Abdomen Flashcards
How many muscles compose the anterolateral abdominal wall? Which type of muscles are these?
5 bilaterally paired: 3 flat muscles and 2 vertical muscles
Which are the flat muscles that compose the anterolateral abdominal wall?
External oblique internal oblique, and transversus abdominis
Where is the external oblique located and what is the direction of its fibers?
- Superificial muscle
- Fibers pass inferomedially and interdigitate with slips of serratus anterior
What is the inguinal ligament and where is it?
Undercurving fibrous band of the external oblique that spans between anterior superior iliac spine and pubic tubercle, at the inferior margin of the muscle
Where is the internal oblique located and what is the direction of its fibers?
Intermediate muscle
Fibers fan out so that its upper fibers are perpendicular and its lower fibers are parallel to. those of the external oblique
Where is the transversus abdominis locared and what is the direction of its fibers?
- Innermost muscle
- Fibers (except for most inferior ones) run horizontally
Where is the rectus sheath?
Between the midclavicular line and the midline, enclosing the rectus abdominis
What is the rectus sheath mede out of?
Interlaced aponeuroses of flat abdominal muscles
What is the linea alba?
Midline raphe made of the interweave of aponeuroses of flat abdominal muscles; this extends from xiphoid process to the pubic symphysis
This interweaving doesn’t just result from the merging of right and left sides of the rectus sheath, but also between superficial, intermediate, and deep layers (flat muscles of abdominal wall)
Which are the vertical muscles that compose the anterolateral abdominal wall?
Rectus abdominis and pyramidalis
How are the muscle fibers of the rectus abdominis arranged?
Muscle fibers don’t run the length of the muscle; rather, they run between 3 or more “tendinous intersections”
Where are the tendinous intersections of the rectus abdominis located?
At the level of xiphoid process, the umbilicus, and halfway between these points
Each intersection is firmly attached to the anterior layer of the rectus sheath
Where should the pyramidalis be located?
Lies in the rectus sheath anterior to the inferior part of the rectus abdominis; arises from the pubic crest and attaches along the linea alba, when it tenses
What is the origin of the external oblique?
External surfaces of 5-12th ribs
What is the insertion of the external oblique?
Linea alba, pubic tubercle, and anterior half of iliac crest
What is the nerve supply of the external oblique?
Thoraco-abdominal and subcostal nerves (anterior rami of T7-T12 spinal nerves)
What ar the main actions of the external oblique?
Compress and support abdominal viscera; flex and rotate the trunk
What is the origin of the internal oblique?
Thoracolumbar fascia, anterior 2/3 of iliac crest, and connective tissue deep to inguinal ligament
What is the insertion of the internal oblique?
Inferior borders of 10-12 ribs, linea alba, and pubis via conjoint tendon
What is the nerve supply of the internal oblique?
Thoraco-abdominal nerves (anterior rami of T7-11), subcostal and first lumbar nerve
What is the main action of the internal oblique?
Compress and support abdominal viscera; flex and rotate trunk
What is the origin of the transversus abdominis?
Internal surface of 7-12th costal cartilages, thoracolumbar fascia, iliac crest, and connective tissue deep to inguinal ligament
What is the insertion of the transversis abdominis?
Linea alba with aponeurosis of internal oblique, pubic crest, and pubis via conjoint tendon
What is the nerve supply of the transversis abdominis?
Thoraco-abdominal nerves (anterior rami of T7-11), subcostal and first lumbar nerve
What are the main actions of the transversis abdominis?
Compresses and supports abdominal viscera
What is the origin of the rectus abdominis
Pubic symphysis and pubic crest
What is the insertion of the rectus abdominis?
Xiphoid process and 5-7th costal cartilages
What is the nerve supply of the rectus abdominis?
Thoraco-abdominal and subcostal nerves (anterior rami of T7-12 spinal nerves)
What are the main actions of the rectus abdominis?
Flex trunk (lumbar vertebrae) and compresses abdominal viscera, stabilizes and controls tilt of pelvis (antilordosis)
How many umbilical peritoneal folds of the infra-umbilical part of the internal surface of the anterolateral abdominal wall are there?
Five; 2 on each side and 1 in the median plane
What is the extension of the median umbilical fold?
From the apex of the urinary bladder to the umbilicus; covers the “medial umbilical ligament”
Where are the medial umbilical folds?
Lateral to the median umbilical fold; cover the medial umbilical ligaments
Where are the lateral umbilical folds?
Lateral to the medial umbilical folds, cover the inferior epigastric vessels
What are the “peritoneal fossae”; how many do we have; and how are these called?
Depressions lateral to the umbilical folds; located between umbilical folds; three; supravesical fossae, medial inguinal fossae, and lateral inguinal fossae
Where is the supravesical fossae?
Between the median and the medial umbilical folds
How does the supravesical fossae form?
Formed as the peritoneum reflect from the anterior abdominal wall onto the bladder
Where is the medial inguinal fossae?
Between the medial and lateral umbilical folds; commonly called “inguinal triangles”
Where are the lateral inguinal fossae?
Lateral to the lateral umbilical folds; include deep inguinal rings and are potential sites for the most common type of hernia
How is the rectus sheath composed superior to the arcuate line?
Rectus abdominis enveloped by
- Anterior layer of rectus sheath (external oblique aponeurosis and anterior lamina of internal oblique aponeurosis)
-Posterior layer of the rectus sheath (posterior lamina of the internal oblique aponeurosis and the transversus abdominis aponeurosis)
How is the rectus sheath composed inferior to the arcuate line?
- Anterior rectus sheat: aponeuroses of all three muscles (external/internal oblique and transversus abdominis) pass anterior to the rectus abdominis
- Posterior rectus sheath: only transversalis fascia cover rectus abdominis posteriorly
