Anterior Abdominal Wall MD4 Flashcards
Inguinal Canal
- passage from deep inguinal ring to superficial inguinal ring that runs inferomedially, parallel & superior to the medial 1/2 of the inguinal lig.
- carries the spermatic cord (males), round lig. (females), ilioinguinal nn (both)
- formed in relation to relocation of testes during fetal development
*indirect inguinal hernias run through deep inguinal ring, inguinal canal, and superficial inguinal ring to descend into scrotum, most common
Inguinal Ligament
- from ASIS to pubic tubercle
- continuation of external oblique aponeurosis
- forms the floor of the inguinal canal
Hesselbach’s Triangle/Inguinal Triangle
borders:
- medial: lateral edge of rectus abdominis (linea semilunaris)
- lateral: inferior epigastric vessels
- inferior: inguinal lig.
*common site of direct inguinal hernias, less common than indirect
**picture shows view when looking outwards
continuations of inguinal lig., deep fibers pass posteriorly to attach to superior pubic ramus
Lacunar lig.
- arching fibers
- only boundary of femoral canal that can be cut to release femoral hernia
Pectineal lig. (lig. of Cooper)
- fibers continue laterally along pectineal line on the superior pubic ramus
- strong, holds sutures well in repair of inferior floor of inguinal canal
Deep Inguinal Ring
- entrance to inguinal canal
- transmits spermatic cord (males), round lig. (females), ilioinguinal nn. (both)
- lateral to inferior epigastric vessels
- common site of indirect inguinal hernias
Camper’s and Scarpa’s Fascia
- inferior to umbilicus there are two layers of subQ tissue
Camper’s:
- superficial fatty thick layer
Scarpa’s:
- deep thin membranous layer
Iliohypogastric nn.
- superior branch off of anterior rami of L1
- passes through posterior transversus abdominis mm.
- supplies skin above iliac crest, upper inguinal and hypogastric regions, muscles (transversus abdominis, internal obliques)
Ilioinguinal nn.
- inferior branch off of anterior rami of L1
- transmitted through inguinal canal
- supplies skin of lower inguinal, anterior scrotum and medial thigh, muscles (transversus abdominis, lowermost internal obliques)
External Oblique mm.
- actions: compression of abdominal cavity, aids in forced expiration, flexion, lateral flexion, rotation of spine
- “opposite side rotators”
Internal Oblique mm.
- @ right angles to external obliques, deep to external obliques
- actions: compresses abdomen (constantly active as antagonist to diaphragm, supports abdominal viscera), aids in forced expiration, rotation and flexion of trunk
- “same side rotators”
Transversus Abdominis mm.
- actions: compression of abdominal cavity, depress ribs
- deep to internal obliques
Conjoint Tendon
- common aponeuroses of transversus abdominis & internal oblique, insert upon pubic crest
- strengthens posteromedial aspect of inguinal canal, prevents direct inguinal hernias
Rectus Abdominis mm.
- flexes trunk, compresses abdomen (supports abdominal viscera), antilordosis
Rectus Sheath
- fusion of aponeuroses of ext, int obliques, transversus abdominis
above arcuate line:
- ext obl + 1/2 of int obl (anterior)
- the rest (1/2 int oblique, transversus abdominis, transversalis fascia) posterior
below:
- everything anterior except transversalis fascia
Round Ligament (of uterus)
- passes through inguinal canal
- from uterine horns->inguinal canal via deep inguinal ring-> labia majora
Ductus Deferens/Vas Deferens
- part of the spermatic cords
- transports sperm from epididymis to ejaculator ducts
Spermatic Cords
contains:
- vas deferens
- pampiniform venous plexus
- testicular, cremasteric, deferential aa.
- autonomics (genitofemoral, cremasteric nn., tesicular sympathetics)
- lymphatics
*ilioinguinal nn runs alongside spermatic cord in inguinal canal
fascia:
- continuations of external oblique aponeurosis, internal oblique, transversalis fascia
- vasectomy includes either cutting or blocking vas deferens
Inferior Epigastric Artery
- arises from external iliac aa just above the inguinal lig.
- enters rectus sheath, drops down b/w rectus abdominis & posterior rectus sheath
- anastomoses w/ superior epigastric aa
- gives rise to cremasteric aa in spermatic cord
- hernias lateral to inferior epigastric (indirect), medial (direct)
- Crura are extensions of external oblique aponeurosis that define the margins of the superficial inguinal ring
Medial Crus- attaches to pubic crest
Lateral Crus- attaches to pubic tubercle
Intercrural fibers- fibers of fascia that pass from medial to lateral crus, preventing expansion of superficial inguinal ring
Peritoneum: serous membrane lining inside of abdominal cavity and covering intrabdominal viscera
Parietal: originates from somatic mesoderm, sensitive to temp, pain, pressure, able to localize pain
Visceral: originates from splanchnic mesoderm, sensitive only to stretch & chemical irritation, unable to localize pain (often refers to midline of dermatome) (foregut = epigastric, midgut = umbilical, hindgut = pubic)
Internal Thoracic aa.
- branch off of inferior 1st portion of subclavian aa.
- bifurcates into superior epigastric and musculphrenic aa.
- branches to anterior intercostal aa (which supply intercostal muscles & spaces)
- runs along side the sternum
- used in CABG
Scrotum:
- cutaneous sack housing the testes, originates from labioscrotal swellings
- heavily pigmented skin layer and tunica dartos
Tunica Dartos:
- continuation of camper’s fascia containing dartos muscle
- responsible for rugosity
- regulates temp of testes: contraction of dartos muscle-> decr surface area for heat loss, incr thickness of layer, assists cremaster muscles in holding testes closer to body-> incr temp
