Brachial Plexus Flashcards
Between what two muscles does the Brachial Plexus emerge from?
Anterior and Middle Scalene
What also travels in between the Anterior and Middle scalene with the Brachial Plexus?
Subclavian artery
What is the Brachial Plexus?
Network of Nerves which supplies Motor and Sensory Information to the Upper Extremity
What sort of information does the BP supply?
Motor and Sensory
What two structures does the BP travel deep to?
Clavicle and Pectoralis Minor
Anterior and Middle scalene with Rib 1 creates what?
Scalene Triangle
Since the Anterior and Middle scalenes create parts of the scalene triangle what structures could be said to travel in the scalene triangle?
Rudimentary of the BP and Subclavian artery
What travels anterior to the anterior scalene?
Subclavian vein
BP is organized into what from most proximal to distal?
Organized into: Roots, Trunks, Division, Cords
What are all named nerves off the BP considered?
Terminals
BP organized into roots are what part of the nerve root are they?
Anterior Rami
Anterior Rami contribute to plexus to what regions?
UE and LE
Name two examples of Terminal branch of BP and what do they innervate?
Dorsal Scapular Nerve: Rhomboid Major/Minor and Levator Scapula Thoraco Dorsal Nerve: Latisimus Dorsi
What level is the Root of BP at? and what structure is at that level?
C5-T1 at the level of the Scalenes
When C5-C6 converge what do they create?
Superior trunk
When C8-T1 converge what do they create?
Inferior trunk
What does C7 continuum create?
Middle Trunk
Each Trunk bifurcates into what two divisions?
Anterior and Posterior Divisions aka the 3rd Dimension
What are all the BP Cords surrounded by?
The BP cords are surrounding Axillary Artery
All 3 Posterior Divisions converge into form the what?
Posterior Cord
The 2 Anterior Divisions of the Superior and Middle Trunk converge into form the what?
Lateral Cord
The Anterior Division of the Inferior Trunk continue by it self as the what?
Medial Cord
What would be immediately behind, lateral, and medial to the Axillary Artery?
BP Posterior Cord, Lateral Cord, and Medial Cord in order
Terminal Branches are also known as what?
Nerves
From ROOTS C3, C4, C5 create what two Terminal Branch?
Dorsal Scapular Nerve and Phrenic Nerve
What does Dorsal Scapular Nerve
Levator Scapula, Rhomboid major, Rhomboid minor
What is the major contributing Root of Phrenic Nerve?
C4
What does C4 Root Phrenic Nerve innervate? and how many on?
Diaphragm two, one each side
Where is the Phrenic nerve in the Anterior neck?
On the Anterior Scalene
From ROOTS C5, C6, C7 comes what Terminal Branch?
Long Thoracic nerve
Once the Long Thoracic Nerve emerges from C5, C6, C7, where does it course along and then finally innervate what?
Course along the lateral aspect of the trunk. it innervates Serratus Anterior.
What is the Long Thoracic Nerve innervated Serratus Anterior do?
Serratus Anterior’s main function is scapular movement and scapular stabilization.
From the Trunk what two terminal branches emerges?
Suprascapular Nerve from Superior Trunk Nerve to Subclavius from Superior Trunk
Where are the two Trunk terminal branches emerging from?
The Superior Trunk
Why can you not see the Nerve to Subclavius?
It is directly behind and attached to the Clavicle. Therefore, when you take out the clavicle to see it, it will be torn out with the clavicle
The Suprascapular nerve innervates what two muscles?
Supraspinatus and Infraspinatus
What is the supraspinatus and infraspinatus muscle part of and what are the rest (2)?
Glenohumeral stabilization functioning rotator cuff muscles. the other two muscles are Subscapularis and Teres Minor
How many Terminal branches emerge from the Divisions?
None
What is the notch on the scapular known as?
Suprascapular Notch
What travels through the Suprascapular Notch?
