Anatomy Topic 4 Case 1 Flashcards
Describe the protective role of the abdomen
- Abdomen houses elements of the GI tract, spleen and urinary system
- Much of the viscera is under the diaphragm and is protected by the thoracic wall
Describe the abdomen’s role in inspiration
- Abdominal muscles relaxes
- To accommodate expansion of the thoracic cavity
- To cause inferior displacement of abdominal organs during contraction of diaphragm
Describe the abdomen’s role in expiration
- Abdominal muscles contract
- To assist in elevating the domes of the diaphragm
- Reducing thoracic volume
How is intraabdominal pressure increased and what is the purpose of this.
- Contraction of abdominal wall muscles
- Assisting in voiding the contents of the bladder, rectum and in giving birth
Which planes form the four-quadrant pattern
- Transumbilical plane passing through umbilicus at the level of L3/L4
- Vertical median plane passing in the mid-sagittal plane
Which planes form the nine-quadrant pattern?
- Subcostal plane at the level of L3 / rib 10
- Intertubercular plane connecting tubercles of iliac crests and L5
- Midclavicular planes passing in the sagittal plane between the midpoint of the clavicle and
Identify the nine regions of the abdomen
- Right and left hypochdonrium, separated by epigastric region
- Right and left flank, separated by umbilical region
- Right and left groin, separated by the pubic region.
Where is a craniocaudal incision performed and what is the purpose?
- Incision from xiphoid process to pubic symphysis
- Provides access to whole of abdominal contents for an exploratory procedure
What is laparoscopic surgery? Identify an advantage of this type of surgery
- Keyhole surgery through small incisions no more than 2cm in length
- Less postoperative pain and shorter recovery times
What are the palpable landmarks used to delineate the extent of the abdomen?
- Costal margin above
- Pubic tubercle and ASIL above
A line between which structures marks the position of the inguinal ligament? What is the purpose of the inguinal ligament?
- Pubi tubercle and ASIL
- Separates anterior abdominal wall above from thigh below
What is the superficial inguinal ring and where is it located?
- Triangular defect in aponeurosis of external oblique
- External opening of inguinal canal
- In lower medial aspect of anterior abdominal wall
What passes through the superficial inguinal ring in men?
- Spermatic cord
What passes through the superficial inguinal ring in women?
- Round ligament of uterus
What is the deep inguinal ring and where is it located?
- Internal opening to inguinal canal
- Superior to inguinal ligament midway between ASIL and pubic symphysis
Where can the femoral pulse be felt?
- Inferior to inguinal ligament
- Midway between ASIL and pubic symphysis
Where is the transpyloric plane located?
- L1 / rib 9 level
- Transverse plane
- Midway between jugular notch and pubic symphysis
Where is the supracristal plane located
- L4
- Transverse plane
- Through highest point of iliac crests
Identify structures found at the level of L1 / transpyloric plane
- Upper limit of end of duodenum
- Hila of kidneys
- Neck of pancreas
- Origin of superior mesenteric artery
Which major blood vessel originates at the upper border of L1?
- Celiac trunk
Which major blood vessel originates at the lower border of L1?
- Superior mesenteric artery
Which major blood vessel originates at the lower border of L2?
- Renal arteries
Which major blood vessel originates at the lower border of L3?
- Inferior mesenteric artery
Which major blood vessel originates at the lower border of L4?
- Common iliac arteries
Which major blood vessel originates at the lower border of L5?
- Inferior vena cava from right and left common iliac veins
Which organs are in the right upper quadrant?
- Liver and gallbladder
Which organs are in the left upper quadrant?
- Stomach and spleen
Which organs are in the right lower quadrant?
- Cecum and appendix
Which organs are in the left lower quadrant?
- Descending and sigmoid colon
How can the inferior of the liver be palpated?
- Just below right costal margin when patient breathes in deeply
- Can be felt slipping under palpating fingers
Where is McBurney’s point and what is it used to identify?
- One-third the way up a line from right ASIL to umbilicus
- Common surface projection of the appendix
The superior poles of the kidneys reach as high as which ribs?
- Left: 11
- Right: 12
At which vertebral level are the inferior poles of the kidneys?
- L3/L4
At which vertebral level are the hila of the kidneys?
- L1
With relation to surface anatomy where is the spleen located?
- Left side and back in the area of ribs 9 to 11
- Follows the counter of rib 10 and extends from the superior pole of the left kidney to just posterior to the midaxillary line
Identify the boundaries of the abdominal wall
- Superiorly by xiphoid process and costal margins
- Posterior by vertebral column
- Inferiorly by pelvic bones
Identify the layers of the abdominal wall
- Skin
- Superficial fascia
- Muscles and their fascia
- Extraperitoneal fascia
- Parietal peritoneum
What is Camper’s fascia?
