Plexuses Flashcards by Hannelore Rivières

What is a plexus ?

Axons from different spinal nerves will come together into a systemic nerve. This occurs at four places along the vertebral column, each identified as a nerve plexus, whereas the other spinal nerves directly correspond to nerves at their respective levels. Therefore a plexus is used to describe a network of nerve fibers with no associated cell bodies.

How well did you know this?

Not at all

Perfectly

What are the four plexus ?

cervical plexus
brachial plexus
lumbar plexus
sacral plexus

How well did you know this?

Not at all

Perfectly

List the muscular branches of the cervical plexus

nerves to the geniohyoid and thyrohyoid
Ansa cervicalis
phrenic nerve
other muscular branches
rectus capitis; longus capitis; paravertebral muscles; sternocleiomastoid; levatore scapulae; trapezius; scalenus

How well did you know this?

Not at all

Perfectly

List the sensory branches of the cervical plexus

greater auricular nerve : external ear and parotid gland
transverse cervical nerve : sensation to the anterior neck
lesser occipital nerve = Arnold’s nerve : postero superior part of scalp
supraclavicular nerve : skin of supraclavicular fossa

How well did you know this?

Not at all

Perfectly

What is the function of the brachial plexus

Network of nerve fibers that supply the skin and musculature of upper body
Formed by the ventral rami of the nerve root C5 to T1
Divided into 5 parts:
- roots
- trunks
- division
- cords
- branches

How well did you know this?

Not at all

Perfectly

List the brachial plexus roots

C5 to T1
Forming :
- dorsal scapular nerve (C5)
- long thoracic nerve (C5-C7)

How well did you know this?

Not at all

Perfectly

List the trunks of the brachial plexus

superior (C5,C6)
middle (C7)
inferior (C8,T1)

Forming the :
- subclavius trunk
- suprascapular trunk

How well did you know this?

Not at all

Perfectly

What is Erb’s point?

The nerve point of neck is a site at the upper trunk of the brachial plexus located 2-3 cm above the clavicle. There are 6 types of nerves that meet at this point. Used for cervical plexus block

How well did you know this?

Not at all

Perfectly

What are the branches emerging from cords of the brachial plexus ?

ANTERIOR DIVISION
- lateral pectoral nerve
- medial pectoral nerve
- medial brachial cutaneous nerve (arm)
- antebrachial cutaneous nerve (forearm)

POSTERIOR DIVISION
- upper and lower subscapular nerves
- thoracodorsal nerve

How well did you know this?

Not at all

Perfectly

List the branches of the brachial plexus

musculocutaneous
axillary
median
radial
ulnar

How well did you know this?

Not at all

Perfectly

What are the sensory functions of the axillary nerve ?

Upper lateral cutaneous nerve of the arm

How well did you know this?

Not at all

Perfectly

What are the motor functions of the axillary nerve ?

teres minor
deltoid

How well did you know this?

Not at all

Perfectly

What are the sensory functions of the musculocutaneous nerve ?

Lateral cutaneous branch of the forearm

How well did you know this?

Not at all

Perfectly

What are the motor functions of the musculocutaneous nerve ?

Brachialis
Biceps brachii
Coracobrachialis

How well did you know this?

Not at all

Perfectly

What are the motor functions of the median nerve ?

Flexors of the forearm
Thenar muscles
Index and middle fingers

How well did you know this?

Not at all

Perfectly

What are the sensory functions of the median nerve ?

Palmar cutaneous branch
Digital cutaneous branch

What are the motor functions of the radial nerve ?

Triceps brachii
Extensors of wrist and fingers

What are the sensory functions of the radial nerve ?

Posterior cutaneous nerve of the arm
Lower lateral cutaneous nerve of the forearm
Posterior cutaneous nerve of the forearm

What are the motor functions of the ulnar nerve ?

Muscles of the hand
Flexor carpi ulnaris
Medial half of flexor digitorum profundus

What are the sensory functions of radial nerve ?

