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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