Lecture 2: Anterior abdominal wall including the inguinal canal Flashcards
Layers of ant abdominal wall
Skin
Sup. Fascia
Muscles and associated deep fascia
Extraperitoneal fascia
Parietal peritoneum
Sup. Fascia of ant. Abdominal wall consists of
connective tissue.
Contents of the superficial fascia of the abdominal wall varies depending on its
Location
Contents of the superficial fascia of the abdominal wall varies depending on its location:
Either above or below the umbilicus
Above the umbilicus the superficial fascia
=Single sheath of connective tissue and is continuous with sup. Fascia of other regions of the body
Below the umbilicus the superficial fascia
Sup. Fascia consists of 2 layers:
Superficial layer: Campers fascia (fatty layer)
Deep layer: Scarpa’s fascia (membranous layer)
In the midline just superior to the penis, we have
scarpas contribution to the formation of the fundiform lig of the penis
Muscles of the ant. Abdominal wall:
5 muscles divided into 2 groups:
Vertical and flat
VERTICAL MUSCLES: (2)
- rectus abdominis
- pyramidalis
- Situated near midline
Rectus abdominis
Rectus abdominis:
- Long, paired muscle
- Either side of the midline
- Divided into two by the linea alba
- Lateral border create a surface marking called the linea semilunaris (Semilunar line)
- Muscle intersected by fibrous strips known as tendinous intersections
- Tendinous intersections & linea alba give rise to the ‘six pack’
Rectus abdominis functions:
- – Bliateral contraction = flexion, compression
- – Unilateral contraction = lateral flexion
- – Assisting flat muscles in compressing the abdominal viscera
- – Stabilises pelvis during walking
- – Depresses ribs
Pyramidalis
Pyramidalis innervation
subcostal nerve (T12)
Pyramidalis characteristics
- Variable
- Small triangle shaped muscle
- Superficial to rectus abdominis
- Base on pubis bone
- Apex of triangle attached to linea alba
Pyramidalis function
Tenses linea alba
Flat muscles: (3)
– External oblique, internal oblique & transversus abdominis
– Situated laterally
– Stacked upon one another
Functions of flat muscles
- Flex, laterally flex & rotate trunk
- Fibres run in differing directions & cross each other
- Strengthening abdominal wall
- Decreasing the risk of herniation
- In anterior medial aspect of abdominal wall, each flat muscle forms an aponeurosis (broad flat tendon) which covers the vertical rectus abdominis muscle
- Aponeurosis of all the flat muscles becomes intertwined at the midline, which forms the linea alba
Linea alba extends from xhiphoid process to the pubic symphasis