- Superficial fatty layer of superficial fascia
- Continuous with the superficial fascia of the thigh
- Forms dartos fascia in men
- Forms labia majora in women
What is Scarpa’s fascia?
- Deep membranous layer of superficial fascia
- It is continuous with the fascia lata in the thigh
What is Colles’ fascia?
- Part of Scarpa’s fascia that is firmly attached to ischiopubic rami and posterior margin of perineal membrane
How does Scarpa’s fascia differ in males and females?
- Males: blends with superficial layer to form dartos fascia, also forms fundiform ligament of penis
- Women: forms labia majora
Identify the five anterolateral muscles
- External oblique
- Internal oblique
- Transversus abdominis
- Rectus abdominis
- Pyramidalis
Identify the combined actions of the anterolateral muscles
- Protection of the viscera
- Maintains position of the viscera
- Quiet and forced expiration
- Increases intraabdominal pressure
Identify the origin, insertion, action and innervation of the external oblique muscle
- Origin: Slips from outer surfaces of ribs 5-12
- Insertion: Lateral lip of iliac crest, aponeurosis ending in linea alba
- Innervation: Anterior rami of T7-T12
- Function: Flexion of trunk, turning anterior part of abdomen to opposite side, compressing abdominal contents
Identify the role of the external oblique in the formation of the inguinal canal
- Lower border of the external oblique aponeurosis forms the inguinal ligament
- Which folds under itself forming a trough
Where does the lacunar ligament form between?
- Medial end of inguinal ligament
- Pectin pubis
Identify the origin, insertion, action and innervation of the internal oblique
- Origin: Thoracolumbar fascia, iliac crest between origins of external oblique and transversus, lateral 2/3 of inguinal ligament
- Insertion: Inferior border of ribs 8 to 12, aponeurosis ending in linea alba, pubic crest and pectineal line
- Innervation: Anterior rami of T7 to L1
- Function: Flexion of trunk, turning anterior part of abdomen to opposite side, compressing abdominal contents
Identify the origin, insertion, action and innervation of the transversalis abdominis muscle
- Origin: Thoracolumbar fascia, medial lip of iliac crest, lateral 1/3 of inguinal ligament, costal cartilages of ribs 7 to 12
- Insertion: Aponeurosis ending in linea alba
- Innervation: T7 to L1
- Action: Compresses abdominal contents
Identify the origin, insertion, action and innervation of rectus abominis
- Origin: Pubic crest, tubercle and symphysis
- Insertion: Costal cartilages of ribs 5-7, xiphoid process
- Innervation: T7-T12
- Function: Compresses abdominal wall, flexion of vertebral column, tenses abdominal wall
Identify the origin, insertion, action and innervation of pyramidalis
- Origin: Front of pubic symphysis
- Insertion: Linea alba
- Innervation: Anterior ramus of T12
- Function: Tenses linea alba
What is the transversalis fascia?
- Layer of deep investing fascia associated with the transversalis muscle
- That lines the abdominal fascia
- Continuous posteriorly with thoracolumbar fascia
- Blends anteriorly with fascia covering pelvic bones to form the parietal pelvic fascia
Where is the extraperitoneal fascia located, where is it most prominent and what does it contain?
- Deep to transversalis fascia and superficial to peritoneum
- More prominent posteriorly (retroperitoneal)
- Contains blood vessels
What is the peritoneum. Where is it located and how does it differ in males and females?
- Thin serous membrane that lines the abdominal walls and reflects onto viscera
- Deep to extraperitoneal fascia
- Closed in men, has two openings in women for passage of uterine tubes
Identify the arterial supply to the superficial superior part of the anterior abdominal wall
- Musculophrenic artery
- The terminal branch of the internal thoracic artery
Identify the arterial supply to the superficial inferior part of the anterior abdominal wall
- Medially by the superficial epigastric artery
- Laterally by the superficial circumflex iliac artery
- Both of which are branches of the femoral artery
Identify the arterial supply to the deep superior part of the anterior abdominal wall
- Superior epigastric artery
- A terminal branch of the internal thoracic artery
Identify the arterial supply to the deep lateral part of the anterior abdominal wall
- Tenth and eleventh intercostal arteries
- Subcostal artery
Identify the arterial supply to the deep inferior part of the anterior abdominal wall
- Medially by the inferior epigastric artery
- Laterally by the deep circumflex iliac artery
- Both of which are branches of the external iliac artery
Which arteries enter the rectus sheath and anastomose?
- Superior and inferior epigastric arteries
Which intercostal nerves are involved in innervation of the anterolateral abdominal wall
- T7 to T11
Outline the pathway of the intercostal nerves supplying the anterolateral abdominal wall
- Leave intercostal spaces
- Pass deep to costal cartilage
- Continue between internal oblique and transversus abdominis muscles
- Enter rectus sheath, posterior to lateral aspect of rectus abdominis
- Approach midline and give off an anterior cutaneous branch
Other than the intercostal nerves, identify three other nerves supplying the anterolateral abdominal wall and their course
- Subcostal nerve (T12) follows similar course as intercostals
- Iliohypogastric and ilioinguinal nerves (L1) branch from lumbar plexus
Which region of skin is supplied by T7-T9?
