Anatomy of Anterior abdominal muscles
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Transcript of Anatomy of Anterior abdominal muscles
MOB TCD
Anterior Abdominal Muscles
Professor Emeritus Moira O’Brien
FRCPI, FFSEM, FFSEM (UK), FTCD
Trinity College
Dublin
Anterior Abdominal Wall
• The muscles of the anterior abdominal wall play a major role in movements of the trunk
• Protecting the abdominal organs• Increase the intra-abdominal
pressure, aid in expiration and all straining activities such as micturition, coughing and vomiting
• Supplied by lower five intercostal and subcostal nerves
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Anterior Abdominal Muscles
• Strong abdominals are important in helping to stabilise the trunk
• Support the spine• They flex and rotate the trunk • Acting with the adductors and
abductors of the hip• They help to stabilise the pelvis
during walking and running
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• Superficial fatty layer• Membranous layer of
superficial fascia• Below umbilicus• Continuous with Colles’
fascia in the perineum
Anterior Abdominal Wall MOB TCD
• Lower five intercostal nerves• Subcostal nerve T12• 10th intercostal nerve is at the
level of the umbilicus• Iliohypogastric nerve L1• Ilioinguinal nerve L1
Skin of Anterior Abdominal Wall MOB TCD
Blood Supply and Lymphatics
• Intercostal vessels• Skin above umbilicus
superficial veins and lymphatics drain to axilla
• Skin below umbilicus superficial veins and lymphatics drain to long saphenous vein
• Superficial inguinal glands
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Inguinal Glands
• Proximal group parallel to inguinal ligament
• Enlarged tender inguinal glands
• Part of a generalised lymphadenopathy
• Secondaries
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• Proximal group• Lesions in local structures• Skin of lower anterior
abdominal wall• Gluteal region • Skin of scrotum or labia
Distal superficial glands• Skin of leg area drained by
long saphenous vein• All drain to deep inguinal
glands along femoral vein
Inguinal Glands MOB TCD
Abdominal Muscles
• External oblique• Internal oblique• Transversus• Rectus abdominus• Pyramidalis• Nerves and vessels • Lie between internal oblique and
transversus
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External Oblique
• Origin • Outer surfaces lower
borders lower eight ribs• Interdigitating with serratus
anterior and latissimus dorsi• Fibres pass medially and
inferiorly
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External Oblique Insertion
• Inserted into anterior half of anterior two thirds outer lip of iliac crest
• Aponeurosis in the inguinal region passes anterior to rectus muscle
• Forms the inguinal ligament• Lacunar ligament• Reflected portion of inguinal
ligament
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Inguinal and Lacunar Ligaments
• Inguinal ligament aponeurosis is folded back from anterior superior iliac spine to pubic tubercle to form inguinal ligament
• Lacunar ligament triangular, attached to pectineal line. lateral free border medial margin of femoral ring
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Insertion External Oblique
• Pubic crest• Gap for superficial
inguinal ring• Pubic bone • Linea alba • Anterior wall of the
rectus sheath• Zyphoid process
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External Oblique• Acting separately• The external oblique flexes the
vertebral column laterally and rotates it to the opposite side
• If the thorax is fixed by contracting both external obliques, you can tilt the symphysis pubis superiorly and flex the trunk, posterior pelvic tilt
• Movement of the iliac crests determines the direction of the tilt
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Internal Oblique
• Muscular origin lateral two thirds of inguinal ligament
• Anterior two thirds intermediate lip of iliac crest
• Lumbar fascia• Muscular fibres arch over
contents of inguinal canal anterior to rectus muscle
• Fibres pass medially and superiorly
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Insertion Internal Oblique
• Into coastal margin, upper three as fleshy fibres
• Next three as aponeurotic• Inserted into linea alba• Between zyphoid and half way
between umbilicus and pubic symphysis aponeurosis splits
• Anterior layer fuses with external oblique
• Posterior layer fuses with transversus
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Internal Oblique Conjoint Tendon
• Half way between umbilicus and pubic symphysis
