Abdomen I and II Flashcards
describe the posterior abdominal wall and its bony boundaries
Bony Boundaries are:
5 Lumbar Vertebrae, Pelvic bones, 12th floating Rib
Permits structures to pass from thoracic to pelvic cavities e.g. Aorta, IVC, Oesophagus
Label and describe this
Describe the spinal curvatures
The vertebral column consists of 4 curves:
- Cervical curvature (present from birth)
- Thoracic curvature(secondary- develop months after birth)
- Lumbar curvature (secondary)
- Sacral curve (present from birth)
Produces an S-shaped compared with C-shaped spine present at birth: allows walking as the head is balanced over the bodies centre of gravity
Which muscles are found in the posterior abdominal wall?
What is the quadratus lumbroum?
Attaches to the transverse processes of L1-4 and inferior border of rib 12
Laterally flexes vertebral column
Innervation: subcostal nerve (T12), anterior rami of spinal nerves L1-L4
Describe the psoas major muscle
Major: joins with the iliacus muscle to form iliopsoas
Originates on vertebral bodies of T12-L4, (and IVDiscs) and transverse processes of L1-L5 vertebrae
Inserts onto lesser trochanter of femur
Innervated by anterior rami of spinal nerves L1-L3
Describe the psoas minor muscle
Minor: inconsistent muscle, found only in 40% people
Originates from vertebral bodies of T12 & L1. Inserts onto pelvic bones
Innervated by anterior ramus of spinal nerve L1
Describe the transversus abdominis
Originates from the inguinal ligament, costal cartilages 7-12, the iliac crest and thoracolumbar fascia.
Functions: compress abdominal contents, also involved in expiration
Innervation: Thoracoabdominal nerves (T7-T11), subcostal nerve (T12) iliohypogastricnerve (L1), ilioinguinal nerve (L1)
What is the lumbar plexus
Nerve fibres that supplies the skin and musculature of the lower limb
The plexus is formed by the anterior rami (divisions) of the lumbar spinal nerves L1-L4
Also receives contributions from thoracic spinal nerve 12
Label the branches of the lumbar plexus
How is the lumbar plexus linked to psoas major?
Lateral border of Psoas contains:
• Iliohypogastric nerve
• Ilioinguinal nerve
• Lateral cutaneous nerve of the thigh
• Femoral nerve
Anterior surface of Psoas: Genitofemoral nerve
Medial border of Psoas: Obturator nerve
Label the divisions of the lumbar plexus on the left
Label the abdominal landmarks shown here
How can the abdomen be divided into 9 sections?
Describe the transpyloric and transtubecular planes
Give the layers of the abdominal wall from superficial to deep
Superficial fascia: Camper’s fascia (fatty). Scarpa’s fascia (membranous)
Anterolateral Muscles: External oblique. This has an inferomedial fibre direction, and its free border is the inginal ligament
Rectus sheath: Anterior layer. Aponeuroses of external and 1/2 internal abdominal obliques.
Label and describe the anterolateral muscles of the abdominal wall
Label and describe the vertical muscles of the abdominal wall
Label and describe the deep layers of the abdominal wall
Label this
What is meant by the following terms?
- Investing fascia:
- Transversalis fascia:
- Extraperitoneal fascia:
- Parietal peritoneum:
Investing fascia: Connective tissue in-between muscles
Transversalis fascia: Very thick layer of investing fascia posterior to transversus abdominis
Extraperitoneal fascia: Contains various amounts of fat
Parietal peritoneum: Thin serous membrane, lining abdominal walls
Describe the rectus sheath and linea alba
Rectus Sheath: Aponeuroses of ex + internal oblique, rect. Ab. The 2 layers of the R.sheath envelope:
- Rectus abdominis
- Pyramidalis
- Distal thoracoabdominal nerves
- Superior and inferior epigastric vessels
- Corresponding lymphatics
Linea Alba: white line of collagen from the xiphoid process to pubic crest. Median surgical incision bc it is avascular
Label this
Label and describe this structure of the rectus sheath.
This is the superior rectus sheath, aka the arcuate line. This arcuate line is found midway between the umbilicus and pubic crest
Internal oblique aponeurosis/tendon splits into two layers:
•Anterior laminae passes anterior to rectus abdominis. Posterior laminae passes posterior to rectus abdominis.
Label and describe this structure of the rectus sheath.
This is the inferior rectus sheath.
All aponeuroses pass anterior to rectus abdominis.
Posterior layer of rectus sheath is weaker as it is only formed by transversalis fascia. Therefore more hernias can occur below the arcuate line.
Label this and use it to describe the arterial supply of the abdominal wall
Superior anterolateral wall supplied by:
•Musculophrenic artery. Superior epigastric
Inferior anterolateral wall supplied by:
•Superficial circumflex iliac. Superficial epigastric. Inferior epigastric. Deep circumflex iliac
What is rectush sheath haematoma?
- Rupture in inferior epigastric artery which ascends between rectus abdominis and posterior laminae of rectus sheath.
- More common in patients on anticoagulants
Describe innervation of the abdominal wall
The skin, muscles and parietal peritoneum of the abdominal wall are supplied by the spinal nerves: T7 – L1
- T7 – T11 (intercostal nerves)
- T12 (subcostal nerve)
- L1 (ilioinguinal nerve)
- L1 (iliohypogastric nerve)
Nerves run in plane between internal oblique and transversus abdominus muscle.