The suprascapular nerve
What is the traveling path of the Suprascapular Nerve?
through the Lateral Suprascapular notch(which is closed off by the Ligamentus Tissue via a foramen), then dives posteriorly in the supraspinous process to innervate the supraspintus, dives under the acromion process, then into the infraspinous process to innervate the infraspinatus.
How many Nerves emerges from the BP Cords?
12
5 from the Posterior Cord
2 from the Lateral Cord
4 from the Medial Cord
1 from the Medial and Lateral Cord
From the Lateral Cord what Nerves emerge?
Lateral Pectoral Nerve
Musculocutaneus Nerve
***part of Median Nerve***with Median Cord
What two Terminal Branches the Pectoral Muscles and where do they emerge from?
Lateral Pectoral Nerve from the Lateral Cord
and
Medial Pectoral Nerve from the Medial Cord
Which is superior and deep Pectoral Major and Pectoral Minor?
Pectorial Major is superior
Pectoral Minor is deep to that?
At the level of the Posterior Cord what set of nerves emerge?
The Subscapular Nerves (3)
How many Subscapular nerves are there and what are they called?
3
Upper
Middle
Lower
What does the Middle Subscapular Nerve Innervate?
aka
Thorcodorsal nerve
Latissimus Dorsi
What is the Middle Subscapular Nerve also known as?
Thoracodorsal nerve
The Upper and Lower Subscapular nerve innervates what muscle?
Subscapularis
Where is the Subscapularis Muscle located?
Anterior surface of the scapular in the subscapular fossa innervated by both Upper and Lower subscapular nerve
The Lower Subscapular nerve alone will innervate what muscle?
Teres Major
Where is the Teres Major located? also what is Teres Major’s nickname
smaller muscle emerging from the scapular, runs parallel to the Latissimus Dorsi.
aka Latissimus Dorsi’s Helper
What muscle does the Teres Major have the same function with?
Latissimus Dorsi
What nerve is the continuation of the Posterior Cord?
Axillary Nerve
What two muscles does the Axillary Nerve innervate?
Deltoid
and
Teres Minor
Name the four muscles of the rotator cuff
SITS
Supraspinatus
Infraspinatus
Teres Minor
Subscapularis
How does the Axillary nerve innervate the Teres Minor and Deltoid?
It dives posteriorly through Quadrangular Space to innervate both Deltoid and Teres Minor
What also travels with the Axillary Nerve through the Quadrangular Space?
Posterior Circumflex Humeral Artery
What forms the Quadrangular space?
Teres Major (inferior boundary)
Teres Minor (superior boundary)
Long head of the triceps brachii (medial boundary)
Neck of the Humerus (lateral boundary)
If someone fractures their humerus at the surgical neck region what nerve would you know they legioned?
and resulting in what?
Axillary nerve
lossing function in the deltoid and teres minor
Once the Axillary nerve emerges posteriorly through the quadrangular space, innervates two muscles (deltoids and teres minor), then dives superfically as cutaneos innervates what does it’s function become?
Sensation of skin on the lateral aspect of the shoulder
Rotator cuff injury patients could complain of what sort of pain or paresthesia?
Pain or paresthesia of the deltoid and teres minor due to damage to axillary nerve
Besides the axillary nerve another thicker terminal nerve emerges from the Posterior cord, what is it?
Radial Nerve
When you hear Radial nerve what word should you think of and why?
Posterior!!!
Because it provides sensory and motor innervation of the entire posterior UE
Why is the radial nerve so thick compared to other UE nerves.
It is usually 2-3x thicker than others since it provides innervation to the entire posterior portion of the UE it’s sensory and motor information.
How does the Radial Nerve course through the UE?
dives to the posterior aspect of the arm, coursing from the medial to lateral aspect of the humerus
What is the area on the humerus where the Radial Nerve will run called?
Musculospiral groove or Radial groove on the posterior humerus
If someone fractured the shaft of the humerus what nerve could be injured?
Radial Nerve
What opening does the Radial Nerve travel through?
The Triangular Interval
What muscles make up the boundaries of the Triangular Interval?
