The Nerves of the Brachial Plexus, Arm, Forearm, Wrists, and Hands
Divisions
*Anterior divisions*: Supply anterior/flexion compartment of upper limb *Posterior divisions*: Supply posterior/extension compartment of upper limb
Dermatomes of Upper Limb
*C6*: Pad of thumb *C7*: Pad of middle finger *C8*: Pad of small finger
Muscle Compartment Testing of Nerves - Arm & Forearm
*Dorsal arm & forearm*: extension, supination → Radial n. *Anterior arm*: forearm flexion → Musculocutaneous n. *Anterior forearm superficial*: wrist flexion, pronation; finger flexion at MP, PIPs → Median n. (except FCU & lateral 2 heads of FDP) *Anterior forearm deep*: finger flexion DIP 2 & 3, thumb flexion, pronation → Anterior interosseous of median n.
Muscle Compartment Testing of Nerves - Hand
*Lateral (radial) hand*: Thumb flexion, adduction, opposition; PIP extension of digits 2-3 → Recurrent branch of median n. Medial (ulnar) hand*: Small finger flexion, finger adduction & abduction, PIP extension of digits 4-5 → Ulnar n.
Cords
*Lateral Cord*: Comprised of anterior division of superior & middle trunks *Posterior Cord*: Comprised of the three posterior divisions *Medial Cord*: Continuation of anterior division of lower trunk
Tomes
*Sclerotomes*: Delineate location of pain due to spinal sensory nerve root pathology. *Dermatomes*: Delineate location of loss of sensation due to spinal sensory nerve root pathology. *Myotomes*: Delineate location of muscle weakness due to spinal motor nerve root pathology.
Muscles with Double Innervation
*Subscapularis*: Upper & lower subscapular nn. *FDP*: AIN to 2nd & 3rd digits, ulnar n. to 4th & 5th *FPB*: deep head (ulnar n.) & superficial head (median n.) *Pectoralis major*: Medial & lateral pectoral nn.
Most distally innervated muscles - KNOW THESE!!!
*Useful for testing nerve continuity.* The distal most representation of a nerve provides the physician with rapid information regarding the health of a nerve. *Radial n.*: Extensor indicies; Weak MCP extension *Median n.*: Opponens pollicis; Thumb opposition *Ulnar n.*: First dorsal interosseous; Abduction of index finger *Musculocuntaneous n.*: Brachialis; Forearm flexion *Axillary n.*: Deltoid; Shoulder abduction
Radial Nerve Clinical Correlations
1st-2nd dorsal webspace sensation + normal extensor indices function = superficial radial neuropathy distal to bifurcation at elbow. Intact 1st-2nd dorsal webspace sensation + extensor indices weakness = motor nerve injury distal to bifurcation at elbow. 1st-2nd dorsal webspace sensation + extensor indices weakness = radial nerve injury proximal to bifurcation at elbow Most typical finding of general radial neuropathy is *"wrist drop"*, since all extensors are lost or weakened. Most distal muscle is extensor indices, which produces a weak MCP extension of index finger if radial motor nerve is injured.
What muscle(s) and/or joint(s) do(es) the Radial nerve innervate?
ALL DORSAL FOREARM MUSCLES. Brachioradialis, Extensor carpi radialis longis, Extensor carpi radialis brevis, Extensor digitorum, Extensor carpi ulnaris, Supinator, Extensor pollicis longis, Extensor indices, Extensor digiti minimi, Abductor Pollicis longis, Pronator Quadratus
What muscle(s) and/or joint(s) does the Musculocutaneous nerve innervate?
ANTERIOR ARM: brachialis, biceps brachii, coracobrachialis
What divisions contribute to the posterior cord?
All 3 posterior divisions of the trunks
origin of the Ulnar nerve
An extension of the medial cord
Upper Trunk
Anterior Cord, Posterior division, suprascapular, nerve to subclavius
Lower Trunk
Anterior and Posterior Division
Middle Trunk
Anterior and Posterior Division
origin of the medial cord
Anterior division of the inferior trunk
Lateral Cord
Anterior divisions of Upper and middle trunk
origin of the lateral cord
Anterior divisions of superior and middle trunks
Medial Cord
Anterior división of lower trunk
origin of medial pectoral nerves
Arises from medial cord
origin of lateral pectoral nerve
Arises from the lateral cord
origin of cutaneous (sensory) nerve to the arm and forearm
Arises from the medial cord.
