anterior abdominal wall antomy

1. ANTERIOR ABDOMINAL WALL
MUSCULO-SKELETAL PELVIC
ANATOMY

2. Anterior abdominal wall
• The anterior abdominal wall confines abdominal viscera, stretches to accommodate the
expanding uterus, and provides surgical access to the internal reproductive organs.
• Anterior abdominal wall muscles consist of following layers
Skin
Subcutaneous tissue
External oblique muscle
Internal oblique muscle
Transverse abdominis muscle
Fascia transversalis
Peritoneum

6. Skin and Subcutaneous layer
Superficial fatty layer : - Camper fascia .
Deep membranous layer : - Scarpa fascia.
• Camper fascia continues onto the perineum to provide fatty substance to
the mons pubis and labia majora and then to blend with the fat of the
ischio-anal fossa.
• Scarpa fascia continues inferiorly onto the perineum as Colles fascia.

8. Beneath the subcutaneous layer,
• primary fascia of the anterior abdominal wall
formed by fibrous aponeurosis of lateral
three muscles.
• These fuse in the midline at the linea alba,
These three aponeuroses also invest the
rectus abdominis muscle as the rectus
sheath.

9. PYRAMIDALIS
• The paired small triangular
muscles originate from the pubic
crest and insert into the linea
alba.

10. Blood supply of anterior abdominal wall
• The superficial epigastric artery, superficial circumflex iliac
artery , and superficial external pudendal arteries arise from
the femoral artery.
- supplies the skin and subcutaneous layers of the
anterior abdominal wall and mons pubis.
• the inferior “deep” epigastric vessels are branches of the
external iliac vessels and supply anterior abdominal wall
muscles and fascia.
• Near the umbilicus, the inferior epigastric vessels anastomose
with the superior epigastric artery and vein, which are
branches of the internal thoracic vessels

11. CLINICAL SIGNIFICANCE:
INTRA OP COMPLICATION:
Blood vessels :superior and inferior epigastric artery:
In midline incision: very little chance of injury.
 In Pfannenstiel incision: more chances of injury if incision given higher up ,incision
on rectus sheath should be given lower down as inferior epigastric artery present
upwards ,if injured and not repaired may lead to hematoma formation.
 Patient may present with Wound complications: abdominal wound sepsis is quite
common, may present with fever, serosanguinous discharge or frank pus ,hematoma
,dehiscence ,burst abdomen.

12. Nerve supply
The entire anterior abdominal wall is innervated
by
1. intercostal nerves (T7–T11 )
2.subcostal nerve (T12 )
3.iliohypogastric and the ilioinguinal nerves (L1 ).
• The intercostal and subcostal nerves are
branches of anterior rami of the thoracic spinal
nerves.

13. • Near the rectus abdominis, anterior branches of
the intercostal and subcostal nerves pierce the
posterior sheath, rectus muscle, and then anterior
sheath to reach the skin.
• The ilio hypogastric and ilioinguinal nerves branch
: the anterior ramus of the first lumbar spinal
nerve. They emerge lateral to the psoas muscle
and travel retroperitoneally across the quadratus
lumborum infero-medially towards the iliac crest.
• Near this crest, both nerves pierce the
transversus abdominis muscle and course
ventromedially.

14. • At a site 2 to 3 cm medial to the anterior superior iliac spine,
the nerves then pierce the internal oblique muscle and
course superficial to it toward the midline .
• The ilio-hypogastric nerve perforates the external oblique
aponeurosis provides sensation to the skin over the
suprapubic area
• The ilioinguinal nerve in its course medially travels through
the inguinal canal and exits through the superficial inguinal
ring, This nerve supplies the skin of the mons pubis, upper
labia majora, and medial upper thigh.

15. CLINICAL SIGNIFICANCE
• Ilioinguinal and illio hypogastric nerve perforate rectus sheath just lateral to rectus
muscle.
• While giving incision: these nerves might get injured if incision is given too lateral.
• Might lead to loss of sensation in area supplied by them .
SPINAL ANESTHESIA: Anatomical land mark :the imaginary line between 2 iliac
crests.
Skin, subcutaneous tissue ,supraspinous ligament ,interspinous ligament ,ligamentum
flavum, dura ,arachnoid.
Level: LSCS : upto T4.(amount of drug should be reduced by 30-40% due to progesterone,
lumbar lordosis ,gravid uterus compressing epidural/subarachnoid space)
For normal delivery:T10 – S1
upper abdominal surgery :T4.

