Lectures 1 And 2- Anterior Abdominal Wall Outline Cont. Flashcards
Actions of abdominal muscles
-Flexion of trunk and pelvis?
-Contraction of EO, IO, and RA muscles bilaterally
Abduction (lateral flexion) of trunk?
Contraction of EO and IO together on one side
Rotation of trunk?
Contraction of EO on one side and contraction of IO on the opposite side (fibers of EO on one side run in same direction as those of IO on other side)
Respiration?
Assist in forced expiration by compressing abdominal contents, forcing viscera up against diaphragm
Fixation of abdominal wall
Contraction of abdominal and thoracic muscles together, with glottis closed, raises thoracoabdominal pressure (Valsalva maneuver)
Abdominal wall muscles also act in?
Coughing, sneezing, urination, defecation, emesis, parturition
Fascia of the anterior abdominal wall
-Superficial (subcutaneous)-2 layers?
- Camper’s fascia
- Scarpa’s fascia
Camper’s fascia
- Type of fascia?
- Continuous with?
- Fatty superficial layer
- Continuous with superficial fatty fascia of thorax, thigh, and perineal fascia
Scarpa’s fascia
-Continuous with?
-Continuous with fascia lata of thigh, deep layer of superficial perineal fascia (Colles’ fascia), and fibrous fascial sheath of penis/clitoris
Scarpa’s fascia
-Fuses with?
Deep fascia of abdomen
Layer that holds sutures?
Scarpa’s fascia
Deep fascia of abdominal wall (investing fascia of abdominal muscles)
-Thin, tough investing fascia of muscles and aponeuroses
Deep fascia of abdominal wall (investing fascia of abdominal muscles)
-Where does it stop?
-“Stops” at the thigh as it fuses with fascia lata
Deep fascia of abdominal wall (investing fascia of abdominal muscles)
-Continues over Spermatic cord as?
-Continues over spermatic cord as external spermatic fascia
Deep fascia of abdominal wall (investing fascia of abdominal muscles)
-Continues over pubis and perineal muscles as?
Deep perineal fascia
Deep fascia of abdominal wall (investing fascia of abdominal muscles)
-Continues over penis/clitoris as?
Deep penile/clitoral fascia
Deep fascia of abdominal wall (investing fascia of abdominal muscles)
- Thoracolumbar fascia of lumbar region of back and anterolateral wall
- Origin for?
Origin for internal oblique and transversus abdominis muscles
Deep fascia of abdominal wall (investing fascia of abdominal muscles)
- Thoracolumbar fascia of lumbar region of back and anterolateral wall
- Splits into?
-Splits into 3 laminae that enclose deep back muscles and quadratus lumborum muscle of posterior abdominal wall
Fascial layers associated with anterior abdominal wall muscles
-Rectus sheath-Encloses?
Encloses rectus abdominis (and pyramidalis if present)
Fascial layers associated with anterior abdominal wall muscles
-Rectus sheath-Contains what nerves?
Contains anterior rami of lower 6 thoracic nerves, superior and inferior Epigastric vessels and lymphatics
Fascial layers associated with anterior abdominal wall muscles
-Rectus sheath-Formed by fusion of?
Formed by fusion of the EO, IO, and transversus abdominis aponeuroses
Fascial layers associated with anterior abdominal wall muscles
-Rectus sheath-What happens to the IO aponeurosis above the arcuate line?
IO aponeurosis splits into two layers-anterior and posterior layers
IO aponeurosis-above arcuate line-splits into two layers
-Anterior layer?
-The anterior layer of sheath is formed by fusion of EO aponeurosis and anterior portion of the split IO aponeurosis
IO aponeurosis-above arcuate line-splits into two layers
-posterior layer?
The posterior layer is formed by fusion of the posterior layer of the split IO aponeurosis and the transversus abdominis aponeurosis
Fascial layers associated with anterior abdominal wall muscles
-Rectus sheath-What happens to the IO aponeurosis below the arcuate line?