Median n. - Pathway in FOREARM
As it enters forearm, the median nerve is sitting on the anterior surface of brachialis and passes between the two heads of pronator teres (medial epicondyle and coronoid) and then between two of the heads of flexor digitorum superficialis (medial epicondyle and radius) and can become entrapped by either of these as well as by the bicipital aponeurosis.
What Nerve(s) innervate the Deltoid
Axillary
What Nerve(s) innervate the Teres Minor
Axillary
What Nerve(s) innervate the Teres minor
Axillary
Useful Testing Sites
Axillary: over lateral deltoid Musculocuntaneous: lateral forearm Median: pad of index finger Ulnar: pad of small finger Radial: first dorsal web space
origin of the terminal branch of the median nerve
Both the lateral and medial cords
What spinal nerves contribute to the Long Thoracic Nerve?
C 5, C6, and C7
Which spinal nerve is the main contributing nerve to the Subclavius nerve?
C4, C5, C6*
What spinal neves contribute to the radial nerve?
C5 - T1
What nerves make up the superior trunk of the brachial plexus?
C5 and C6
What spinal nerves contribute to the upper subscapular nerve?
C5*, C6
Which spinal nerve is the main contributing nerve to the suprascapular nerve?
C5*, C6
What spinal nerves contribute to the axillary nerve?
C5, C6
What spinal nerves contribute to the lower subscapular nerve?
C5, C6*, C7
Which spinal nerves contribute to the lateral pectoral nerve?
C5, C6*, C7
Which spinal nerves contribute to the Musculocutaneous nerve?
C5, C6, C7
Five nerve roots
C5, C6, C7, C8, and T1
What spinal nerves contribute to the thoracodorsal nerve?
C6, C7*, C8
What spinal nerves contribute to the median nerve?
C6, C7, C8, T1
What spinal nerves contribute to the medial brachial cutaneous nerve?
C8, T1
What spinal nerves contribute to the medial pectoral nerve?
C8, T1
What spinal nerves contribute to the Ulnar nerve?
C8, T1 (sometimes C7)
Lateral Antebrachial cutaneous n.
Continuation of musculocuntaneous nerve after all motor branches have been given off.
Ulnar n. - Pathway in FOREARM
Crosses fascia of flexor carpi ulnaris & becomes anterior in forearm. For distal 1/2 of forearm, travels with ulnar artery. Crosses the wrist in Guyon's canal superficial to flexor retinaculum (not in carpal tunnel). It crosses under the cover of the volar/palmar carpal ligament (from the sleeve fascia). Ulnar innervated skin is normal to pinprick in carpal syndrome Well cushioned in forearm between FDS and FDP.
Superficial radial n.
Crosses over the anatomical snuffbox superficial to tendon of extensor pollicis longus, where it separates into several branches. Clinical correlation: Can be injured traumatically by handcuffs Innervates wide areas of skin on the dorsal hand & fingers, along with cutaneous branches of median & ulnar nerves. Radial nerve is ONLY cutaneous innervation over 1st-2nd dorsal webspace (radial n. tested sensorially in this region).
Medial antebrachial cutaneous n.
Cutaneous sensory ONLY - NO MOTOR Root: C8, T1 Origin: Medial cord Reaches cutaneous destination by following veins.
Medial brachial cutaneous n.
Cutaneous sensory ONLY - NO MOTOR Root: C8, T1 Origin: Medial cord Reaches cutaneous destination by following veins.
The Axillary nerve innervates
Deltoid and Teres Minor
Course of the PIN
Distal to the radial nerve split, the main branch of the radial nerve, called the posterior interosseous nerve (PIN), pierces the supinator muscle to again reach posterior compartment of forearm, & innervates all muscles of posterior forearm. Clinical correlation: can be entrapped in a contracting supinator and is called the supinator syndrome (the fibers of the supinator are called the "Arcade of Frohse").
