Abdomen Flashcards
Where is the abdomen located?
Between thorax and pelvis
What separates the thoracic cavity?
Thoracic diaphragm
Why is the abdomen divided into regions?
Descriptive purposes
What may abdomen regions assist with?
Identifying source of pain
What are the two abdomen regions?
Quadrants or 9 regions
What are the two planes in the quadrant region?
- Horizontal = transumbilical
- Vertical = median
What are the planes that make up the 9 regions of the abdomen?
Subcostal: passes through inferior borders of 10th costal cartilages
Transtubercular: passes through iliac tubercles located approx. 5cm posterior to ASIS, at lvl of L5
Midclavicular (2): Mid point of clavicles to midinguinal points (1/2 way between the ADID and the pubic symphysis)
How to remember subcostal plane?
sub = under
costal = ribs
under ribs
How to remember transtubercular plae?
trans = across
tubercular = tubercles
across (iliac) tubercles
How to remember mid clavicular?
mid = middle
calvicular = clavicle
mid clavicle
What does the anterolateral abdominal wall consist of?
Skin, subcutaneous tissue, muscles, deep fascia, extraperitoneal fat, parietal peritoneum
What are the aterior abdominal wall muscles from superficial to deep?
- External oblique
- Internal oblique
- Transverse abdominal muscle
What is another name for extraperitoneal fat?
Endoabdominal fat
What are the flat anterior abdominal muscles?
Exteral oblique (superficial)
Internal oblique (intermediate)
Transverse abdominal (innermost)
What are the vertical anterior abdominal muscles?
Rectus abdominis
Pyramidalis
External oblique origin and insertion
O: Ext. surface of ribs 5-12
I: Linea alba, pubic tubercle, ant. 1/2 iliac crest
External oblique nerve supply and actions
N: Thoracoabdominal nn (vetral rami inf. 6 thoracic nn) and subcostal n
A: Flexion and contralateral rotation of trunk
What direction do the fibres of external oblique run?
Inferomedially
What does the inferior margin of the external oblique aponeurosis form?
Inguinal ligament
Internal Oblique origin and insertion
O: Thoracolumbar fascia, ant. 2/3 iliac crest, lat 1/2 inguinal lig
I: Inferior borders of ribs 10-12, pectineal line via conjoint tendon
Internal Oblique nerve supply and actions
N: Thoracoabdomial nn (ventral rami inf. 6 thoracic nns) and first lumbar n
A: Flexion and ipsilateral rotation of trunk, compression and support of abdominal viscera
What direction do the internal oblique fibres run?
Horizontally: at level of ASIS
Obliquely upward: superior to ASIS
Obliquely downward: inferior to ASIS
Tranverse abdominal origin and insertions
O: Inf. surfaces of costal cartilages 7-12, thoracolumbar fascia, iliac crest, lateral 1/3 of inguinal lig.
I: Linea alba with aponeurosis of internal oblique, pubic crest and pectineal line via conjoint tendon
Transverse abdominal nerve supply and actions
N: AThoracoabdominal nn (ventral rami inf. 6 thoracic nn) and first lumbar n
A: Compression ad support of abdominal viscera
What direction do the fibres of traverse abdominal travel?
Transversomedially
Inferior fibres run parallel to fibres of IO
What do all the flat muscles end in?
Sheet-like aponeurosis
Where do the aponeurosis interlace and what do they form?
Linea alba and form the tough, tendinous rectus sheath
What is intramuscular exchange?
Aponeurosis of the left external oblique will cross at the linea alba and communicate with the fibres of the right external oblique
What is intermuscular exchange?
Right INTERAL oblique fibres will intercept with the fibres of the left EXTERNAL oblique at the midclavicular line
What does the interlacing of fibres cause?
Rectus sheath
What muscle runs in the rectus sheath?
Rectus abdominis
Rectus abdominis origin and insertions
O/Distal: pubic symphysis ad pubic crest
I/Proximal: Xiphoid process and costal cartilages 5-7
Rectus abdominis nerve supply and actions
N: Thoracoabdominal nn (ventral rami of inf. 6 thoracic nn)
A: Flexes trunk; compression and support of abdominal viscera
Where is most of the rectus abdominis found?
Mostly in rectus sheath
Where is the rectus abdominis anchored?
Transversely to ant. layer of rectus sheath at tendinous intersections
What forms the openings of each end of the inguinal canal?
Lateral end: deep inguinal ring
Medial end: superficial inguinal ring
What is the deep inguinal ring?
Opening in the transversalis fascia
What is the superficial inguinal ring?
Opening in exteral oblique aponeurosis
What is the inguinal canal?
Anatomical passageway - 4cm in length (adults)
Runs in oblique, inferomedial direction across the anterolateral abdominal wall
What is the anterior wall of the inguinal canal?
Aponeurosis of external oblique
What is the posterior wall of the inguinal canal?
Transversalis fascia
Conjoint tendon of internal oblique and transverse abdominal mm
What is the floor of the inguinal canal?
Inguinal ligament
- Folds back on itself to form a trough
What is the roof of the inguinal canal?
Fibres of internal oblique and transverse abdominal mm
What is the contents of the inguinal canal?
Males: Spermatic cord
Females: Round ligament of uterus, nerves, vessels ad lymphatics
Where is the parietal peritoneum and what separates it?
Deep to transversalis fascia
Separated by variable amount of extraperitoneal (endoabdominal fat)