Abdominal Wall 2

Lecture - 2

Anatomy of the anterior abdominal wall part II

Dr .Raya Abdul Ameer

MBCHB,CABHS-RAD

Rectus sheath

A long fibrous sheath formed by aponeurosis of the three anterior abdominal muscle ( external oblique , internal oblique and transversus abdominis muscle )
encloses the rectus abdominis and pyramidalis muscles and forms an important component of the anterior abdominal wall
Boundaries of the rectus sheath
Two walls
Anterior wall
Posterior wall
Two margins
Medial margin
Lateral mrgin

Formation of the rectus sheath

From superior to inferior, the composition of the rectus sheath walls changes
For description it consider at three levels
1-At the level of the xiphisternum /above the costal margin
2-from costal margin to mid point between umbilicus and symphysis pubis ( arcuate line )..upper three quarter of the rectus abdominis
3-from arcuate line to symphysis pubis


Level 1 ..above costal margin
Ante wall …apponeurosis of external oblique only
Posterior wall ..by thoracic wall and 5th , 6th and 7th costal cartilages

At level 2 ..upper three quarters of rectus abdominis muscle

At level above arcute line
The internal oblique aponeurosis split to enclose the rectus mm ( anterior and posterior lamella )
Anterior wall … aponeurosis of the external abdominal oblique and internal abdominal oblique muscles

Posterior wall ..

aponeurosis of the internal abdominal oblique and transversus abdominis muscles.

At level 3 Inferior to the arcuate line, the lower quarter of the rectus abdominis muscle

is covered by the rectus sheath on its anterior surface only, while the posterior surface is in direct contact with the transversalis fascia.
The rectus sheath here is made of aponeuroses of all three muscles – external and internal abdominal oblique muscles and the transversus abdominis muscle

The function of the rectus sheath

1) to protect the muscles and vessels which it encloses.
2)keeping the rectus abdominis and pyramidalis muscle together helps in providing maximal compression of and support to abdominal viscera

.

Arcuate line : or semicircular line

It is located one third the distance from pubic crest to the umbilicus .
It is the demarcation where the internal oblique and transverse abdominis aponeuroses of the rectus sheath start to pass anteriorly to the rectus abdominis muscle leaving only the transversalis fascia posteriorly

• Contents of rectus sheath

• 1) 2 muscles (rectus abdomins , pyramidalis )
• 2) 4 vessles superior . Epigastric a &v
inferior. Epigastric a&v
• 3) 6 nerves (5 lower intercostal T7-T11 & subcostal T12 )
• 4) Lymphatic vv

Linea alba

(Latin white line ) ..is tendineous fibrous raphe that run vertically down at the mid line of the abdomen , separating rectus abdominis muscles
-It is thickening of the anterior wall of the rectus sheath. Formed by aponeurosus of external oblique, . Internal oblique and transversus abdominis
-This entire thickening extends from the xiphoid process of the sternum to the pubic symphysis
.


linea alba generally lacks blood supply and innervation , but few small blood vessels cross to other side over its anterior surface ,due to this it is a common site for incision in abdominal surgery and puncture site for suprapubic bladder catheterization

Linea semilunaris =spigelian line

It is a vertical curved fibrous connective tissue structure , run along the lateral edge of rectus abdominis muscle , it is site of union of lateral abdominal mm (external ,internal ,transverse abdominis ) and lateral aspect of rectus sheath
-it runs between 9th costal cartilage and pubic tubercle bilaterally
-hernia at linea semilunaris
called Spigelian hernia

Inguinal canal anatomy

Its oblique intramuscular passage in the lower part of anterior abdominal Wall
-It presents in both sexes
-It is about 1 ½ inches or 4 cm in length
-extend from deep inguinal ring down ward and medially to the superficial inguinal ring

-it lies parallel to and immediately above the inguinal ligament

Deep inguinal ring

Its is oval opening in the fascia transvesrsalis
Lies above inguinal ligament between Anterior superior iliac spine and pubic tubercle
Margin of the ring give origin of the internal spermatic fascia

Superficial inguinal ring

-Triangular in shape
-Defect in the aponeurosis of external oblique muscle
-Lies immediately above and medial to the pubic tubercle
-Its margin give attachment to the external spermatic fascia

Walls of inguinal canal

Anterior wall
It is formed by aponeurosis of external oblique and re enforced at lateral third by fleshy part of the internal oblique
Posterior wall
It is formed by fascia transversalis and reinforced at medial part by conjoint tendon

Inferior wall /floor

By inguinal ligament and lacunar ligament
Superior wall / roof
Internal oblique and transverses abdominis muscle

Function of inguinal canal

It allows structures of spermatic cord to pass to and from the testis to the abdomen in male
Allows passage of round ligament of uterus from the uterus to the labia majora in female

Contents of inguinal canal in male

1-spermatic cord and its contents
2-genital branch of genitofemoral nerve
3-ilio inguinal nerve

Contents in female

1- round ligament of uterus
2-genital branch of genitofemoral nn
3-ilio inguinal nerve

Spermatic cord

It is a cord like Collection of structures that pass through inguinal canal to and from the testis
It is covered by three concentric layers of fascia developed from layers of the anterior abdominal wall
It begin at the deep inguinal ring lateral to the inferior epigastric artery and ends at the testis

