Brachial Plexus Flashcards
The brachial plexus is a network of nerve fibres that supplies the ___ and ___ of the upper limb.
It begins in the _______ , passes through the ____, and runs through the entire _____
skin and musculature
root of the neck
axilla
upper extremity.
The brachial plexus is formed by the anterior rami (divisions) of cervical spinal nerves __,___,___,____ and the _____
C5, C6, C7 and C8,
first thoracic spinal nerve, T1
The brachial plexus is divided into five parts; ____,____,___,___, and ____
roots, trunks, divisions, cords and branches
The ‘roots’ refer the (anterior or posterior ?) rami of the spinal nerves that comprise the brachial plexus. These are the anterior rami of spinal nerves C5, C6, C7, C8, and T1.
Anterior
At each vertebral level, paired spinal nerves arise. They leave the spinal cord via the _____ foramina of the vertebral column.
intervertebral
Each spinal nerve then divides into an ____ and _______ ramus.
The roots of the brachial plexus are formed by the ______ rami of spinal nerves ___-___ (the posterior divisions innervate the ___ and ____ of the ____ muscles).
After their formation, these nerves pass between the —— and ——— muscles to enter the base of the neck.
anterior and a posterior
anterior
C5-T1
skin and musculature
intrinsic back
anterior and medial scalene
At the base of the neck, the roots of the brachial plexus converge to form three trunks. These structures are named by their relative anatomical location:
Superior trunk – a combination of ____roots.
Middle trunk – continuation of ___.
Inferior trunk – combination of _____ roots.
The trunks traverse (medially or laterally?) , crossing the ____ triangle of the neck.
C5 and C6
C7
C8 and T1
laterally
posterior
Each trunk divides into two branches outside the posterior triangle of the neck.
T/F
F
Divisions combine into cords in the ____ and are named based on their relative relation to the _____
Axilla
Axillary artery
The lateral cord is formed by:
The ____ division of the ____ trunk
The _____ division of the ____ trunk
The posterior cord is formed by:
___________
The medial cord is formed by:
The ____ division of the _____ trunk.
anterior; superior
Anterior; middle
The posterior division of the superior trunk
The posterior division of the middle trunk
The posterior division of the inferior trunk
anterior; Inferior
Musculocutaneous Nerve
Roots: _____
Motor Functions: Innervates the _____ muscles.
Sensory Functions: Gives off the ____ branch of the ___, which innervates the (medial or lateral?) half of the anterior forearm, and a small (medial or lateral?) portion of the posterior forearm.
C5, C6, C7.
brachialis, biceps brachii and coracobrachialis
lateral cutaneous
forearm
Lateral; lateral
Axillary Nerve
Roots:_____
Motor Functions: Innervates the ____ and ____ muscles.
Sensory Functions: Gives off the _____ nerve of arm, which innervates the ____ region of the ____ (“____ area”).
C5 and C6.
teres minor and deltoid
superior lateral cutaneous
Lateral
deltoid
regimental badge
Median Nerve
Roots: ____ . (Also contains fibres from __ in some individuals).
Motor Functions: Innervates most of the ___ muscles in the forearm, the ___ muscles, and the _____ lumbricals associated with the index and middle fingers.
Sensory Functions: Gives off the ____ branch, which innervates the ____ part of the palm, and the____ branch, which innervates the lateral ____ fingers on the ____ surface of the hand.
C6 – T1
C5
flexor
thenar
two lateral
palmar cutaneous; lateral
digital cutaneous; three and a half
anterior (palmar)
Radial Nerve.
Roots: _____
Motor Functions: Innervates the triceps brachii, and the muscles in the posterior compartment of the forearm (which are primarily, but not exclusively, extensors of the wrist and fingers).
Sensory Functions: Innervates the ____ aspect of the arm and forearm, and the _____ aspect of the hand.
C5 – T1.
posterior
posterolateral
Ulnar Nerve
Roots: ____
Motor Functions: Innervates the muscles of the hand (apart from the thenar muscles and two lateral lumbricals), flexor carpi ulnaris and ____ half of flexor digitorum ____
Sensory Functions: Innervates the anterior and posterior surfaces of the _____ fingers, and associated palm area.
C8 and T1.
medial
profundus
medial one and half
The important structure to look for in a cadaver is an ‘ ___’ shape.
This is formed by the _____,____,____ nerves, usually (superficial or deep?) to the ____ artery.
M
musculocutaneous, median, and ulnar
Superficial
axillary
2 minor nerves that comes from roots
2 minor nerves that comes from trunks
Dorsal scapular nerve ; Long thoracic nerve
Suprascapular nerve ; Nerve to subclavius
Minor nerves from lateral cord of brachial plexus
Minor nerves from medial cord of brachial plexus
Lateral pectoral nerve
Medial pectoral nerve
Medial cutaneous nerve of arm
Medial cutaneous nerve of forearm
Minor nerves from posterior cord of brachial plexus
Superior subscapular nerve
Thoracodorsal nerve
Inferior subscapular nerve
Erb’s palsy refers to an injury to the _____ of the brachial plexus (typically ____).
It most commonly occurs as a result of a ____ injury during a difficult _____
upper roots
C5-6
stretching
vaginal delivery.
Nerves affected in erbs palsy– the peripheral nerves derived from ____ roots are most affected.
This includes the ___,___,___,and____.
C5-6
musculocutaneous, axillary, suprascapular, and nerve to subclavius
Muscles affected in erb’s palsy –
List 8
supraspinatus, infraspinatus, subclavius, biceps brachii, brachialis, coracobrachialis, deltoid and teres minor.
Motor functions affected in erb’s palsy –
___uction at ____, _____ rotation of ___, __nation of ____, and _____ion at ____.
abd; shoulder
lateral; arm
supi; forearm
flex; shoulder
Sensory functions affected in erb’s palsy –
sensation over the ____ aspect of upper limb (C5-6 dermatomes).
lateral
The affected limb in erb’s palsy hangs limply, ____ rotated by the unopposed action of pectoralis major.
The forearm is ____ due to the loss of biceps brachii.
The wrist is ____ due to the normal tone of the wrist flexors relative to the weakened wrist extensors.
This is position is known as ‘ _____ ’ and is characteristic of Erb’s palsy.
medially
pronated
weakly flexed
waiter’s tip
Klumpke’s palsy is an injury of the ____ of the brachial plexus (____).
It is most commonly associated with a difficult____
lower roots
C8-T1
vaginal delivery
Erb’s palsy has a higher incidence rate than klumpke’s paralysis
T/F
T
Nerves affected in klumpke’s paralysis–
the peripheral nerves derived from ___ root are most affected; the ____ and _____ nerves
T1
ulnar and median
Muscles affected in klumpke’s paralysis –
the _____ muscles
intrinsic hand
Sensory functions affected –
sensation along ____ side of upper limb (C8-T1 dermatomes).
medial
The primary feature of Klumpke’s palsy is a ____ hand.
This occurs due to paralysis of the ___ muscles, which normally act to ___ the metacarpophalangeal joints (MCPJs) and ___ the interphalangeal joints (IPJs).
When paralysed, the fingers subsequently become ____ at the MCPJs and ___ at the IPJs, producing a ____ appearance.
clawed
lumbrical
flex
extend
extended
Flexed
clawed
