Anatomy Flashcards

1
Q

Retroperitoneal structures include GI structures that lack mesentery and non-GI structures.

A

Suprarenal (adrenal) glands

Aorta + IVC

Duodenum (2nd through 4th parts)

Pancreas (except tail)

Ureters

Colon (descending and ascending)

Kidneys

Esophagus (thoracic portion)

Rectum (partially)

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2
Q

Important gastrointestinal ligaments (6)

A
  1. Falciform
  2. Hepatoduodenal
  3. Gastrohepatic
  4. Gastrocolic
  5. Gastrosplenic
  6. Splenorenal
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3
Q

Falciform ligament

A
  • Connects: liver to anterior abdominal wall
  • Structures contained:
    • Ligamentum teres hepatis (derivative of fetal umbilical vein)
  • Notes:
    • Derivative of ventral mesentery
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4
Q

Hepatoduodenal ligament

A
  • Connects: liver to duodenum
  • Structures contained:
    • Portal triad - proper hepatic a., portal vein, common bile duct
  • Notes:
    • Pringle maneuver - ligament may be compressed between thumb and index finger (placed in omental foramen to control bleeding)
    • Borders omental foramen (foramen of Winslow), which connects greater and lesser sacs
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5
Q

Gastrohepatic ligament

A
  • Connects liver to lesser curvature of stomach
  • Structures contained:
    • Gastric arteries
  • Notes:
    • Separates greater and lesser sacs on the right
    • May be cut during surgery to access lesser sac
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6
Q

Gastrocolic ligament

A
  • Connects greater curvature and transverse colon
  • Structures contained:
    • Gastroepiploic arteries
  • Notes:
    • Part of greater omentum
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7
Q

Gastrosplenic ligament

A
  • Connects: Greater curvature and spleen
  • Contains:
    • Short gastrics, left gastroepiploic vessels
  • Notes:
    • Separates greater and lesser sacs on the left
    • Part of greater omentum
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8
Q

Splenorenal ligament

A
  • Connects: Spleen to posterior abdominal wall
  • Structures contained:
    • Splenic artery and vein, tail of pancreas
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9
Q

Digestive Tract Anatomy

Layers of the gut (inside to outside - MSMS)

A
  • Mucosa - epithelium, lamina propria, muscularis mucosa
  • Submucosa - submucosal nerve plexus (Meissner), secretes fluid
  • Muscularis externa - myenteric nerve plexus (Auerbach), motility
  • Serosa (when intraperitoneal), adventitia (when retroperitoneal)
    • Vasculature
    • Lymphatics

Ulcers can extend into submucosa, inner or outer muscular layer.

Erosions = mucosa only

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10
Q

Frequencies of basal electric rhythm (slow waves)

A
  • Stomach - 3 waves/min
  • Duodenum - 12 waves/min
  • Ileum - 8-9 waves/min
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11
Q

Digestive Tract Histology

Esophagus

Stomach

Duodenum

Jejunum

Ileum

Colon

A
  • Esophagus:
    • nonkeratinized stratified squamous epithelium
  • Stomach:
    • gastric glands
  • Duodenum:
    • villi and microvilli increase absorptive surface
    • brunner glands (HCO3- secreting cells of submucosa)
    • crypts of Lieberkuhn
  • Jejunum
    • Plicae circulares
    • crypts of lieberkuhn
  • Ileum
    • Peyer patches (lymphoid aggregates in lamina propria, submucosa)
    • Plicae circulares (proximal ileum)
    • crypts of lieberkuhn
    • Largest number of goblet cells in small intestine
  • Colon
    • crypts of lieberkuhn but NO VILLI
    • Abundant goblet cells
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12
Q

Abdominal aorta and branches

A

Arteries supplying GI structures branch anteriorly.

Arteries supplying non-GI structures branch laterally and posteriorly.