Teres Major (superior border)
Long head of Triceps brachii (medial border)
Lateral head of Triceps brachii (lateral border)
The Radial Nerve will course through what two areas with what blood vessel?
Triangular Interval and Radial Groove(musculospiral groove)
Deep Brachial Artery
If you split the two heads of the Triceps brachii what two structures should you see inbetween?
Deep brachial artery
and
Radial nerve
At the level of the humerus the Radial Nerve will dive very superficially called what?
Posterior Brachial Cutaneous Nerve
What two muscle groups are innervated on the Posterior arm by the Radial nerve?
Triceps Brachii
and
Anconeous
What 2 things happen with the Radial Nerve in the posterior arm?
Innervation: Triceps Brachii & Anconeous
Branches off as: Posterior Brachial Cutaneous Nerve
How does the Radial Nerve course the Humerus?
From medial to lateral
At the level of the Elbow what happens to the Radial Nerve?
Travels Anterior to the Lateral Epicondyle and goes through the Radial Tunnel
What two muscles is the Radial nerve easily seen in between once it passes anteriorly to the Lateral Epicondyle? and via what?
Between the Brachialis and Brachioradialis
via the Radial Tunnel
The Radial Nerve splits in the Forearm as what two nerves?
Superficial and Deep Radial Nerve
What sort of nerve is the Superficial Radial nerve?
Purely Cutaneous, having no function in the forearm.
What muscle does the Superficial Radial nerve travel deep to?
Superficial travels deep to the Brachioradialis
Where is the destination for the Superficial Radial Nerve?
Dorsal portion of the hand
Where does the Superficial Radial nerve provide sensation to?
Dorsum of digits 1, 2, and 3
Lateral aspect of the Dorsal palm
***some lateral half of the 4th digit***
Where is hand is the Superficial Radial nerve not providing sensation?
Distal tips of digits 1, 2, and 3
What sort of nerve is the Deep Radial nerve?
Purely motor
What muscles does the Deep Radial Nerve innervate?
Brachioradialis
Extensor Carpi Radialis Longus
Supinator *before piercing through the Supinator*
Once the Deep Radial nerve pierces through the Supinator what nerve does it become?
Posterior Interosseous Nerve
Where and what does the Posterior Interosseous nerve innervate?
the rest of the distal remaining muscles in the Extensor compartment
The muscles of the posterior aspect of the forearm causes what motion?
Wrist extension
Lesion of the Posterior Interosseous nerve causes what?
“Wrist Drop”
when someone is not able to extend their wrist
What muscles does the Superficial Radial Nerve innervate?
None due to it being just a cutaneus innervation for sensation of the skin
If someone has Posterior Interosseus syndrome what effect are effected?
Motor since it branches from the Deep Radial Nerve(motor)
where as Superficial Radial Nerve (sensory)
What is the continuum of the Lateral Cord after the terminal nerve Lateral Pectoral Nerve?
Musculocutaneous Nerve
What does the Musculocutaneous Nerve pierce through?
Coracobrachialis Muscle
What sort of information is traveling in the Musculocutaneous Nerve?
Both Motor and Sensory
What muscles does the Musculocutaneous Nerve innervate?
Muscles of the Anterior Arm
What Nerve is close in proximity to the Musculocutaneous Nerve?
Axillary nerve
What three anterior arm muscles does the Musculocutaneous Nerve innervate?
Coracobrachilais
Biceps Brachii
Brachialis Muscle (deep to the Biceps brachii)
What structure does Musculocutaneous Nerve travel lateral to as it contineus into the forearm?
Bicipital Apeneurosis
As Musculocutaneous Nerve travels into the forearm and passes lateral of Bicipital Apeneurosis what does it turn into?
Lateral
Ante
Brachial
Cutaneous
nerve
What information travels in the Lateral AnteBrachial Cutaneous nerve?
