Anterolateral abdomen Flashcards
External oblique - attachment, innervation, action
Origin: External surfaces of 5th-12th rib.
Insertion: Linea alba, pubic tubercle, anterior half of iliac crest.
Innervation: Thoraco-abdominal nerves and subcostal nerve.
Action: Compresses and supports abdominal viscera, flexes and rotates trunk.
Internal oblique - attachment, innervation, action
Origin: Thoracolumbar fascia, anterior 2/3 of iliac crest, connective tissue deep to lateral third of inguinal ligament.
Insertion: Inferior borders of 10th-12th ribs, linea alba, pecten pubis via conjoint tendon.
Innervation: Thoraco-abdominal nerves (anterior rami of T6-T12), first lumbar nerves.
Action: Compresses and supports abdominal viscera, flexes and rotates trunk.
Transversus abdominis - attachment, innervation, action
Origin: Internal surfaces of 7th-12th costal cartilages, thoracolumbar fascia, iliac crest, connective tissue deep to lateral third of inguinal ligament.
Insertion: Linea alba with aponeurosis of internal oblique, pubic crest, pecten pubis via conjoint tendon.
Innervation: Thoraco-abdominal nerves (anterior rami of T6-T12 and first lumbar nerves.
Action: Compresses and supports abdominal viscera.
Rectus abdominis - attachment, innervation, action
Origin: Pubic symphysis and pubic crest.
Insertion: Xiphoid process and 5th-7th costal cartilages.
Innervation: Thoraco-abdominal nerves (anterior rami of T6-T12).
Action: Flexes trunk, compresses abdominal viscera, stabilizes and controls tilt of pelvis (antilordosis).
Muscles of anterolateral abdominal wall.
External oblique.
Internal oblique.
Transversus abdominis.
Rectus abdominis.
Midinguinal points
Midpoints of the lines joining the anterior superior iliac spina and pubic tubercles on each side.
- Subcostal plane
2. Transtubercular plane
(Transverse planes)
- Passes through inferior border of 10th costal cartilage on each side.
- Passes through the iliac tubercles and body of L5.
Transpyloric plane
Extrapolated midway between the superior borders of the manubrium and pubic symphysis.
Interspinous plane
Passes through ASIS on each side.
Transumbilical plane
Passing through the umbilicus (The horizontal line that divides the upper and lower quadrants.
Bounderies of the anterolateral abdominal wall
Superiorly: Cartilages of 7th-10th ribs and xiphoid process.
Inferiorly: Inguinal ligament and superior margins of anterolateral aspects of the pelvic girdle (Iliac crests, pubic crests, pubic symphysis).
Linea alba
A midline raphe formed by the recus sheaths and aponeuroses of anterolateral abdominal muscles. Also between superficial and intermediate and intermediate and deep layers.
Extends from xiphoid process to pubic symphysis.
Contents of rectus sheath
Rectus abdominis and pyramidalis, superior and inferior epigastric arteries and veins, lymphatic vessels and distal portions of the anterior rami of T7-T12.
Inguinal ligament (Poupart ligament)
Thickening of inferior margin of external oblique aponeurosis as an undercurving fibrous band with a free edge that spans between ASIS and pubic tubercle.
Pyramidialis
Small insignificant triangular muscle. Absent in approximately 20% of people. Lies anterior to inferior part of rectus abdominis. Attaches to anterior surface of pubis and the anterior pubic ligament, ends in linea alba.
Functions and actions of anterolateral abdominal muscles
- Form a strong expandable support for the anterolateral abdominal wall.
- Support the abdominal viscera and protect them from most injuries.
- Compress the abdominal contents to maintain or increase the intra-abdominal pressure, and in doing so, oppose the diaphragm.
- Move the trunk and help to maintain posture.
Nerves of anterolateral abdominal wall
- Thoraco-abdominal.
- 7th-9th lateral cutaneous branches.
- Subcostal (anterior ramus of T12).
- Iliohypogastric (L1).
- Ilio-inguinal (L1).
