10/4: Posterior Abdominal Wall

Question 1

Is there a physical barrier between the abdominal and pelvic cavities?

Answer 1

No

Question 2

What is at the ceiling of the abdominal wall?

Answer 2

Diaphragm

Question 3

What is anterior to the abdomen?

Answer 3

Antero-lateral wall

Question 4

What is posterior to the abdomen?

Answer 4

Posterior wall

Question 5

What is inferior to the abdomen?

Answer 5

Abdomenopelvic cavity
Floor: pelvic organs

Question 6

What are innervations of the quadratus lumborum?

Answer 6

ventral rami of T12-L4

Question 7

Where does the quadratus lumborum attach from?

Answer 7

Iliac crest to 12th rib transverse process of vertebrae

Question 8

What is the function of the quadratus lumborum?

Answer 8

Stabilize trunk to maintain balance while walking

Question 9

What does the quadratus lumborum do bilaterally and unilaterally?

Answer 9

Bilaterally: weak extensor of the trunk
Unilaterally: laterally flexes the trunk (flexes toward active muscle site)

Question 10

What are innervations of the psoas major?

Answer 10

ventral rami of L1-3, iliacus, and femoral nerve

Question 11

Where does the psoas major attach from?

Answer 11

L and T vertebral bodies and transverse processes (anterior to QL) to femur lesser trochanter

Question 12

What is the function of the psoas major?

Answer 12

Flexes the hip and flexes spine if hip is held stationary

Question 13

What is the innervation of the psoas minor?

Answer 13

Ventral rami of L1-L3
- absent in many people, no consequence bc small function

Question 14

Where does the psoas minor attach from?

Answer 14

Lumbar spines to the pubic bone

Question 15

What is the function of the psoas minor

Answer 15

Not much, proprioception

Question 16

What are innervations of the illiacus?

Answer 16

femoral nerve

Question 17

What does the iliacus fuse with?

Answer 17

Psoas major (iliopsoas)

Question 18

What does the iliacus attach from?

Answer 18

Iliac fossa to femur (common with PM)

Question 19

What is the function of the iliacus?

Answer 19

Flex the thigh

Question 20

What are the diaphragm attachments?

Answer 20

Medial arcuate ligament
Lateral arcuate ligament
Right crura
Left crura

Question 21

Where does the medial arcuate ligament attach?

Answer 21

To psoas major

Question 22

Where does the lateral arcuate ligament attach?

Answer 22

Quadratus lumborum

Question 23

Where does the right crura attach?

Answer 23

To L1-L3, longer

Question 24

Where does the left crura attach?

Answer 24

To L1-L2, shorter

Question 25

What is the lumbar plexus?

Answer 25

Set of nerves (bilateral) made of the ventral rami of T12 through L5 spinal nerves

Question 26

What nerves do the lumbar plexus carry?

Answer 26

Somatic motor Somatic sensory Sympathetics to visceral body wall structures (e.g., sweat glands)

Question 27

Why is the lumbar plexus necessary?

Answer 27

Large muscle of the limbs are derived from multiple myotomes so they require corresponding innervation from many spinal nerves

Question 28

What are limb muscles derived from?

Answer 28

Multiple myotomes, so they require innervation from the corresponding, multiple spinal nerves

Question 29

When do the patterns of somatic sensory supply differ when comparing supply to the skin of the limbs?

Answer 29

When comparing dermatomes to nerves

Question 30

What are motions at the hip?

Answer 30

Extension & Flexion Abduction & Adduction

Question 31

What are motions at the knee?

Answer 31

Flexion & Extension

Question 32

The ventral rami that innervate muscles and skin have what kind of axons?

Answer 32

Sympathetic Some have somatic motor and/or sensory axons (autonomic control)

Question 33

The genitofemoral nerve is present as sensory only in what sex?

Answer 33

Females - sensory only Males - sensory and motor

Question 34

The lateral femoral cutaneous nerve is present as sensory in what sex?

Answer 34

Females + Males - sensory **No motor

Question 35

Subcostal nerve

Answer 35

T12 contributes **mixed innervation (SS, SM, symp) *in front of quadratus lumborum*

Question 36

What does the subcostal nerve supply?

Answer 36

Sensory, motor, and sympathetic supply to mucles of anterior abdominal wall

Question 37

Iliohypogastric nerve

Answer 37

L1 **mixed innervation (SS, SM, symp)** *always runs above iliac crest*

Question 38

What does the iliohypogastric nerve supply?

Answer 38

Motor function to supply muscles of anterior abdominal wall and some cutaneous (skin) distribution

Question 39

Ilioinguinal nerve

Answer 39

L1 **mixed innervation (SS, SM) ** inferior branch of L1 *crosses and runs below the iliac crest*

Question 40

What does the ilioinguinal nerve supply?

Answer 40

Skin of the genital and groin, medial thigh

Question 41

Lateral femoral cutaneous nerve

Answer 41

L2-L3 **purely sensory ** *goes to skin on lateral part of thigh by passing under inguinal ligament (some sympathetics)*

Question 42

What does the lateral femoral cutaneous nerve supply?

Answer 42

Skin on lateral thigh

Question 43

Femoral nerve

Answer 43

L2-4 largest branch of plexus **Mixed innervation (SS, SM) ** *passes between iliacus and psoas major*

Question 44

What does the femoral nerve supply?

Answer 44

Allows hip flexion and knee extension (kicking a ball) Supply muscles on front thigh

Question 45

Obturator nerve

Answer 45

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*

Question 46

What does the obturator nerve supply?

Answer 46

Somatic motor to medial thigh muscles which are responsible for adducting the hip, as well as skin covring this area

Question 47

Sympathetic trunk

Answer 47

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)

Question 48

Lumbosacral trunk

Answer 48

L4-5 **no function of own ** Contributes to sciatic nerve *no branches of own*

Question 49

What does the miliary tuberculosis of the spine eventually form?

Answer 49

Abscess over psoas major

Question 50

What nerves are involved in the milliary tuberculosis of the spine?

Answer 50

Femoral

Question 51

What are symptoms of the miliary tuberculosis of the spine?

Answer 51

Numbness over anterior thigh and hip flexion and knee extension difficulty