Principles of abdominal anatomy

Anatomy of Abdomen- GI tract Adonye Banigo & Abigail Vooght, Oct 2010

Plan- Lecture 1
Abdo Wall
Surface markings
Regions
Layers
Inguinal canal & hernias
Incisions
Abdo cavity
Whistlestop tour of GI tract
Viscera + peritoneum + embryology
Peritoneal cavity
Surface markings
Abdominal wall
surgical incisions
Inguinal canal
hernias
Whistle stop tour of gut (mouth > anus) incl. landmarks
Embryology of gut
Foregut/ midgut/ hindgut principles
Peritoneum and mesenteries
Referred pain

Plan- Lecture 2
Key features of each organ
The GI adnexae- liver, gallbladder, pancreas, spleen
Not including the bony pelvis, genitourinary system, or histology of the gut

The Abdominal Wall

Role of Abdo Wall
Moving the trunk
Depressing the ribs
Compressing the abdomen
Supporting and protecting organs

Surface Markings Linea Alba Linea semilunaris Tendinous intersections (3)

Landmarks Xiphisternum T9 Iliac crest Costal Margin Umbilicus L3/4

9 regions Midclavicular line

9 regions Midclavicular line Transpyloric plane (L1) Transtubercular plane (L4/5)

9 regions Umbilical Suprapubic Epigastric

9 regions Lumbar Iliac Fossae Hypochondrium

Layers of Abdo Wall- Laterally
Skin
Superficial fascia
Camper’s (soft & spongy fat!)
Scarpa’s (membranous)
External Oblique (Aponeurosis)
Internal Oblique
Transversus Abdominis
Transversalis Fascia
Extraperitoneal fat
Peritoneum

Layers of Abdo Wall- Medially
Skin
Superficial fascia
Camper’s (soft & spongy fat!)
Scarpa’s (membranous)
Rectus Abdominis and Rectus Sheath
Transversalis Fascia
Extraperitoneal fat
Peritoneum

Abdo wall- Layers Medially Costal Margin Arcuate line (of Douglas)

Inguinal canal
Passage for spermatic cord ♀ // round ligament ♂
4cm long
Deep (internal) ring to superficial (external) ring
Boundaries:
Anteriorly- E-O aponeurosis + I-O lateral 1/3
Posteriorly- transversalis fascia + conjoint tendon medially
Above- arching fibres of internal oblique + transversalis
Below- inguinal ligament (infolded gutter of E-O)

1) External oblique aponeurosis, 2) Internal oblique muscle, 3) Transversus abdominis muscle, 4) Endo abdominal fascia, 5) Internal inguinal ring, 6) Iliopubic tract, 7) Inguinal ligament, 8) Pubic symphisis, 9) Spermatic cord, 10) Interparietal connective tissue (cremasteric fascia), 11) cremasteric muscle, 12) Aponeurotic layer of posterior inguinal wall, 13) Fascial layer of posterior inguinal wall

Inguinal Canal- conceptual- from above Extenal Oblique Aponeurosis Transversalis fascia ASIS Pubic Tubercle Posterior Anterior Conjoint Tendon Internal Oblique

Deep and Superficial Rings
Deep Ring:
Transversalis fascia evagination into canal as internal spermatic fascia
½ inch above midpoint of inguinal ligament
Transmits spermatic cord or round ligament
Superficial Ring:
V-shaped defect in E-O aponeurosis
Transmits spermatic cord + ilioinguinal nerve

Spermatic Cord: 3 coverings,6 constituents
Coverings
External spermatic Fascia (from E-O apo)
Cremastic muscle + fascia (?I-O, TA)
Internal spermatic Fascia (transversalis fascia)
Constituents
Ductus Deferens
Arteries: Testicular artery, artery to ductus
Veins: Pampiniform plexus
Lymphatics
Nerves: Genital br of genitofemoral n + sympathetic twigs
Processus Vaginalis

Indirect Inguinal Hernia
Generally congenital
Lax deep ring
Repair by excising hernia sac and mesh to reinforce ring

