Anterior Abdominal Wall and Inguinal Canal

Layers of rectus sheath below arcuate line

1. External oblique - anterior to rectus abdominis 2. Internal oblique - anterior to rectus abdominis 3. Transversus abdominis - anterior to rectus abdominis 4. Transversalis fascia - posterior to rectus abdominis muscle 5. Peritoneum

Layers of rectus sheath above arcuate line

1. External oblique - tendon passes anterior to rectus abdominis muscle 2. Internal oblique - tendon divides to surround the rectus abdominis muscle 3. Transversus abdominis - passes posterior to the rectus abdominis muscle 4. Transversalis fascia 5. Peritoneum

Epididymis

A long, coiled duct on the outside of the testis in which sperm mature.

Which option most accurately describes the attachment sites of the inguinal ligament? ASIS to public symphysis PSIS to pubic tubercle ASIS to pubic tubercle PSIS to pubic symphysis

ASIS to pubic tubercle

external abdominal oblique muscles

Accessory muscles of expiration

lateral cutaneous branches

Has anterior and posterior branches; supplies the skin of the lateral thoracic and abdominal walls intercostal nerves iliohypogastric nerves

inguinal rings

Openings where the testicles pass through the abdominal wall, and the vas deferens and testicular vessels then continue to course medial crus superficial inguinal ring pubic tubercle lateral crus

contents of female inguinal canal

Round ligament of uterus and ilioinguinal nerve

layers of the abdominal wall

Skin Fat (camper's fascia) Scarpa's fascia (membranous) External oblique Internal oblique Transverse abdominal Transversalis fascia Preperitoneal fat Peritoneum

transversalis fascia

Structure that forms deep inguinal ring --> continuous with internal spermatic fascia

inguinal canal

a short canal passing through the abdominal wall in the region of the groin in males where testes descends into the scrotum

abdominal wall derivative of the scrotal skin

abdominal skin

transversus abdominis muscles

abdominal support and compression

Boundaries of Abdomen

abdominopelvic cavity four planes: two sagittal (vertical) and two transverse (horizontal)

anterior rectus sheath

all 3 muscle layer aponeurosis (external, internal, transversus) - posterior rectus sheath is absent below the arcuate line

borders of the inguinal canal

anterior --> aponeurosis of external oblique, reinforced by the internal oblique muscle laterally posterior --> transversalis fascia roof --> transversalis fascia, internal oblique, transversus abdominis floor --> inguinal ligament ('rolled up' portion of the external oblique aponeurosis), thickened medially by the lacunar ligament

inguinal region

anterior superior iliac spine inguinal ligament (passing anterior to the pecten pubis) pubic tubercle

medial third/superficial ring of the anterior wall of inguinal canal

aponeurosis of external oblique (intercrural fibers) fascia of external oblique continuing onto cord as external spermatic fascia

middle third of the anterior wall of inguinal canal

aponeurosis of external oblique (lateral crus and intercrural fibers)

unilateral action of external abdominal oblique muscles

bends trunk to same side rotates trunk to opposite side

unilateral action of internal abdominal oblique muscle

bends trunk to same side rotates trunk to same side

bilateral action of transversus abdominis muscles

compresses abdomen

origin of transversus abdominis muscles

costal cartilages of ribs 7 - 12 thoracolumbar fascia iliac crest anterior superior iliac spine (ASIS)

Deep (internal) ring

created by transversalis fascia which invaginates to form a covering of the contents of the inguinal canal found above the midpoint of the inguinal ligament lateral to epigastric vessels

abdominal wall derivative of the tunica dartos

dartos fascia and muscle

structure leaving scrotum

ductus deferens

lower region lymphatics

external and common iliac nodes superficial inguinal nodes

contents of male inguinal canal

external oblique --> external spermatic fascia internal oblique --> cremaster muscle transversalis fascia --> internal spermatic fascia testicular artery pampiniform plexus (testicular veins) testicular plexus ductus deferens

abdominal wall derivative of the external spermatic fascia

external oblique fascia

Muscles of the abdominal wall

external oblique, internal oblique, transversus abdominis, rectus abdominis

rectus sheath

fibrous sheath formed by aponeuroses of abdominal muscles continuous layer of connective tissue from the linea alba to the external oblique muscles splits into two layers at the linea alba to cover the abdominal muscles

rectus abdominis muscles

flexes and rotates vertebral column (abs)

action of rectus abdominis muscles

flexes trunk compresses abdomen stabilizes pelvis

bilateral action of external abdominal oblique muscles

flexes trunk compresses abdomen stabilizes pelvis

bilateral action of internal abdominal oblique muscle

flexes trunk compresses abdomen stabilizes pelvis

Valsalva maneuver

forcible exhalation against a closed glottis, resulting in increased intrathoracic pressure