16. TYPES OF INCISIONS:
PFANNENSTIEL INCISION CHERNEY MAYLARD
Slightly curved, 10-15 cm
long,2cm above the symphysis
pubis .muscle separating
transverse incision.
Uses: LSCS, abdominal
hysterectomy
These are made 2-3 cm above
the groin area lower than
Pfannenstiel incisions incision.
They provide excellent access
to urinary bladder or vaginal
repair surgeries. Because they
are tendon detaching operation
,reattachment of tendon is
tedious.
It is a true transverse muscle
cutting incision .They give
excellent exposure to
traditional placement of
Pfannenstiel incisions. They
are also popular as
Pfannenstiel incision for
cesarean delivery and cancer
surgeries.
VERTICAL INCISION(MEDIAN /PARAMEDIAN):
This give good access to whole abdomen with excellent exposure. It spares all major nerves
,vessels, muscles as opposed to transverse incision.it gives rapid entry into abdominal cavity.
JOEL COHEN INCISION:
Straight incision,3cm below the line that joins anterior superior iliac spines slightly higher than
Pfannenstiel .subsequent layers opened bluntly, if necessary extended with scissors and not a
knife.

18. TRANSVERSUS ABDOMININIS PLANE BLOCK

20. • TAP block is a regional technique for analgesia of Antero lateral abdominal wall.
• It targets the plane between internal oblique and transversus abdominis muscle
since the thoraco lumbar nerves originating from T6 –L1 spinal roots run in this
plane and supply sensory nerves to anterolateral abdominal wall.
• This technique is used in caesarean, hysterectomy, cholecystectomy, hernia repair.

21. Perineum
• This diamond-shaped, bounded by
Anteriorly : pubic symphysis
Anterolaterally : ischiopubic rami and
ischial tuberosities
Postero lateral : Sacro tuberous
ligaments
Posteriorly : coccyx
• An arbitrary line joining the ischial tuberosities divides
the perineum into an anterior triangle, also called
urogenital triangle and a posterior triangle, termed
anal triangle.

22. PERINEUM
• Urogenital diaphragm: Pelvic diaphragm:
• Deep transverse perineal muscles levator ani muscle
• Constrictors of urethra coccygeus muscle
• Internal and external fascial coverings fascia covering the muscles

23. BLOOD SUPPLY OF PERINEUM

24. Pudendal Nerve
• formed from the anterior rami of S2–4 spinal nerves.
• It courses between the piriformis and coccygeus
muscles and exits through the greater sciatic foramen
at a location posterior to the sacrospinous ligament
and just medial to the ischial spine
• The pudendal nerve then runs beneath the
sacrospinous ligament and above the sacrotuberous
ligament as it reenters the lesser sciatic foramen to
course along the obturator internus muscle.
• the nerve lies within the pudendal canal, also known
as Alcock canal, which is formed by splitting of the
obturator internus investing fascia

25. • The pudendal nerve leaves this canal to enter the perineum and divides into three terminal
branches
• First, The dorsal nerve of the clitoris, runs between the ischiocavernosus muscle and perineal
membrane to supply the clitoral glans.
• Second, the perineal nerve runs superficial to the perineal membrane.
• It divides into posterior labial branches and muscular branches, which serve the labial skin and the
anterior perineal triangle muscles, respectively.
• Last, the inferior rectal branch runs through the ischioanal fossa to supply the external anal
sphincter, the anal mucosa, and the perianal skin .

27. Perineal body
• A fibromuscular pyramidal mass found in the midline at
the junction between these anterior and posterior
triangles also called the central tendon of the perineum’
• Superficially, the bulbospongiosus, superficial transverse
perineal, and external anal sphincter muscles
• More deeply, the perineal membrane, portions of the
pubococcygeus muscle, and internal anal sphincter

28. Superficial Space of the Anterior Triangle
• This triangle is bounded
superiorly : pubic rami
laterally : ischial tuberosities
posteriorly : superficial transverse perineal
muscles
• It is divided into superficial and deep spaces by the perineal
membrane.
• The perineal membrane attaches laterally to the ischiopubic rami,
medially to the distal third of the urethra and vagina, posteriorly to
the perineal body, and anteriorly to the arcuate ligament of the
pubis

29. • The superficial space of the anterior triangle is bounded
deeply by the perineal membrane and superficially by
Colle’s fascia.
• Colle’s fascia is the continuation of Scarpa fascia onto
the perineum.
• On the perineum, Colle’s fascia attaches
laterally : pubic rami and fascia lata of the thigh
inferiorly : superficial transverse perineal muscle ,
inferior boarder of perineal membrane
medially : urethra, clitoris, and vagina.

