Surface Anatomy - Abdomen Flashcards
How can we define the quadrants of the abdomen?
One vertical line through the umbilicus
One horizontal line through the umbilicus
How can we define the 9 regions of the abdomen?
Draw the 2 midclavicular lines: - From midpoint of clavicle - To midpoint of inguinal ligament - On both sides Draw the transpyloric plane: - Horizontally from level of tips of 9th costal cartilages Draw the transtubercular line: - Horizontally across tubercles of iliac crest (upper L5 VB)
What is the superior boundary of the abdomen?
The thoracic outlet:
- Xiphoid process
- Costal margin
What rib forms the lowest part of the costal margin?
Rib 10
Where is the tip of rib 11 palpable?
Just anterior to midaxillary line
Where is the tip of rib 12 level with?
Spinous process of L1
What forms the inferior boundary of the abdomen?
Pubic bones
What forms the posterior boundary of the abdomen?
Lumbar vertebral bodies
How can the spinous processes be more easily palpated?
By asking someone to lie prone and placing a pillow under their abdomen
Where can the transverse processes of lumbar vertebrae be palpated?
5cm lateral to spinous processes
Just beyond bulk of erector spinae muscles:
- Deep palpation = May be uncomfortable
What muscles form the walls of the abdominal cavity?
External obliques Internal obliques Transversus abdominis Rectus abdominis Quadratus lumborum
What muscle forms the roof of the abdominal cavity?
Diaphragm
What muscle forms the floor of the abdominal cavity?
Pelvic diaphragm
What muscles of the abdomen cannot be palpated? Why?
Roof (diaphragm)
Floor (pelvic diaphragm)
They are too deep
How can rectus abdominis be palpated?
Ask someone to lie supine
Place one hand above and one hand below of their umbilicus
Ask them to raise their head and shoulders off floor
A column of muscle either side of the midline = Rectus abdominis
How can the right external oblique be palpated?
Ask someone to lie supine
Ask them to rotate their trunk to the left
Oppose rotation by holding their right shoulder gently
Palpate near right iliac crest = Attachment of right external oblique will tighten
How can the left internal oblique be palpated?
Ask someone to lie supine
Ask them to rotate their trunk to the left
Oppose rotation by holding their right shoulder gently
Palpate between left iliac crest and umbilicus
How can quadratus lumborum be palpated?
Ask someone to lie prone
Ask them to raise shoulders
Anterior border of quadratus lumborum can be palpated just posterior to the midaxillary line
How can the erector spinae be palpated?
Ask someone to lie prone
Ask them to raise their head and shoulders
Palpate just lateral to lumbar spines
Why can most of the large neurovascular structures of the abdomen not be palpated?
Lie too deep within abdominal cavity
Why can the deep and superficial nerves of the abdomen not be palpated?
Deep nerves are too deep to palpate
Superficial nerves are too small to palpate
What are the superficial nerve branches to the abdominal wall?
Anterior and lateral cutaneous branches of: - Thoracoabdominal (T7-T11) nerves - Subcostal (T12) nerve Cutaneous branches of: - Iliohypogastric (L1) nerve - Ilioinguinal (L1) nerve
How can the aorta be palpated?
Compress against lumbar vertebrae by pressing down with both hands just lateral to midline
What are the surface markings of the abdominal aorta?
Vertical line to left of midline of the trunk:
- Runs from 2.5cm above transpyloric line
- Runs to 2.5cm below supracristal plane
What is the supracristal plane?
A transverse plane roughly at the level of L4 vertebra
What happens to the aorta at the supracristal plane?
Bifurcates into the common iliac arteries
At what level does the aorta enter the abdominal cavity? Via what and with what other structures?
T12 Via aortic hiatus of diaphragm With: - Azygos vein - Thoracic duct
Can the large veins of the abdomen be palpated?
No - they are too deep
What are the surface markings of the IVC?
Vertical line just to right of midline:
- From 2.5cm below supracristal plane (union of common iliac veins)
- To just above right 6th costal cartilage
At what level does the IVC leave the abdomen? Via what?
T8
Caval opening
What are the dimensions of the spleen?
10cm long
7cm wide
3-4cm thick
Where does the spleen lie?
On the left side
Posterior to ribs 9-11
Near midaxillary line
Is the spleen normally palpable?
No
What are the functions of the spleen?
Lymphocyte proliferation Immune surveillance Haematopoiesis: - Prenatally - In times of bone marrow stress Haemolysis Destruction of old platelets
What region of the abdomen does the liver fill?
Right hypochondrium
Describe the size of the right and left lobes of liver?
Right lobe is large
Left lobe is small and tapers towards left side of abdominal cavity
Where does the upper border of the liver lie?
On the left:
- 7cm to left of xiphisternal joint
On the right:
- From xiphisternal joint all the way around the right side of the thoracic cage
Where does the lower border of the liver lie?
Passes in oblique line from:
- 7cm left of the midline
- To 8th costal cartilage on left
- Follows the border of the costal margin around to the right
Can the liver be normally palpated?
