Thoracic And Lumbar Plexuses

Question 1

Each mixed thoracic nerve divides into what structures?

Answer 1

Anterior and posterior primary ramus

Question 2

Each posterior primary ramus splits into what branches?

Answer 2

Medial and lateral

Question 3

What muscles make up the motor supply of the medial branches of the posterior primary rami of the thoracic spinal nerves?

Answer 3

Semispinalis (upper six)
Longissimus (lower six)
Multifidi

Question 4

What makes up the sensory supply of the medial branches of the posterior primary rami of the thoracic spinal nerves?

Answer 4

Skin paraspinally

Question 5

What is different about the medial branches of the posterior rami of the thoracic spinal nerves compared to the cervical spinal nerves?

Answer 5

They are mixed in the thoracic region (both sensory and motor supply)

Question 6

The lateral branches of the posterior primary rami of the thoracic spinal nerves increase in size in which direction?

Answer 6

Superior to inferior

Question 7

Are the lateral branches of the posterior primary rami of the thoracic spinal nerves mixed like the medial branches?

Answer 7

Yes

Question 8

What muscles make up the motor supply of the lateral branches of the posterior primary rami of the thoracic spinal nerves?

Answer 8

Longissimus, iliocostalis, levator costarum

Question 9

What makes up the sensory supply of the lateral branches of the posterior primary rami of the thoracic spinal nerves?

Answer 9

Skin near the costal angles

Question 10

What forms the first intercostal nerve?

Answer 10

Small branch from T1 (anterior primary ramus of T1 contributes to the brachial plexus)

Question 11

Which anterior primary rami contribute to the intercostobrachial nerve?

Answer 11

T2 and sometimes T1

Question 12

Each intercostal nerve gives off what branch to supply the overlying skin?

Answer 12

Lateral cutaneous branch (which divides into an anterior and posterior branch)

Question 13

Intercostal nerves terminate as what?

Answer 13

Anterior cutaneous branches

Question 14

What do the anterior cutaneous branches supply?

Answer 14

Skin close to the midline

Question 15

How many pairs of thoracic roots are there?

Answer 15

12

Question 16

What muscles are supplied by intercostal nerves?

Answer 16

Internal, external, and innermost intercostals, serratus posterior, transversus thoracis, transverse abdominal, internal and external abdominal oblique, rectus abdominus

Question 17

What extra things besides muscles are supplied by the intercostal nerves?

Answer 17

Adjacent blood vessels, bones, joints, and ligaments

Question 18

What is the largest of the thoracic nerves?

Answer 18

T12 (subcostal nerve)

Question 19

What plexus does the subcostal nerve also contribute to?

Answer 19

Lumbar plexus

Question 20

What is the sensory supply of the subcostal nerve?

Answer 20

Skin as far inferior as the superior buttocks

Question 21

Which thoracic nerves communicate with the sympathetic trunk via white and gray rami communicans?

Answer 21

All

Question 22

Which is more medial: white or gray ramus communicans?

Answer 22

Gray

Question 23

At what levels do we find white ramus communicans?

Answer 23

T1-L2 (therefore, all thoracic nerves)

Question 24

Describe the fibers of the gray ramus communicans.

Answer 24

Postganglionic sympathetic

Question 25

Describe the fibers of the white ramus communicans.

Answer 25

Preganglionic sympathetic

Question 26

How are the lumbar spinal nerves named?

Answer 26

For the bone above, just like the thoracics

Question 27

The posterior primary rami of the lumbar nerves divide into what?

Answer 27

Medial and lateral branches

Question 28

What do the medial branches of the posterior primary rami of the lumbar nerves supply?

Answer 28

Multifidi

Question 29

What do the lateral branches of the posterior primary rami of the lumbar nerves supply?

Answer 29

Erector spinae group

Question 30

The anterior primary rami of the lumbar nerves contribute to what plexuses?

Answer 30

Lumbar and sacral

Question 31

Which lumbar nerves can have white rami communicans?

Answer 31

L1, L2, L3 (sometimes)

Question 32

Which lumbar nerves have gray ramus communicans?

Answer 32

All of them

Question 33

How many lumbar sympathetic ganglia do we see?

Answer 33

4

Question 34

What forms the lumbar plexus?

Answer 34

Anterior primary rami of L1-L3, part of L4, and T12 through a communication with L1

Question 35

What muscles are supplied by the muscular branches of the anterior primary rami of the lumbar plexus?