• Aponeurosis of the internal oblique and transversus fuse to form conjoint tendon
• Anterior portion of rectus sheath
• Inserted into pectineal line behind superficial inguinal ring
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Internal Oblique
• The right side of the muscle twists to the right and the left side twists to the left
• The lower six intercostals nerve• Subcostal nerve• Iliohypogastric nerves
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Transversus Abdominus
• Origin• Lateral one third of inguinal
ligament• Anterior two thirds of inner lip of
iliac crest• Lumbar fascia• Lower border and inner
surfaces lower six ribs interdigitating with diaphragm
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Insertion Transversus Abdominus
• Into zyphoid, linea alba• Half way between umbilicus
and pubic symphysis• Fuses with posterior lamella of
internal oblique • Below forms conjoint tendon• Inserted into pectineal line
behind superficial inguinal ring
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Transversus Abdominus
• The transversus abdominus helps to support the abdominal viscera
• Maintain intra-abdominal pressure
• Stabilises the lumbar spine• It is supplied by the lower six
intercostals nerves• Subcostal nerves• Iliohypogastric nerves
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Rectus Abdominus
• Segmental muscle• Two heads• Anterior pubic symphysis• Pubic crest• Inserted anterior aspect of 5, 6, 7th
costal cartilages • Adhesions anterior surface• Segmental blood and nerve
supply from Intercostals• The rectus abdominus flexes the trunk
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Rectus Abdominus
• The rectus muscles (recti) are the most powerful flexors of the vertebral column
• When raising the head from a supine position
• A movement often used to strengthen the abdominals
• It is the recti that contract first • When the shoulders start to rise upwards, the
obliques start to contract
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Rectus Sheath
• Above zyphoid• Anterior wall is the external
oblique• Posterior, costal cartilages• From ziphoid and half way
between umbilicus and pubic symphysis
• Anterior is external oblique and anterior lamella of internal oblique
• Posterior lamella internal oblique and transversus
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• Below half way between umbilicus and pubic symphysis
• The aponeurosis of the external oblique, internal oblique and transversus (conjoint tendon) pass anterior to the rectus
• Posterior lies the transversalis fascia
Rectus Sheath MOB TCD
• Contents• Rectus muscle • Pyramidalis• Superior and inferior epigastric
vessels• Lower five intercostal vessels and
nerves
Rectus Sheath MOB TCD
Transversalis Fascia
• Lines deep aspect of transversus abdominus
• Fuses with inguinal ligament• Continuous with iliac fascia• Except in the region of the
femoral vessels• Forms anterior wall of
femoral sheath
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Extraperitoneal Tissue
• Extraperitoneal connective tissue
• If fatty, it separates the
transversalis fascia from
the peritoneum• If thin, they are in close
contact with one another
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Peritoneal Pouches
• Peritoneal pouches are found in the region of the deep inguinal ring
• Medial portion of the posterior wall
Posterior aspect anterior abdominal wall
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Inguinal Canal
• Intra muscular canal• Lower portion of anterior
abdominal wall
From • Deep inguinal ring• Superficial inguinal ring• Transmits spermatic cord
in male • Round ligament in female
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Superficial Inguinal Ring
• Triangular opening in aponeurosis of external oblique
• Base, pubic crest• Superior crus attached to
the pubic crest• Inferior attached to pubic
tubercle• External spermatic fascia
arises from its margins
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Deep Inguinal Ring
• Oval opening 2.5 cm• Above the middle of inguinal
ligament• Inferior epigastric artery
passes medial to the deep ring
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Interfoveolar Ligament
• The interfoveolar ligament is an inconstant band
• Medial to deep inguinal ring• Anterior to inferior epigastric
vessels• From lower margin of
transversus abdominus • To pectineal lineMcVay & Anson, 1949
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Inguinal Canal
• Anterior Wall• External oblique forms• Whole anterior wall• Internal oblique forms• Lateral half only
