Abdomen, Pelvis and Perineum Part 1 Flashcards
What are the superior & inferior boundaries of the abdominal cavity?
- Superior limit: Diaphragm
- Inferior limit: No inferior limit - continues with the pelvic cavity
The abdominal can be divided in to 4 quadrants. Name them starting from the most superolateral point and going clockwise.
- Right upper quadrant
- Left upper quadrant
- Left lower quadrant
- Right lower quadrant
What lines divide the abdomen into 4 quadrants?
- Transumbilical plane
- Median plane
The abdominal can be divided in to 9 regions. Name them starting from the most superolateral point and going S - shaped.
- Right hypochondrium
- Epigastric
- Left hypochondrium
- Left lumbar
- Umbilical
- Right lumbar
- Right inguinal
- Pubic
- Left inguinal
What lines divide the abdomen into 9 regions?
- Left & Right Midclavicular line
- Subcostal plane
- Intertubercular plane
What are the main characteristics of Lumbar Vertebra (5)?
- Large size
- Lack facets for articulation with ribs
- The transverse processes are generally thin and long, with the exception of those on vertebra L5, which are massive and somewhat cone shaped for the attachment ofiliolumbar ligamentsto connect the transverse processes to the pelvic bones.
- The vertebral body of a typical lumbar vertebra is cylindrical
- The vertebral foramen is triangular in shape and larger than in the thoracic vertebrae
Name the ligament
Inguinal ligament
Strong band of tendonous tissue that joins the anterior superior iliac spine to the pubic tubercule
Lowest part of the external oblique aponeurosis
What are the 2 rings found on the ends of the inguinal canal?
- Superficial inguinal ring
- Deep inguinal ring
What structures go through the inguinal canal (5)?
- Spermatic cord (males)
- Testicular artery (males)
- Testicular vein (males)
- Round ligament (females)
- Genitofemoral nerve (both)
Which muscles make up the posterior wall of the abdomen? (Posterior to Anterior)
- Erector spinae muscles
- Quadratus lumborum muscle
- Psoas major
- Psoas minor
Name the muscle
Quadratus lumborum muscle
What is the origin of the quadratus lumborum muscle muscle?
- Iliac crest
- Iliolumbar ligament
What is the insertion of the quadratus lumborum muscle?
- Inferior border of the 12th rib
- Transverse processes of L1 - L4
What is the action of the quadratus lumborum muscle?
- Extends & laterally flexes trunk
- Stabilises 12th rib during inspiration
What is the innervation of the quadratus lumborum muscle?
- Anterior rami of T12
- Spinal nerves L1 - L4
What is the arterial blood supply of the quadratus lumborum muscle?
- Lumbar artery
- Subcostal artery
- Lumbar branch of iliolumbar arteries
Name the muscle
Psoas major muscle
What is the origin of the psoas major muscle muscle?
- Transverse processes of L1 - L5
- Vertebral bodies of T12 - L5
What is the insertion of the psoas major muscle?
Lesser trochanter of femur
What is the action of the psoas major muscle?
- Flexes thigh at hip joint
- Flexes trunk
What is the innervation of the psoas major muscle?
- Anterior rami of spinal nerves L1 - L3
What is the arterial blood supply of the psoas major muscle?
- Lumbar artery
- Lumbar branch of iliolumbar arteries
- Obturator artery
- External iliac artery
- Femoral artery
Name the muscle
Iliopsoas muscle
How is the iliopsoas muscle formed?
The medial fibres of the iliacus and the lateral fibres of the psoas major join forming the iliopsoas
Where does the iliopsoas major muscle insert?
Passes under the inguinal ligament and backwards to insert at the lesser trochanter of the femur
What structure covers the iliopsoas muscle?
Ilio-psoas fascia
Name the muscle
Iliacus muscle
What is the origin of the iliacus muscle?
- Iliac crest
- Iliac fossa
- Ala of sacrum
- Anterior sacroiliac ligaments
What is the insertion of the iliacus muscle?
Lesser trochanter of femur
What is the action of the iliacus muscle?
- Flexes thigh at hip joint
- Flexes trunk
What is the innervation of the iliacus muscle?
Femoral nerve L2 - L3
What is the arterial blood supply of the iliacus muscle?
- Iliac branch of iliolumbar arteries
- Deep circumflex iliac artery
- Obturator artery
- Femoral arteryc
Name the muscle
Psoas minor muscle
What is the origin of the psoas minor muscle muscle?
Vertebral bodies of T12 - L1
What is the insertion of the psoas minor muscle?
Iliopectineal eminence & pecten pubis of hip bone
What is the action of the psoas minor muscle?
Assists flexion of trunk
What is the innervation of the psoas minor muscle?
Anterior ramus of spinal nerve L1
What is the arterial blood supply of the psoas minor muscle?