Sensory
Where does the Lateral Antebrachial Cutaneous Nerve provide sensation?
the lateral aspect of the forearm
Why is it difficult to see the sensory/cutaneous nerve in lab?
due to the superficial nature of its attachment to skin, when you disect the skin it will be cut
Medial Brachial Cutaneous Nerve
and
Medial Antebrachial Cutaneous Nerve
both branch from which cord?
Medial Cord
What terminal nerve is the Medial brachial cutaneous nerve and Medial antebrachial cutaneous nerve past?
it’s after the Medial pectoral nerve
What is the function of the Medial Brachial Cutaneous Nerve?
Sensation to the medial aspect of the arm
What is the function of the Medial Antebrachial Cutaneous Nerve?
sensation to the medial aspect of the forearm
Distal continuation of the Medial Cord is what and what is it commonly known as?
Ulnar Nerve
aka Funny Bone
Where is the Ulnar Nerve found protected by what?
in the arm between the Biceps brachii and brachialis muscle
What other two structures travel along side with the Ulnar nerve between the Biceps brachii and brachealis muscle?
Brachial Artery
Median Nerve
As the Ulnar nerve travels down what aspect of the arm does it travel distally?
Medially
If the Ulnar nerve courses Medially as it travels distally in the arm what is the opposite course taken Laterally by?
The Radial nerve travels Laterally down the arm
As the Ulnar nerve travels distally, it will approach the medial Epicondyle, how does it travel past it?
Posteriorly
As the Radial Nerve travels distally in the arm it approaches the Lateral Epicondyle, how does it travel past it?
Anteriorly
As the Ulnar Nerve passes posteriorly past the Medial Epicondyle, what does it past?
travels through a groove in between Olecranon process and the Medial Epicondyle known as the Cubital Tunnel
***Tommy John Surgery***
What two structures creat the Cubital Tunnel
Medial Epicondyle
and
Olecranon process
The Medial AnteBrachial Cutaneous Nerve which emerges from the Medial Cord runs parallel with the Ulnar nerve. How can you differenciate them in the elbow region?
Only the Ulnar nerve travels through the Cubital Tunnel
Once the Ulnar Nerve transmits into the forearm, it will dive deep to the most medial muscle known as what?
Flexor Carpi Ulnaris
What is the most Medial Muscle in the forearm? and innervates it?
Flexor Carpi Ulnaris
innervated by the Ulnar nerve
What blood vessel does the Ulnar nerve course the forearm with?
Ulnar Artery
Which structure will be more medial Ulnar nerve or the Ulnar artery?
Ulnar Nerve will be more medial
The Ulnar nerve in the Anterior forearm will innervate how many muscles?
1.5 muscles
What 1.5 muscles does the Ulnar nerve innervate?
Flexor Carpi Ulnaris in the Anterior forearm
and deep to it is the
Flexor digitorum profundus (medial half)
While continuing distally deep in the Flexor carpi ulnaris BEFORE the wrist arrises what two nerve terminals?
very superficial:
Palmar Cutaneous branch
and
Dorsal Cutaneous branch
What is the Palmar Cutaneous and Dorsal Cutaneous’ funciton.
Palmar Cutaneous provides sensation to the medial aspect of the Palm side of the hand
Dorsal Cutaneous provides sensatoin to medial aspect of the Dorsal side of the hand
Since Palmar/Dorsal Cutanteous Nerve of the Ulnar are very superficial what motion does it not effect it?
Very uneffected by the wrist compression.
The main branch of the Ulnar Artery will continue distal to the level of the wrist and will enter the hand via what opening?
Guyon’s Canal
What is the Guyon’s Canal also known as and why?
Piso-Hamate Canal
because it an opening formed by the Piscoform and Hook of Hamate
Once the Ulnar Nerve is in the hand it will bifricate into what two nerves?
Superficial Ulnar Nerve
and
Deep Ulnar Nerve
The Superficial Ulnar Nerve innervates what ONE muscle?
Palmaris Brevis a small squarish muscle on the medial aspect of the palm
Once the Superficial Ulnar Nerve innervates the Palmaris Brevis muscle it dives superficially and provides what?