- There is an anterior layer ONLY
- Rectus abdominis lies directly on transversalis fascia
IO aponeurosis-below arcuate line
-Anterior layer is formed by?
Fusion of all 3 muscles: EO, IO, and transversus abdominis
Arcuate line
- Inferior free edge of the posterior part of the rectus sheath
- Located about midway between umbilicus and pubic crest (or symphysis)
Transversalis fascia
-What is it?
-Thin, rather transparent membrane
Transversalis fascia
-Location relative to transversus abdominis?
-Lies on the deep surface of transversus abdominis m and aponeurosis
Transversalis fascia
-Specialized regions (named according to structures it is associated with)?
- Diaphragm
- Iliacus muscle
- psoas muscle
- femoral artery
Transversalis fascia
-Separated from peritoneal membrane (lining of abdominal cavity) in some areas by?
A layer of extra-peritoneal fat
Linea alba ("white line") -What is it?
Anterior midline where aponeurotic fibers of the rectus sheath interlace to form a tough raphe
Layers of abdominal wall at level of umbilicus, just lateral to midline, through the rectus sheath are?
- Skin
- Superficial fascia
- Camper’s layer
- Scarpa’s layer
- Anterior layer of rectus sheath
- Rectus abdominis muscle
- Posterior layer of rectus sheath
- Transversalis fascia
- Extraperitoneal CT and fat
- Peritoneum
Arterial supply of the anterior abdominal wall
- General considerations-Arterial supply to abdominal wall is derived from several sources, providing opportunities for collateral circulation via anastomoses between the sources
- 2 main sources?
- Superficial vessels
- Deep vessels
Arterial supply of anterior abdominal wall
-Deep vessels run their course in what layer?
Deep vessels run their course within the muscular layer
Arterial supply of anterior abdominal wall
-Deep vessels have 3 possible origins?
- Originate superiorly from subclavian artery
- Originate in mid-abdomen from aorta
- Originate inferiorly from external iliac artery
Arterial supply of anterior abdominal wall
-Superficial vessels run their course in what layer?
Superficial vessels run their course in the subcutaneous connective tissue
Arterial supply of anterior abdominal wall
-Superficial vessels have 2 possible origins?
- Originate from perforating branches of deeper vessels located within muscular layer
- Originate from branches of the femoral artery
Deep vascular system
- Superior epigastric artery
- Arises from?
- Arises from internal thoracic artery (a branch of subclavian)
- Internal thoracic artery branches into musculophrenic and superior epigastric
Deep vascular system
- Superior epigastric artery
- Where does it enter the rectus sheath?
Beneath the costal margin
Deep vascular system
- Superior epigastric artery
- Anastomoses with? Where do they anastomose?
Anastomoses with inferior epigastric artery within rectus abdominis muscle
Deep vascular system
- Superior epigastric artery
- Supplies?
Upper central part of anterior abdominal wall
Deep vascular system
- Inferior epigastric artery
- Arises from?
Arises from external iliac artery just above inguinal ligament
Deep vascular system
- Inferior epigastric artery
- Where does it run?
- Runs superomedially along medial side of deep inguinal ring
- Courses toward umbilicus in extraperitoneal (subserous) CT, raising along with its accompanying vein the lateral umbilical fold on the internal aspect of the anterior abdominal wall
Deep vascular system
- Inferior epigastric artery
- Where does it enter the rectus sheath?
Pierces transversalis fascia at level of arcuate line to enter rectus sheath
Deep vascular system
- Inferior epigastric artery
- Anastomoses with? Where?
Anastomoses with superior epigastric artery within rectus abdominis muscle
Clinical relevance of the epigastric arterial anastomosis?
- Epigastric arterial anastomosis can provide collateral circulation to lower part of body when the aorta is occluded
- Pulsations of epigastric arteries in such a case can erode the adjacent ribs, producing a radiographically observable “notched rib” sign
Other major (deep) anterior abdominal arteries
- Musculophrenic artery
- Arises from?