Thoraco-abdominal nerve
T7-T11.
Origin: Continuation of lower (7th-11th intercostal nerve, distal to costal margin.
Course: Run between second and third layers of abdominal miscles.
Distribution: Muscles of anterolateral abdominal wall and overlying skin.
7th-9th lateral cutaneous branches
Origin: 7th-9th intercostal nerves (anterior rami of T7-T9)
Course: Anterior divisions continue across costal margin in subcutaneous tissue.
Distribution: Skin of right and left hypochondriac regions.
Subcostal nerve
Origin: Spinal nerve T12.
Course: Runs along inferior border of 12th rib, then passes onto subumbilical abdominal wall between second and third layers of abdominal muscles.
Distribution: Muscles of anterolateral abdominal wall, overlying skin superior to iliac crest and inferior to umbilicus.
Iliohypogastric nerve
Origin: Superior terminal branch of anterior ramus of L1.
Course: Pierces transversus abdominis muscles to course between 2nd and 3rd layers of abdominal muscles.
Distribution: Skin overlying iliac crest, upper inguinal, and hypogastric regions, internal oblique and transversus abdominis muscles.
Ilio-inguinal nerve
Origin: As inferior terminal branch of anterior ramus of L1.
Course: Passes between 2nd and 3rd layers of abdominal muscles, then transverses inguinal canal.
Distribution: Skin of lower inguinal region, inferiormost internal oblique and transversus abdominis muscles.
Primary blood vessels (arteries and veins) of anterolateral abdominal wall
- Superior epigastric vessels and branches of the musculophrenic vessels from the internal thoracic vessels.
- Inferior epigastric and deep circumflex iliac vessels from the external iliac vessels.
- Superficial circumflex iliac and superficial epigastric vessels from the femoral artery and greater saphenous vein respectively.
- Posterior intercostal vessels of the 11th intercostal space and the anterior branches of subcostal vessels.
Arteries of anterolateral abdominal wall
Musculophrenic. Superior epigastric. 10th and 11th posterior intercostal arteries. Subcostal artery. Inferior epigastric. Deep circumflex iliac. Superficial circumflex iliac. Superior epigastric.
Origin of musculophrenic and superior epigastric arteries
Internal thoracic artery.
Origin of 10th and 11th posterior intercostal arteries and the subcostal artery
Aorta.
Origin of inferior epigastric and deep circumflex iliac arteries
External iliac artery.
Origin of superficial circumflex iliac and superficial epigastric arteries
Femoral artery.
Boundaries of inguinal canal
Posteriorly - Lateral third: Transversalis fascia, Middle third: Transversalis fasca, Medial third: Inguinal falx (conjoint tendon) plus reflected inguinal ligament.
Anteriorly - Lateral third: Internal oblique m. plus lateral crus of aponeurosis of external oblique, Middle third: Aponeurosis of external oblique, Medial third: Aponeurosis of external oblique continuing as external spermatic fascia.
Roof - Lateral third: Transversalis muscle, Middle third: Musculo-aponeurotic arches of internal oblique and transverse abdominal. Medial third: Medial crus of aponeurosis of external oblique.
Floor: Lateral third: Iliopubic tract, Middle third: Inguinal ligament, Medial third: Lacunar ligament.
Muscle causing cervical constriction of esophagus
cricopharyngeus muscle
Median umbilical fold extends between?
Apex of urinary bladder to umbilicus and covers median umbilical ligament.
Subcutaneous tissue in the anterior abdominal wall forms what layer of the scrotum?
Dartos fascia
External oblique fascia in anterior abd. wall forms what layer of scrotum?
External spermatic fascia
Internal oblique muscle in ant. abd. wall forms what layer of scrotum?
Cremaster muscle
Fascia of internal oblique in anterior abd. wall forms what scrotal layer?
Cremasteric fascia
Transversalis fascia in ant. abd. wall forms what layer of scrotum?
Internal spermatic fascia
Peritoneum in ant. abd. wall forms what layer of scrotum?
Tunica vaginalis
