ABDOMEN I Flashcards
What’s the superior boundary of the anterior abdominal wall?
The xiphoid process and the costal margin
What’s the inferior boundary of the anterior abdominal wall?
The pubic symphysis, the anterior superior iliac spine, the iliac crest and the inguinal ligament
What 2 planes are used to divide the abdomen into 4 quadrants?
The trans umbilical plane and the median plane
What 4 planes divide the abdomen into 9 regions?
The transpyloric plane, the intertubercular plane and the left and right midclavicular planes
What does the superficial fascia of the abdomen contain?
Fat, superficial veins and nerves of the anterior abdominal wall
What are the 2 layers of the superficial fascia of the anterior abdomen?
Camper’s fascia (fatty) and Scarpa’s fascia (membranous)
Which layer of the superficial fascia is the inner layer and which layer is outer?
Camper’s fascia is the outer layer and Scarpa’s fascia is the inner layer
What 3 muscles make up the anterolateral abdominal wall?
External oblique, internal oblique and transversus abdominis
What are the 2 vertical muscles in the midline of the abdomen?
Rectus abdominis and pyramidalis
What are the vertical muscles of the medial anterior abdomen enclosed in?
The rectus sheath
What is found deep to the medial muscles of the anterior abdomen?
Transversalis fascia and parietal peritoneum
What’s the fibre direction of external obliques?
Inferomedial
What’s the fibre direction of the internal obliques?
Superomedial
What’s the fibre direction of the transversus abdominis?
Horizontal
What’s the fibre direction of rectus abdominis?
Vertical
What’s the fibre direction of pyramidalis?
Vertical
What’s the action of the external obliques?
Contralateral rotation of the torso
What’s the action of the internal obliques?
Ipsilateral rotation of the torso
What’s the action of the transversus abdominis?
Compression of the abdomen
What’s the action of the rectus abdominis?
Compression of the abdomen and stabilisation of the pelvis and hips
What’s the action of the pyramidalis muscle?
Tense the linea alba
What’s the nervous supply to the external obliques?
Thoracoabdominal and subcostal nerves (T7-T11)
What’s the nervous supply to the internal obliques?
Thoracoabdominal and subcostal nerves (T7-T11) and the lumbar plexus
What’s the nervous supply to the transversus abdominis?
The thoracoabdominal and subcostal nerves (T7-T11) and the lumbar plexus
What’s the nervous supply to the rectus abdominis?
Thoracoabdominal nerve
What’s the nervous supply to the pyramidalis?
Subcostal nerves
What is the linea alba?
The midline between the rectus abdominis
What is the rectus sheath?
A large aponeurosis formed from the 3 anterolateral abdominal muscles, which envelopes the 2 rectus abdominis muscles
Where does the linea alba run between? (where does it start and end?)
The xiphoid process to the pubic symphysis
What’s the surgical importance of the linea alba?
It’s a weak point through which paraumbilical hernias can occur. It’s a common incision and puncture site for abdominal surgery and suprapubic bladder catheterisation
What’s the linea semilunaris?
The linea semilunaris forms the lateral border of the rectus abdominis and is identified as the ‘curved groove’ in the overlying skin.
At what costal cartilage does the linea semilunaris cross the costal margin?
The 9th costal cartilage
What is the arcuate line?
A crescent shaped line that represents a weakening of the anterior abdominal wall. It is formed due to a change in the structure of the anterior and posterior lamellae of the rectus sheath
Where do all aponeuroses join?
Beneath the arcuate line
What vessels run in the rectus sheath?
The inferior epigastric artery, the inferior epigastric vein, the superior epigastric arteries and veins, and lymphatic vessels
Where does the inferior epigastric artery arise?
The external iliac artery
What does the inferior epigastric artery anastomose with?
The superior epigastric artery
Where does the inferior epigastric vein drain?
The external iliac vein
What is the median umbilical ligament a remnant of?
The foetal urachus, which itself is a remnant of the allantois
What are the medial umbilical folds?
Bilateral raised ridges of parietal peritoneum in the deep aspect of the anterior abdominal wall formed by the underlying medial umbilical ligaments running from the pelvis to the umbilicus
What are the lateral umbilical folds?
Bilateral raised ridges of parietal peritoneum in the deep aspect of the anterior abdominal wall overlying the inferior epigastric vessels
What are the boundaries of Hesselbach’s inguinal triangle?