Bifurcation of internal thoracic artery (internal thoracic splits into superior epigastric and musculophrenic)
Other major (deep) anterior abdominal arteries
- Musculophrenic artery
- where does it run its course?
Runs along the costal margin
Other major (deep) anterior abdominal arteries
- Musculophrenic artery
- Supplies?
Supplies branches to abdominal wall and diaphragm
Posterior intercostal arteries 10/11 and subcostal artery
-Arise from?
-Arise from thoracic aorta and extend ventromedially beyond costal margin onto abdominal wall, lying between transversus abdominis and internal oblique
Posterior intercostal arteries 10/11 and subcostal artery
-Where do they enter the rectus sheath?
Enter rectus sheath laterally to anastomose with epigastric arteries
Lumbar arteries
- Abdominal counterparts of?
- How many are there?
- Abdominal counterparts of posterior intercostal arteries
- Four on each side
Lumbar arteries
- Arise from?
- Where do they run?
- Abdominal aorta at level of lumbar vertebra 1-4
- Course laterally to provide branches to posterior and posterolateral abdominal wall muscles
Deep circumflex iliac artery
-Arises from?
Arises from external iliac artery
Deep circumflex iliac artery
-Where does it run?
-Runs deep to inguinal ligament toward ASIS, then along iliac crest
Deep circumflex iliac artery
-Supplies?
Supplies deep inguinal region of lower lateral part of abdominal wall
Deep circumflex iliac artery
-Anastomoses with?
Anastomoses with lower intercostal arteries by an ascending branch
The superficial arteries arise from what artery? Run in what fascia?
Femoral artery and run in the superficial fascia
Superficial arteries
- Superficial circumflex iliac artery
- Goes to what region?
Iliac region
Superficial arteries
- Superficial epigastric artery
- Goes to what region?
Umbilical region
Superficial arteries
- External pudendal artery
- Goes to what regions?
Suprapubic, pubic, and genital regions
Superficial arteries
-Anastomose with?
Perforating branches of deep arteries
Venous drainage of the anterior abdominal wall
General considerations?
Superficial and deep veins tend to run with arteries of the same name
Superficial drainage (of skin and subcutaneous tissue) -Main drainage pathway?
Drain superiorly to axillary vein via thoracic and thoracoepigastric veins
Superficial drainage (of skin and subcutaneous tissue)
- Variably developed connections between?
- What do each of these drain into?
-Variably developed connections between lateral thoracic veins (axillary vein tributaries) and superficial epigastric vein (femoral vein tributaries)
Superficial drainage
-Variably developed connections between lateral thoracic veins (axillary vein tributaries) and superficial epigastric vein (femoral vein tributaries)
One of these is a system of veins that follows the former umbilical artery (paraumbilical veins) and connect to the superficial veins within the fatty layer of the anterior abdominal wall
Superficial veins
- Variably developed connections between lateral thoracic veins (axillary vein tributaries) and superficial epigastric vein (femoral vein tributaries) - When these veins are enlarged they form?
A “caput medusae”
Superficial veins
-This superficial system of veins drains inferiorly to the?
femoral vein via superficial tributaries that empty through saphenous opening in femoral triangle
Superficial veins
- This superficial system of veins drains inferiorly to the femoral vein via superficial tributaries that empty through saphenous opening in femoral triangle
- 4 veins?
- Superficial epigastric, superficial circumflex iliac, superficial external, pudendal
- May empty independently into femoral vein
Deep drainage of (muscular wall) via veins that accompany deep arteries of same name
-Tributaries to subclavian vein?
Superior epigastric and musculophrenic
Tributaries to external iliac vein?
Inferior epigastric and deep circumflex iliac
Tributaries to inferior vena cava?
Lumbar veins
Tributaries to azygous system?
-Ultimately goes to?