Lumbar artery
Which muscles make up the lateral & anterior wall of the abdomen? (Anterior to Posterior)
- Rectus abdominis muscle
- External abdominal oblique muscle
- Internal abdominal oblique muscle
- Transversus abdominal oblique muscle
Name the muscle.
Rectus abdominis muscle
What is the origin of the rectus abdominis muscle?
- Pubic crest
- Pubic symphysis
What is the insertion of the rectus abdominis muscle?
- Xiphoid process
- Costal cartilage of 5th to 7th ribs
What is the action of the rectus abdominis muscle?
- Flexes trunk
- Compresses & provides structural support to adjacent abdominal structures
What is the innervation of the rectus abdominis muscle?
Anterior rami of T6 - T12
What is the arterial blood supply of the rectus abdominis muscle?
Superior & Inferior epigastric arteries
Name the structure
Anterior rectus sheath
Firmly attached to the tendonous intersections of the rectus abdominis muscle.
The anterior rectus sheath & the posterior rectus sheath both meat at the linea alba (the midline).
Name the muscle
External abdominal oblique muscle
What is the origin of the external abdominal oblique muscle?
External surfaces and inferior borders of 5th - 12th ribs
What is the insertion of the external abdominal oblique muscle?
- Anterior superior iliac spine
- Anterior half of iliac crest
- Pubic crest
- Pubic tubercule
- Linea alba
What is the action of the external abdominal oblique muscle?
- Flexes, laterally flexes & rotates trunk
- Compresses & provides structural support to adjacent abdominal structures
What is the innervation of the external abdominal oblique muscle?
Anterior rami of T7 - T12
What is the arterial blood supply of the external abdominal oblique muscle?
- Lower posterior intercostal artery
- Subcostal artery
- Circumflex artery
- Superior & Inferior epigastric arteries
Where does the external abdominal oblique muscle end?
At the external oblique aponeurosis tendon
Name the muscle.
Internal abdominal oblique muscle
What is the origin of the internal abdominal oblique muscle?
- Thoracolumbar fascia
- Iliac crest
- Inguinal ligament
What is the insertion of the internal abdominal oblique muscle?
- Inferior margins of 10th - 12th ribs
- Linea alba
- Pecten pubis
What is the action of the internal abdominal oblique muscle?
- Flexes, laterally flexes & rotates trunk
- Compresses & provides structural support to adjacent abdominal structures
What is the innervation of the internal abdominal oblique muscle?
- Anterior rami of T7 - T12
- Iliohypogastric nerve
- Ilioinguinal nerve
What is the arterial blood supply of the internal abdominal oblique muscle?
- Lower posterior intercostal artery
- Subcostal artery
- Deep circumflex artery
- Superior & Inferior epigastric arteries
Where does the internal abdominal oblique muscle end?
At the internal oblique aponeurosis tendon
Name the muscle.
Transversus abdominal oblique muscle
What is the origin of the transversus abdominal oblique muscle?
- Costal cartilages of 7th - 12th ribs
- Thoracolumbar fascia
- Iliac crest
- Inguinal ligament
What is the insertion of the transversus abdominal oblique muscle?
- Linea alba
- Pubic crest
- Pecten pubis
What is the action of the transversus abdominal oblique muscle?
Compresses & provides structural support to adjacent abdominal structures
What is the innervation of the transversus abdominal oblique muscle?
- Anterior rami of T7 - T12
- Iliohypogastric nerve
- Ilioinguinal nerve
What is the arterial blood supply of the transversus abdominal oblique muscle?
- Lower posterior intercostal artery
- Superficial & Deep circumflex artery
- Superior & Inferior epigastric arteries
Where does the transversus abdominal oblique muscle end?
At the transversus aponeurosis tendon
What is the inner lining of the abdominal cavity?
Parietal peritoneum
What are the two main arteries of the anterior abdominal wall?
- Inferior epigastric vessels
- Superior epigastric vessels
What is the innervation of the anterolateral abdominal wall?
Intercostal nerves from T7 - T12 (mixed)
What is the innervation of the posterior abdominal wall?
- Subcostal nerve (Sensory)
- Ilio-hypogastric nerve (Mixed)
- Ili-inguinal nerve (Sensory)
- Lateral cutaneous nerve of the thigh (Sensory)
- Genito-femoral nerve (Sensory)
- Femoral nerve (Motor)
- Obturator nerve (Motor)
- Sympathetic trunk (Sensory)
- Sympathetic ganglion (Sensory)
- Right vagus nerve (Sensory)
Outline the gastrointestinal tract.
- Mouth
- Oesophagus (through the oesophageal hiatus of the diaphragm)
- Stomach
- Duodenum
- Jejunum
- Ileum
- Cecum
- Ascending colon
- Transverse colon
- Descending colon
- Sigmoid colon
- Rectum
- Anal canal
What are the 3 main sections of the gastrointestinal tract?