“BiFOURcation” at L4

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13
Q

SMA (Wilkie’s) Syndrome

A

Intermittent intestinal obstruction symptoms (primarily postprandial pain) when transverse (third) portion of duodenum is compressed between SMA and aorta

Typically occurs in conditions associated with diminished mesenteric fat (e.g., low body weight/malnutrition)

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14
Q

GI Blood Supply and Innervation: Foregut

A

Artery: Celiac trunk (L gastric, common hepatic, splenic)

PSNS: Vagus

SNS: T5-T11

Vertebral level: T12-L1

Structures supplied:

  • Pharynx (vagus nerve only), lower esophagus (celiac artery only) to proximal duodenum
  • Liver, gallbladder, pancreas, spleen (mesoderm)
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15
Q

GI Blood Supply and Innervation: Midgut

A

Artery: SMA

PSNS: Vagus

SNS: T11-T12

Vertebral level: L1

Structures supplied:

  • Distal duodenum to proximal 2/3 transverse colon
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16
Q

GI Blood Supply and Innervation: Hindgut

A

Artery: IMA

PSNS: S2-S4

SNS: L1-L2

Vertebral level: L3

Structures supplied:

  • Distal 1/3 transverse colon to upper portion of rectum
17
Q

Celiac Trunk = main blood supply of stomach

Strong anastomoses exist between:

A

Common hepatic artery, L gastric a., splenic artery

Anastomoses:

L and R gastroepiploics

L and R gastrics

18
Q

Portosystemic anastomoses (3)

Site of anastamosis

Clinical Sign

Portal Systemic

Treatment

A
  1. Esophagus
    1. Esophageal varices
    2. Left gastric azygos
  2. Umbilicus
    1. Caput medusae
    2. Paraumbilical small epigastric veins of anterior abdominal wall
  3. Rectum
    1. Anorectal varices
    2. Superior rectal middle and inferior rectal

Treatment: TIPS (transjugular intrahepatic portosystemic shunt) b/w portal vein and hepatic vein relieves portal HTN by shunting blood to systemic circulation, bypassing liver

19
Q

Pectinate (dentate) line

A

Formed where endoderm (hindgut) meets ectoderm

20
Q

Above pectinate line issues

Blood supply

Lymphatic drainage

A

Internal hemorrhoids, adenocarcinoma

**Internal hemorrhoids receive visceral innervation –> not painful

Arterial supply: superior rectal artery (branch of IMA)

Venous drainage: superior rectal vein –> inferior mesenteric vein –> portal system

Lymphatic drainage to internal iliac lymph nodes

21
Q

Below pectinate line issues

Blood supply

Lymphatic drainage

A

External hemorrhoids, anal fissures, SCC

**External hemorrhoids receive somatic innervation (inferior rectal branch of pudendal n.) –> PAINFUL if thrombosed

Arterial supply: inferior rectal artery (branch of internal pudendal a.)

Venous drainage: inferior rectal vein –> internal pudendal vein –> internal iliac vein –> common iliac vein –> IVC

Lymphatic drainage to superficial inguinal nodes

22
Q

Anal Fissure

A

Tear in anal mucosa below pectinate line

  • Pain while pooping
  • Blood on toilet Paper
  • Located Posteriorly b/c area is Poorly Perfused

Associated with low-fiber diets and constipation

23
Q

Liver tissue architecture

What does the apical surface of hepatocytes face?

What does the basolateral surface face?

Kupffer cells?

Hepatic stellate (Ito) cells?

A

Apical: Bile canaliculi

Basolateral: sinusoids

Kupffer cells (specialized macrophages) form lining of sinusoids

Hepatic stellate (Ito) cells in space of Disse store vitamin A (when quiescent) and produce ECM (when activated)

24
Q

Zone I, II, III

A

Zone I - periportal zone

  • Affected 1st by viral hepatitis
  • Ingested toxins (e.g., cocaine)

Zone II - intermediate zone

  • Yellow fever

Zone III - pericentral vein (centrilobular) zone

  • Affected 1st by ischemia
  • Contains cytochrome P-450 system
  • Most sensitive to metabolic toxins
  • Site of alcoholic hepatitis
25
Q

Biliary Structures

Gallstones –> symptoms

Tumors that arise in head of pancreas (usually ductal adenocarcinoma) can cause what?

