Peripheral Nerve Anatomy Flashcards

1
Q

peripheral nerves

A

-continuation from spinal anatomy -spinal nerves split, converge, and branch - form peripheral nerves

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2
Q

Cervical Plexus

A

Innervates - muscles, joints, and skin in the anterior neck - Ventral Rami C1-C4

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3
Q

Brachial Plexus

A

Large network of nerves - extend from neck through axilla Innervate the upper extremity Composition -

ventral Rami (Roots) 5 -

Trunks 3 -

Divisions 6 -

Cords 3 -

Branches 4

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4
Q

BP: Roots, Trunks, and Divisions

A
  • Found in posterior triangle of the neck - Supraclavicular
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5
Q

BP: Cords and Branches

A

-Found in the Axilla - Infraclavicular

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6
Q

BP: Roots

A
  • 5 Rami (Roots) involve C5-T1 - May include C4 and T2
  • Pass to lateral border of scalene muscles
  • Reorganize to 3 Trunks
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7
Q

BP: Trunks

A

3 Trunks - Superior C5-C6

-Middle C7

-Inferior C8-T1

Enveloped in fascial sheath

  • Interscalene space - between anterior and middle scalene muscle
  • Injection into sheath - commonly produces complete block of upper extremity
  • May have individual septa - thus we see incomplete blocks
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8
Q

BP: Divisions

A

Posterior to clavicle divide into:

  • 3 ventral (Anterior) divisions-supply flexor portions
  • 3 Dorsal (Posterior) Divisions - supply extensor portions
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9
Q

BP: Cords

A

In axilla:

  • 3 Dorsal Divisions combine to form posterior cord
  • 3 Ventral divisions combine to form lateral and medial cords
  • Now name in position to axillary artery
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10
Q

BP: Branches

A
  • At lateral border of pectoralis minor
  • each cord divides into 2 branches
  • become peripheral nerves
  • Lateral Cord, Medial Cord, Posterior Cord
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11
Q

Lateral Cord

A
  • Musculocutaneous nerve
  • Lateral root of median nerve
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12
Q

Medial Cord

A
  • Medial root of medial nerve
  • Ulnar Nerve
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13
Q

Posterior Cord

A
  • -Axillary Nerve
  • -Radial Nerve
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14
Q

Axillary Nerve

A
    • Formed from C5-C6
    • Passes from axilla to shoulder
    • Posterior to the neck of humerous
  • Innervation - Deltoid and skin covering it
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15
Q

Radial Nerve

A

Formed from fiber of C5-T1

  • Passes from axilla to arm*
  • Innervates long head of triceps
  • -posterior brachial cutaneous branch
  • -innervates skin covering the muscle

Descends along shaft of humerous

  • -Inferior lateral cutaneous branch innervates posterior arm
  • -Posterior antebrachial cutaneous branch innervates surface of forearm
  • Crosses elbow anterior to lateral epicondyle*
  • Divides into deep and Superficial branch
  • -Superficial continues down to hand innervates dorsum of the hand onto the thumb, index, middle, and ring fingers
    • Deep innervates many of the muscles of wrist and hand
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16
Q

Radial Nerve: Response to stimulation

A
    • wrist extension
    • metacarpo-phalangeal extension
  • thumb abduction
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17
Q

Musculocutaneous Nerve

A

Formed by fibers from C5-7

  • Pierces through coracobrachialis muscle
  • -Descends between brachialis muscle and the biceps brachii muscle – innervates all of these muscles

At elbow :

  • becomes Lateral antebrachial cutaneous nerve -
    • Runs along brachoradialis muscle -
    • Innervates skin above muscle

Also innervated elbow and proximal radioulnar joints

18
Q

Musculocutaneous nerve motor response

A

Biceps Flexion

19
Q

Median Nerve

A

Fibers from C5-T1

  • Descends arm with brachial artery
  • Crosses cubital fossa medial to the artery
  • Passes into forearm through the carpel tunnel
    • branches and innervates the skin
20
Q

Median Nerve Innervation

A

many of the muscles of forearm, wrist, fingers, and thumb forearm - pronators wrist - flexors fingers - flexors Thumb - abduction and opposition Skin - Thumb, index, middle, lateral half of ring fingers on palmar surface and nail beds

21
Q

Medial Cutaneous Branches: Branches of Medial Cord (T1)

A

Medial Brachial cutaneous Branch - Innervates skin covering the medial surface of the arm Medial antebrachial cutaneous branch - crosses the cubital fossa - Innervates skin on the medial aspect of the forearm

22
Q

Ulnar Nerve

A

Fibers from C8-T1 - Descends with brachial artery - Crosses the elbow posterior to medial epicondyle - continues down the forearm

23
Q

Ulnar Nerve innervation

A
  • many muscles in wrist, fingers and thumb Skin - Dorsal and medial surface of the hand - Dorsal surface of the ring and little fingers
24
Q

motor respone to ulnar nerve stimulation

A
  • ulnar deviation of the wrist - metacarpo-phalangeal flexion - Thumb adduction
25
Q

Lumbosacral Plexus

A
  • *Formed by Ventral Rami L1-S5**
  • May include T12*

-Anterior and Posterior Divisions of some
Innervates:Lower Abdomen and Lower Extremities
▪Muscles
▪Joints
▪Skin
▪Peritoneal lining

