Brachial Plexus Flashcards
What level do nerve roots change from emerging above the vertebrae to below?
T1
Where do brachial plexus roots emerge from the spinal column?
Ventral or anterior rami
Where is the C8 nerve root located?
Above T1 vertebra
Where is the T1 nerve root located?
Below T1 vertebra
What are the brachial plexus sections and how many of each are there?
Read - Roots - 5
The - Trunks - 3
Damn - Divisions - 6
Cadaver - Cords - 3
Book - Branches - 5
BP trunks location, anatomically
Btw anterior & middle scalene
Behind subclavian artery
Over apex of lung to 1st rib
BP nerve trunks and root origins
Superior - C5 & 6
Middle - C7
Inferior - C8 & T1
BP divisions and trunk origins
Each trunk bifurcates into an anterior and posterior division
BP divisions and compartment innervation
Anterior Divisions - 3 - anterior upper limb compartments
Posterior Divisions- 3 - posterior upper limb compartments
BP cords and origins
Lateral Cord - anterior divisions of superior and middle trunk
Posterior Cord - all 3 posterior divisions of sup/mid/inf trunks
Medial Cord - continuation of anterior division of inferior trunk
BP Division location, anatomically
Posterior aspect of middle third of clavicle
BP Cord locations relative to axillary artery
Cords are named for location to axillary artery:
Lateral to, Medial to, Posterior to
BP cord muscle innervation
(general compartments)
Lateral & Medial - anterior (flexor) forearm
Posterior - posterior (extensor) forearm
BP cord pre-terminal branches
Lateral - lateral pectoral
Medial - medial pectoral, medial cutaneous nerves of arm and forearm
Posterior - thoracodorsal, upper & lower subscapular
BP cord termination, anatomically
Inferior margin of pectoralis minor muscle
BP cord terminal nerves
Lateral - musculocutaneous nerve & lateral root of median nerve
Posterior - radial nerve & axillary nerve
Medial - ulnar nerve & medial root of median nerve
BP Supraclavicular Branches
- Name branches
- Name location/origin
DSLS
- Dorsal Scapular Nerve - C5 Root
- Suprascapular Nerve - Superior Trunk (C5&6)
- Long Thoracic Nerve - C5,6,7 roots
- Subclavian Nerve - Superior Trunk (C5&6)
Suprascapular Nerve
- Function
- Point of origin
Sensory - scapula joint (glenohumoral & acromioclavicular)
Motor - supraspinatus & infraspinatus
Superior Trunk (C5&6)
Dorsal Scapular Nerve
- Function
- Point of origin
- Motor - levator scapulae, rhomboid major & minor
- C5 Root or Superior Trunk
Long Thoracic Nerve
- Function
- Point of Origin
- Motor - serratus anterior
- C5-7 roots
Subclavian Nerve
- Function
- Point of Origin
- Motor - subclavius muscle
- Superior Trunk (C5&6)
BP Lateral Cord Branches
- Name Branches
- Preterminal or Terminal
- Lateral Pectoral Nerve - PT
- Lateral Root of Median Nerve - T
- Musculocutaneous - T
Lateral Pectoral Nerve
- Function
- Point of Origin
- Innervation of pectoralis major
- Preterminal branch of Lateral Cord (C5-7)
Musculocutaneous Nerve
- Function
- Point of Origin
- Motor - anterior arm - biceps brachii, coracobrachialis, brachialis
Sensory - skin on lateral forearm via lateral cutaneous nerve
- Terminal branch of Lateral Cord (C5-7)
BP Medial Cord Branches
- Name Branches
- Preterminal or Terminal
MMMMU
- Medial Pectoral Nerves - PT
- Medial Brachial Cutaneous Nerve - PT
- Medial Antibrachial Cutaneous Nerve - PT
- Medial Root of Median Nerve - T
- Ulnar Nerve - T
Medial Pectoral Nerves
- Function
- Point of origin
- Motor - pectoralis minor & lower sternocostal portion of pectoralis major
- Preterminal branches of the Median Cord (C8 & T1)
Medial Brachial Cutaneous Nerve
- Function
- Point of origin
aka : medial cutaneous nerve of arm
Sensory - skin over medial arm
Preterminal branch of Median Cord (C8 & T1)
Medial Antibrachial Cutaneous Nerve
- Function
- Point of Origin
aka medial cutaneous nerve of the forearm
Sensory - biceps and medial side of forearm
Preterminal branch of Median Cord (C8 & T1)
Ulnar Nerve
- Function
- Point of Origin
Motor
- Forearm: flexor carpi ulnaris & medial 1/2 of flexor digitorum profundus
- Hand: HILA - Hypothenar muscles, Interossei muscles, Lumbricals (medial), Adductor pollicis
Sensory
- skin on the anterior and posterior aspect of the medial ½ of the palm.