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• Posterior Wall• Transversalis fascia• Whole of wall• Medial half conjoint tendon• Medial quarter reflected
portion of inguinal ligament
Inguinal Canal MOB TCD
• Roof• Arching fibres of internal oblique • Transversus as they both arise
from the inguinal ligament
Roof of Inguinal Canal MOB TCD
• Floor• Inguinal ligament
forms whole of floor• Medial half by the
lacunar ligament• Reflected part of
inguinal ligament forms medial quarter
Floor of Inguinal Canal MOB TCD
Passing Through Deep Ring Male
• Vas Deferens• Testicular artery• Pampiniform plexus of veins• Remains of processus vaginalis• Genital branch of genitofemoral
nerve• Lymphatics from testes• Cremaster artery
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Passing through Superficial Ring Male
• Everything that went through deep ring
• Plus• Ilioinguinal nerve• Internal spermatic fascia from
margins of the deep ring• Cremaster muscle and fascia
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Passing through Deep Ring Female
• Round ligament of uterus• Remains of processus vaginalis• Genital branch of genitofemoral
nerve• Lymphatics from uterus, region
of cornu
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Passing through Superficial Ring Female
• Everything that went through deep ring
• Plus ilioinguinal nerve
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Inguinal Canal
• Contraction of the abdominal muscles increases the obliquity of the inguinal canal
• Protecting the two ringsLytle, 1945
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Increase in Intra-Abdominal Pressure
• Pain aggravated by an increase in intra- abdominal pressure
• Hernia• Inguinal or femoral hernia• Entrapment of the
ilioinguinal nerve
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Hernia
• Chronic pain in the groin in an athlete may be due to a hernia or a potential hernia
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Inguinal Hernia
• Sudden severe pain in lower abdomen
• Associated with lifting a heavy object
• Common history of a direct inguinal hernia
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• Passes through• Deep inguinal ring• May extend to pass
through the superficial ring into the scrotum
• Congenital or acquired • Congenital inside the
tunica vaginalis (serous membrane, covers part of testes)
• Acquired outside
Indirect Inguinal Hernia MOB TCD
• Enters through posterior wall of the inguinal canal
• Leaves through superficial inguinal ring
• Above and medial to the pubic tubercle
Direct Inguinal Hernia MOB TCD
Inguinal Hernia MOB TCD
Inguinal Versus Femoral Hernia
• Inguinal hernia above and medial to pubic tubercle
• Femoral hernia below and lateral to the tubercle
• More common in females and more likely to strangulate
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Femoral Ring MOB TCD
Femoral Hernia
• Enters through femoral ring• Enters femoral canal• Medial compartment of femoral
sheath• More common in women
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Femoral Hernia MOB TCD
Saphenous Varix
• Swelling is soft and diffuse
• Empties on minimal pressure
• Refills on release• Cough impulse is
present
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Gilmore’s Groin
• Common cause of chronic groin pain in field sports
• Particularly soccer players• Pain on any sudden change
of movement, sneezing, coughing
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• Trying to sprint• Will increase the pain • Pain is worse getting out of
bed• The day after a match or a
training session
Gilmore’s Groin MOB TCD
• Pain is increased by external rotation
• Or hyperextension of hip• Pain is localised to lower
anterior abdominal wall• Adductor or perineal
region
Gilmore’s Groin MOB TCD
• Torn external oblique aponeurosis
• Torn conjoint tendon• A dehiscence between
conjoint tendon and the inguinal ligament
• The absence of a hernial sac• Superficial inguinal ring on the
affected side is dilated and tender
• Cough impulse
Gilmore’s Groin MOB TCD
• Treatment is surgical • 90% return to sport• Strengthen lower
abdominal muscles
1. Plication of the transversalis fascia in “Shouldice hernia repair”
2. Repair of torn conjoint tendon
Gilmore’s Groin Surgery MOB TCD
3. Approximation of conjoint tendon to the inguinal ligament
4. Repair of the external oblique
5. Reconstitution of the superficial inguinal ring
Gilmore’s Groin Surgery MOB TCD
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