Superficial (external) ring

formed by the evagination of the external oblique marks the end of the inguinal canal and lies superior to the pubic tubercle

anterior cutaneous branches

has medial and lateral branches; supplies the skin of the anterior thoracic and abdominal walls intercostal nerves iliohypogastric nerves

lateral third/deep ring of floor of inguinal canal

iliopubic tract

middle third/superficial ring of the posterior wall of inguinal canal

inguinal falx aka conjoint tendon reflected inguinal ligament

middle third of floor of inguinal canal

inguinal ligament

innervation of rectus abdominis muscles

intercostal nerves (T6 - T12)

innervation of transversus abdominis muscles

intercostal nerves (T6 - T12) iliohypogastric nerve ilioinguinal nerve

innervation of internal abdominal oblique muscle

intercostal nerves (T6 - T12) iliohypogastric nerve ilioinguinal nerve

innervation of external abdominal oblique muscles

intercostal nerves (T7-T12)

innervation to the abdominal wall

intercostal nerves, lateral cutaneous branches intercostal nerves, anterior cutaneous branches iliohypogastric nerve, lateral cutaneous branch iliohypogastric nerves, anterior cutaneous branch

lateral third/deep ring of the anterior wall of inguinal canal

internal oblique lateral crus of aponeurosis of external oblique

abdominal wall derivative of the cremaster muscle and fascia

internal oblique muscle and fascia

Veins of abdominal wall

internal thoracic vein (superficial, superior) axillary vein lateral thoracic vein (superficial, superior) thoracoepigastric vein (deep) peri-umbilical veins (deep) superficial epigastric vein (superficial, inferior) inferior epigastric vein (superficial, inferior)

medial third/superficial ring of floor of inguinal canal

lacunar ligament

what creates the passage to the inguinal canal?

lacunar ligament --> connects with deep inguinal ring

upper region lymphatics

left and right venous angles axillary and parasternal nodes

lymphatics of abdominal wall

like other superficial regions of the body, the lymph from the abdominal wall has both superficial & deep channels of drainage lymph from skin & superficial fascia from the anterior abdominal wall above the umbilicus drains mainly to axillary nodes. lymph from below the umbilicus drains to superficial inguinal nodes lymph from deeper aspects of the body wall (muscles) terminates in internal & common iliac nodes; these then drain to lateral aortic nodes

insertion of transversus abdominis muscles

linea alba pubic crest

insertion of external abdominal oblique muscles

linea alba pubic tubercle anterior half of the iliac crest

middle third/superficial ring of roof of inguinal canal

medial crus of aponeurosis of external oblique

middle third of roof of inguinal canal

musculophrenic arches of internal oblique and transverse abdominal

external view of the epididymis

parietal layer of tunica vaginalis visceral layer of tunica vaginalis

Direct inguinal hernia

peritoneal sac enters the inguinal canal through the posterior wall of the inguinal canal to the epigastric vessels (medial) and can enter the superficial inguinal ring acquired due to weakening in the abdominal musculature

abdominal wall derivative of the tunica vaginalis

peritoneum

why are the regions of the abdominal wall important?

planes can be used to establish nine regions (more detailed) or four quadrants (more general) important to know what organs are located in each abdominal region/quadrant so that one knows where to auscultate, percuss, and palpate them and record locations of findings during a physical examination

An indirect inguinal hernia can result from the failure of the ____ to regress.

processus vaginalis

origin of rectus abdominis muscles

pubic symphysis pubic crest

insertion of internal abdominal oblique muscle

ribs 10 - 12 linea alba

origin of external abdominal oblique muscles

ribs 5 - 12

unilateral action of transversus abdominis muscles

rotates trunk to the same side

internal abdominal oblique muscle

runs in a posteroinferior direction splits to contribute to the rectus sheath contributes to the formation of the conjoint tendon in men gives rise to the middle spermatic fascia and the cremasteric muscle of the spermatic cord

scrotum

sac-like continuation of the skin of the anterior abdominal wall

covering of the testis

scrotal skin tunica dartos external spermatic fascia cremaster muscle and cremasteric fascia internal spermatic fascia tunica vaginalis, parietal layer tunica vaginalis, viserval layer

posterior rectus sheath

seen when rectus abdominis is removed underneath the aponeurosis

structure entering scrotum

spermatic cord

internal view of epididymis

spermatic cord visceral layer of tunica vaginalis tunica albuginea

arterial supply to anterior abdominal wall

superior epigastric artery inferior epigastric artery (IEA) superficial epigastric artery superficial circumflex iliac artery

general functions of abdominal muscles

support and protect viscera flex and rotate vertebral column forced expiration flatten anterior abdominal wall help lift lower limb valsalva maneuver

surface features of the abdomen

tendinous intersections linea semilunaris linea alba umbilicus pubic symphysis inguinal ligament anterior superior iliac spine

origin of internal abdominal oblique muscle

thoracolumbar fascia anterior 2/3 of iliac crest

Which of the following forms the posterior wall of the inguinal canal? internal oblique inguinal ligament aponeurosis of external oblique transversalis fascia

transversalis fascia

abdominal wall derivative of the internal spermatic fascia

transversalis fascia

lateral third/deep ring of roof of inguinal canal

transversalis fascia

lateral third/deep ring of the posterior wall of inguinal canal

transversalis fascia

middle third of the posterior wall of inguinal canal

transversalis fascia

Indirect inguinal hernia

where peritoneal sac enters the inguinal canal through the deep inguinal ring --> may transverse the entire inguinal canal, emerge through the superficial inguinal ring, and reach the scrotum. This condition usually is due to a congenital defect in the abdominal wall.

tunica albuginea

white fibrous capsule on testes - innermost layer

insertion of rectus abdominis muscles

xiphoid process 5th - 7th costal cartilages