- skin on the anterior and posterior aspect of the medial 1½ fingers.
- Terminal branch of Medial Cord (C8 & T1)
Terminal Branches of BP
MARMU (superior to inferior)
Musculocutaneous
Axillary
Radial
Medial
Ulnar
Preterminal Branches of BP
- Origin (How many per section?)
- Names
Roots - 2
Trunks - 2
Divisions - 0
Cords - 7
Roots:
Dorsal Scapular
Long Thoracic
Trunks:
Suprascapular
Subclavian
Cords:
Medial Pectoral
Lateral Pectoral
Upper Subscapular
Lower Subscapular
Medial Brachial Cutaneous
Medial Antibrachial Cutaneous
Thoracodorsal
Subscapular Nerves
- Function
- Point of origin
Superior Subscapular - superior portion of subscapularis
Inferior Subscapular - inferior portion of subscapularis & teres major
Preterminal branches of posterior cord (C5&6)
Thoracodorsal Nerve
- Function
- Point of origin
Innervates latissimus dorsi
Preterminal branch of posterior cord (C6-8)
Axillary Nerve
- Function
- Point of origin
Mixed (motor & sensory) deltoid and teres minor
Cutaneous innervation of lateral aspect of upper arm
Terminal branch of posterior cord (C5&6)
Radial Nerve
- Function
- Point of origin
Motor:
- Posterior compartment of arm (triceps brachii)
- Posterior compartment of forearm ( (brachioradialis, anconeus, supinator, extensor carpi radialis longus and brevis, extensor carpi ulnaris, extensor digitorum, extensor pollicis longus and brevis, extensor indicis, extensor digiti minimi, abductor pollicis longus)
Sensory:
- Skin on the posterior surface of the arm.
- Skin on the central, posterior surface of the forearm.
- Skin on the lateral surface of the dorsum of the hand.
- Skin on the posterior aspect of the lateral 2½ fingers.
Terminal branch of the posterior cord (C5-T1)
Median Nerve
- Function
- Point of Origin
Motor:
-All muscles of the anterior (flexor) compartment of the forearm except for the flexor carpi ulnaris and the medial ½ of the flexor digitorum profundus.
-LOAF of Hand.
Lateral two lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Sensory:
-Skin of the lateral ½ of the palm.
-Skin on the anterior aspect of the lateral 3½ fingers.
-Skin on the posterior aspect of the lateral 2½ fingers.
Terminal branch of the brachial plexus. Formed by lateral root of lateral cord and medial root of medial cord.
Look for “M”. Median - middle. Axillary is lateral and Ulnar is medial to Median.
Lateral Cord Branches
LLM
- Lateral Pectoral
- Lateral Root of Medial
- Musculocutaneous
Posterior Cord Branches
ULTRA
Upper (Superior) Subscapular
Lower (Inferior) Subscapular
Thoracodorsal
Radial
Axillary
Medial Cord Branches
MMMMU
Medial Pectoral
Medial Cutaneous of Arm
Medial Cutaneous of Forearm
Medial Root of Median
Ulnar
Injuries of Brachial Plexus Mnemonic
DR. CUMA
Drop Wrist - Radial
Claw Hand - Ulnar
Median - Ape/Apostle’s Hand
Median Nerve Injury Manifestation
Ape Hand
Inability to abduct thumb
Loss of sensation to lateral 3.5 fingers (thumb is a finger)
Radial Nerve Injury Manifestation
Drop Wrist
Inability to extend forearm, wrist, hand, fingers.
Ulnar Nerve Injury Manifestation
Claw Hand
HILA Muscles
Hypothenar
Interosseous
Lumbricals (medial)
Adductor pollicis
Hyperextension of MCP
Hyperflexion of IP
