The Abdominal WallThe Abdominal WallInguinal and Posterior Abdominal WallInguinal and Posterior Abdominal Wall

Lectured by Bien Eli Nillos, MDLectured by Bien Eli Nillos, MD

Inguinal CanalInguinal Canal

►An oblique passage through the lower An oblique passage through the lower part of the anterior abdominal wallpart of the anterior abdominal wall

►Present in both sexesPresent in both sexes►Males: spermatic cord and ilioinguinal Males: spermatic cord and ilioinguinal

nervenerve►Females: round ligament of the uterus Females: round ligament of the uterus

and ilioinguinal nerveand ilioinguinal nerve►About 1 and ¼ inches long in the adultAbout 1 and ¼ inches long in the adult

►Extends from the Extends from the deep inguinal ring deep inguinal ring which is a hole in the transversalis which is a hole in the transversalis fascia, downward and medially to the fascia, downward and medially to the superficial inguinal ringsuperficial inguinal ring which is a hole which is a hole in the aponeurosis of the external in the aponeurosis of the external oblique muscle. oblique muscle.

►Lies parallel to and immediately above Lies parallel to and immediately above the inguinal ligamentthe inguinal ligament

► In the newborn, the deep ring lies In the newborn, the deep ring lies almost directly almost directly posteriorposterior to the to the superficial ring, thus the canal is superficial ring, thus the canal is considerably short at this age.considerably short at this age.

►As one grows up, the deep ring moves As one grows up, the deep ring moves laterallylaterally

Deep Inguinal RingDeep Inguinal Ring

►Oval openingOval opening►½ inch above the inguinal ligament ½ inch above the inguinal ligament

midway betwee the anterior superior midway betwee the anterior superior iliac spine and the symphysis pubisiliac spine and the symphysis pubis

►Medially are the inferior epigastric Medially are the inferior epigastric vesselsvessels

Superficial Inguinal RingSuperficial Inguinal Ring

►Triangular shaped defect Triangular shaped defect ►Base is formed by the pubic crestBase is formed by the pubic crest►The The cruracrura – margins of the ring, give – margins of the ring, give

origin to the external spermatic fasciaorigin to the external spermatic fascia

►Anterior wall of the canal – formed by Anterior wall of the canal – formed by the aponeurosis of the external the aponeurosis of the external oblique muscle, reinforced in its lateral oblique muscle, reinforced in its lateral third by the fibers of origin of the third by the fibers of origin of the internal oblique.internal oblique.

►This wall is therefore strongest where This wall is therefore strongest where it lies opposite the it lies opposite the weakest partweakest part of of the posterior wall --- the deep inguinal the posterior wall --- the deep inguinal ringring

►Posterior Wall of the Canal – formed by Posterior Wall of the Canal – formed by the transversalis fascia, reinforced in its the transversalis fascia, reinforced in its medial third by the medial third by the conjoint tendonconjoint tendon (the common tendon of insertion of the (the common tendon of insertion of the internal oblique and transversus internal oblique and transversus muscles)muscles)

►The wall is therefore strongest where it The wall is therefore strongest where it lies opposite the weakest part of the lies opposite the weakest part of the anterior wall --- superficial inguinal ring. anterior wall --- superficial inguinal ring.

► Inferior wall or floor of the canal – Inferior wall or floor of the canal – formed by the rolled-under inferior formed by the rolled-under inferior edge of the aponeurosis of the edge of the aponeurosis of the external oblique muscle (the inguinal external oblique muscle (the inguinal ligament) and at its medial end the ligament) and at its medial end the lacunar ligamentlacunar ligament

►Superior wall or roof of the canal – Superior wall or roof of the canal – formed by the arching lowest fibers of formed by the arching lowest fibers of the internal oblique and transversus the internal oblique and transversus abdominis muscle. abdominis muscle.

►On coughing or straining, the arching On coughing or straining, the arching lowest fibers of the internal oblique lowest fibers of the internal oblique and transversus abdominis muscles and transversus abdominis muscles contract contract flattening out the arched flattening out the arched roof so that it is lowered toward the roof so that it is lowered toward the floor floor making the canal virtually making the canal virtually closed. closed.