What Nerve(s) innervate the Rhomboid Major
Dorsal Scapular
What Nerve(s) innervate the Rhomboid Minor
Dorsal Scapular
What Nerve(s) innervate the Levator scapulae (sometimes)
Dorsal scapular
What Nerve(s) innervate the Rhomboids
Dorsal scapular
Other Muscle Weaknesses
Dorsal scapular n.: rhomboids → scapular retraction Long thoracic n.: serratus anterior → scapular protraction Suprascapular n.: Supraspinatus → Initiate shoulder abduction Pectoral nn.: Pectoralis major → Shoulder flexion Lower subscapular n.: Teres major → Internal rotation, extension Thoracodorsal n.: Latissimus dorsi → Adduction, internal rotation Axillary n.: Deltoid, Shoulder abduction (numb over lateral deltoid)
What are the pre-plexus nerves discussed? (names only)
Dorsoscapular, Long Thoracic
Median n. in wrist & hand
Enters hand through carpal tunnel. It is the most superficial structure in carpal tunnel & shares space with 9 tendons: FDP (4), FDS (4), FPL *Carpal Tunnel Syndrome*: Median nerve is compressed in carpal tunnel & causes symptoms. Sensation in 4th digit (1/2 median nerve & 1/2 ulnar n.) important in diagnosis. *Clinical Correlation*: The *recurrent branch* of the median nerve (thenar branch) is motor to the thenar eminence. It is very superficial & susceptible to injury.
Median n. - Pathway in ARM
Exits shoulder *lateral to brachial artery* & continues in medial intermuscular septum (between triceps and anterior muscles) As the biceps brachii becomes tendinous distally, the median nerve becomes anterior to the proximal attachment of brachialis. *Crosses brachial artery anteriorly to travel on medial side* at mid-arm. Proximal to elbow it lies medial to the artery and it crosses the cubital fossa deep to bicipital aponeurosis with brachial artery.
The intrinsic plus position
Finger MP flexion, PIP and DIP extension tests the ulnar nerve. Full extension of the fingers is negative for ulnar nerve palsy - positive is the ulnar claw, sometimes referred to as the Bishop's sign: PIP flexion, MP hyperextension, and the small finger is often abducted.
Muscle Compartment Testing of Nerves - Shoulder
Flexion, abduction, extension, adduction → Spinal accessory, axillary, pre-plexus nerves
Course of the radial nerve
Forms as a terminal branch of posterior cord (along with the axillary nerve) just distal to the coracoid process on anterior surface of subscapularis. Enters the posterior arm with the deep brachial artery just inferior to trees major, between the long & medial heads of the triceps and follows the radial groove. Upon exiting radial groove, it pierces the lateral intermuscular septum to enter the anterior compartment, where it lies between the brachialis & brachioradialis. It crosses anteriorly over lateral epicondyle (where it can be injured in epicondylar fractures). Just past this, the superficial radial n. splits off to go to wrist.
Lower subscapular n.
Glenohumeral & acromioclavicular joints NO CUTANEOUS Root: C5, C6 Origin: Posterior cord (distal to origin of thoracodorsal n.) Innervates: Inferior subscapularis, teres major
Upper subscapular n.
Glenohumeral & acromioclavicular joints NO CUTANEOUS Root: C5, C6 Origin: Posterior cord Innervates: Superior subscapularis Travels lateral and posterior to thoradorsal nerve between subscapularis muscle and chest wall.
Thoracodorsal n.
Glenohumeral & acromioclavicular joints NO CUTANEOUS Root: C6, C7, C8 Origin: Posterior cord (distal to the origin of the upper subscapular n.) Innervates: Latissimus dorsi On the chest wall it lies posterior to long thoracic nerve.
Lateral pectoral n.
Glenohumeral & acromioclavicular joints NO CUTANEOUS, but provides propioception & pain fibers to glenohumeral joint. Root: C5, C6, C7 Origin: Lateral cord Innervates: Pectoralis major (inferior 2/3) Lateral to axillary artery at level of clavicle. Travels anterior to the first part of axillary artery & vein. Pierces clavipectoral fascia to reach the deep surface of the inferior portion of the pectoralis major muscle.
Medial pectoral n.
Glenohumeral, acromioclavicular & sternoclavicular joints NO CUTANEOUS Root: C8, T1 Origin: Medial cord Innervates: Pectoralis minor, pectoralis major (sternocostal part) Note: Actually lateral to lateral pectoral n. (named for cord of origin) Enters deep surface of pectoralis minor & some fibers pass through to innervate part of pectoralis major
What muscle(s) and/or joint(s) do(es) the ulnar nerve innervate?