Sensation
to
all of digit 5 on the palmar and dorsal surfaces and at least medial half/or all of digit 4.
If the Superifical Ulnar Nerve was predominately sensory what is the Deep Ulmar Nerve provide?
Motor
Which has a larger role in the hand, Radial or Ulnar Nerve?
Ulnar Nerve
Which has a larger role in the forearm, Ulnar or Radial nerve?
Radial Nerve
If someone had long Ulnar nerve damage where would you see the effects?
the Hands
Medial and Lateral Cords contribute to form what nerve?
Median Nerve
What muscle does the Median Nerve dive deep to?
Biceps brachii
Median Nerve runs parallel with what two structures?
Brachial artery
Ulnar Nerve
Just like the Ulnar Nerve the Median Nerve will serve what purpose in the arm?
NONE!
they have no purpose in the arm
The Median Nerve dives through what aspect of the elbow?
goes through the Anterior aspect of the elbow
The Median Nerve will course through what anatomical location?
Cubital Fossa
What are the boundaries of the Cubital Fossa?
The invisible line formed by dotting btwen the medial and lateral epicondyle (superior border)
Pronator teres
Brachioradialis
forming a triangle
After the Median Nerve passes the Cubital Fossa what does it do?
slides under the Bicipital Apeneurosis and pears in between the two heads of the Pronator teres
As soon as the Median Nerve pears past the two heads of the Pronator teres it gives off a deep branch known as what?
Anterior interosseous nerve
What sort of nerve is the Anterior Interosseous nerve?
Motor branch of the median nerve
What does the Anterior Interosseous nerve course through?
the interosseous membrane
What two structures travels together with the Anterior interosseous nerve?
anterior interosseous artery
anterior interosseous vein
after piercing through the interosseous membrane the Anterior Interosseous nerve will innervate what group of muscles?
the Deep anterior muscles of the forearm
Name the deep anterior muscles of the forearm.
***innervated by the Anterior interosseous nerve***
Lateral half of the Flexor digitorum profundus
Flexor pollicus longus
Pronator quadratus
At what level will the Anterior Interossuos nerve terminate?
at the Pronator quadratus muscle
Does the Anterior interosseous nerve enter the hand?
No, becuase it is terminated before entering the hand at the wrist (Pronator quadratus muscle)
The main branch of the Median nerve will continue distally and what two muscles will it be sandwiched in between?
Flexor digitorium profundus
and
Flexor digitorum superficialis
When you dissect and flip the Flexor digitorum superficialis what nerve will you see adhered to that muscle?
Median nerve
Just before the level of the wrist the Median Nerve will give off what superficial nerve?
Palmar cutaneous branch of the median nerve
Where will the Median nerve provide sensation to?
Lateral aspect of the palmer hand
What is the Carpal Tunnel Syndrome?
compression of the Median nerve in the Carpal Tunnel.
If someone comes with Carpal Tunnel Syndrome, where should there be numbness and thingling?
Lateral aspect of the palmer side
How many structures transmit through the Carpal tunnel?
9 tendons
1 nerve
Digit branches from the Median Nerve provides what?
Sensation to the 1, 2, 3 (sometimes half of 4) and the tips of those fingers
One last nerve that branches off the median nerve swings back proximally, what is that nerve?
Recurrent median nerve
What does the recurrent median nerve provide?
sensation to the Thenar eminence
What is Parasythesia?
partial or weird sensation
What is Anasthyia?
No sensation
What does Dermatomes portray?
the sensation relations with nerve ROOT and skin
What does Myotomes portray?
relations with nerve ROOT and action
Where is the usual location of impingement of the Median Nerve?
As the Median Nerve enters in between the two heads of Pronator teres
What does the Main branch of Median Nerve travel along to innervate the majority of the Flexor compartment muscles?
underside of the Flexor Digitorum Superficialis
What are the Flexor compartment muscles?
Pronator teres
Flexor Carpi Radialis
Palmaris Longus
Flexor Carpi Ulnaris