Direct Inguinal Hernia
Generally weakness in EO aponeurosis
Repair by reinforcing external ring, suturing mesh to conjoint tendon

PRINCIPLES OF INCISIONS
Adequate exposure of the organ
Follow cleavage lines in skin (Langer’s lines)
Avoid neurovascular structures
Consider direction of muscles fibres and location of aponeuroses

Abdo wall nerve supply 7 8 9 10 11 12-s/c L1-i/h L1-i/i

Abdo Wall Arterial Supply

Principles of Abdominal Incisions
Adequate exposure of the organ
Follow cleavage lines in skin (Langer’s lines)
Avoid neurovascular structures
Consider direction of muscle fibres and location of aponeurosis

Abdominal Incisions- access vs healing Midline Paramedian Pfannenstiel Subcostal (Kochers) Gridiron Muscle split

The Abdominal Cavity Viscera + peritoneum Peritoneal Cavity

Viscera
Urinary- kidneys, ureters
Endocrine- adrenal glands
Develop on post. Abdo wall (1 ° retroperitoneal)
Arterial supply from corresponding side of aorta
Nerve supply bilateral , true to level of origin
Referred pain to corresponding side
Digestive- GI tract, liver & biliary tract, pancreas
Haemopoietic- Spleen
Develop on a mesentery (which some lose to become 2 ° retroperitoneal)
Arterial supply from front of aorta
Nerve supply bilateral
Referred pain to midline
Paired Unpaired

Intro: the Peritoneum
Serous membrane (latin =thin skin)
2 layers- visceral + parietal
Parietal
Lines interior of body wall
Nerve & vascular supply from body wall (somatic)
Visceral
Covers viscera (!)
Visceral supply

Mesenteries
Double layer of serous membrane (peritoneum), suspends all intraperitoneal viscera
Intermediary structure between parietal and visceral peritoneum
Function
Provide mobile attachment for viscus
Contains supply lines (sandwiched between 3 layers)
All unpaired viscera develop on a mesentery

Whistlestop tour of gut

Stomach

Duodenum

Jejenum

Caecum

Large Bowel

Rectum & Anus

Embryology of gut- 6/40 Midgut Foregut Hindgut Posterior abdo wall Mesentery (ventral) Mesentery (dorsal)

Foregut
Oropharynx to D2 (precisely opening of bile duct)
Includes
Outgrowths: biliary tract
Glands: liver & pancreas
Spleen
Artery: Coeliac
Nerve supply: T6- T9 spinal segments
Rotation (on vertical axis of gut)- 90 º left
Spleen from posterior (dorsal mesogastrium) to left
Liver from anterior (ventral mesogastrium) to right
Retroperitoneal: 2 nd part duodenum, spleen, most of pancreas

Rotation of foregut Midgut Foregut Hindgut Mesentery (ventral) Mesentery (dorsal) liver Spleen

Foregut rotation 2 Greater sac Lesser sac

Midgut
D2 to mid-transverse colon
Artery: SMA
Nerve supply: spinal segments T9, T10
Rotation:
On axis of SMA 270 ° anticlockwise
6- 10/40 gestation
Via physiological hernia
Retroperitoneal: duodenum, ascending colon

Midgut rotation 6-10/40 Rotation occurs around the axis of the SMA on a single mesentery, “the mesentery”

Hindgut
Mid-transverse colon- upper anal canal
Artery: IMA
Nerve supply: T11 -S4
Mesenteries:
transverse mesocolon (shared with midgut)
sigmoid mesocolon
Rotation: swings to left vertical axis of dorsal mesentery
Retroperitoneal: L colon (line of Toldt), rectum

Peritoneal Attachments Bare area of liver Lesser sac Epiploic foramen Greater sac

Abdominal Viscera
Next time!

Any Questions? ?

Principles of abdominal anatomy

by jehh87 on Oct 12, 2010

Accessibility

Categories

Tags

Upload Details

Usage Rights

1 Embed 576

Statistics

Principles of abdominal anatomy — Presentation Transcript