Anatomy 1. Surgical Anatomy Flashcards
What is the anterolateral abdominal wall bounded by?
Superiorly - the cartilages of the 7th-10th ribs, and the xiphoid process of the sternum.
Inferiorly - the inguinal ligament and superior margins of the anterolateral aspects of the pelvic girdle.
What does the anterolateral abdominal wall consist of?
Skin, subcutaneous tissue, muscles and their aponeuroses, deep fascia, extraperitoneal fat, and parietal peritoneum.
What is the major landmark of the abdominal wall at spinal level L3?
The umbilicus.
What is the epigastric fossa?
Pit of the stomach, a slight depression in the epigastric region, just inferior to the xiphoid process.
Which site of the abdominal wall where heartburn is felt?
At the epigastric fossa.
What is the linea alba?
The aponeuoses of abdominal muscles visible in lean individuals due to the vertical skin groove superficial to it.
What is divarication of the recti?
The linea alba is lax so when the rectus abdominis contracts, the muscles spread apart.
What unites the pubic crest and symphysis?
Upper margins of the pubic bones and the cartilaginous joint.
Where can the pubic crest and symphysis be felt?
At the inferior end of the linea alba.
What is the inguinal groove?
A skin crease parallel and just inferior to the inguinal ligament.
What does the inguinal groove mark?
The division between the abdominal wall and the thigh.
What are the semilunar lines?
The slightly curved, tendinous line on either side of the rectus abdominis.
What is the arcuate/ Douglas’ line?
Where the rectus fibrous sheath stops 1/3 of the way from the umbilicus to the pubic crest.
How many muscles are in the anterolateral abdominal wall?
Five - three flat and two vertical muscles.
What are the flat muscles in the anterolateral abdominal wall?
External oblique, internal oblique, and transversus abdominis.
What are the vertical muscles in the anterolateral abdominal wall?
Rectus abdominis and pyramidalis.
What are the orientations of the flat muscle fibres in the anterolateral abdominal wall?
The fibres of the obliques run diagonally and perpendicular to each other. The fibres of the transversus muscle run transversely.
What is the origin and insertion of the external oblique muscle?
Origin - external surfaces of the 5th-12th ribs.
Insertion - linea alba, pubic tubercle, and anterior half of iliac crest.
What is the origin and insertion of the internal oblique muscle?
Origin - thoracolumbar fascia, anterior two thirds of iliac crest, and connective tissue deep to lateral third of inguinal ligament.
Insertion - inferior borders of the 10th-12th , linea alba, and pectin pubis via conjoint tendon.
What is the origin and insertion of the transversus abdominis muscle?
Origin - internal surface of 7th-12th costal cartilages, thoraculumbar fascia, iliac crest, and connective tissue deep to lateral third of inguinal ligament.
Insertion - linea alba with aponeuroses of internal oblique, pubic crest, and pectin pubis via conjoint tendon.
What makes up the rectus sheath?
The three flat muscles as they continue anteriorly and medially as aponeuroses. Between the mid-clavicular line and the midline.
Which two vertical muscles does the rectus sheath enclose?
The rectus abdominis and the small pyramidalis.
What forms the linea alba?
The aponeuroses interweaving with their fellows of the opposite side.
What does the linea alba extend between?
The xiphoid process to the pubic symphysis.
What is an important consideration when designing an incision?
It should be able to close and provide long-lasting strength to minimise the incidence of incisional herniae.
Why is a midline incision a good design for an incision?
Surgeons suture the linea alba together and this provides strong closure.
Why is a transverse incision a good design for an incision?
Surgeons suture the external oblique aponeuroses together which provides strong closure.
What is the incision point of an appendicectomy?
McBurney’s point.
Where is McBurney’s point?
2/3rds of the distance between the umbilicus and ASIS.
What type of incision is used in appendicectomies?
Gridiron muscle-splitting incision at McBurney’s point.
What is meant by gridiron incision?
Put scissors in and open and close them to separate out the muscle fibres. In appendicectomy, this has to be done for the external oblique, then internal oblique, then transversalis abdominis muscles in turn.
What is patent urachus?
An opening in the urachus leading to the bladder.
When does a patent urachus present?
At birth or later in life in men when they develop bladder outflow obstruction due to benign prostatic hypertrophy.
What is Meckel’s diverticulum?
The most common GI abnormality, it is a ‘cul-de-sac’ in the ileum.
What is meant by Meckel’s diverticulum following a rule of 2’s?
2% of the population are affected, 2 feet from the ileocecal valve, 2 inches long, detected in under 2’s, 2:1 male:female.
What may Meckel’s diverticulum contain?
Ectopic gastric or pancreatic tissue.
What is a complication of Meckel’s diverticulum?
The ectopic tissue may secrete eznymes and acids into tissues, causing ulceration.
What is a vitelline cyst?
When the vitelline duct forms fibrous strands at either end.
What is a vitelline fistula?
Direct communication between the umbilicus and intestinal tract.
What is the result of vitelline fistulae?
Faecal matter coming out of the umbilicus.
What is omphalocoele?
Persistence of physiological herniation. Part of the gut tube fails to return to the abdominal cavity following its normal herniation into the umbilical cord.
Why does an epithelial layer cover the defect in omphalocoele?
The umbilical cord is covered by a reflection of the amnion.
What is gastroschisis?
The failure of closure of the abdominal wall during folding of the embryo so the gut tube and its derivative are outside the body cavity.
Why does the gut die in gastroschisis?
There is no covering over the gut tube and its derivatives as they herniate through the abdominal wall directly into the amniotic cavity.
What is somatic referred pain?
Pain caused by noxious stimulus to the proximal part of the somatic nerve that is perceived in the distal dermatome of the nerve.