Not easily
Can be percussed
What is the diameter of the gallbladder?
3cm
Where does the gallbladder lie?
Midclavicular line on right 9th costal cartilage
What is the function of the gallbladder?
Storage and release of bile
Can the gallbladder be palpated? When may it be palpable?
Not easily
Murphy’s sign:
- Pain on inspiration when palpating below right costal margin
- Due to cholecystitis
How does the stomach vary?
In size and shape between individuals
Whether its full or not
Where can the stomach be palpated when its full?
On left side below costal margin
Where can the stomach be palpated when empty?
Cannot be palpated:
- Is lying completely behind rib cage
What are the fixed portions of the stomach and where do they li?
Cardiac orifice: - Along 7th costal cartilage - 2.5cm to left of midline - Level with xiphoid process Pyloric orifice: - On transpyloric plane (tip of 9th costal cartilage) - 1.5cm to right of midline
Where can the fundus lie in its extremes?
May rise as high as the 5th intercostal space, 7cm to left of midline
May lie as far down as the 10th costal cartilage
How long is the duodenum?
~25cm
Where does the duodenum run from and to?
From pyloric valve to the jejunum
What is the course of the 1st part of the duodenum?
From pylorus, it passes 5cm to right side as far as costal margin
What is the course of the 2nd part of the duodenum?
Passes down and to the left for 7.5cm to the 10th costal cartilage
What is the course of the 3rd part of the duodenum?
Crosses 10cm to the left side across L3 vertebral body
What is the course of the 4th part of the duodenum?
Ascends 2.5cm to duojejunal junction:
- L2
- 2cm left of midline
Which part of the duodenum is the ampulla of Vater found?
2nd part
What are the dimensions of the pancreas?
10cm long
4cm wide
What is the course of the pancreas?
Crosses from right to left anterior to vertebral body of L1
What are the relations of the head of pancreas?
Surrounded by duodenum
Related to:
- IVC
- Right crus of diaphragm
On what plane does the body of the pancreas lie on?
Transpyloric plane
What is the body of the pancreas related to?
Superior mesenteric vein
Splenic vein
What does the tail of the pancreas abut into?
Hilum of spleen
Is the spleen normally palpable?
No
Which large vein is formed posterior to the spleen?
IVC from junction of:
- Splenic vein
- Superior mesenteric vein
How long is the small intestine?
8m
Where does the jejunum start?
L2
Just to left of midline
Where does the small intestine end?
Iliocaecal junction:
- Lies at junction of right midclavicular and transtubercular line
What blood vessels supply the small intestine?
Duodenum:
- Superior pancreaticoduodenal artery (from gastroduodenal)
- Inferior pancreaticoduodenal artery (from SMA)
Jejunum:
- Jejunal arteries from SMA
Ileum:
- Ileal arteries from SMA
Where does the caecum lie?
Right iliac region
Above lateral half of right inguinal ligament
Where does the appendix lie?
Midclavicular line
1.5cm medial to ASIS
Are the caecum and appendix usually palpable?
No
Where is pain from the appendix referred?
Umbilicus initially
As it swells from inflammation, pain moves down to RIF
Where does the ascending colon run?
From caecum in RIF to level of transpyloric plane (forming hepatic flexure)
Where does the transverse colon run?
Through umbilical region to form splenic flexure just above transpyloric plane on left side
Where does the descending colon run?
Down from splenic flexure into inguinal region where it becomes the sigmoid colon
Where does the sigmoid colon run?
Forms an ‘s-shape’
Passes backwards and down the sacrum to the pelvic floor where it becomes the anal canal
Is the large intestine palpable?
No
What ribs protect the kidneys? Why is one lower than the other?
Left: - Ribs 11 and 12 Right: - Rib 12 - Lower because of liver
What are the dimensions of a kidney?
11cm long
6cm wide
3cm thick
Where does the hilum of each kidney lie?
~L1 level
~3cm from midline
What vertebral levels do the upper and lower poles of the kidneys lie at?
Upper margin = T12
Lower margin = L3
Where does the lateral border of each kidney lie?
~6.5cm from midline
What part of the kidneys can be palpated? Where?
Lower pole of right kidney by deep pressure:
- Just lateral to midclavicular line
- Just below level of right 10th rib
Where does the bladder usually lie?
Behind bodies of pubic bones
Where does the bladder rise to as it fills?
Rises ~3cm above pubic bones
Where can the bladder be palpated when full?
Just superior to pubic symphysis
What organs can be visualised with median and paramedian incisions?
Often exploratory:
- Therefore visualise all abdominal organs
What organs can be accessed by gridiron and transverse incisions?
Appendix
Caecum
Which incision is preferable, gridiron or transverse?
Transverse:
- Gridiron incision is oblique = Worse scar as it crosses Langer’s lines
What organs can be accessed by a suprapubic (Pfannenstiel) incision?
Uterus
Bladder
(Prostate)
What organs can be accessed by subcostal (Kochner) incisions?
Right: - Gallbladder - Liver - Biliary tree Left: - Oesophagus - Stomach - Spleen