HYPOTHENAR group: abductor digiti minimi, flexor digiti minimi, opponens digiti minimi; the flexor carpi ulnaris, 1/2 of the flexor digitorum profundus, the interosseus muscles (dorsal and palmar), 1/2 of lumbricals
"Hook 'em horns" sign
If patient can extend thumb, index & small fingers, the radial nerve is intact to the brachial plexus.
What muscle does the lower subscapular nerve innervate?
Inferior subscapularis muscle and teres major muscle
branches of the superior trunk
Inferior: the nerve to subclavius Superior: Suprascapular nerve
Sensory ulnar n.
Innervates 5th digit, medial 1/2 of 4th digit, medial palm. The pad of the small finger is exclusively innervated by the unlar n.
origin of the musculcutaneous nerve
Is an extension of the lateral cord
What cords contribute to the median nerve?
Lateral Cord and the Medial Cord
What nerve branches off from the Lateral Cord of the brachial plexus? (name only)
Lateral Pectoral Nerve
What Nerve(s) innervate the Pectoralis major and minor
Lateral and Medial pectoral
What Nerve(s) innervate the Pectoralis major
Lateral pectoral
What muscle does the Thoracodorsal nerve innervate?
Latissimus Dorsi muscle
thoracodorsal nerve innervates
Lattisimus dorsi
What Nerve(s) innervate the Serratus Anterior
Long Thoracic
What Nerve(s) innervate the Serratus Anterior
Long thoracic
What Nerve(s) innervate the Teres Major
Lower Scapular
C8-T1
Lower Trunk
Dejerene Klumpke Palsy
Lower Trunk Injury (C8, T1) *Causes*: Traction on arm during childbirth, fall or pull on upper limb in adults *Signs & Symptoms*: Paralysis of intrinsic hand muscles, loss of medial hand sensation, weak wrist (with flexion stronger than extension), shoulder is "normal" & strong
What Nerve(s) innervate the Flexor Digitorum Superficialis
Medial
What nerves branch off of the medial cord of the brachial plexus? (names only)
Medial Pectoral, Medial Brachial Cutaneous, and Medial Antebrachial Cutaneous nerves
What Nerve(s) innervate the Skin on medial side of forearm
Medial antebrachial cutaneous
What Nerve(s) innervate the Skin on medial side of arm
Medial brachial cutaneous
What Nerve(s) innervate the Abductor Pollicis Brevis
Median
What Nerve(s) innervate the Extensor Carpi Radialis Longus
Median
What Nerve(s) innervate the Flexor Carpi Radialis
Median
What Nerve(s) innervate the Flexor Pollicis Brevis
Median
What Nerve(s) innervate the Flexor Pollicis Longus
Median
What Nerve(s) innervate the Opponens Pollicis
Median
What Nerve(s) innervate the Pronator Quadratus
Median
What Nerve(s) innervate the Prontator Teres
Median
What Nerve(s) innervate the Thenar muscles
Median
What Nerve(s) innervate the Lumbricals
Median and Ulnar
Common Sites of Major Nerve Entrapment
Median n. at carpal tunnel Ulnar n. at cubital tunnel, by heads of flexor carpi ulnaris PIN at supinator muscle Radial n. at radial groove of humerus
terminal brachnes of the brachial plexus
Median, Ulnar, Radial and musculocutaneous nerves
C7
Middle Trunk
What Nerve(s) innervate the Biceps Brachii
Musculocutaneous
What Nerve(s) innervate the Biceps brachii
Musculocutaneous
What Nerve(s) innervate the Brachialis
Musculocutaneous
What Nerve(s) innervate the Coracobrachialis
Musculocutaneous
Branches of Medial and Lateral Cord
Musculocutaneous, medial cutaneous of forearm and arm, ulnar, median, medial pectoral, lateral pectoral
What Nerve(s) innervate the Subclavius
Nerve to subclavius
Musculocutaneous n.
Origin: Lateral cord (terminal branch) Root: C5, C6 *Motor*: Coracobrachialis, brachialis, biceps brachii *Cutaneous sensory*: Lateral forearm
Median n.