Answer 35

Quadratus lumborum, psoas major, psoas minor if present

Question 36

What muscles are supplied by L1?

Answer 36

Quadratus lumborum and psoas minor

Question 37

What muscles are supplied by L2?

Answer 37

Quadratus lumborum and both psoas muscles

Question 38

What muscles are supplied by L3 and L4?

Answer 38

Quadratus lumborum and psoas major

Question 39

The iliohypogastric nerve contains what fibers?

Answer 39

T12 and L1

Question 40

What is the course of the iliohypogastric nerve?

Answer 40

Anterior and inferior between the quadratus lumborum and the kidney, then through the transverse abdominal muscle and in between it and the internal abdominal oblique

Question 41

What is the sensory supply of the the lateral cutaneous branch of the iliohypogastric nerve?

Answer 41

Posterolateral gluteal region

Question 42

What is the sensory supply of the anterior cutaneous branch of the iliohypogastric nerve?

Answer 42

Skin of the pubic region

Question 43

What muscles are supplied by the iliohypogastric nerve?

Answer 43

Internal abdominal oblique and transversus abdominus

Question 44

What fibers are contained in the ilioinguinal nerve?

Answer 44

T12 and L1

Question 45

What is the course of the ilioinguinal nerve?

Answer 45

Similar to iliohypogastric but is transmitted through the inguinal canal Leaves the canal through the superficial inguinal ring and travels with the spermatic cord (round ligament in females)

Question 46

What is the sensory supply of the ilioinguinal nerve?

Answer 46

Skin of the upper medial thigh, base of penis and anterior scrotum in men, mons pubis and labium majus in females

Question 47

What muscles are supplied by the ilioinguinal nerve?

Answer 47

Internal abdominal oblique and transversus abdominus

Question 48

The genitofemoral nerve contains what fibers?

Answer 48

L1 and L2

Question 49

When passing anteriorward through the psoas major, what does the genitofemoral nerve divide into?

Answer 49

Genital and femoral branches

Question 50

Which branch of the genitofemoral nerve passes through the inguinal canal?

Answer 50

Genital branch

Question 51

What is the motor supply of the genital branch of the genitofemoral nerve?

Answer 51

Cremaster muscle

Question 52

What is the sensory supply of the genital branch of the genitofemoral nerve?

Answer 52

Skin of the superior anterior scrotum in males | Skin of the mons pubis and labium majus in females

Question 53

How can we test for the cremasteric reflex?

Answer 53

Scrap sharp side of the reflex hammer over the medial thigh and one testicle will contract and rise

Question 54

The cremasteric reflex involves what nerve?

Answer 54

Genital branch of genitofemoral nerve

Question 55

What is the supply of the femoral branch of the genitofemoral nerve?

Answer 55

Skin of the upper anterior thigh

Question 56

What is the course of the femoral branch of the genitofemoral nerve?

Answer 56

Into the thigh posterior to the inguinal ligament

Question 57

What fibers are contained in the lateral cutaneous nerve of the thigh?

Answer 57

L2 and L3

Question 58

What is the supply of the lateral cutaneous nerve of the thigh?

Answer 58

Skin of the lateral thigh, superior to the knee

Question 59

What is the course of the lateral cutaneous nerve of the thigh?

Answer 59

Leaves abdominal cavity by passing posterior to the inguinal ligament Travels to the sartorius and through the fascia lata to reach the skin

Question 60

What is the largest branch of the lumbar plexus?

Answer 60

Femoral nerve

Question 61

What fibers are contained in the femoral nerve?

Answer 61

L2, L3, and L4

Question 62

All branches of the femoral nerve are given off in what locations?

Answer 62

Abdomen, femoral triangle

Question 63

What is the course of the femoral nerve?

Answer 63

Posterior to psoas major, then emerges lateral to the psoas, anterior to the iliacus Posterior to inguinal ligament and enters femoral triangle just lateral to femoral artery Inferior and medially through adductor canal Into the leg, medially to the knee

Question 64

What branches of the femoral nerve are given off in the abdomen?

Answer 64

Muscular branches to iliacus and pectineus, some fibers to the femoral artery

Question 65

When does the femoral nerve divide into anterior and posterior divisions?

Answer 65

Once past the inguinal ligament

Question 66

The anterior division of the femoral nerve gives rise to which three nerves?