30. • Superficial pouch contains Bartholin glands, vestibular
bulbs, clitoral body and crura, branches of the pudendal
vessels and nerve, and the ischiocavernosus,
bulbospongiosus, and superficial transverse perineal
muscles.
• ischiocavernosus muscles attaches
inferiorly : medial aspect of the ischial
tuberosity
laterally : ischiopubic ramus
Anteriorly : attaches to a clitoral crus

31. • The bilateral bulbospongiosus muscles overlie the
vestibular bulbs and Bartholin glands.
1. Anteriorly : body of the clitoris
2. Posteriorly : perineal body
• The muscles constrict the vaginal lumen and aid
release of secretions from the Bartholin glands. They
also may contribute to clitoral erection by compressing
the deep dorsal vein of the clitoris.
• the superficial transverse perineal muscles are
narrow strips that attach to the ischial tuberosities
laterally and the perineal body medially.

32. vestibular bulbs
• Almond-shaped structure that lie beneath
the bulbospongiosus muscle on either side of
the vestibule.
• The bulbs terminate inferiorly at
approximately the middle of the vaginal
opening and extend upward toward the
clitoris.

33. Deep Space of the Anterior Triangle
• This space lies deep to the perineal
membrane and extends up into the pelvis.
• It contains portions of urethra and vagina,
certain portions of internal pudendal artery
branches, and muscles of the striated
urogenital sphincter complex.

34. Urethra
• The distal two thirds of the urethra are fused with the anterior
vaginal wall.
• The epithelial lining of the urethra changes from transitional
epithelium proximally to nonkeratinized stratified squamous
epithelium distally.
• The walls of the urethra consist of two layers of smooth
muscle, an inner longitudinal and an outer circular.

35. • At the junction of the middle and lower third of the urethra, and just above the perineal
membrane, two strap skeletal muscles called the urethrovaginal sphincter
• Here, the urethra has a prominent submucosal layer that is lined by hormonally sensitive stratified
squamous epithelium. Within the submucosal layer on the dorsal (vaginal) surface of the urethra
lie the paraurethral glands
• The urethra receives its blood supply from branches of the inferior vesical, vaginal, or internal
pudendal arteries.

36. Pelvic Diaphragm
• Found deep to the anterior and posterior
triangles, this broad muscular sling provides
substantial support to the pelvic viscera.
• The pelvic diaphragm is composed of the
levator ani and the coccygeus muscles. The
levator ani, contains the pubococcygeus,
puborectalis, and iliococcygeus muscles.
• The pubococcygeus muscle is also termed the
pubovisceral muscle

37. Posterior Triangle
• This triangle contains the ischioanal fossae, anal
canal, and anal sphincter complex, which
consists of the internal anal sphincter, external
anal sphincter, and puborectalis muscle.
• Branches of the pudendal nerve and internal
pudendal vessels are also found within this
triangle.
• Ischioanal Fossae Also known as ischiorectal
fossae, these two fat-filled wedge-shaped spaces
are found on either side of the anal canal and
comprise the bulk of the posterior triangle

38. laterally : obturator internus muscle
fascia and ischial tuberosity
Inferomedially : anal canal and
sphincter complex
Superomedially : inferior fascia of
levator ani
Posteriorly : gluteus maximus muscle and
sacrotuberous ligament
Anteriorly : inferior border of the
anterior triangle.

39. DE LANCEYS THREE LEVEL
SYSTEM OF SUPPORT
Level 1 LEVEL 2 LEVEL 3
Cardinal
/uterosacral
ligament
Anteriorly:
pubo cervical
fascia
Perineal
membrane and
urogenital
diaphragm
Posteriorly:
rectovaginal fascia
Levator ani
muscles

40. Anal Canal
• This distal continuation of the rectum begins at
the level of levator ani attachment to the rectum
and ends at the anal skin.
• The mucosa consists
1. Uppermost portion : Columnar epithelium
2. At the pectinate line / dentate line : simple
stratified squamous epithelium .
3. Keratin and skin adnexa : squamous
epithelium

41. • The anal canal has several tissue layers :
1.Inner layers include the anal mucosa, the
internal anal sphincter,
2. inter-sphincteric space that contains
continuation of the rectum’s longitudinal
smooth muscle layer.
3. An outer layer contains the puborectalis
muscle as its cephalad component and the
external anal sphincter caudally