Abdomen 1 Flashcards
(43 cards)
Rectus Abdominis Origin & Insertion
Origin: 5, 6, 7 costal cartilage
Insertion: Pubic crest
Rectus Abdominis Function
Flexion of Lumbar Spine (acts in opposition to erector spinae)
Static function: Keeping the spine straight
3 Flat Muscles (from deep to superficial)
Transversus Abdominis, Internal Oblique, External Oblique
Aponeurosis
Tendon in the form of a sheet - flat muscle insertions have aponeuroses
Transversus Abdominis Origin & Insertion
Different parts of the muscle have different origins and insertion points
Origin: Ribs 6-12 of inner aspect of costal margin + Iliac Crest + Thickening of Iliopsoas Fascia
Insertion: Transversus Aponeurosis
Which flat muscle is the deepest?
Transversus Abdominis
Of which other aponeurosis of which flat muscle does the aponeurosis of the transversus abdominis fuse with?
Internal oblique (overlying muscle, superficial to TA)
Internal Oblique Origins & Insertion
Different parts of the muscle have different origins and insertion points
Origin: Arises from thoracolumbar fascia + Iliac Crest + Thickening of Iliopsoas Fascia (like TA)
Insertion: Lowest 3 ribs + Internal Oblique Aponeurosis
What type of border do all 3 flat muscles have in common?
Short free lower border
Of which other aponeurosis of which flat muscle(s) does the aponeurosis of the internal oblique fuse with?
Transversus Abdominis (deep) and External Oblique (superficial) on outer aspect
Functions of anterolateral abdominal wall
- Protection of viscera within the abdomen
- Accessory muscles for respiration
- Compress abdominal contents to increase intra-abdominal pressure for coughing, sneezing, defecation and parturition
- Movement of trunk
Which flat muscle is the outermost/superficial?
External Oblique
External Oblique Origins & Insertion
Origin: Ribs 5-12 on outside of rib cage, zig-zag line of origin (fits in with line origin of serratus anterior)
Insertion: Depends on which part:
Anterior: origin - ribs 6-9, insertion - external oblique aponeurosis
Posterior: origin - ribs 10-12, insertion - outer edge of anterior half of iliac crest
Functions of flat muscles
- When 3 flat muscles on both sides contract together (as they usually do), they raise pressure inside the abdominal cavity, aiding in respiration and defecation.
- When they contract in isolation, they play a part in producing lateral flexion of the lumbar spine and rotation of thoracic spine.
What do the aponeuroses of the 3 flat muscle insertions form?
The rectus sheath
Inguinal ligament origin and insertion
Anterior superior iliac spine –> Pubic tubercle
Why is there a gap between the inguinal ligament and the underlying bone?
Important structures pass through from abdomen –> thigh, including femoral vein, artery and nerve medially and the belly of the psoas and iliacus musles laterally
What is the inguinal ligament the lowest part of?
The external oblique aponeurosis
What do the lowest fibres of the inguinal ligament curl around to form?
A triangular extension known as the Lacunar ligament
Where does the Lacunar ligament insert?
Sharp upper edge of the superior pubic ramus - the pectin.
What do the tendinous fibres of the transversus abdominis and internal oblique unite to form?
Conjoint tendon
What does the Conjoint tendon attach to?
The pubic crest and pectin (Sharp upper edge of the superior pubic ramus)
What is the superficial inguinal ring part of?
External oblique aponeurosis - it’s an opening in it
What passes through the superficial inguinal ring?
Spermatic cord (men) or Round ligament of the uterus (women) - this is contained within the inguinal canal
+ ilioinguinal nerve + genital branch of genitofemoral nerve