Origin: Medial & lateral cords Root: C6-T1 (contributions from all 3 trunks) Primary nerve of flexor/anterior compartment of forearm. Supplies all the long flexor muscles of the wrist and hand/digits except FCU, and ulnar half of the FDP. Via the named branch, the "anterior interosseus nerve," it also supplies: pronator quadrates, lateral 1/2 of the FDP, and the FPL (of the deep sub-compartment). Sensory branches supply the wrist joint. Remains in anterior compartment. Crosses anterior to medial epicondyle, where it can be injured in epicondylar fractures. No branches in arm. Provides some articular supply to elbow.
Suprascapular n.
Origin: Upper trunk Innervates: Supraspinatus, infraspinatus Traverses scapular notch on its way to innervate infraspinatus m.
Musculocutaneous n. - Pathway in ARM
Originates at the split of the lateral cord. Travels inferiorly & *pierces coracobrachialis from superior-posterior-medial to inferior-anterior lateral*. It then lies between brachialis & biceps brachii.
Anterior interosseous branch of median n.
Originates deep to bicipital aponeurosis, the 3 heads of flexor digitorum superficialis, and the 2 heads of pronator teres. Innervates deep anterior compartment: flexor pollicis longus, pronator quadratus, lateral 1/2 of flexor digitorum profundus NO CUTANEOUS BRANCHES.
What portion of the skin does the sensory portion of the median nerve innervate?
Palmar Skin, from the thumb to the lateral 1/2 of the ring finger.
What muscle does the medial pectoral nerve innervate? (name only)
Pectoralis Minor muscle, some of pectoralis major
What muscle(s) do(es) the lateral pectoral nerve innervate?
Pectoralis major muscle (some minor)
Posterior Cord
Posterior division of upper, middle and lower trunks
What Nerve(s) innervate the Abductor Pollicis Longs
Radial
What Nerve(s) innervate the Anconeus
Radial
What Nerve(s) innervate the Brachioradialis
Radial
What Nerve(s) innervate the Extensor Carpi Radialis Brevis
Radial
What Nerve(s) innervate the Extensor Carpi Ulnaris
Radial
What Nerve(s) innervate the Extensor Digiti Minimi
Radial
What Nerve(s) innervate the Extensor Digitorum
Radial
What Nerve(s) innervate the Extensor Indicis
Radial
What Nerve(s) innervate the Extensor Pollicis Brevis
Radial
What Nerve(s) innervate the Extensor Pollicis Longus
Radial
What Nerve(s) innervate the Extensors of the forearm
Radial
What Nerve(s) innervate the Supinator
Radial
What Nerve(s) innervate the Triceps Brachii
Radial
What Nerve(s) innervate the Triceps brachii
Radial
What area of the skin does the musculocutaneous nerve contribute to?
Radial Forearm Skin
Important Nerve Bifurcations
Radial n. at elbow → superficial & posterior interosseous Median n. distal to elbow → anterior interosseous branch & main median n. Posterior cord → radial & axillary nn. Medial cord → ulnar & median nn. Lateral cord → musculocutaneous & median nn.
Branches of Posterior Cord
Radial, axillary, thoracodorsal, lower sub scapular, upper subscapular
What does the dorsoscapular nerve innervate?
Rhomboid Major and Minor, and Levator Scapulae muscles
dorsal scapular nerve innervates
Rhomboid major, Rhomboid minor and Levator scapulae
Dorsal scapular n.
Root: C5 Innervates: Rhomboids, levator scapulae *Pre-plexus nerve* No cutaneous branches
Long thoracic n.
Root: C5, C6, C7 Innervates: Serratus anterior *Pre-plexus nerve* No cutaneous branches
Lateral cord contribution to median n.
Root: C6, C7 *Main branch, Motor*: Pronator teres Flexor carpi radialis Palmaris longus Flexor digitorum superficialis Abductor pollicis brevis 1/2 of flexor pollicis brevis Opponens pollicis Lateral 2 lumbricals Anterior interosseous branch, Motor*: Flexor pollicis longus Lateral 1/2 of flexor digitorum profundus Pronator quadratus *Cutaneous sensory*: Sensory to radial half of palm & to lateral side of 4th digit & thumb and fingers 1 & 2.
Medial cord contribution to median n.
