Anterior Abdominal wall Flashcards
What are the boundaries of the abdominal wall?
Superior - 5th intercostal space, xiphoid process: diaphragm
Inferior - Pubic bone and iliac crest L4
Anterior - Umbilicus L3-4
Posterior - Lumbar vertebrae and lateral muscles.
Posterior boundary of abdominal wall muscles x 3
- Iliacus
- Psoas major
- Quadratus lumborum
What are the horizontal planes of region division?
- Transpyloric plane
- Intertubercular plane
Where is the transpyloric plane?
Midway between the plendar gap and pubic symphysis (between xiphoid and umbilicus) L1.
Where is the intertubercular plane?
Through tubercles of iliac crests. 5cm posterior to ASIS – body of L5.
What are the upper 3 regions of the abdomen?
- Right hypochondriac region
- Epigastric region
- Left hypochondriac region
What are the 3 middle regions in the abdomen?
- Right lumbar region
- Umbilical region
- Left lumbar region
What are the 3 lower regions in the abdomen?
- Right iliac region
- Hypogastric region
- Left iliac region
What is present in the right upper quadrant? x8
- Right lobe of the liver
- Gallbladder
- Duodenum
- Head of pancreas
- Right adrenal gland
- Upper lobe right kidney
- Hepatic flexure of colon
- Section of ascending and transverse colon
What is present in the left upper quadrant? x8
- Left lower part of liver
- Upper lobe of left kidney
- Splenic flexure of colon
- Section of transverse and descending colon
- Stomach
- Spleen
- Pancreas
- Left adrenal gland
What is present in the right lower quadrant? x9
- Lower lobe of right kidney
- Section of ascending colon
- Right fallopian tube
- Right ovary
- Part of uterus (if enlarged)
- Right spermatic cord
- Cecum
- Appendix
- Right ureter
What is present in the left lower quadrant?
- Lower lobe of left kidney
- Section of descending colon
- Left spermatic cord
- Part of uterus (if enlarged)
- Sigmoid colon
- Left ureter
- Left ovary
- Left fallopian tube
What is present in the right hypochondria region?
- Right lobe of liver
- Gallbladder
- Part of duodenum
- Hepatic flexure of colon
- Part of right kidney
- Suprarenal gland
What is present in the epigastric region?
- Pyloric end of stomach
- Duodenum
- Pancreas
- Aorta
- Portion of liver
What is present in the left hypochondriac region?
- Stomach
- Spleen
- Tail of pancreas
- Splenic flexure of colon
- Upper pole of left kidney
- Suprarenal gland
What is present in the lumbar region?
- Ascending colon
- Lower half of right kidney
- Part of duodenum and jejunum
What is present in umbilical region?
- Omentum
- Mesentery
- Transverse colon
- Lower part of duodenum
- Jejunum and ileum
What is present in left lumbar region?
- Descending colon
- Lower half of left kidney
- Part of jejunum and ileum
What is present in the right iliac region?
- Cecum
- Appendix
- Lower end of ileum
- Right ureter
- Right ovary in female
What is present in the hypogastric region? x2
- Ileum
- Bladder
What is present in the left iliac region?
- Sigmoid colon
- Left ureter
- Left ovary in female
What is Camper’s fascia continuous with?
Fascia over thorax and thigh
What does Scarpa’s fascia continue into perineum as?
As superficial perineal fascia = Colle’s fascia
What are the 7 functions of the abdominal wall?
✓protect the abdominal viscera ✓move the vertebral column, ✓assist in forced expiration (e.g. coughing sneezing) ✓defecation ✓vomiting (also known as emesis) ✓urination ✓childbirth (parturition)
What does contraction of abdominal wall muscles and relaxation of diaphragm cause?
Pushes the dome of the diaphragm further up into the thoracic cavity, compressing the lungs deep / rapid / forced expiration
What does contraction of abdominal wall muscles and contraction of diaphragm cause?
Increases the intraabdominal pressure - expulsion of the contents
External oblique innervation
Thoraco-abdominal
Subcostal nerves
Insertion of external oblique
- Aponeurotic insertion in midline at the linea alba
- Iliac crest
- Pubic tubercle
Origin of external oblique
External posterior surface of ribs 5-12
Function of external oblique
LATERAL ROTATOR and LATERAL FLEXOR
Origin of internal oblique
- Thoracolumbar fascia
- Anterior 2/3 of the iliac crest
- Lateral 1/3 of the inguinal ligament
Insertion of internal oblique
Inferior borders of 10th -12th ribs and the linea alba
Innervation of internal oblique
- Thoraco-abdominal
- Subcostal nerves T6-T12
Function of internal oblique
Lateral rotator and flexor
Origin of transversus abdominus
- Inner aspect of the costal margin - ribs 7-12
- Thoraco-lumbar fascia
- Anterior 2/3 of the iliac crest
- Lateral third of the inguinal ligament
Insertion of transversus abdominus
- Linea alba,
- Pubic crest and the pectineal line (pelvic
floor) - Inferior part of the internal oblique muscle
What is the conjoint tendon?