- Posterior intercostal veins 10/11 and subcostal vein
- Ultimately goes to superior vena cava
Veins of abdominal wall
- Clinical note about veins of the abdominal wall?
- If IVC is obstructed?
- Veins of the abdominal wall anastomose to a high degree
- If IVC is obstructed, blood may flow from inferior epigastric to superior epigastric via anastomoses the to subclavian vein to SVC
Lymphatic of anterior abdominal wall
-Subcutaneous lymphatics usually drain to?
Subcutaneous lymphatics usually drain to superficial lymph nodes located in the subcutaneous tissue of thigh and thorax (axilla)
Lymphatic of anterior abdominal wall
-Lymphatics of the muscular abdominal wall and testes drain to?
Internal nodes of the abdomen and thorax
Superficial layers (skin, subcutaneous CT) of abdomen, perineum, and external genitalia drain as follows: -Above the umbilicus?
Cutaneous and subcutaneous lymphatics drain toward sternal and axillary LNs
Superficial layers (skin, subcutaneous CT) of abdomen, perineum, and external genitalia drain as follows: -Below the umbilicus?
Cutaneous and subcutaneous lymphatics drain toward superficial inguinal nodes
-(superficial inguinal nodes are arranged in a “T” located just inferior to the inguinal ligament. They receive drainage from the lower abdomen, perineum and genitalia, and lower limb)
Lymphatic drainage of the muscular layers of the abdominal wall parallels the major vascular supplies
-Four main groups?
- Along the inferior epigastric vessels to the external iliac nodes
- Along the deep circumflex iliac vessels to the external iliac nodes
- Along the lumbar vessels to the lumbar nodes
- Along the superior epigastric vessels to the sternal nodes
Lymphatic drainage of the muscular layers of the abdominal wall parallels the major vascular supplies
- Along the inferior epigastric vessels to the external iliac nodes
- Found along the?
Found along the external iliac artery
Lymphatic drainage of the muscular layers of the abdominal wall parallels the major vascular supplies
- Along the lumbar vessels to the lumbar node
- Found along the?
Lumbar part of the aorta and IVC
Lymphatic drainage of the muscular layers of the abdominal wall parallels the major vascular supplies
- Along the superior epigastric vessels to the sternal nodes
- Found along the?
Internal thoracic vessels
Nerves of the anterior abdominal wall
-Dermatomes of abdominal wall are supplied by?
Cutaneous sensory branches of ventral rami of spinal nerves T7-L1
Muscles of abdominal wall
-Innervated by?
Ventral rami of of spinal nerves T7-L4
Muscles of abdominal wall
-abdominal branches of T7-T11 arise from what nerves?
Intercostal nerves
Muscles of abdominal wall
-Abdominal branches of T12 arise from what nerves?
Subcostal nerves
Muscles of abdominal wall
-Abdominal branches of ventral rami of L1-L4 originate within the?
Lumbar plexus
Thoracoabdominal intercostal nerves (T7-T12)
- Where are they located?
- Run in between what muscles?
- Run in what plane?
- Continue beyond costal margin onto abdominal wall
- Lie between internal oblique and transversus abdominis muscles
- Run in neurovascular plane
- Run with arteries and veins
Thoracoabdominal intercostal nerves (T7-T12)
-Pierce the rectus sheath to innervate what muscle?
Rectus abdominis
Thoracoabdominal intercostal nerves (T7-T12)
-Supply?
Supply skin, muscles, and parietal peritoneum
Thoracoabdominal intercostal nerves (T7-T12)
-Branch to form?
Branch to form lateral cutaneous branches and anterior cutaneous branches
Thoracoabdominal intercostal nerves (T7-T12)
- Lateral cutaneous branches
- Where do they arise?
- Pierce abdominal muscles to reach?
- Bifurcate into?
