Abdomen Flashcards
(28 cards)
Bony framework for abdominal musculature
-Adjacent cavities (thorax and pelvis) have a greater bony contribution to their walls than the abdomen
-Abdominal muscles use some of the bony landmarks in these adjacent regions for attachment
-Antero-lateral abdominal muscles anchor to: costal margin and ribs/ iliac crest and ASIS/ pubic tubercle, crest and symphysis
External Oblique
-The outer muscular layer
-EO has an inferomedial fibre direction
Attachments:
Ribs 5-12 (passes over costal margin)
* Iliac crest
* Pubic tubercle (via EO aponeurosis)
* Linea alba
Inguinal ligament
attaches from the ASIS to the pubic tubercle
Internal Oblique
-The middle muscular layer
-Has a superomedial fibre direction
Attachment:
Iliac crest, inguinal ligament
* Costal margin
* Linea alba (via IO aponeurosis)
* Pubic crest (via conjoint tendon)
Transverse Abdominis
-Deepest of muscular layers
-Transverse fibre orientation
Attachments:
Costal margin, Iliac crest and inguinal ligament
* Linea alba (via IO aponeurosis)
* Pubic crest (via conjoint tendon)
Rectus Abdominis
-Most anterior muscle of the abdominal wall
-Vertically orientated fibres divided by tendinous intersections
-Muscle fibres are enclosed by the rectus sheath
Attachment:
Xiphoid process, 5th-7th costal cartilages
* Pubic symphysis and crest
Anterolateral abdominal wall layer
skin > superficial fascia > external oblique > internal oblique > transverse abdominis > transversalis fascia > peritoneum
Inguinal canal
-Short oblique passage through the abdominal wall layers
-Begins at the deep inguinal ring and finishes at the superficial inguinal ring
Provides pathway for relocation of gonadal structures during fetal development
* Spermatic cord in males
* Round ligament of the uterus in females
* Neurovasculature for external genitalia
Bony framework for abdominal musculature
Posterior abdominal wall muscles anchor to:
-Lumbar vertebrae
-Inferior rib (rib 12)
-Iliac bone (iliac crest and fossa)
-Femur (lesser trochanter)
Posterior abdominal wall
Psoas major > anchors strongly onto the lumbar vertebrae
Iliacus > primary hip flexor
Quadratus lumborum > assists in stabilising rib 12 and produce trunk lateral flexion
Peritoneum
-Serous membrane- lining the abdominal cavity wall and many viscera
-Parietal and visceral peritoneum
Viscera can be described as intraperitoneal or retroperitoneal:
‘Intra’- viscera enclosed by peritoneum
‘Retro’- viscera are on the posterior abdominal wall, posterior to peritoneum
Peritoneal reflections: mesenteries
Double layer folds of peritoneum that form during embryonical development and connect the gut tube to the abdominal wall
Two functions:
1. Mobility for viscera
2. Pathway for neurovascular supply to/from viscera
- Mesentery
-Connect viscera with abdominal wall
-Embryologically we begin with ventral and dorsal mesentery - Omenta
-Connect stomach and proximal duodenum with other viscera - Peritoneal ‘ligaments’
-Connect viscera with another viscera or abdominal wall
N.B- ‘Omenta’ are subdivided into peritoneal ligaments
Greater omentum
-Double layered large fold of peritoneum
-Attaches to the greater curvature of the stomach and 1st part of duodenum
-Drapes down in the anterior abdominal cavity before folding back upon itself posteriorly
-Ascends to attach to transverse colon
Lesser Omentum
-Extends from the lesser curvature of the stomach and 1st part of duodenum to attach to the visceral surface of the liver
1. Hepatotactic ligament
-Broad sheet attaching liver to stomach
2. Hepatoduodenal ligament
-Free edge of lesser omentum, attaching liver to duodenum
-Contains portal triad
‘The Mesentery’
MESENTERY OF THE SMALL INTESTINE
Oesophagus
-Extends from pharynx to the stomach
-Thorax: superior and posterior mediastinum
-Abdomen: small journey to stomach
Stomach
-Primarily in upper left quadrant
-4 major region: cardia, fundus, body, pyloric area
-Lesser and greater curvatures
-Gastric rugae accommodate stomach expansion/ pyloric sphincter
Small Intestine- Duodenum
-Extends from the stomach to the jejunum
-Receives contents from stomach for digestion and juices from the liver and pancreas to aid digestion
-Retroperitoneal
-Initial aspect of duodenum is mobile and attaches to liver by hepatoduodenal ligament
Liver
-Mainly in right upper quadrant
-Functions: bile production, processing absorbed nutrients
-Diaphragmatic surface + visceral surface
-Blood supply is venous (portal vein)
Gall Bladder
-Pear shaped sac on visceral surface of liver, wedged in fossa between the right and quadrate lobes
-Receives, stores and concentrates bile from the liver
-Empties into the cystic duct, a component of the bile duct system
Pancreas
-Very deep (retroperitoneal) with abdominal cavity
-Head (with uncinate process), neck, body and tail
-Close anatomical relationship with many structures e.g- duodenum
Pancreatic ducts
-Pancreas produces digestive enzymes
-Main pancreatic duct begins in the tail and merges with bile duct to empty in duodenum
-Accessory pancreatic duct also empties into duodenum superiorly
Small Intestine
Jejunum
-Begins at duodeno-jejunal flexure
-Largely in left upper quadrant
-Larger diameter and thicker walls
-More prominent luminal folds (pilcae circulares)
Illeum
-Largely in right lower quadrant
-Smaller diameter and thinner walls
-Less prominent and prevalent pilcae circulares
-Ends at ileocaecal junction- emptying contents into large intestine
Large Intestine
-Begins at caecum at the ileocecal junction
-Components: caecum, ascending colon, transverse colon, descending colon, sigmoid colon
-Major flexures: right colic flexure, left colic flexure
-Taeniae Coli: Longitudinal bands of smooth muscle
-Haustra: sacculation of the colon
-Omental Appendices: small pouches of peritoneum filled with fat
