Peripheral Nerve Anatomy Flashcards
(40 cards)
1
Q
peripheral nerves
A
-continuation from spinal anatomy -spinal nerves split, converge, and branch - form peripheral nerves
2
Q
Cervical Plexus
A
Innervates - muscles, joints, and skin in the anterior neck - Ventral Rami C1-C4
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
4
Q
BP: Roots, Trunks, and Divisions
A
- Found in posterior triangle of the neck - Supraclavicular
5
Q
BP: Cords and Branches
A
-Found in the Axilla - Infraclavicular
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
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
8
Q
BP: Divisions
A
Posterior to clavicle divide into:
- 3 ventral (Anterior) divisions-supply flexor portions
- 3 Dorsal (Posterior) Divisions - supply extensor portions
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
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
11
Q
Lateral Cord
A
- Musculocutaneous nerve
- Lateral root of median nerve
12
Q
Medial Cord
A
- Medial root of medial nerve
- Ulnar Nerve
13
Q
Posterior Cord
A
- -Axillary Nerve
- -Radial Nerve
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
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
16
Q
Radial Nerve: Response to stimulation
A
- wrist extension
- metacarpo-phalangeal extension
- thumb abduction
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
Lumbosacral Plexus
* *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
Iliohypogastric Nerve
**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
Ilioinguinal Nerve
**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
Genitofemoral Nerve
**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
Iliohypogastric, Ilioinguinal, Genitofemoral
30
Pudendal Nerve
**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
Lateral Femoral Cutaneous Nerve
**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
Posterior Femoral Cutaneous Nerve
**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
Obturator Nerve
**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
Femoral Nerve
**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
Femoral Nerve Innervation
**Innervation:**
* Muscles
* Rectus femoris
* Vastus lateralis
* Vastus Intermedius
* Vastus medialisSartorious
* Skin
* Anterior thigh
36
Saphenous Nerve
***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
Sciatic Nerve
* 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
Tibial Nerve
**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
Common Peroneal
* **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
Sural Nerve
**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
