Lecture 3 - The posterior abdominal wall and introduction to mesentries Flashcards
The anatomy of the posterior abdominal wall between L3-L4
Label “BIOL21921 - L3 posterior image”
The 33 components of the vertebral spine
7 - Cervical
12 - Thoracic
5 - Lumbar
5 - sacral (fused)
3-5 - Coccyx
Primary vertebral curvature: what is it, where can it be seen, what does it do?
Concave anterior surface and convex posterior surface
~ C7-L2 (mainly T1-T12)
The way we are born
Primary vertebral curvature: what is it, where can it be seen, what does it do?
Convex anterior surface and concave posterior surface
~ C2-C6
~ L1-L5
Allows us to stand straight
Lumbar vertebrae features
- 2 transverse processes
- 2 superior articular processes
- 2 inferior articular processes
- 1 spinous processes
- Articulation
- 1 body
The body of the lumbar vertebrae
Anterior to the vertebrae, takes the load from that vertebrae and those above and transmits it down to lower vertebrae via the intervertebral discs
Vertebral canal
Posterior to the vertebral body, contains the spinal cord - protected by the arch of the vertebrae formed by the pedicles and laminae
Transverse processes
Reach out posteriorly to the vertebrae
Provide support and movement to the vertebral column via muscular and ligamentous attachments (paraspinal muscles)
Spinous processes
Hatchet-shaped, reaches out inferiorly to the vertebrae
Provide support and movement to the vertebral column via muscular and ligamentous attachments (paraspinal muscles)
How do the vertebrae articulate with one another?
Posteriorly - Superior articular processes and inferior articular processes
Anteriorly - intervertebral discs
Superior and inferior articular processes
Restricting the range of movement of the spinal cord, transmitting loading, and stopping disarticulation of the vertebral column
Superior articular process of one vertebrae articulates with the inferior articular process of the vertebrae above
Anterior longitudinal ligament: what does it do and where can it be found?
Strong, broad fibrous sheet that limits the amount of extension that can occur
C1 - sacrum
Posterior longitudinal ligament: what does it do and where can it be found?
Weakly limits the amount of flexion that can occur - is narrower and weaker than the ALL, though - and herniation of the intervertebral discs (very important - no pinched nerves)
In the vertebral canal, C2 - sacrum
The two key parts of the IV discs
Annulus fibrosus - fibrous ring posterior to the ALL and anterior to the vertebral canal, surrounding the nucleus pulposus
Nucleus pulposus - the centre part, gelatinous mass that can be moved, allowing spinal limited range of movement
Slipped disc
Rupture in the annulus fibrosus causing leakage
NP loses its protection and may move around - can end up pinching spinal nerves if it moves posteriorly
Posterior abdominal muscles
Quadratus lumborum, Iliacus, Psoas major, and psoas minor
Quadratus lumborum: appearance, origin, insertion, function
Trapezium shaped, BIOL21921 - L3 Quadratus lumborum image
Iliac crest
Transverse processes of L1 to L4, 12th rib
Lateral bending of trunk and fixes 12th rib
Iliacus: appearance, origin, insertion, function
Triangular shape - think pizza
Superior part of the iliac fossa and sacral ala
Lesser trochanter of the femur
Flexion of thigh at hip joint
Psoas major: appearance, origin, insertion, function
Cylindrical
Transverse processes and lateral surface of T12 to L5
Lesser trochanter of the femur
Flexion of thigh at hip joint
Psoas minor: appearance, origin, insertion, function
Iliopsoas
Combination of both the psoas and iliacus
Postural and dynamic roles - The combined iliopsoas is a stabiliser of the vertebral column and the hip joint and flexes the thigh when it contracts and the vertebral column laterally (superior part of the psoas major is responsible for this)
As a consequence, it also acts to flex the
trunk during sitting
Major abdominal arteries: what are they and where are they located?
The Aorta and the common iliac arteries
The aorta descends from the diaphragm and is slightly to the left (IVC is on the right)
The common iliac arteries are formed by the splitting of the aorta at L4 and descend inferiorly in the body
Smaller abdominal arteries: what are they and what do they supply?
Coeliac trunk - The foregut
Suprarenal artery - The adrenal gland
Renal artery - The kidneys
Superior mesenteric - The intestines (midgut)
Gonadal artery - The gonads
Inferior mesenteric - The intestines (hindgut)
Lumbar artery - The lumbar region
Arteries are listed based on which are superior to the others
Smaller abdominal arteries: which are single anterior branches, which are paired lateral branches, and which are paired parietal branches?
SAB - Coeliac trunk, superior mesenteric artery, and inferior mesenteric artery
PLB - Suprarenal artery, renal artery, and gonadal artery
PPB - lumbar artery