- Skin from xiphoid process to just above umbilicus
Which region of skin is supplied by T10?
- Umbilicus
Which region of skin is supplied by T11-L1
- Below umbilicus including pubic region
- Ilioinguinal nerve also supplies anterior surface of scrotum, labia majora, and small part of proximal thigh
Outline the superficial lymphatic drainage of the anterior abdominal wall
- Above umbilicus: Axillary nodes
- Below umbilicus: Superior inguinal nodes
Outline the deep lymphatic drainage of the anterior abdominal wall
- Parasternal nodes along internal thoracic artery
- Lumbar nodes along the abdominal aorta
- External iliac nodes along the external iliac artery
At which vertebral levels does the oesophagus start and finish?
- C6 superiorly
- T11 inferiorly
Outline the pathway taken by the oesophagus
- Descends on anterior bodies of vertebrae
- Moves anteriorly and slightly left as it approaches the diaphragm
- Passes through oesophageal hiatus at T10
Which structure passes posterior to the oesophagus?
- Thoracic duct
- Right side inferiorly
- Crosses superiorly onto left side
Which structure passes anterior to the oesophagus?
- Right pulmonary artery and left main bronchus at tracheal bifurcation
At which locations can the trachea be narrowed by surrounding structures? What is the clinical significance of this?
- Junction of oesophagus with pharynx
- Superior mediastinum where it is crossed by aortic arch
- Posterior mediastinum where it is compressed by left main bronchus
- Posterior mediastinum at oesophageal hiatus in the diaphragm
- Swallowed object is most likely to lodge at a constricted area, causing more damage at this site than elsewhere along the oesophagus.
What is the abdominal oesophagus? Where does it emerge and pass between?
- Short distal part of diaphragm
- Right crus at T10
- Passes from oesophageal hiatus to cardiac orifice
Outline the arterial supply to the thoracic oesophagus
- Oesophageal arteries (from aorta)
- Bronchial artereis
- Ascending branches of left gastric artery (from celiac trunk)
Outline the arterial supply to the abdominal oesophagus
- Oesophageal branches from left inferior phrenic artery (from aorta)
Outline the venous drainage of the oesophagus
- Small vessels to azygos vein
- Small vessels to hemiazygos vein
- Oesophageal branches to left gastric vein
Outline the lymphatic drainage of the oesophagus
- Posterior mediastinal nodes
- Left gastric nodes
Identify the sensory innervation of the oesophagus
- Visceral afferents from vagus nerves, sympathetic trunks and splanchnic nerves
What is the oesophageal plexus?
- Right and left vagus nerves give off branches forming oesophageal plexus
- Just above diaphragm many fibres converge
- To form anterior vagal trunk on anterior surface of oesophagus (mainly from left vagus nerve)
- And posterior vagal trunk on posterior surface of oesophagus (mainly from right vagus nerve)
What type of epithelia lines the lumen of the oesophagus?
- Stratified squamous
What is contained within the underlying lamina propria of the oesophagus?
- Lymphoid aggregates
What is contained within the submucosa of the oesophagus?
- Elastin fibres allowing for distension
- Seromucinous glands which aid lubrication and are most prominent in the upper and lower thirds
Identify the two layers of muscle in the muscularis propria?
- Outer longitudinal fibres
- Inner circular fibres
What is Barret’s oesophagus?
- Epithelium in lower oesophagus undergoes metaplasia
- From stratified squamous epithelia to columnar-mucus secreting epithelia
- High risk of developing dysplasia and invasive adenocarcinoma
Identify the four distinct functional layers of the GI tract
- Mucosa: Epithelia, lamina propria, muscularis mucosa
- Submucosa: contains blood vessels, lymphatics and nerves
- Muscularis propria (outer longitudinal, inner circular fibres)
- Adventitia: loose supporting tissue that conducts vessels, nerve and adipose tissue.
What is the rectus sheath?
- Sheath that encloses the rectus abdominis and pyramidalis
- Composed of the aponeurosis of the external and internal oblique, and the transversus abdominis muscle
Describe the arrangement of the rectus sheath in the upper three quarters of the rectus abdominis
- Anterior wall from external oblique and half of internal oblique
- Posterior wall from half of internal oblique and the transversus abdominis
Describe the arrangement of the rectus sheath in the lower quarters of the rectus abdominis
- Anterior wall from aponeurosis of all three muscles
- No posterior wall
What is the arcuate line and what is its position?
- Point of transition of rectus sheath
- Halfway between umbilicus and pubic symphysis