Medial- Lateral border of the rectus abdominis
Lateral- Inferior epigastric vessels
Inferior- Inguinal ligament
What’s the clinical importance of the inguinal triangle?
It demarcates a point of weakness through which abdominal organs may herniate
What happens in a direct inguinal hernia?
Bowel herniates through a weakness in the inguinal triangle and enters the inguinal canal. It can then exit the canal via the superficial inguinal ring to form a ‘lump’ in the scrotum or labia major
What makes an inguinal hernia direct?
It occurs medial to the inferior epigastric vessels
What does the inguinal ligament attach to?
The anterior superior iliac spine and the pubic tubercle
How is the inguinal ligament related to the external oblique?
The aponeurosis of the external oblique forms the inguinal ligament
What’s the importance of the inguinal ligament to the external iliac artery?
As the external iliac artery passes under the inguinal ligament, it becomes the femoral artery (same with corresponding veins)
What forms the inguinal canal?
The inguinal canal is formed due to the embryological descent of the testes, from the posterior abdominal wall, through the layers of the inferior part of the anterior abdominal wall, to reside within the scrotum
What are the boundaries of the inguinal canal?
2M’s, 2A’s, 2L’s, 2T’s
The roof is formed by overarching fibres of the internal obliques and transversus abdominis. The anterior wall is the aponeuroses of external oblique and internal oblique. The floor is the inguinal ligament and the lacunar ligament. The posterior wall is the conjoint tendon and transversalis fascia
What’s the superficial inguinal ring?
A triangular-shaped opening in the aponeurosis of the external oblique muscle. It is palpable 2-3cm superolateral to the pubic tubercle.
What’s the deep inguinal ring?
A slit-like opening in the transversalis fascia, 2cm above the mid-point of the inguinal ligament
What runs in the inguinal canal?
The ilioinguinal nerve and the spermatic cord or round ligament of the uterus
What are the 3 concentric layers of fascia that cover the spermatic cord?
The internal spermatic fascia from the transversalis fascia. The cremasteric muscle and fascia from the internal oblique muscle and fascia. The external spermatic fascia from the external oblique muscle
What are the 3 arteries in the spermatic cord?
The testicular artery, the artery of vas deferens and the cremasteric artery
What are the 3 nerves in the spermatic cord?
The sympathetic nerve, the parasympathetic nerve and the genitofemoral nerve
What are the 3 tubes in the spermatic cord?
The vas deferens, the pampiniform plexus and the lymphatics
Where does the testicular artery arise from?
The abdominal aorta
Where does the artery to vas deferens arise?
The superior vesicle artery (a branch of the internal iliac artery)
Where does the cremasteric artery arise?
The inferior epigastric artery
What does the round ligament of the uterus attach to?
The uterus
What does the round ligament of the uterus pass through?
The inguinal canal
What does the round ligament of the uterus spread out within?
The labia majora
What should the deep inguinal ring feel like on palpation in adult males?
With the palmar surface of the finger against the anterior abdominal wall, the deep inguinal ring may be felt as a skin depression superior to the inguinal ligament, 2-4cm superolateral to the pubic tubercle
What would a hernia feel like?
A sudden impulse against the tip of the pad of the examining finger when the patient is asked to cough
What forms the hernial sac of a direct inguinal hernia?
The transversalis fascia
Where would a direct inguinal hernia lie?
Outside the process vaginalis, parallel to the spermatic cord and outside the inner one or two fascial coverings of the cord
What makes a direct inguinal hernia different from an indirect inguinal hernia?
Direct hernias are acquired, while indirect hernias are congenital. Direct hernias almost never enter the scrotum, while the indirect hernia commonly does. Direct hernias don’t traverse the entire inguinal canal, but indirect hernias traverse the entire inguinal canal and exit through the superficial inguinal ring. In direct hernias, the hernial sac is formed by a persistent processes vaginalis and all 3 fascial coverings of the spermatic cord (internal spermatic fascia, cremasteric fascia and external cremasteric fascia
Are inguinal hernias more common in men or women?
They’re more common in men
When does a femoral hernia strangulation occur?
When a constriction of the hernia limits or completely obstructs blood supply to a part of the bowel involved in the hernia
Why are femoral hernias more common in women than men?
Because of the wider pelvis
