L18- Abdominal Wall and Inguinal Region Flashcards
Where is the abdomen located?
Part of the trunk between the thorax and pelvis
The Os Coxae is composed of what?
The ilium, ischium and pubis
At what level does the ilic crest fall?
L4 level
At what level does the iliac tubercle fall?
L5 level
The umbilicus usually falls at what level?
at the L4 level
What line separates the abdominal muscles down the midline?
Linea alba
What separates the abdominal muscles transversely?
Tendinous intersections
What line runs medially and inferiorly on the abdominal muscles? (sex lines ;)
Inguinal groove
What two planes separate the abdominal wall into quadrants?
median and transumbilical
What fascial layer lies just deep to the skin?
Camper’s fascia
What fascial layer lies deep to camper’s fascia?
Scarpa’s fascia
What are the functions of the muscles of the abdominal wall?
-contain and protect the viscera -defecation, micturition, parturition -flexion and rotation of trunk -tilt pelvis -maintaining posture -accessory muscle of forced respiration
What are the three flat muscles of the abdomen? What do they do?
-external abdominal oblique -internal abdominal oblique -transversus abdominis Work to flex and rotate the trunk
What is the vertical muscle of the trunk? What does it do?
Rectus abdominis -flexes trunk and tilts the pelvis
What is the origin and insertion of the external oblique?
Origin: Ribs 5-12 Insertion: Iliac crest, pubic tubercle, linea alba
What is the innervation of the external oblique?
Lower thoracic anterior rami
What is the action of the external oblique?
support abdominal viscera, flex trunk
What direction do the fibers of the external oblique run?
infero-medially
What is the origin and insertion of the internal oblique?
Origin: thoracolumbar fascia and iliac crest Insertion: Ribs 10-12, linea alba, pectineal line
What is the innervation of the internal oblique?
Lower thoracic anterior rami
What is the action of the internal oblique?
Support abdominal viscera and flex trunk
What direction do the fibers of the internal oblique run?
supero-medial (pretty much horizontal)
What is the origin and insertion of the transversus abdominis?
Origin: thorcolumbar fascia, iliac crest, ribs 7-12 Insertion: linea alba, pubic crest, pectineal line
what is the innervation of the transversus abdominis?
Lower thoracic anterior rami
what is the action of the transversus abdominis?
support the abdominal viscera
What direction do the fibers of transversus abdominis run?
horizontally
What is the origin and insertion of the rectus abdominis?
Origin: pubic symphysis and pubic crest Insertion: Xiphoid process and costal cartilages 5-7
what is the innervation of the rectus abdominis?
lower thoracic anterior rami
what is the action of the rectus abdominis?
support the abdominal viscera and flex the trunk
What direction do the fibers of the rectus abdominis run?
vertically
What cuts across the rectus abdominis? (gives the 6-pack look)
tendinous intersections
What is origin and insertion of the pyramidalis?
Origin: pubic crest Insertion: linea alba
what is the innervation of pyramidalis?
subcostal nerve- T12
what is the action of the pyramidalis?
pulls linea alba inferiorly
Where is the pyramidalis?
within the rectus sheath anterior to rectus abdominis
What is the rectus sheath composed of?
aponeurosis of other abdominal muscles
The rectus sheath encloses what?
the rectus abdominis and pyramidalis
Superior to the umbilicus, the aponeurosis of what muscle encloses the rectus abdominis?
The internal oblique splits to surround it
Inferior to the arcuate line, what parts of the sheath pass anteriorly to the rectus abdominis?
All 3 aponeuroses from the EO, IO and TA (the transversalis fascia passes posteriorly)
Why is the rectus sheath a point of weakness inferior to the arcuate line?
It is only composed of the transversalis fascia at that point. Vulnerable to herniation
The xiphoid dermatome runs at what level?
T5 (sometimes T6)
The umbilicus dermatome runs at what level?
T10
The pubis dermatome runs at what level?
L1
What is a TAP block?
A transversus abdominis plane block: anesthesia injected between the internal oblique and transverses abdominis
What are caval-caval anastomoses?
If the IVC is blocked, the poorly oxygenated blood can become rerouted and travel back to the heart
Where does the caval-caval anastomosis lie?
Between the IVC and SVC (superior and inferior epigastric veins)
What are the portal-caval anastomoses?
the communication between the caval (IVC/SVC) and portal venous systems (paraumbilical veins communication with superficial epigastric veins)
What is caput medusea the result of?
Due to a portal vein obstruction/portal hypertension. Blood backsup and causes an enlargement of the epigastric veins
Name the two openings of the inguinal canal
the deep ring and superficial ring
What is formed by the transversalis fascia and is the entrance to the inguinal canal?
The deep inguinal ring
What is the exit to the inguinal canal and splits the external oblique aponeurosis?
The superficial inguinal ring
Where can you palpate the inguinal rings?
Deep: 1cm superior to the inguinal ligament at midpoint superficial: superior and lateral to pubic tubercle
What is the gubernaculum in males?
The fibrous tract connection the developing testes to the anterior abdominal wall at the scrotum
What is the out pocketing of the peritoneum into the developing scrotum called?
processus vaginalis
What is the spermatic cord made up of?
Vessels, nerves, ductus deferens and muscle layers (- vas deferens -testicular arteries -pampiniform plexus -genital branch of genitofemoral nerve -testicular plexus of nerves -lymphatics)
What is the function of the scrotal ligament?
anchors testes to skin (remnant of gubernaculum)
What does the gubernaculum in females derive into?
- round ligament of the uterus
- ovarian ligament: anchors ovaries to uterus
The labia majora and scrotum are outpocketings of what?
the abdominal wall
What runs through the inguinal canal in females?
- round ligament of the uterus
- ilioinguinal nerve (L1)
- genital branch of genitofemoral nerve (L1-L2)
What runs through the inguinal canal in males?
- ilioinguinal nerve (L1)
- genital branch of genitofemoral nerve (L1-L2)
- spermatic cord
Name the fascial layers of the spermatic cord from outer to inner.
1) external spermatic fascia
2) cremasteric fascia (& muscle)
3) internal spermatic fascia
The cremasteric muscle helps to do what?
ascend and descend the testes
The dartos fascia can be found where?
deep to the skin on the scrotum
What is the somatic innervation of the scrotum and labia majora?
branches of the ilioinguinal and genitofemoral nerves (also motor to cremaster muscle)
What is a direct (acquired) hernia?
pushes through the abdominal fascia, enters posterior wall of inguinal canal, rarely enters scrotum/labia majora Less common!
What is a indirect (congenital) hernia?
Most common Enters the deep inguinal ring, transverses the inguinal canal, exits the superficial ring, can enter the scrotum/labia majora more common in men as their canal has been stretched by the descent of the testes
What is the cremasteric reflex?
scratch on upper thigh contracts the cremaster muscle as genital branch of genitofemoral nerve innervates both (L1-L2)
Where does the lymph superior to the umbilicus drain?
The axillary nodes
Where does the lymph inferior to the umbilicus drain?
superficial inguinal nodes
The lymphatics of the testes and ovaries drain into what?
Mostly lumbar nodes (often metastatic pathway in cancer)
The lymphatics of the scrotum and labia majora drain into what?
superficial inguinal nodes
Identify a, b, c
- a: Pubic Tubercle
- b: Pubic symphysis
- c: Pectineal line
Identify
Linea semilunaris (semilunar lines)
Identify
- red/brown region
- green/purple region
- dark blue region
- hypochondriac
- lateral (lumbar)
- inguinal
