with food the force of gravity doesn’t make the stomach drop and squash organs
- Stores fat, contains macrophage deposits, isolates infections
Greater: Larger of them both, double layer of peritoneum that descends from the greater curvature of stomach to form an apron anterior to the other intraabdominal organs, end up with four layers of peritoneum stuck together.
Anterolateral abdominal wall
- The abdominal wall is made up of skeletal muscle and connective tissue, both of which are soft tissue
- Skeletal muscles are important for increasing the pressure ding various physiological processes like respiration, defecation, micturition and changing the size of the stomach after feeding
The flexibility of soft tissue walls allows for abdominal distension during pregnancy and obesity
- Skeletal muscles are important for increasing the pressure ding various physiological processes like respiration, defecation, micturition and changing the size of the stomach after feeding
Posterior thoracic and abdominal walls:
- The posterior thoracic and abdominal walls are made up of spinal vertebrae and back muscles the largest group being the erector spinae
The bones of the spine (hard tissues) provide stability and support for the trunk, while the skeletal muscles of the posterior thoracic and abdominal walls produce reinforce stability of the spine and facilitate movement
In which quadrant of the abdominopelvic cavity do you find the gallbladder?
Right Upper
What is the name of an abdominal structure that plays a role in the storage of fat around the visceral organs?
The Mesentary
Which of the following visceral organs would be located behind the peritoneum?
Kidneys
After cutting through the muscles to expose the appendix, what would you expect to have to cut through first?
The Peritoneum
What artery would normally supply the region where the appendix is located?
The Superior Mesenteric Artery
What are the acronyms for the blood supply, quadrants intraperitoneal/retroperitoneal?
Inferior mesenteric artery: RASDT
Celiac trunk: SPLEDS
Superior mesenteric artery: JICAAT
Right upper Quadrant:
STADG PRRL
Right lower:
BIARACURU
Left upper quadrant:
JILL PLSTD
Left Lower Quadrant:
(B)LUDSLULU
Retroperitoneal: SAD PUCKER
Intraperitoneal: SALT PRSS
Which of the following options CORRECTLY identifies the (A) superior landmark, and (B) inferior landmark that, together, divide the abdominopelvic cavity into left and right halves?
Xiphoid process, pubic symphysis