Root: C8, T1 *Motor main branch*: Pronator teres Flexor carpi radialis Pollicis longus Flexor digitorum superficialis Abductor pollicis longus 1/2 of flexor pollicis brevis Opponens pollicis Lateral 2 lumbricals *Motor anterior interosseous branch*: Flexor pollicis longus lateral 1/2 of flexor digitorum profundus Pronator quadratus *Cutaneous sensory*: Sensory to radial half of palm & to lateral side of 4th digit & thumb & digits 1 & 2
Ulnar n.
Root: C8, T1 Origin: Medial cord *Motor*: Flexor carpi ulnaris Medial 1/2 of flexor digitorum profundus Medial 2 lumbricals Flexor digiti minimi Abductor digiti minimi Opponens digiti minimi All 3 palmar interosseous All 4 dorsal interosseous Adductor pollicis *Cutaneous sensory*: Sensory medial half of ring finger, all of small finger
Ulnar n. - Pathway in ARM
Runs from its origin in the anterior compartment of arm, with no branches in arm, to pierce medial septum & enter posterior compartment. Crosses the elbow posterior to medial epicondyle, where it is susceptible to entrapment by flexor carpi ulnaris and injury by *medial epicondylar fractures*.
Median n. in the hand
Sensory fibers innervate lateral 3 digits & lateral 1/2 of 4th digit. Motor fibers innervate lateral 2 lumbricals & via the recurrent branch, the 3 muscles of the thenar eminence (APB, FPB, OP).
Dorsal cutaneous branch of ulnar n.
Sensory to dorsal medial 1/2 of the long, proximal 3/4 of the ring & small fingers. NO MOTOR ACTION. Originates from ulnar n. approximately halfway between wrist & elbow.
Deep ulnar n.
Separates from sensory branch in the hypothenar eminence & innervates hypothenar muscles, the medial 2 lumbricals, the deep head of flexor pollicis brevis & adductor pollicis.
What muscle(s) do(es) the Long Thoracic nerve innervate?
Serratus Anterior muscle
Which nerves are involved in the brachial plexus?
Spinal nerves C5 - T1
What muscles(s) and/or joints do(es) the subclavius nerve innervate?
Subclavius muscle, sternoclavicular joint
Erb Duchenne Palsy
Superior Trunk Injury (C5, C6) *Causes*: Usually results from excessive increase in angle between neck & shoulder from: -traction on head during delivery -seatbelt injury -fall striking head & shoulder with head laterally flexed *Signs & Symptoms*: Weak shoulder muscles (except pectoralis minor & trapezius), numb deltoid & lateral forearm
What muscle does the upper subscapular nerve innervate?
Superior subscapularis muscle
What trunk(s) contribute to the radial nerve?
Superior trunk, Middle Trunk, Inferior Trunk
What trunks contribute to the median nerve?
Superior, Middle and Inferior Trunks
What Nerve(s) innervate the Glenohumeral joint
Suprascapular
What Nerve(s) innervate the Infraspinatus
Suprascapular
What Nerve(s) innervate the Supraspinatus
Suprascapular
What two nerves branch off of the Superior trunk of the brachial plexus? (names only)
Suprascapular and Subclavius Nerves
What muscle(s) and/or joints do(es) the suprascapular nerve innervate?
Supraspinatus, Infraspinatus, Glenohumeral joint
What muscle(s) and/or joint(s) do(es) the median nerve innervate?
THENAR group: Flexor Pollicus Brevis, Abductor Pollicus Brevis, Opponens Pollicus; Anterior Forearm: Pronator Teres, Flexor Carpi Radialis, Palmaris Longis, NOT Flexor Carpi Ulnaris, NOT 1/2 of flexor digitorum profundus, 1/2 of lumbricals
What muscle(s) and/or joint(s) do(es) the Axillary nerve innervate?
Teres Minor muscle, Deltoid muscle, Glenohumeral Joint
Axillary n.
Terminal branch of posterior cord Root: C5, C6 *Motor*: deltoid, teres minor *Sensory*: over lateral deltoid Exits to the posterior axillary region through the quandrangular space accompanied by posterior circumflex humeral artery. Encircles the surgical neck of the humerus.
Radial n.
Terminal branch of posterior cord Root: C5-T1 Motor: Triceps brachii, brachioradialis, extensor carpi radialis longus Superficial radial (sensory only): Dorsal 1st-2nd webspace skin PIN (Posterior interosseous branch of radial nerve) Motor only: Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indices
What cord(s) contribues to the axillary nerve?