26
Q

Iliohypogastric Nerve

A

Formed from T12-L1
Travels in abdominal wall to level of symphysis pubis
Innervates:

  • Muscle, skin, and parietal peritoneum
  • Skin over inferior abdomen and buttocks
27
Q

Ilioinguinal Nerve

A

Formed by T12-L1

  • Travels in abdominal wall
  • Pierces posterior wall of the inguinal canal
  • Passes through superficial inguinal ring
  • Terminates on the anterior scrotum or labia majora

Innervates:

  • Muscle, skin, parietal peritoneum along course
  • Skin
    • Superior, medial thigh
    • Portions of external genitalia
28
Q

Genitofemoral Nerve

A

Formed by L1-L2

  • Travels in abdominal wall
  • Passes through deep inguinal canal
  • Passes through superficial inguinal ring
  • Terminates on anterior scrotum or labia majora

Innervates:

  • Skin covering femoral hiatus
  • Skin on the scrotum or labia majora
29
Q

Iliohypogastric, Ilioinguinal, Genitofemoral

A
30
Q

Pudendal Nerve

A

Anterior division of S2-S4

  • Passes from pelvis through greater sciatic foramen into gluteal region
  • Passes posterior to ischial spine and into perineum

Innervates muscle and skin of perineum

31
Q

Lateral Femoral Cutaneous Nerve

A

Posterior Division L2-3

  • Descends posterior abdominal wall
  • Crosses iliac crest into pelvis and down to inguinal ligament and anterior iliac spine

Innervates:

  • Skin
    • Lateral aspect of thigh to the level of the knee
32
Q

Posterior Femoral Cutaneous Nerve

A

Anterior and Posterior Division of S1-S3

  • Passes from pelvis into gluteal region
  • To posterior thigh

Innervates:

  • Skin
    • Posterior thigh
    • Hip to mid calf
33
Q

Obturator Nerve

A

Anterior Division L2-4

  • Travels to medial compartment of thigh

Innervates:

  • Many muscles of thigh
  • Articular branches to hip
    • Controls adduction, flexion and extension of hip
  • Cutaneous branches to the skin
    • Medial thigh
34
Q

Femoral Nerve

A

Posterior Division L2-L4

  • Through pelvis
  • Deep into inguinal ligament
  • Enters anterior compartment of thigh
  • Divides into multiple branches
    • Below inguinal ligament splits to anterior and posterior branches
    • Posterior contains saphenous nerve

Position:

  • At femoral crease
    • Nerve lateral to femoral artery and vein
    • From medial – lateral
    • VAN
    • Venous – Penis
    • V for Vagina
  • From lateral – medial
    • NAVEL
    • Nerve, artery, vein, empty space, ligament
35
Q

Femoral Nerve Innervation

A

Innervation:

  • Muscles
    • Rectus femoris
    • Vastus lateralis
    • Vastus Intermedius
    • Vastus medialisSartorious
  • Skin
    • Anterior thigh
36
Q

Saphenous Nerve

A

Posterior Cutaneous Branch from Femoral Nerve

  • Follows deep surface of Sartorius muscle to attachment on tibia
  • Accompanied by saphenous vein

Passes to skin

  • Innervates
    • Medial leg from knee to the arch of the foot
  • Stimulation
    • Sartorious muscle contraction (bandlike across thigh)
    • Patellar twitch (snap)
37
Q

Sciatic Nerve

A
  • Formed by junction of
    • Tibial Nerve (anterior) L4-S3 (largest)
    • Common Peroneal Nerve (posterior) L4-S2
  • Distinct nerves from the beginning in the same sheath
  • Passes from pelvis through greater sciatic foramen into gluteal region
  • Descends between:
    • §gluteus maximus (posteriorly)
    • §obturator internus (anteriorly)
    • §lateral to ischial tuberosity
  • Enters Posterior thigh
  • Innervates Muscles there
    • Hip Extension
    • Flexion of knee
  • Descends popliteal fossa where it splits
    • Tibial
    • Common Peroneal
38
Q

Tibial Nerve

A

Anterior division L4-S3

  • Exits popliteal fossa and into superficial posterior compartment of leg
  • Passes between tibial and fibular heads and enters deep posterior compartment
  • Passes posterior to medial malleolus into foot and branches
    • Medial plantar nerve
    • Lateral plantar nerve
    • Two branches innervate plantar surface of foot
39
Q

Common Peroneal

A
  • From popliteal fossa
    • Follows tendon of biceps femoris to attachment on fibula
    • Divides to superficial and deep branches
  • Superficial
    • Enters lateral compartment of leg and terminates in lateral and dorsal surface of foot
  • Deep
    • Enters anterior compartment
    • crosses anterior surface of ankle into foot
    • Terminates as cutaneous fibers
      • Skin between hallux and second toe
40
Q

Sural Nerve

A

Formed from union of branch from tibial and common peroneal

  • Travels with the saphenous nerve
  • ¡Posterior to the lateral malleolus into foot

Innervates:

  • Posterior sole of foot
  • Posterior heel
  • Achilles tendon above ankle