Palmar cutaneous branch
Dorsal branch
Superficial branch
Deep branch

What is the function of the lumbar plexus ?

It is a network of nerve fibers that supply the skin and muscles of the lower limbs. Located within the posas major
Formed by the ventral rami of the lumbar spinal nerves L1 to L4

What are the peripheral nerves composing the lumbar plexus ?

iliohypograstric nerve
ilioinguinal nerve
genitofemoral nerve
lateral cutaneous nerve of the thigh
obturator nerve

What are the functions of the iliohypogastric nerve ?

Originated from T12 and C1

Motor functions:
Transverse abdominis
Internal oblique

Sensory functions:
Gluteal skin in pubic region

What are the fonctions of the ilioinguinal nerve ?

L1
Motor functions :
-transverse abdominis
- internal oblique

Sensory functions :
-skin on the upper middle thigh
-root of penis and anterior scrotum
- skin on mons pubis and labia majora

What are the functions of the genitofemoral nerve ?

L1, L2 Motor functions: - genital branch : cremaster muscle Sensory functions: - genital branch : Skin of anterior scrotum Mons pubis/labia majora - femoral branch : Skin on upper anterior thigh

What are the functions of the lateral cutaneous nerve of the thigh ?

L2,L3 No motor function Sensory functions: -anterior and lateral thigh down to knee

What are the functions of the obturator nerve ?

L2,L3,L4 Motor functions : - obturator externus - pectineus - adductor longus - adductor brevis - adductor magnus - gracilis Sensory function : Skin over the medial thigh

What are the functions of the femoral nerve ?

L2,L3,L4 Motor functions: - illiac us - pectineus - sartorius - quadriceps group Sensory: —> medial and lateral branches of the anterior cutaneous thigh : skin of anterior thigh and medial leg —> saphenous nerve : skin of front and side knee, down to foot (big toe)

What is the function of the sacral plexus ?

A network of nerve fibers supplying the skin and muscles of pelvis and lower limb. Formed by the ventral rami of sacral spinal nerves S1 to L5

What are the major peripheral nerves coming out of sacral plexus ?

- superior gluteal nerve - inferior gluteal nerve - sciatic nerve - posterior femoral cutaneous nerve - pudendal nerve

What are the functions of the superior gluteal nerve

L4,L5,S1 Motor functions: - gluteus minimus -gluteus medius - tensor fascia lata No sensory functions

What are the functions of the inferior gluteal nerve?

L5,S1,S2 Motor functions : Gluteus Maximus No sensory function

What are the functions of the posterior cutaneous nerve ?

S1,S2,S3 No motor function Sensory functions : - skin of the posterior thigh and leg - skin of the perineum

What are the functions of the pudendal nerve ?

S2,S3,S4 Motor functions: - skeletal muscles in the perineum - external urethral sphincter - external anal sphincter - levatore ani Sensory functions: - penis - clitoris - skin of perineum

What are the functions of the sciatic nerve ?

L4 to S3 Motor function: Tibial portion: - muscles in the posterior compartment of the thigh and hamstring component of the adductor magnus - muscles in the posterior compartment of the leg and sole of the foot Common fibular portion : - short head of biceps femoris - muslces in the anterior and lateral compartments of the leg and extensor digitorum brevis Sensory functions : Tibial portion : - skin on the posterolateral and medial surfaces of the foot and sole of the foot Common fibular portion : -skin on the anterolateral surface of the leg and the dorsal aspect of the foot

Describe the different branches of the peroneal nerve

CUTANEOUS BRANCHES - lateral sural cutaneous nerve - sural communicating nerve MOTOR BRANCHES - superficial peroneal nerve - deep peroneal nerve

What are the branches of the tibial nerve ?

CUTANEOUS BRANCHES - medial calcaneal branches - medial plantar nerve - lateral plantar nerve MOTOR BRANCHES -posterior compartment of the leg