Anterior Abdominal Wall and Inguinal Region Flashcards
What is an aponeurosis?
Flattened tendinous structure that connects anterolateral abdominal wall muscles to linea alba
What are the functions of the anterior abdominal wall muscles?
Movement (flexion and rotation of trunk, control of pelvic tilt)
Increasing intra abdominal pressure
Whatg is the nerve supply to the skin and muscle of the anterior abdominal wall?
T7-T11 (Intercostal nerves)
T12 (Subcostal nerve)
L1 (Iliohypogastric and ilioinguinal)
Which dermatome lies at the level of the xiphisternum?
T6
Which dermatome lies at the level of the umbilicus?
T10
Which dermatome lies at the level of the pubic tubercle?
T12/L1
What is Scarpa’s fascia?
Membranous layer of superficial fascia on the anterior abdominal wall
Scarpa’s fascia is continuous inferiorly with the membranous layer of superficial fascia of the perineum.
What name is given to this fascia in the perineum?
Colle’s fascia
In which direction do the fibres of external oblique run?
Downwards and forwards (like external intercostal)
The free inferior border of external oblique forms what structure?
Inguinal ligament
What structure is found superior to the pubic tubercle, as a ‘gap’ in the aponeurosis of external oblique?
Superficial inguinal ring
As it passes through the superficial inguinal ring, the aponeurosis of external oblique forms which component the spermatic cord?
External spermatic fascia
What forms the anterior wall of the inguinal canal?
Aponeurosis of external oblique
also has lateral reinforcement by muscle fibres of internal oblique
What forms the posterior wall of the inguinal canal?
Transversalis fascia, with medial reinforcement by conjoint tendon
What forms the roof of the inguinal canal?
Laterally: transversalis fascia
Centrally: musculoaponeurotic arches of internal oblique and transversus abdominis
Medially: Medial crus
What forms the floor of the inguinal canal?
Laterally: iliopubic tract
Centrally: inguinal ligament
Medially: Lacunar ligament
What is the origin(s) of external oblique?
External surfaces of ribs 5-12
What are the insertions of external oblique?
Linea alba
Pubic tubercle
Anterior half of iliac crest
What is the origin(s) of internal oblique?
Thoracolumbar fascia
Anterior two-thirds of iliac crest
Connective tissue deep to lateral third of inguinal ligament
What are the insertions of internal oblique?
Inferior borders of ribs 10-12
Linea alba
Pecten pubis (via conjoint tendon)
What is the origin(s) of transversus abdominis?
Internal surface of 7th-12th costal cartilages
Thoracolumbar fascia
Iliac crest
Connective tissue deep to lateral third of inguinal ligament
What are the insertions of transversus abdominis?
Linea alba
Pubic crest
Pecten pubis (via conjoint tendon)
Where does the neurovascular plane of the anterior abdominal wall lie?
Between transversus abdominis and internal oblique
What is the origin(s) of rectus abdominis?
Pubic symphysis and pubic crest
What are the insertions of rectus abdominis?
Xiphoid process
5th-7th costal cartilages
In which direction do the fibres of internal oblique run?
Upwards and forwards
How to the fibres of transversus abdominis relate to the inguinal canal?
Superior to deep inguinal ring
Roof, then posterior wall as conjoint tendon
What and where is the conjoint tendon?
Union of internal oblique and transversus abdominis
Located posterior to the superficial inguinal ring
What and where is the transversalis fascia?
This connective tissue layer, between transversus abdominis and parietal peritoneum.
Thickest at level of inguinal canal
Which vessels run through the rectus sheath, deep to rectus abdominis?
Inferior and superior epigastric
The deep inguinal ring is a defect in which layer of the abdominal wall?
Transversalis fascia
What is the tunica vaginalis, from where is it derived?
Serous covering of the testes, derived from the processus vaginalis (embryonic outpouching of the parietal peritoneum)
What is the cremasteric reflex?
Reflex observed when the superomedial portion of the thigh is stroked. This tightens the cremaster muscles, elevating the testes on the ipsilateral side
What structures are found in the spermatic cord?
Mnemonic: Papers Don’t Contribute To A Good Specialist Level
3 arteries, 3 nerves, 3 other things
P: pampiniform plexus D: ductus deferens C: cremasteric artery T: testicular artery A: artery of the ductus deferens (deferential artery) G: genital branch of the genitofemoral nerve S: sympathetic nerve fibers L: lymphatic vessels
Where is the deep inguinal ring located?
2cms above the midpoint of the inguinal ligament
What are the medial and lateral borders of the deep inguinal ring?
Medial: Inferior epigastric artery
Lateral: Transversalis fascia
What are the medial and lateral borders of the superficial inguinal ring?
Medial and lateral crura of external oblique muscle
What is the approximate length of the inguinal canal?
4cm
Which nerve enters the inguinal canal through the deep inguinal ring and what does it supply?
Genital branch of genitofemoral artery
Females: Labia majora and mons pubis
Males: Cremaster and skin of scrotum
How does the ilioinguinal nerve enter the inguinal canal and what does it supply?
Enters anterior abdominal wall between transversus abdominis and internal oblique
Supplies skin of the upper and medial part of the thigh, and::
Males (“anterior scrotal nerve”): to the skin over the root of the penis and upper part of the scrotum.
Females (“anterior labial nerve”): to the skin covering the mons pubis and labia majora.
What is a hernia?
Protrusion of a structure through the body cavity in which it is normally contained
What is the difference between an indirect and a direct hernia?
Direct: Protrudes through anterior abdominal wall via Hesselbach’s triangle
Indirect: Protrusion through deep inguinal ring