A

Gallstones (filling defects) that reach confluence of common bile duct and pancreatic ducts at ampulla of Vater can block both common bile and pancreatic ducts (double duct sign), caushing both cholangitis and pancreatitis respectively.

Tumors that arise in head of pancreas –> obstruc common bile duct –> painless jaundice

26
Q

Femoral region organization (lateral to medial)

Femoral triangle

Femoral sheath

A

Nerve-Artery-Vein-Lymphatics

Femoral triangle: femoral nerve, artery, vein (venous near the penis)

Femoral sheath: Fascial tube 3-4 cm below inguinal ligament (contains femoral vein, artery, and canal - deep inguinal lymph nodes…. but NOT femoral nerve)

27
Q

Inguinal canal

A

Internal spermatic fascia (transversalis fascia)

Cremasteric muscle and fascia (Internal oblique)

External spermatic fascia (External oblique)

28
Q

Hernias

Complicated hernia presentation

A

Protrusion of peritoneum through an opening, usually at a site of weakness

Contents at risk for incarceration (not reducible back into abdomen/pelvis) and strangulation (ischemia and necrosis)

Complicated hernia presentation: tenderness, erythema, fever

29
Q

Diaphragmatic hernia

Most commonly a hiatal hernia (stomach herniates upward through esophageal hiatus of diaphragm) - 2 types

A

Abdominal structures enter thorax; may occur due to congenital defect of pleuroperitoneal membrane, or as a result of trauma

Commonly occurs on L side due to relative protection of right hemidiaphragm by liver

Sliding hiatal hernia: most common (GEJ displaced upward; “hourglass stomach”)

Paraesophageal hernia: GEJ normal –> fundus protrudes into thorax

30
Q

Indirect inguinal hernia

A

Indirect Inguinal Hernia

Goes through internal (deep) inguinal ring, external (superficial inguinal ring), and into scrotum –> follows path of descent of testes… covered by all 3 layers of spermatic fascia

Enters internal inguinal ring LATERAL to inferior epigastric vessels

Occurs in infants owing to failure of processus vaginalis to close (can form hydrocele); much more common in males

31
Q

Direct Inguinal Hernia

A

Direct Inguinal Hernia

  • Protrudes through inguinal (Hesselbach) triangle
    • Inferior epigastric vessels
    • Lateral border of rectus abdominis
    • Inguinal ligament
  • Bulges directly through abdominal wall medial to inferior epigastric vessels
  • Goes through external (superficial) inguinal ring only
  • Covered by external spermatic fascia
  • Usually in elderly men (weak abdominal muscles - transversalis fascia)

**MDs don’t LIe

32
Q

Femoral hernia

A

Protrudes below inguinal ligament through femoral canal below and lateral to pubic tubercle

More common in females

More likely to present with incarceration or strangulation than inguinal hernias

33
Q

What is the cause of indirect hernias?

A

Patent Processus Vaginalis

(allows communication b/w peritoneum and testes)

34
Q

The diaphragm is derived from four embryonic structures.

A
  1. Septum transversum
  2. Pleuroperitoneal membranes
  3. Mesoderm of body wall
  4. Esophageal mesoderm
35
Q

What is the most common type of hernia?

A

Bochdalek hernia

Occurs in posterolateral portion of diaphragm

36
Q

Mesenteries divide coelomic cavity into R and L halves.

Upper abdomen:

Stomach and gut are suspended in the middle.
Liver is suspended in _______ mesentary.

Spleen is suspended in _______ mesentary.

A

Liver is suspended in ventral mesentary.

  • Persists as hepatic ligaments and lesser omentum
    • _​_Falciform ligament (remnant of ligamentum teres)
    • Lesser omentum
      • Hepatogastric
      • Hepatoduodenal

Spleen is suspended in dorsal mesentary.

37
Q

Dorsal Mesentary derivatives

A

Greater Omentum

  • Gastrocolic
  • Gastrosplenic
  • Gastrorenal
  • Splenorenal
  • Mesentery of small intestine
  • Mesocolon