- Foregut
- Midgut
- Hindgut
Outline the development of the midgut.
- As the midgut develops, it protrudes into the yolk stalk forming a loop, with the superior mesenteric artery forming the axis of the loop.
- As it protrudes the midgut loop makes a quarter turn counter - clockwise, so its distal part is to the the left & its proximal part is to the right.
- The distal part of the loop develops a bulge that will become the cecum and the proximal part of the loop become quite convoluted
- During this time the body grows and allows the midgut to return into the abdomen. The proximal part of the loop returns first. It passes under the distal part, and over to the left. The distal part passes in front of the proximal part and ends up over to the right
Name the structure.
Stomach
Where do the oesophagus & the stomach connect (1)?
Oesphago - gastric junction
Where do the oesophagus & the duodenum (2)?
Pylorus
What is the part of the stomach leading to the pylorus (3)?
Pyloric antrum
What are the two curves of the stomach called?
- Greater curve (Yellow)
- Lesser curve (Green)
What is the upward & backward bulge of the stomach called?
Fundus (4)
Outline the structure of the stomach going from superficial layer to inner layer.
- Smooth muscle layer:
- Forms a highly effective sphincter in the pylorus
- Mucosa:
- Form a party effective sphincter in the oesophagogastric junction
- Prominent longitudinal folds in the pyloric antrum
What structure is attached on the greater curve of the stomach?
Greater omentum
Where does the greater omentum attach?
- Greater curve of the stomach
- Transverse colon
What is the part of the greater omentum between the stomach and the transverse colon?
Gastrocolic Ligament
What structure is attached on the lesser curve?
Lesser omentum
Where does the lesser omentum end?
- On the underside of the liver and the diaphragm
- Forms a bag-like structure called omental bursa / lesser sac
What is the opening of the lesser sac called?
Epiploic foramen
Name this part of the small intestine.
Duodenum
Where does the duodenum end?
Duodeno-jejunal flexure
How many parts does the duodenum have?
4
What structure does the duodenum surround?
The head of the pancreas
What structures empty into the duodenum?
- Pancreatic duct
- Common bile duct
What are the two peritoneal attachments of the duodenum (proximally & distally)?
- Proximally: Distal part of the lesser omentum
- Distally: Suspensory ligament
What part of the small intestine follows the duodenum?
Jejuno - ileum (6m length)
What structure acts as superior & lateral boundary of the jejuno - ileum?
- Ascending colon
- Transverse colon
- Descending colon
What peritoneal structure attaches the jejuno - ileum to the posterior abdominal wall?
- Mesentery
- Blood supply traveling through the mesentery is arranged in arcades (Single arch is an arcade)
- Attached all the way from the last part of the duodenum to the cecum
Describe the mucosa of the jejuno - ileum.
- Thrown into folds that project into the lumen
- More pronounced in the jejunum than the ileum
- Carpet of minute projections called villi (increase the absorptive surface area of the jejuno - ileum)
Where does the ileum end?
When it attached to the cecum at the ileocecal valve
What is the first part of the large intestine?
Caecum
What is the name of the valve between the large and small intestine?
Ileo - cecal valve
Not an effective one way valve
What structure is attached to the cecum?
Appendix
What are the four parts of the the colon?
- Ascending colon (Yellow)
- Transverse colon (Green)
- Descending colon (Blue)
- Sigmoid colon (Pink)
Where does the ascending colon end & the transverse colon start?
Right colic (hepatic) flexure
Where does the transverse colon end & the descending colon start?
Left colic (splenic) flexure
Where does the sigmoid colon end?
S3 level, where it merges with the rectum
What is the parietal peritoneum that attaches the the colon to the abdominal walls called?
Mesocolon
What are the differences between the small & large intestine?
- The longitudinal muscle is continuous in the small intestine, not in the large intestine. It’s gathered into strips called Tenia(e) coli (Green parts)
- The large intestine is divided into haustra (outward bulges divided by mucosal folds), whereas the small intestine is not.
- There are no villi in the large intestine, unlike the small intestine.
Where does the rectum end?
Pelvic diaphragm formed by the levator ani muscle
What happens to the rectum after it goes through the pelvic diaphragm?
It becomes the anal canal
Where does the anal canal end?
Anus
What is the angulation between the rectum and the anal canal called?
- Perineal flexure
- Maintained by the forward pull of the levator ani muscle
How is the closure of the anal canal maintained?
Internal & external anal sphincter muscles
What are the characteristics of the internal sphincter muscle?
- Involuntary
- Runs the posterior 2/3 of the anal canal
What are the characteristics of the internal sphincter muscle?
- Voluntary
- Runs throughout the anal canal