The Posterior Cord
What cord(s) contributes to the radial nerve?
The Posterior Cord
What trunk(s) contribute to the axillary nerve?
The Superior trunk
What divisions contribute to the Lateral Cord of the brachial plexus?
The anterior division of the Middle Trunk and the continuation of the Superior Trunk
What skin does the sensory portion of the axillary nerve innervate?
The lateral arm skin, skin over the deltoid
What cord(s) contribute to the Ulnar nerve?
The medial cord
What does the medial brachial cutaneous nerve innervate?
The skin on the medial arm
What does the medial antebrachial cutaneous nerve innervate?
The skin on the medial forearm
origin the divisions
The splitting of the superior, middle and inferior trunks anteriorly and posteriorly
origin of the posterior chord
The three posterior divisions
What portion of the skin is specific to the sensory innervation by the radial nerve?
The web between the thumb and the index finger, dorsally
What Nerve(s) innervate the Latissimus Dorsi
Thoracodorsal
What Nerve(s) innervate the Latissimus dorsi
Thoracodorsal
What Nerve(s) innervate the Adductor Digiti Minimi
Ulnar
What Nerve(s) innervate the Adductor Pollicis
Ulnar
What Nerve(s) innervate the Adductor pollicis
Ulnar
What Nerve(s) innervate the Flexor Carpi Ulnaris
Ulnar
What Nerve(s) innervate the Flexor Digiti Minimi
Ulnar
What Nerve(s) innervate the Flexor carpi ulnaris
Ulnar
What Nerve(s) innervate the Hypothenar muscles
Ulnar
What Nerve(s) innervate the Interossei
Ulnar
What Nerve(s) innervate the Opponens Digiti Minimi
Ulnar
What Nerve(s) innervate the Flexor Digitorum Profundus
Ulnar and Median
Trunks
Upper (superior): C5, C6 Middle: C7 Lower (inferior): C8, T1
C5-C6
Upper Trunk
Subscapularis
Upper and Lower Subscapular
What Nerve(s) innervate the Subscapularis
Upper subscapular
What branch(es) come(s) off from the Posterior Cord of the brachial plexus? (names only)
Upper subscapular, Thoracodorsal, Lower subscapular nerves.
three smaller nerves the posterior cord gives rise to
Upper subscapular, thoracodorsal, and lower subscapular nerve
Roots
Ventral rami of C5-T1
origin of the middle trunk
a continuation of the C7 nerve root
Median, Ulnar, Radial and musculocutaneous nerves innervate
all muscles in the arm, forearm and hand
origin of dorsal scapular nerve
directly off C5 nerve root
origin of long thoracic nerve
directly off C5, C6, C7 nerve roots
origin of the superior trunk
joining of C5 and C6 nerve roots
origin of the inferior trunk
joining of C8 and T1 nerve roots
other name for thoracodorsal nerve
middle subscapular nerve
the musculcutaneous nerve innervates
muscles in anterior compartment of the arm
What nerves branch off of the inferior trunk of the brachial plexus?
none
medial pectoral nerves innervate
pectoralis major and pectoralis minor
two larger nerves the posterior cord gives rise to
radial nerve, axillary nerve.
long thoracic nerve innervates
serratus anterior muscle
What Nerve(s) innervate the Inferior portion of subscapularis
subscapular
What Nerve(s) innervate the Teres major
subscapular
upper subscapular nerve innervates
subscapularis
lower subscapular nerve innervates
teres major and subscapularis
Which nerve does the dorsoscapular nerve originate from?
the C5 spinal nerve
Which cord(s) contribute to the musculocutaneous nerve?
the Lateral Cord
What does the Posterior Cord turn into? (names only)
the Radial Nerve and the Axillary Nerve
Which trunk(s) contribute to the musculocutaneous nerve?
the Superior Trunk and the anterior division of the Middle Trunk
shape of the combination of the lateral and median cords
the letter M
lateral pectoral nerve innervates
the pectoralis major muscle.
What trunks make up the posterior chord of the brachial plexus?
the posterior division of the superior trunk and the posterior division of the inferior trunk
What area of the skin does the sensory portion of the ulnar nerve innervate?
the skin on the medial hand
path of long thoracic nerve
travels inferiorly along rib cage
