Unit 2_Lumbosacral Plexus Flashcards
What are networks of nerves that are going to innervate not only the muscles from the waist down to provide sensory information, but also have responsibilities in our sympathetic and parasympathetic systems?
Lumbosacral Plexus
What do the following structures make up?
Two 12th Ribs
Lumbar Spine
Ilium and Iliac Crest
Iliacus muscle
Psoas Major muscle (insertion - Lesser Trochanter; Iliacus & Psoas Major are 1 degree hip flexors)
Quadratus Lumborum muscle
Posterior body wall
Where do the Lumbosacral nerves originate?
Two 12th Ribs
Lumbar Spine
What is another word for the Ilium?
Coxal bone
What is the most superior aspect of the Ilium?
Iliac Crest
Where does the posterior body wall span down to?
Ilium/Iliac Crest
What muscle lines the interior aspect of the Ilium fossa/concavity?
Iliacus muscle
What muscle runs longitudinally and comes off the vertebral bodies of the posterior body wall?
Psoas Major muscle
What muscle includes the blending of the bellies at the tendon of the Iliacus and Psoas major, which wraps around to insert on the lesser trochanter of the femur?
Iliopsoas muscle
What two muscles help to form the posterior body wall over which will lie the Lumbosacral Plexus?
Iliacus muscle
Psoas Major muscle
What muscle is the primary hip flexor?
Iliopsoas muscle
What muscle spans from the inferior aspect of the 12th rib down to grab onto the Iliac Crest and holds the pelvis in place?
Quadratus Lumborum muscle (QL)
What fascia lines the posterior abdominal wall?
Endoabdominal or transversalis fascia
*Derived from the fascia of the Transverse Abdominis
What fascia is deep to the Transversalis Fascia and supports/protects/insulates the abdominal viscera and the pelvic viscera?
Preperitoneal Fat
*Peritoneal Lining - lines the abdomen & supports the abdominal viscera
What muscle overlies the Quadratus Lumborum and the Ilium?
Psoas Major muscle
What kind of nerves make up the Lumbar Plexus?
Ventral Primary Rami
Where do the majority of the Lumbar Plexus nerves originate and lie right on top of/anterior to?
Quadratus Lumborum muscle
Where do the majority of the Lumbar Plexus nerves originate and lie deep to?
Psoas Major muscle
What is the Lumbar Plexus comprised of?
Ventral Primary Rami (L1-L4 spinal cord segments)
What nerves will network and meet up/diverge and form the peripheral nerves and the cutaneous nerves that will go on to provide information to and from our lower limb?
Ventral Primary Rami (L1-L4 spinal cord segments) of the Lumbar Plexus
What VPR nerve segment sends a slip to join L1 50% of the time?
T12
What is T12 VPR called within the Lumbar Plexus?
Subcostal Nerve (Intercostal Nerve; T12)
What does the L1 VPR bifurcate into within the Lumbar Plexus?
Iliohypogastric Nerve (L1)
Ilioinguinal Nerve (L1)
What muscles do the Iliohypogastric Nerve (L1) provide innervation to?
Abdominal muscles
*“Hypo” below the stomach