Brachial plexus Flashcards
(20 cards)
Describe the structure of the spinal nerves
Dorsal and central root come from the spinal cord
Both roots join to form the dorsal root ganglion => spinal nerve
3 branches
- post ramus
- ant ramus
- communicating rami <=> sympathetic chain ganglion
Describe the locations of the dermatomes of the upper limb
C3, shoulder C4, upper arm C5, lateral mid arm, forearm C6, forearm and thumb C7, middle 3 digits, middle of hand C8, little finger T1, medial surface of forearm T2, medial surface of arm and axilla
Describe the myotomes of the upper limb
C5, abduction of shoulder C5-6, flexion at elbow C6-8, extension at elbow C7-8, flexion at finger T1, abduction, adduction at finger
Describe the axillary region
Area under the glenohumeral joint at the junction of the upper limb and thorax
A passage for neuromuscular and muscular structures between cervicoaxillary canal and axillary fossa
What is the brachial plexus
All sensory innervation to upper limb and most of axilla
All motor innervation to upper limb and pectoral girdle expect trapezius
Passes under clavicle and pectoralis minor => upper limb
What are the 5 roots of the brachial plexus
What nerves comes off the roots
C5-T1
C5, dorsal scapula
C5-7, long thoracic
What are the 3 trunks of the brachial plexus
What nerves come off the trunks
C5-6, superior
C7, middle
C8-T1, inferior
Superior, suprascapular and subclavius
Describe the divisions of the brachial plexus
All trunks have an anterior and posterior division
Superior posterior div, down to middle
Middle anterior div, up to superior
Inferior anterior div, up to middle
`Describe the 3 cords of the brachial plexus
What nerves come off the cords
Superior => lateral
Middle => posterior
Inferior => medial
Lateral, lateral pectoral
Posterior, sup subscapular, thoracodorsal, inf subscapular
Medial, medial pectoral, medial arm cutaneous, medial forearm cutaneous
Name the 5 terminal branches of the brachial plexus
Lateral => musculocutaneous and medial
Posterior => axillary and radial
Medial => Medial and ulnar
What is the root of the dorsal scapular
What muscles does it innervate
What does it travel with
Does it pierce any muscles
C5
Rhomboids and levator scapulae
Dorsal scapular artery/transverse cervical
Pierces middle scalene
What are the roots of the long thoracic
What muscles does it innervate
What does it travel with
What pathologies are associated with damage here
C5-7
Serratus anterior
C5-6 pierces middle scalene
C7 passes infront => descends post to brachial plexus, axillary artery and vein
Winged scapula
What are the roots of the suprascapular
What muscles does it innervate
What does it travel with
What pathologies are associated with damage here
C4-6
Supraspinatus and infraspinatus, GH joint
Across suprascapular notch, under suprascapular ligament
Artery crosses above ligament
If suprascapular ligament ossifies, suprascapular nerve is compressed and paralyzed so cannot initiate abduction
What are the roots of the lateral pectoral
What muscles does it innervate
C5-7
Pectorals major
Pectoralis minor via communicating branch => medial pectoral nerve
What are the roots of the medial pectoral
What muscles does it innervate
What does it travel with
C8-T1
Pectoralis major and minor
Between axillary artery and vein, pierces pectoralis minor
What are the roots of the axillary
What muscles does it innervate
What does it travel with
What other nerves branch off it
C5-6
Teres minor, deltoid, GH joint, skin of inferior deltoid
Leaves axilla via quadrangular space w post circumflex humeral
Gives superior lateral brachial cutaneous nerve => around surgical neck
What are the roots of the musculocutaneous
What muscles does it innervate
What else does it innervate
C5-7
Ant arm comp (biceps brachialis, brachialis, coracobrachialis)
Supplies humerus as lateral cutaneous nerve of forearm
What are the roots of the median
What muscles does it innervate
What does it travel with
What pathologies are associated with damage to the median nerve
C6-T1
Ant forearm comp and thenar eminence and lumbricals
Sensory innervation of lateral 3 1/2 digits and palm
Passes ant => cubital fossa => palm
Carpal tunnel syndrome
- median nerve passes under transverse carpal ligament with ant comp muscles
- rubbing => inflammation => distal paralysis
What are the roots of the ulnar
What muscles does it innervate
What does it travel with
What pathologies are associated with damage to the ulnar nerve
C8-T1
1 1/2 ant forearm muscles (flexor corpi ulnaris, flexor digitorum profundis) and hand muscles
Sensory innervation of lateral 1 1/2 digits
Passes ant => behind med epicondyle => palm
Damage to ulnar => claw hand (can’t extend medical digits)
What are the roots of the radial
What muscles does it innervate
What does it travel with
C5-T1
Post comp of arm and forearm
Post of humerus => ant lateral epicondyle => post forearm => back of the hand and medial 3 1/2 digits