The blending of the transversus abdominus and internal oblique at the superficial inguinal ring
Innervation of transversus abdominus
- Thoraco-abdominal
- Subcostal nerves T6-T12
Where do the thoraco-abdominal and subcostal nerves travel between?
Between internal oblique and transversus abdominus
Function of rectus abdominus
Most powerful flexor
What are the 3 transverse fibrous bands of tissue in the rectus abdominus?
Transverse tendinous
intersections and linea alba
Where is linea alba located
Located along the midline = connective tissue raphe.
Where is linea semilunaris located?
Along each lateral border of rectus abdominis.
Where is linea transversa located?
Tendinous bands of rectus abdominis.
Where does the linea alba extend from?
Xiphoid process to pubic symphysis
What do teh semilunaris and linea alba fuse oto foorm and where?
At the lateral margin of the rectus abdominus, the aponeuroses fuse to form the linea semilunaris
What are the 4 roles of abdominal muscles?
- Move the trunk
- Depress the ribs in expiration
- Compress the abdomen
- Support the intestines
What does the rectus sheath enclose?
Rectus abdominus
What is the rectus sheath formed by?
Fusion of fascia of other three layers of abdominal
muscles
What is the arcuate line?
The lower free edge of the posterior lamina.
Where does the arcuate line of Douglas lie?
1/3rd the way between the umbilicus + pubic symphysis
Blood supply of rectus sheath
Superior epigastric arteries
- Internal thoracic
Inferior epigastric arteries
- External iliac
What is the nerve supply to abdominal muscles?
From T6-L1 (at L1 the ilioinguinal nerve – originates from ventral ramus of L1 spinal nerve – continues through inguinal canal)
Where does the inguinal region extend between?
The ASIS and pubic tubercle
Why is the inguinal region clinically important?
For hernia
Where does the inguinal ligament run from?
The anterior superior iliac spine to pubic tubercle
Why are herniated surgical interventions controversial in the inguinal canal?
Due to variations
NB what is present in the spermatic cord?
- Artery to Vas deferens.
- Vas deferens
- Genital branch of genitofemoral nerve – skin of scrotum / mons pubis.
- Testicular arteries.
- Pampiniform plexus of testicular veins – venous return, temp regulation
- Lymph vessels.
- Cremaster artery and vein and muscle -involuntary smooth muscle, raise and lower testes – raise in response to fear etc.
- Processus vaginalis – embryonic out pouching of parietal peritoneum / embryonic structure
- Autonomic nerves
- Ilioinguinal nerve.
Female inguinal canal contents
- Round ligament of uterus
- Ilioinguinal nerve
- Lymph vessels
Where is the inguinal canal present?
Between superficial and deep inguinal rings
Where does the superficial inguinal ring lie?
Above and lateral to pubic tubercle
What muscle layer is the superficial inguinal ring in?
External oblique
What is the deep inguinal ring and opening of?
Of the evagination of the transversalis fascia
Boundaries of inguinal canal
Anterior - ant apon of external oblique + lil internal oblique laterally
Posterior - transversalis fascia + medial by conjoint tendon
Roof - arching fibres of int oblique and transverse ab
Floor - sup surfaces of inguinal and lacunar ligaments
What is an inguinal hernia?
A rupture or separation of a portion of the inguinal area of the anterior abdominal wall resulting in the protrusion of part of the small intestine
When do direct hernias normally occur and why?
In older men (rarely women) due to weakness in abdominal wall behind or lateral to superficial inguinal ring.
Where do direct inguinal hernias pass through?
Through abdominal wall to Hesselbecks triangle
Do direct inguinal hernias extend into scrotum?
NO
Location of direct inguinal hernia in relation to epigastric vessels.
Medial to the epigastric vessels
What is the sac in direct inguinal hernias formed by?
Peritoneum
What do indirect inguinal hernias tranverse?
Transverses deep and superficial inguinal rings and inguinal canal.
Where do indirect inguinal hernias lie within?
Coverings of spermatic cord
Do indirect inguinal hernias descend into scrotum?
Yes they can
What is more common, direct or indirect inguinal hernias?
Indirect
Where are indirect inguinal hernias in relation to epigastric vessels?
Lateral to epigastric vessels
Borders of Hesselbach’s triangle
Laterally: Inferior epigastric vessels
Medially: Lateral border of the rectus muscle
Inferiorly: Inguinal ligament
Where do direct hernias leave the abdomen through?
Through Hasselbach’s Triangle
