TBL 15 Flashcards
What is the abdominopelvic cavity?
It consists of the large abdominal cavity and small pelvic cavity and extends between the thoracic and pelvic diaphragms
Where can the cavity ascend to?
Even superiorly to the 4th ICS so more superiorly positioned abdominal organs (liver, stomach, spleen) are partially protected by the thoracic cage
Name the quadrants of the abdominal cavity and which planes divide the body into the four quadrants?
Right Upper Quadrant Right Lower Quadrant Left Upper Quadrant Left Lower Quadrant transumblical and medial
Which planes demarcate the regions of the abdomen?
midclavicular subcostal transtubercular
What are the regions of the body? What do they do?
epigastric, umbilical, and hypogastric (pubic) They localize visceral pain referred from the abdominal organs onto the anterior abdominal wall.
What is the anterolateral abdominal wall mainly formed by?
A musculocutaneous sheet consisting of three laterally positioned muscle layers (external and internal obliques and transverse abdominis) with their fused aponeuroses forming the anterior aspect of the sheet.
What causes prune belly syndrome and why does the abdomen become distended?
Partial or complete absence of abdominal musculature causes the abdominal wall to become so thin that organs are visible/ easily palpated. It is associated with malformations of the urinary tract/ bladder so there is an accumulation of fluid so this distends the abdomen and there is atrophy of the abdominal muscles.
Where is the sheet forming the anterolateral abdominal wall derived from?
myoblasts and fibroblasts of the parietal mesoderm
What forms the superficial muscle layer of the wall and where does its fibers run?
External oblique forms the superficial muscle layer and its fibers run inferomedially from the lateral surfaces of the 5th-12th ribs to the illiac crest.
Which muscle forms the intermediate muscle layer and where do its fibers run?
Internal obliques an they run superomedially from the illiac crest to the inferior borders of the 10th-12th ribs.
What do the external oblique and contralateral internal oblique form? What does it do?
They form a two bellied muscle sharing a common aponeurosis and synergistic actions of the muscle bellies cause flexion and rotation for torsional movement of the trunk.
Which muscle forms the innermost muscle layer? Describe this muscle. What is it ideal for?
Transverse abdominis and the transverse circumferential orientation of its fibers (from the internal surfaces of the 7th-12th ribs to the linea alba) is ideal from compressing abdominal contents and increasing intraabdominal pressure.
What does the fusion of the aponeuroses of the three muscle layers form?
It forms the rectus sheath that encloses the paired rectus abdominis muscles.
What forms the linea alba? What is it used for?
The midline fusion of the bilateral rectus sheaths form the vertical linea alba that seperates the rectus abdominis muscles. It is used surgically for rapid midline incisions that are relatively bloodless and avoid major nerves.
What do the rectus abdominus muscles do?
The extend vertically from the pubic symphysis to the 5th-7th costal cartilages and the muscles powerfully flex the vertebral column, especially the lumbar region.
Why does lack of anterolateral wall muscle tone contribute to visceroptosis (sinking of abdominal organs) and excessive lordosis?
When muscles are atrophic, they provide insufficient tonus to resist the increased weight of a protuberant abdomen on the anterior pelvis. The six common causes of abdominal protrusion: food, fluid, fat, feces, flatus and fetus. The pelvis tilts anteriorly at the hip joints when standing (the pubis descends and the sacram ascends) producing excessive lordosis.
Why do palpation-induced spasms of anterolateral wall muscles provide a clinical sign of acute abdomen?
Cold hands during palpation can cause involuntary muscle spasms known as intense guarding, board-like reflexive muscular rigidity cannot be willfully suppressed, occurs during palpation when an organ (such as the appendix) is inflamed and constitutes a clinically significant sign of acute abdomen. The involuntary muscular spasms attempt to protect the viscera from pressure, which is painful when an abdominal infection occurs. The common nerve supply of the skin and muscles of the wall explain why these spasms occur.
Why can transverse incisions of the rectus abdominis be made without permanent damage to the muscle?
This muscle may be divided transversely without serious damage because a new transverse bands forms when the muscle segments are rejoined.
Artery stuff?
See paper! Remember the abdominal aorta branches at L4 to give rise to: 1. bilateral external iliac –> femoral and inferior epigastric 2. internal iliac which supplies the pelvis
Why does palpation of an impulse at the superficial inguinal ring and a mass at the deep inguinal ring define an indirect inguinal hernia? How is a direct inguinal hernia detected by palpation?
Direct inguinal: palpate inguinal triangle and superficial ring indirect: impulse at superficial ring and mass at deep inguinal ring because processus vaginalis persists.
What is the processus vaginalis?
Diverticulum beginning in the deep inguinal ring of the parietal peritoneum created by the testis pushes muscular and fascial layers of the anterolateral wall ahead of it into the inguinal canal Eventually… stalk part collapses and distal part forms the tunica vaginalis which adheres to the testis and epididymis
How is a persistent processus vaginalis related to a hydrocele of the testis and how does a hydrocele of the spermatic cord differ from a hydrocele of the testis?
A hydrocele is the prescence of excess fluid in a persistent processus vaginalis. A hydrocele of the testis is confined to the scrotum and distends the tunica vaginalis. A hydrocele of the cord is confined to the spermatic cord and distends the persistent part of the stalk of the processus vaginalis.
