Abdominal Wall part 1 Flashcards
inferiorly by the
symphysis pubis
Pelvic bones
posteriorly by the
vertebral column
origin and develops as bilateral migrating sheets, which originate in the paravertebral region and envelop the future abdominal area
Mesodermal
The leading edges of these structures develop into the ________________, which eventually meet in midline of the anterior abdominal wall
rectus abdominus muscles
The muscle fibers of the rectus abdominus are arranged vertically and are encased within an aponeurotic sheath, the anterior and posterior layers of which are fused in the midline at the
Linea alba
The rectus abdominus has insertions on the
symphysis pubis and pubic bones
anteroinferior aspects of the fifth and sixth ribs
seventh costal cartilage
xiphoid process
The lateral border of the rectus muscles assumes a convex shape that gives rise to the surface landmark, the
Linea semilunaris
There are usually three tendinous intersections or inscriptions that cross the rectus muscles
Level of xiphoid process
Level of umbilical
halfway between the xiphoid process and the umbilicus
The complexities of the anterior and posterior aspects of the rectus sheath are best understood in their relationship to the
arcuate line (semicircular line of Douglas
Above the arcuate line
The anterior rectus sheath is formed by the
external oblique aponeurosis
external lamina of the internal oblique aponeurosis
Above the arcuate line
The posterior rectus sheath is formed by the
internal lamina of the internal oblique aponeurosis
transversus abdominis aponeurosis,
transversalis fascia
Below the arcuate line
The anterior rectus sheath is formed by the
external oblique aponeurosis
The laminae of the internal oblique aponeurosis
The transversus abdominis aponeurosis
There is no aponeurotic posterior covering of this lower portion of the rectus muscles, although the ___________ remains a contiguous structure on the posterior aspect of the abdominal wall in this area as well
transversalis fascia
The majority of the blood supply to the muscles of the anterior abdominal wall is derived from the
superior
inferior epigastric arteries
The superior epigastric artery arises from the
internal thoracic artery
The inferior epigastric artery arises from the
external iliac artery
also contributes to the abdominal wall blood supply
branches of the subcostal and lumbar arteries
The lymphatic drainage of the abdominal wall is predominantly to the major nodal basins in the
superficial inguinal and axillary areas
The motor nerves to the rectus muscles,
the internal oblique muscles,
and the transversus abdominis muscles run from the
anterior rami of spinal nerves at the T6 to T12 levels
The overlying skin is innervated by afferent branches of the
T4 to L1 nerve roots
Umbilicus nerve root
T10
The rectus muscles, the external oblique muscles, and the internal oblique muscles work as a unit to
flex the trunk anteriorly or laterally
Rotation of the trunk is achieved by the contraction of: the
external oblique muscle
contralateral internal oblique muscle
diaphragm is relaxed when the abdominal musculature is contracted
expiration of air from the lungs or a cough if this contraction is forceful
diaphragm is contracted when the abdominal musculature is contracted (Valsalva maneuver
micturition, defecation, and childbirth
connects the embryonic and fetal midgut to the yolk sac
Vitelline duct
During the sixth week of development, the abdominal contents grow too large for the abdominal wall to contain and the embryonic midgut
herniates into the umbilical cord
While outside the confines of the developing abdomen, it undergoes a
270degree counterclockwise rotation
Defects in abdominal wall closure may lead to
omphalocele or gastroschisis
, viscera protrude through an open umbilical ring and are covered by a sac derived from the amnion
omphalocele
, the viscera protrude through a defect lateral to the umbilicus and no sac is present
gastroschisis
is a fibromuscular, tubular extension of the allantois that develops with the descent of the bladder to its pelvic position
urachus
Persistence of urachal remnants can result in ________________ with drainage of urine from the umbilicus
cysts as well as fistulas to the urinary bladder,
describes a clinically evident separation of the rectus abdominus muscle pillars, generally as a result of decreased tone of the abdominal musculature
Rectus abdominis diastasis (or diastasis recti)
The characteristic bulging of the abdominal wall in the epigastrium is sometimes mistaken for a
ventral hernia
Diastasis may be congenital, as a result of a more lateral insertion of the rectus muscles to the
ribs and costochondral junctions
Diastasis but is more typically an acquired condition with
advancing age, obesity, or following pregnancy
In the postpartum setting, rectus diastasis tends to occur in women of
advanced maternal age,
after multiple or twin pregnancies, or
in women who deliver high-birthweight infants
provides an accurate means of measuring the distance between the rectus pillars and will differentiate rectus diastasis from a true ventral hernia if clarification is required
CT Scan
Surgical correction of a severe rectus diastasis by plication of the anterior rectus sheath may be undertaken for
cosmetic indications
Rectus Sheath Hematoma
The terminal branches of the superior and inferior epigastric arteries course deep to the posterior aspect of the
left and right rectus pillars
and penetrate the posterior rectus sheath
Injury to these vessels or to any of the network of collateralizing vessels within the rectus sheath and muscles can result in a
rectus sheath hematoma
Spontaneous rectus sheath hematomas have been described in the
elderly and
anticoagulation therapy
Rectus sheath hematoma
Patients frequently describe the sudden onset of unilateral abdominal pain that may be confused with lateralized peritoneal disorders such as
appendicitis