10/4: Posterior Abdominal Wall Flashcards
Is there a physical barrier between the abdominal and pelvic cavities?
No
What is at the ceiling of the abdominal wall?
Diaphragm
What is anterior to the abdomen?
Antero-lateral wall
What is posterior to the abdomen?
Posterior wall
What is inferior to the abdomen?
Abdomenopelvic cavity
Floor: pelvic organs
What are innervations of the quadratus lumborum?
ventral rami of T12-L4
Where does the quadratus lumborum attach from?
Iliac crest to 12th rib transverse process of vertebrae
What is the function of the quadratus lumborum?
Stabilize trunk to maintain balance while walking
What does the quadratus lumborum do bilaterally and unilaterally?
Bilaterally: weak extensor of the trunk
Unilaterally: laterally flexes the trunk (flexes toward active muscle site)
What are innervations of the psoas major?
ventral rami of L1-3, iliacus, and femoral nerve
Where does the psoas major attach from?
L and T vertebral bodies and transverse processes (anterior to QL) to femur lesser trochanter
What is the function of the psoas major?
Flexes the hip and flexes spine if hip is held stationary
What is the innervation of the psoas minor?
Ventral rami of L1-L3
- absent in many people, no consequence bc small function
Where does the psoas minor attach from?
Lumbar spines to the pubic bone
What is the function of the psoas minor
Not much, proprioception
What are innervations of the illiacus?
femoral nerve
What does the iliacus fuse with?
Psoas major (iliopsoas)
What does the iliacus attach from?
Iliac fossa to femur (common with PM)
What is the function of the iliacus?
Flex the thigh
What are the diaphragm attachments?
Medial arcuate ligament
Lateral arcuate ligament
Right crura
Left crura
Where does the medial arcuate ligament attach?
To psoas major
Where does the lateral arcuate ligament attach?
Quadratus lumborum
Where does the right crura attach?
To L1-L3, longer
Where does the left crura attach?
To L1-L2, shorter
What is the lumbar plexus?
Set of nerves (bilateral) made of the ventral rami of T12 through L5 spinal nerves
What nerves do the lumbar plexus carry?
Somatic motor
Somatic sensory
Sympathetics to visceral body wall structures (e.g., sweat glands)
Why is the lumbar plexus necessary?
Large muscle of the limbs are derived from multiple myotomes so they require corresponding innervation from many spinal nerves
What are limb muscles derived from?
Multiple myotomes, so they require innervation from the corresponding, multiple spinal nerves
When do the patterns of somatic sensory supply differ when comparing supply to the skin of the limbs?
When comparing dermatomes to nerves
What are motions at the hip?
Extension & Flexion
Abduction & Adduction
What are motions at the knee?
Flexion & Extension
The ventral rami that innervate muscles and skin have what kind of axons?
Sympathetic
Some have somatic motor and/or sensory axons (autonomic control)
The genitofemoral nerve is present as sensory only in what sex?
Females - sensory only
Males - sensory and motor
The lateral femoral cutaneous nerve is present as sensory in what sex?
Females + Males - sensory
**No motor
Subcostal nerve
T12 contributes
**mixed innervation (SS, SM, symp)
in front of quadratus lumborum
What does the subcostal nerve supply?
Sensory, motor, and sympathetic supply to mucles of anterior abdominal wall
Iliohypogastric nerve
L1
mixed innervation (SS, SM, symp)
always runs above iliac crest
What does the iliohypogastric nerve supply?
Motor function to supply muscles of anterior abdominal wall and some cutaneous (skin) distribution
Ilioinguinal nerve
L1
**mixed innervation (SS, SM)
**
inferior branch of L1
crosses and runs below the iliac crest
What does the ilioinguinal nerve supply?
Skin of the genital and groin, medial thigh
Lateral femoral cutaneous nerve
L2-L3
**purely sensory
**
goes to skin on lateral part of thigh by passing under inguinal ligament (some sympathetics)
What does the lateral femoral cutaneous nerve supply?
Skin on lateral thigh
Femoral nerve
L2-4 largest branch of plexus
**Mixed innervation (SS, SM)
**
passes between iliacus and psoas major
What does the femoral nerve supply?
Allows hip flexion and knee extension (kicking a ball)
Supply muscles on front thigh
Obturator nerve
L2-4
**Mixed innervation (SS, SM)
**
innervate thigh adductor
*goes into pelvis and medial part of thigh, important in adduction
goes through obturator foramen and behind psoas major
What does the obturator nerve supply?
Somatic motor to medial thigh muscles which are responsible for adducting the hip, as well as skin covring this area
Sympathetic trunk
Only gray rami, no white (bc below L2)
Paravertebral ganglion
Preganglionic sympathetics
*runs medially in front of psoas major and on sides of vertebrae
converge when going over sacral bone*
**postganglionic sympathetics will be found in all previous nerves (i.e., skin sweat glands)
Lumbosacral trunk
L4-5
**no function of own
**
Contributes to sciatic nerve
no branches of own
What does the miliary tuberculosis of the spine eventually form?
Abscess over psoas major
What nerves are involved in the milliary tuberculosis of the spine?
Femoral
What are symptoms of the miliary tuberculosis of the spine?
Numbness over anterior thigh and hip flexion and knee extension difficulty