The Spermatic CordThe Spermatic Cord

►Vas DeferensVas Deferens►Testicular arteryTesticular artery►Cremasteric ArteryCremasteric Artery►Genital branch of the Genitofemoral Genital branch of the Genitofemoral

nervenerve►Pampiniform plexusPampiniform plexus►Lymphatic vesselsLymphatic vessels►Processus vaginalisProcessus vaginalis

►The spermatic cord is sensitive to The spermatic cord is sensitive to torsion, in which the testicle rotates torsion, in which the testicle rotates within its sac and kinks off its own within its sac and kinks off its own blood supply. Testicular torsion may blood supply. Testicular torsion may result in irreversible damage to the result in irreversible damage to the testicle within hours.testicle within hours.

Coverings of the Spermatic Coverings of the Spermatic CordCord

► Internal spermatic fascia – derived Internal spermatic fascia – derived from the transversalis fasciafrom the transversalis fascia

►Cremasteric Fascia – derived from the Cremasteric Fascia – derived from the internal oblique muscleinternal oblique muscle

►External spermatic fascia – derived External spermatic fascia – derived from the external oblique aponeurosisfrom the external oblique aponeurosis

ScrotumScrotum

►Outpouching of the lower part of the Outpouching of the lower part of the anterior abdominal wallanterior abdominal wall

►Contains the testes, epididymes and Contains the testes, epididymes and the lower ends of the spermatic cordthe lower ends of the spermatic cord

►The skin is wrinkled and pigmented The skin is wrinkled and pigmented and forms a single pouchand forms a single pouch

►The slightly raised ridge in the midline The slightly raised ridge in the midline indicates the line of fusion of the two indicates the line of fusion of the two lateral labioscrotal swellings. lateral labioscrotal swellings.

►The superficial fascia is continuous The superficial fascia is continuous with the fatty and membranous layers with the fatty and membranous layers of the anterior abdominal wall: the fat of the anterior abdominal wall: the fat is replaced by a smooth muscle is replaced by a smooth muscle Dartos muscleDartos muscle

►The Cremaster muscle can be made to The Cremaster muscle can be made to contract by stroking the skin on the contract by stroking the skin on the medial aspect of the thigh medial aspect of the thigh cremasteric reflexcremasteric reflex

►Tunica vaginalis Tunica vaginalis lies within the lies within the spermatic fasciae and covers the spermatic fasciae and covers the anterior, medial and lateral surfaces of anterior, medial and lateral surfaces of each testis. each testis.

► It is a closed sac, invaginated from It is a closed sac, invaginated from behind by the testis.behind by the testis.

Posterior Abdominal WallPosterior Abdominal Wall

►Formed in the midline by the five Formed in the midline by the five lumbar vertebrae and their lumbar vertebrae and their intervetebral discs; laterally by the intervetebral discs; laterally by the 1212thth ribs, the upper part of the bony ribs, the upper part of the bony pelvis, psoas muscles, the quadratos pelvis, psoas muscles, the quadratos lumborum, aponeurosis of origin of the lumborum, aponeurosis of origin of the transversus abdominis muscles.transversus abdominis muscles.

►The iliacus muscles lie in the upper The iliacus muscles lie in the upper part of the bony pelvispart of the bony pelvis

Psoas MusclePsoas Muscle

►Origin: transverse process, bodies and Origin: transverse process, bodies and intervertebral discs of 12intervertebral discs of 12thth thoracic thoracic and five lumbar vertebraeand five lumbar vertebrae

► Insertion: with iliacus into lesser Insertion: with iliacus into lesser trochanter of the femurtrochanter of the femur

►Nerve supply: lumbar plexusNerve supply: lumbar plexus►Action: flexes thigh on trunkAction: flexes thigh on trunk

Quadratus LumborumQuadratus Lumborum

►Origin: iliolumbar ligament, iliac crest, Origin: iliolumbar ligament, iliac crest, tips of the transverse processes of the tips of the transverse processes of the lower lumbar vertebraelower lumbar vertebrae

► Insertion: 12Insertion: 12thth rib rib►Nerve supply: Lumbar plexusNerve supply: Lumbar plexus►Action: Fixes 12Action: Fixes 12thth rib during inspiration; rib during inspiration;

laterally flexes vertebral column same laterally flexes vertebral column same sideside

IliacusIliacus

►Origin: iliac fossaOrigin: iliac fossa► Insertion: with psoas into lesser Insertion: with psoas into lesser

trochanter of femurtrochanter of femur►Nerve supply: femoral nerveNerve supply: femoral nerve►Action: Flexes thigh on trunkAction: Flexes thigh on trunk