- Arise at about anterior axillary line
- Pierce abdominal muscles to reach dermis
- Bifurcate into anterior and posterior branches
Thoracoabdominal intercostal nerves (T7-T12)
- Anterior cutaneous branches - Arise as? - How do they get to the dermis? - Bifurcate into?
- Arise as terminal branches of the ventral rami
- Enter rectus sheath laterally and exit from it anteriorly to reach the dermis
- Bifurcate into medial and lateral branches
Lumbar nerves 1 and 2
- Are part of lumbar plexus
- Formed by?
- 2 divisions?
- Lumbar plexus is formed by ventral primary rami of T12 through L4 nerves
- Plexus has anterior and posterior divisions
Iliohypogastric and ilioinguinal nerves supply?
Iliohypogastric and ilioinguinal nerves supply cutaneous sensation to the hypogastric, inguinal, anterior perineal, and superomedial thigh regions
Iliohypogastric (L1, sometimes with contribution from L2 and/or T12)
- Where does it Pierce IO?
- Where does it run?
Superomedial to ASIS and runs inferomedially between IO and EO muscles
Iliohypogastric
-Sends a lateral branch to the?
Skin of the gluteal region
Iliohypogastric
-Innervates?
Innervates anterolateral abdominal muscles
Iliohypogastric
-Communicates with?
Ilioinguinal nerve
Iliohypogastric
-terminates as?
Terminates as anterior cutaneous branches to hypogastric (suprapubic) regions
Ilioinguinal (L1)
- Where is it located?
- Enters?
- Where does it run?
- Emerges through?
- Lies parallel and slightly inferior to iliohypogastric nerve
- Enters inguinal canal
- Runs on surface of spermatic cord or round ligament of uterus
- Emerges through superficial inguinal ring
Ilioinguinal
-Supplies skin of?
Supplies skin of groin and scrotum/labium majus
Genitofemoral n (L1, L2) -Exits the? Runs through?
-Exits the intervertebral foramen and runs through the psoas muscle
Genitofemoral n (L1, L2)
- Divides into what 2 branches?
- What do the branches run In between?
- Divides into a genital branch and a femoral branch and a femoral branch either within the muscle or after emerging from the muscle
- The branches run in between the muscle and the overlying peritoneum
Genitofemoral n
-Genital branch enters? Passes through? Emerges through?
Genital branch enters the deep inguinal ring, passes through the inguinal canal and emerges through the superficial inguinal ring
Genitofemoral n
- Genital branch supplies
- in males?
- in females?
- In males the genital branch supplies the cremaster muscle and skin of the scrotum
- In females the genital branch supplies the skin of the labium majora
Genitofemoral n
- Femoral branch
- Where does it exit the abdomen?
The femoral branch exits the abdomen inferior to the inguinal ligament (sometimes through the femoral sheath)
Genitofemoral n
- Femoral branch
- Supplies?
Supplies the skin of the thigh over the femoral triangle
Hernias of the upper abdominal wall
-What is a hernia?
Protrusion of any of the abdominal contents outside of the abdominal cavity
-includes herniations through the diaphragm, umbilicus, or any other weak spots in abdominal wall
Umbilical hernias in infants
- The ‘scar’ of the umbilicus doesn’t heal completely
- Will usually heal with time
Umbilical hernias in adults
- Result from?
- How are they fixed?
- More common in which gender?
- Result from a weakened abdominal wall around the umbilicus
- Require surgical repair
- More common in females
Umbilical hernias in adults
-Where are they usually located?
Usually superior to umbilical scar
Epigastric hernias
- compare to umbilical hernias?
- protrude through?
- How are they fixed?
- Do not involve the umbilicus
- Herniations that protrude through the linea alba
- Repaired surgically if large or symptomatic
Epigastric hernias
-Where are they usually located?
-Usually superior to the umbilicus
Incisional hernias
-Where do they occur?
Can occur at surgical/laparotomy sites
Spigelian hernias
-Where are they located?
Hernias located at the semilunar line of the anterior rectus sheath