The Abdominal WallThe Abdominal WallLectured by Bien Eli Nillos, MDLectured by Bien Eli Nillos, MD

PRE-TEST: IdentifyPRE-TEST: Identify

Where is the Where is the Abdomen?Abdomen?

The region of the trunk that lies The region of the trunk that lies between the diaphragm above and between the diaphragm above and the inlet of the pelvis belowthe inlet of the pelvis below

Xiphoid ProcessXiphoid Process

• Thin cartilaginous lower part of the Thin cartilaginous lower part of the sternumsternum

• Easily palpated in the depression where Easily palpated in the depression where the costal margins meet in the upper the costal margins meet in the upper part of the anterior abdominal wallpart of the anterior abdominal wall

• Xiphisternal junction – lies opposite the Xiphisternal junction – lies opposite the body of the ninth thoracic vertebra.body of the ninth thoracic vertebra.

Costal MarginCostal Margin

• The curved lower margin of the thoracic The curved lower margin of the thoracic wall, formed in front by the cartilages of wall, formed in front by the cartilages of the seventh, eighth, ninth and tenth ribs the seventh, eighth, ninth and tenth ribs and behind by the cartilages of the and behind by the cartilages of the eleventh and twelfth ribseleventh and twelfth ribs

• Reaches its lowest level at the tenth Reaches its lowest level at the tenth costal cartilage, which lies opposite the costal cartilage, which lies opposite the body of the third lumbar vertebrabody of the third lumbar vertebra

Iliac CrestIliac Crest

• May be felt along its entire length and May be felt along its entire length and ends in front at the ends in front at the Anterior Superior Anterior Superior Iliac Spine (ASIS)Iliac Spine (ASIS)..

• Its highest point lies opposite the Its highest point lies opposite the body of the fourth lumbar vertebra.body of the fourth lumbar vertebra.

• About 2 inches posterior to the ASIS, About 2 inches posterior to the ASIS, the outer margin projects to form the the outer margin projects to form the tubercle of the cresttubercle of the crest – lies at the level – lies at the level of the body of 5of the body of 5thth Lumbar Vertebra. Lumbar Vertebra.

Inguinal LigamentInguinal Ligament

• Rolled-under inferior Rolled-under inferior margin of the external margin of the external oblique muscleoblique muscle

• Attached laterally to the Attached laterally to the ASIS, curves downward ASIS, curves downward and medially to be and medially to be attached to the pubic attached to the pubic tubercletubercle

Symphysis PubisSymphysis Pubis

• Cartilaginous joint that lies in the Cartilaginous joint that lies in the midline between the bodies of the pubic midline between the bodies of the pubic bonesbones

• Felt as a solid structure beneath the Felt as a solid structure beneath the skin in the midline at the lower skin in the midline at the lower extremity of the anterior abdominal wallextremity of the anterior abdominal wall

• Pubic crest Pubic crest – ridge on the superior – ridge on the superior surface of the pubic bones medial to surface of the pubic bones medial to the pubic tuberclethe pubic tubercle

Superficial Inguinal RingSuperficial Inguinal Ring

• Triangular aperture in the aponeurosis Triangular aperture in the aponeurosis of the external oblique muscle situated of the external oblique muscle situated above and medial to the pubic tubercleabove and medial to the pubic tubercle

• In males – the margins can be felt by In males – the margins can be felt by invaginating the skin of the upper part invaginating the skin of the upper part of the scrotum with the tip of the little of the scrotum with the tip of the little fingerfinger

• In females – smaller and difficult to In females – smaller and difficult to palpatepalpate

ScrotumScrotum

• Pouch of skin containing the testes, Pouch of skin containing the testes, the epididymides, lower ends of the the epididymides, lower ends of the spermatic cord.spermatic cord.

• Testis on each side is a firm ovoid Testis on each side is a firm ovoid body surrounded on its lateral, body surrounded on its lateral, anterior and medial surfaces by two anterior and medial surfaces by two layers of layers of tunica vaginalistunica vaginalis. .

• Testis should lie free and not tethered Testis should lie free and not tethered to the skin or subcutaneous tissue. to the skin or subcutaneous tissue.

Linea AlbaLinea Alba

• Fibrous band that extends from Fibrous band that extends from symphysis pubis to the xiphoid symphysis pubis to the xiphoid process and lies in the midline.process and lies in the midline.

• Fusion of the aponeuroses of the Fusion of the aponeuroses of the muscles of the anterior abdominal muscles of the anterior abdominal wall and is represented on the wall and is represented on the surface by a slight median groovesurface by a slight median groove

UmbilicusUmbilicus

• Lies in the linea alba and is Lies in the linea alba and is inconstant in positioninconstant in position

• Puckered scar and is the site of Puckered scar and is the site of attachment of the umbilical cord in attachment of the umbilical cord in the fetusthe fetus

Linea SemilunarisLinea Semilunaris

• Lateral edge of the rectus abdominis Lateral edge of the rectus abdominis muscle, crosses the costal margin at muscle, crosses the costal margin at the tip of the ninth costal cartilagethe tip of the ninth costal cartilage

• To accentuate, the patient is asked To accentuate, the patient is asked to lie on his back and raise his to lie on his back and raise his shoulders off the couch without using shoulders off the couch without using his armshis arms

Abdominal RegionsAbdominal Regions

The Superficial FasciaThe Superficial Fascia

• Divided into: superficial fatty layer and deep Divided into: superficial fatty layer and deep membranous layermembranous layer

• Fatty layer – continuous with the superficial Fatty layer – continuous with the superficial fat over the rest of the body and may be fat over the rest of the body and may be extremely thick in obese patients. extremely thick in obese patients.

