6.1 Abdominal wall Flashcards
What are the components of the Abdominal wall and where does it extend from (boarders)
Partly bone, mainly muscle (multiple layers of muscles with various fibre directionality)
Superior: Thoracic cage (cartilages of ribs 7-10 + xiphoid process)
Inferior: Pelvis (inguinal ligament + superior margins of pelvic girdle)
From outside in what are the layers of the abdominal wall? (7)
1) skin
2) superficial fascia: 2 components
- Fatty ( Camper’s fascia)
- Membranous (Scarpa’s fascia)
3) Muscles
- external oblique
- internal oblique
- transversus abdominis
4) Transversalis fascia
5) Extraperitoneal fascia
6) Parietal peritoneum
7) Visceral peritoneum
What are the 5 muscles in the antero-latera; abdominal wall, how are they classified?
Classified as flat or vertical
3 Flat: External oblique, Internal oblique, Transversis Abdominis
2 Vertical: Rectus abdominis on either side
What is the innervation to the parietal and visceral peritoneum?
What is the reflection of the parietal peritoneum on the visceral peritoneum and what is contained here?
Parietal peritoneum:
- somatic innervation- perceive pain as being where it is
- lines the abdominal cavity
Visceral peritoneum:
- visceral innervation- referred pain
- surrounds abdominal viscera
When parietal peritoneum reflects off the abdominal wall and becomes visceral peritoneum surrounding organs, the reflection of the wall is known as mesentery (contains blood vessels, lymphatics, nerves)
List 4 functions of the 3 main abdominal muscles
1) protection and stability of abdominal viscera
2) urination and defecation
3) assist in breathing
4) labour and delivery during childbirth
5) coughing
Describe the orientation of fibres in the External Oblique muscle and where its aponeurosis converges
Describe what 2 things the inferior fibres of the external oblique form
Fibres pass in an inferior and medial direction
External oblique aponeurosis is a continuation of the muscle. It intertwines at the midline at the “linea alba” and continues untill the pelvis
Inferior fibres of the external oblique form:
- 1) superficial inguinal ring
- 2) Inguinal ligament
Where does the inguinal ligament stretch from and too?
Stretches from the anterior superior illiac spine (ASIS) to the pubic tuburcle
What is the superficial ingual ring?
Opening in the inferior fibres of the aponeurosis of the external oblique muscle
Describe the orientation of fibres in the Internal Oblique muscle and where its aponeurosis converges
Describe what is formed from the inferior fibres of the external oblique form and where this found
Fibres are multidirectional and the aponeurosis blends into the linea alba
- Superior fibres: posterior to superior direction
- Inferior fibres: fibres: superior to medial direction
The inferior fibres the of the Internal oblique AND the transversus abdominis form the conjoint tendon
This tendon forms the posterior wall of the inguinal canal and helps to strengthen the abdominal wall. It is located medial and posterior to the superficial inguinal ring
Describe the orientation of fibres in the Transversis abdominis muscle and where its aponeurosis converges
Describe what 2 things the inferior fibres of the transversis abdominis form
Fibres are transverse
Its inferior aponeurosis also contributes to formation of the conjoint tendon
Its Inferior boarder forms the deep inguinal ring
What is the deep inguinal ring?
What “triangle” does this structure contribute to?
Formed from the inferior boarder of the Transversis abdominis
- This is the entrance into the inguinal canal
It is located lateral to the inferior epigastric artery and vein which creates hasselbalch triangle which is is prone to herniation
Give 2 potential sites of weakness that are prone to herniation in the inferior part of the abominal wall
What is located in the area between these?
1) Superficial (external) inguinal ring
2) Deep (internal) inguinal ring
The area between them forms the inguinal canal through which structures leave and enter the abdominopelvic cavity
What are the boarders of Hesselbach’s triangle
Medial: lateral border of the rectus abdominis muscle
Lateral: inferior epigastric vessels
Inferior: inguinal ligament.
What is the transversalis facia and where is it located?
What specific line does this fascia create?
The transversalis facia is a continuous layer of deep fascia that lines the abdominal cavity and continues into the pelvic cavity.
Lines the deep surface of the transversus abdominis muscle and its aponeurosis
When the transversalis fascia is the ONLY covering remaining POSTERIOR to the rectus abdominus muscle this is known as the arcuate line (see image)
Where is the arcuate line located?
What is the significance of the arcuate line? (2)
The arcuate line is located at the level of the umbilicus
Arcuate line:
1) marks the point where the posterior wall of the rectus sheath ends
2) It is also where the inferior epigastric vessels perforate/ pierce the rectus abdominis