Coverings of spermatic cord

Internal spermatic fascia derived from the fascia transversals and attached to the margin of the deep inguinal ring
Cremastric fascia and mm derived from the internal oblique
External spermatic fascia derived from external oblique aponeurosis and attach to the margin of superficial inguinal ring

Anatomical Course of spermatic cord

Begin at the inferior abdomen and end at scrotum
It is formed at the deep inguinal ring the pass through inguinal canal and enter the scrotum via superficial inguinal ring
It continue in the scrotum ending at the posterior border of the testes , here its contents disperse to supply various structured of the testes and scrotum

Contents of spermatic cord

1) three arteries
1-testicular artery …branch from aorta
2-crematris artery ..branch from inferior epigastria artery
3-artery to vas deferens …branch from vesical artery from internal iliac artery

2) Three nerves

1-Genital branch of genitofemoral nn
2-Cremastric nn
3-Sympathetic nn fibers ./autonomic nn
3)Three other structures
• 1-pampinofroma plexus of testicular v drain venous blood from the testis in to testicular vein
2-Vas deferens
3-Lymphatic vessles


Round ligament
Its is one of the supporting structures of the uterus
It is rope like fibro muscular band extend from the anterolateral aspect of the uterus just below the origin of fallopian tube and pass through the deep inguinal ring into the superficial inguinal ring to labia majora

Scrotum

Its fibro muscular cutaneous sac located between the penis and anus
Its divided into Rt & Lt portions by septum

Layers of scrotum :

Extension from layers of abdominal wall
From superficial to deep
1-Skin :- brown , thin , rogues
• 2-Dartos m:- .. fatty layer of superficial. fascia
3-Membranous layer of superficial fascia
4-Ext, spermatic fascia …from external oblique
5-Cremasteric muscle &fascia …from .internal oblique + transversalis abd.
6-Internal layer of spermatic f transversalis f
7-Parietal layer of tunica veginalis


Contents of scrotum
Three major paired structures
1-testis
2-epididymis
3-spermatic cord
Blood supply
Anterior scrotal artery …branch from external pudendeal artery
Posterior scrotal artery branch from internal pudendal artery

Veins

Scrotal veins ..drain to external pudendal vein …to great saphenous vein
Nerves
Anterior and anterolateral aspect
Anterior scrotal nn derived from genital branch of genitofemoral nn and ilioinguinal nn
Posterior aspect …
Posterior scrotal nn derived from perineal branches of pudendal nn and posterior femoral cutaneous nn

Lymphatic drainage

Superficial inguinal lymph nodes

Testis

Its male primary organ, located in scrotum, oval in shape ,
Two poles upper & lower(spermatic cord attached to upper pole)
•
its function :-
-spermatogenesis  production of sperms
-Hormonal production testesteron

Covering of testis 3 special coats from inner to outer

1-tunica albugenea( fibrous capsul)
2-visceral layer of tunica vaginalis
3-parietal layer of tunica vaginalis

Abdominal wall hernia

Hernia : is abnormal protrusion of visira out of the wall of its containing cavity as a result of weakness in these walls
Anterior abdominal wall hernia
Epigastric hernia
Umbilical hernia
Spigelian hernia
Paraumbilcal hernia
Supraumbilcal hernia
Groin region hernia :
Inguinal hernia
Femoral hernia

Inguinal hernia

1) Direct inguinal hernia
Due to weakness in the abdominal wall behind or lateral to superficial inguinal ring .
Protrude through inguinal triangle (Hesselbach triangle )
Passes directly through abdominal wall to superficial inguinal ring
Does not extend to the scrotum
More common in old men
Located medial to inferior epigastric artery

Hesselbach triangle (inguinal triangle )

Is region of the lower anterior abdominal wall
It represent potential area of weakness in the anterior abdominal wall through which direct inguinal hernia protrude
Boundaries
Medially …rectus abdominis
Laterally… inferior epigastric artery
Inferiorly .inguinal ligament

In direct inguinal hernia

Traverse deep and superficial inguinal rings and inguinal canal
May descend to the scrotum
More common than direct
More in boys and young men
May be con genital
Located lateral to inferior epigastric artery

Femoral hernia

-Herniation through femoral canal
-More common in female
-It lies lateral and inferior to pubic tubercle
-The femora Canal located at anterior thigh
Its is the smallest and most medial part of femoral sheath

Boundaries of femoral canal

Medially …lacunar ligament
Laterally femoral vein
Anterior ..inguinal ligament
Posterior pectineal ligament , superior ramus of pubic bone

Surface anatomy

Abdominal quadrants
By two intersecting lines at the umbilicus
Rt upper quadrant
Lt upper quadrant \
Rt lower quadrant
Lt lower quadrant

Abdominal regions

Divided in to nine regions by two pairs of plain
Vertical planes
Lt and R lateral plane =mid clavicular line
Horizontal planes :
Trans pyloric plane …L1 level
Inter tubercular plane ..through tubercle of iliac crest …L5 level


Epigastric , umbilical and hypogastric
RT hypochondrial ,RT lumbar, RT iliac region
LT Hypochondrial , LT lumbar , LT iliac regions