• Membranous layer – fades out over the Membranous layer – fades out over the thoracic wall above and along the midaxillary thoracic wall above and along the midaxillary line laterally, inferiorly it passes onto the front line laterally, inferiorly it passes onto the front of the thigh where it fuses with the deep of the thigh where it fuses with the deep fasciafascia

Clinical NotesClinical Notes

• Camper’s Fascia – a.k.a. Superficial Camper’s Fascia – a.k.a. Superficial fatty layerfatty layer

• Scarpa’s Fascia – a.k.a. deep Scarpa’s Fascia – a.k.a. deep membranous layermembranous layer

• Colles fascia – extension of the Colles fascia – extension of the Scarpa’s in the perineumScarpa’s in the perineum

External ObliqueExternal Oblique

• Origin – lower eight ribsOrigin – lower eight ribs

• Insertion – xiphoid process, linea alba, Insertion – xiphoid process, linea alba, pubic crest, pubic tubercle, iliac crestpubic crest, pubic tubercle, iliac crest

• Nerve supply – lower 6 thoracic nervesNerve supply – lower 6 thoracic nerves

• Action – supports abdominal contents, Action – supports abdominal contents, assists in forced expiration, micturition, assists in forced expiration, micturition, defecation, partuition, vomitingdefecation, partuition, vomiting

Clinical NotesClinical Notes

• Triangular shaped defect in the Triangular shaped defect in the external oblique aponeurosis, lies external oblique aponeurosis, lies immediately above and medial to the immediately above and medial to the pubic tubercle pubic tubercle (hmmm….sounds familiar?)(hmmm….sounds familiar?)

• The lower border of the aponeurosis The lower border of the aponeurosis is folded backward on itself, forming is folded backward on itself, forming the the inguinal ligamentinguinal ligament..

Internal ObliqueInternal Oblique

• Origin – lumbar fascia, iliac crest, lateral Origin – lumbar fascia, iliac crest, lateral two thirds of the inguinal ligamenttwo thirds of the inguinal ligament

• Insertion – Lower three ribs and costal Insertion – Lower three ribs and costal cartilages, xiphoid process, linea alba, cartilages, xiphoid process, linea alba, symphysis pubissymphysis pubis

• Nerve supply – lower six thoracic nervesNerve supply – lower six thoracic nerves

• Action – same with external obliquesAction – same with external obliques

1.1. Inguinal ligament Inguinal ligament 2.2. Muscular part of transversus abdominis Muscular part of transversus abdominis 3.3. Transversus abdominis aponeurosis Transversus abdominis aponeurosis 4.4. Muscular part of internal oblique Muscular part of internal oblique 5.5. Internal oblique aponeurosis Internal oblique aponeurosis 6.6. Transversalis fascia Transversalis fascia 7.7. Cremasteric fascia forming middle coating of spermatic cord Cremasteric fascia forming middle coating of spermatic cord 8.8. Pubic tubercle Pubic tubercle

Transversus AbdominisTransversus Abdominis

• Origin – lower six costal cartilages, Origin – lower six costal cartilages, lumbar fascia, iliac crest, lateral third of lumbar fascia, iliac crest, lateral third of inguinal ligamentinguinal ligament

• Insertion – xiphoid process, linea alba, Insertion – xiphoid process, linea alba, symphysis pubissymphysis pubis

• Nerve supply – lower six thoracic nervesNerve supply – lower six thoracic nerves

• Action – compresses abdominal Action – compresses abdominal contentscontents

Rectus AbdominisRectus Abdominis

• Origin – symphysis pubis and pubic crestOrigin – symphysis pubis and pubic crest

• Insertion – fifth, sixth and seventh costal Insertion – fifth, sixth and seventh costal cartilages and xiphoid processcartilages and xiphoid process

• Nerve supply – lower six thoracic nervesNerve supply – lower six thoracic nerves

• Action – compresses abdominal contents Action – compresses abdominal contents and flexes vertebral columnand flexes vertebral column

• When it contracts, its lateral margin When it contracts, its lateral margin forms a curved ridge that can be forms a curved ridge that can be palpated and often seen palpated and often seen (hmmm…sounds (hmmm…sounds familiar again)familiar again)

• It is enclosed between the It is enclosed between the aponeuroses of the external oblique, aponeuroses of the external oblique, the internal oblique and the the internal oblique and the transversus, which form the transversus, which form the rectus rectus sheathsheath..

PyramidalisPyramidalis

• Origin – anterior surface of pubisOrigin – anterior surface of pubis

• Insertion – Linea albaInsertion – Linea alba

• Nerve supply – Twelfth thoracic nerveNerve supply – Twelfth thoracic nerve

• Action – tenses the linea albaAction – tenses the linea alba

It is often absentIt is often absent

Rectus SheathRectus Sheath

Arteries of the Anterior and Arteries of the Anterior and Lateral Abdominal WallsLateral Abdominal Walls

• Superior epigastric artery – terminal Superior epigastric artery – terminal branch of the internal thoracic artery; branch of the internal thoracic artery; supplies the upper central part of the supplies the upper central part of the anterior abdominal wallanterior abdominal wall

• Inferior epigastric artery – branch of the Inferior epigastric artery – branch of the external iliac artery, just above the external iliac artery, just above the inguinal ligament; supplies the lower inguinal ligament; supplies the lower central part of the anterior abdominal central part of the anterior abdominal wallwall

• Deep circumflex iliac artery – branch of Deep circumflex iliac artery – branch of the external iliac artery; supplies the the external iliac artery; supplies the lower lateral part of the abdominal wall. lower lateral part of the abdominal wall.

• Posterior Intercostal arteries – 2, Posterior Intercostal arteries – 2, branches of the descending thoracic branches of the descending thoracic aorta; supply the lateral part of the aorta; supply the lateral part of the abdominal wall. abdominal wall.