Answer 66

Intermediate cutaneous nerve of the thigh, medial cutaneous nerve of the thigh, nerve to the sartorius

Question 67

What is the supply of the intermediate cutaneous nerve of the thigh?

Answer 67

Skin on the anterior thigh down to the knee | Lateral branch communicates with femoral branch of genitofemoral nerve

Question 68

What is the supply of the medial cutaneous nerve of the thigh?

Answer 68

Skin of the medial thigh, medial knee, and knee across to the lateral side of the patella Some branches supply skin of the medial leg through communications with the the saphenous nerve

Question 69

With what other nerve does the intermediate cutaneous nerve of the thigh communicate with for its supply?

Answer 69

Femoral branch of the genitofemoral nerve

Question 70

With what other nerve does the medial cutaneous nerve of the thigh communicate with for its supply?

Answer 70

Saphenous nerve

Question 71

What does the nerve to the sartorius supply?

Answer 71

Sartorius muscle

Question 72

What makes up the posterior division of the femoral nerve?

Answer 72

Muscular branches to quadriceps, vascular branches to femoral artery and its branches, articular branches to knee joint

Question 73

The femoral nerve continues into the leg as what nerve?

Answer 73

Saphenous nerve

Question 74

What muscular branches are given off in the femoral triangle from the posterior division of the femoral nerve?

Answer 74

Sartorius, rectus femoris, vastus lateralis, vastus medialis, vastus intermedialis

Question 75

The saphenous nerve is transmitted through what opening?

Answer 75

Adductor canal

Question 76

The saphenous nerve lies medial to what structure as it emerges from the adductor canal?

Answer 76

Femoral artery

Question 77

What is the supply of the saphenous nerve as it emerges from the adductor canal?

Answer 77

Skin medial and anterior to the patella

Question 78

What is the supply of the saphenous nerve in the leg?

Answer 78

Skin of the medial leg and foot

Question 79

The saphenous nerve travels with what vascular structure in the leg?

Answer 79

Great saphenous vein

Question 80

How can one check for sensory deficits by analyzing the femoral nerve?

Answer 80

Checking dermatome levels

Question 81

What tendon reflex can be used to analyze function of the femoral nerve?

Answer 81

Patellar reflex

Question 82

What fibers are contained in the obturator nerve?

Answer 82

L2, L3, and L4

Question 83

Which nerve is the primary contributor to the obturator nerve?

Answer 83

L3 (L2 contribution is minimal)

Question 84

Through what opening does the obturator nerve leave the pelvis?

Answer 84

Obturator foramen

Question 85

What separates the anterior and posterior branch of the obturator nerve?

Answer 85

First by the obturator externus then by the adductor brevis

Question 86

What is the course of the obturator nerve?

Answer 86

Medial to psoas major, posterior to common iliac vessels, descends into their pelvis traveling on the obturator internus

Question 87

The anterior branch of the obturator nerve travels posterior to what muscles?

Answer 87

Pectineus and adductor longus

Question 88

What forms the subsartorial plexus?

Answer 88

Branches from the anterior branch of the obturator nerve with branches of the femoral nerve

Question 89

What does the subsartorial plexus supply?

Answer 89

Skin of the medial thigh

Question 90

What does the termination of the anterior branch of the obturator nerve supply?

Answer 90

Femoral artery

Question 91

To which joint does the anterior branch of the obturator nerve send articular branches?

Answer 91

Hip joint

Question 92

What muscles are supplied by the anterior branch of the obturator nerve?

Answer 92

Adductor longus, gracilis, pectineus (usually), adductor brevis (usually)

Question 93

The anterior branch of the obturator nerve may send fibers to connect with what other nerve if it is present?

Answer 93

Accessory obturator nerve

Question 94

The anterior branch of the obturator nerve sends fibers to what other nerves to contribute to the supply of the skin on the upper medial side of the leg?

Answer 94

Medial cutaneous nerve of the thigh and the saphenous nerve

Question 95

What is the course of the posterior branch of the obturator nerve?

Answer 95

Through the obturator externus, posterior to the adductor brevis, anterior to the adductor magnus

Question 96

What muscles are supplied by the posterior branch of the obturator nerve?

Answer 96

Obturator externus, adductor magnus, adductor brevis if not supplied by anterior branch

Question 97

To which joint does the posterior branch of the obturator nerve send articular branches?

Answer 97

Knee joint