Brachial plexus Flashcards
Draw brachial plexus
After their formation, roots of brachial plexus pass between
anterior and middle scalene muscles to enter posterior triangle of neck
What is superior trunk
C5 and C6 roots
What is middle trunk
C7 root continuation direct
What is inferior trunk
combination of C8 and T1 root
Axillary and radial nerves are terminal branches of posterior cord and supply
extensor compartments within upper limb
Ulnar, medina and musculocutanous nerve are formed from anterior divisions via medial and lateral cords and supply the
flexor compartments
Long thoracic nerve spinal root values
C5-C7
Medial pectoral nerve spinal root value and lateral
C8-T1
C5-C7
What is M shape
musculocutaneous, median and ulnar nerves
Superficial to axially artery
Mechanism of upper brachia plexus injury
excessive increase in angle between neck and shoulder e.g. fall or when a baby is born if shoulder dystocia
C5 and C6
What is waiter’s tip
Limb hangs by the side in internal rotation with an adducted arm and extended elbow
Injury to upper roots of brachial plexus- Erb’s palsy
Mechanism of injury to lower brachial plexus
forced hyperextension or hyperabduction
e.g. grab onto tree branch or baby’s arm delivered first
Klumpke’s palsy
C8 and T1
What is claw hand
hyperextension of all metacarpophalangeal joints (not just ring and little finger seen in ulnar nerve injury)
Flexion of interphalangeal joints and abduction of the thumb and wasting of interossei
Which nerve passes anterior to the lateral epicondyle of the humerus
Median
Which nerve innervates pectoralis minor
Medial pectoral nerve
Which nerve provides the sensory innervation to the radial side of the forearm
Musculocutaneous nerve
Which nerve passes posteriorly to medial epicondyle of humerus
Ulnar
Which nerve is responsible for wrist flexion
Median nerve- innervates anterior forearm
Which nerve provides the motor innervation to the posterior arm
Radial nerve
Which nerve provides sensory innervation to the regimental badge
Axillary
Which nerve innervates teres minor
Axillary nerve
Which nerve passes down lateral side of upper arm between bicep brachii and brachialis muscles
Musculocutaneous nerve
Which nerve enters the hand via Guyon’s canal
Ulnar nerve
Which muscle without innervation is responsible for the pathology of winged scapula
Serratus anterior muscle
What does the Latissmus dorsi do
Extend, adduct and medially rotate the humerus at the shoulder
Point of origin for the Supraspinatus muscle
Supraspinous fossa
What is innervated by the lateral pectoral nerve
Pec major
What does trapezius muscle do
Abduct the shoulder
Attachments of the trapezius muscle
Skull, T2 spinous process and clavicle
Extrinsic shoulder muscles
Trapezius, rhomboid major, latissimus dorsi
Which muscle is mainly responsible for shoulder abduction from 0-15 degrees
Supraspinatous
Muscles of rotator cuff
Supraspinatous, infraspinatous, teres minor and subscapularis
SITS
Which nerve innervates deltoid muscle
Axillary nerve
Which muscle may undergo atrophy in long standing axillary nerve palsy
Deltoid
Which vessel accompanies the axillary nerve as it passes through the quadrangular space
Posterior circumflex humoral artery and vein
Which structure forms the inferior border of the quadrangular space
Teres major
A patient with stab wound to axilla- which branch of musculocutaneous nerve affected
Lateral cutaneous nerve or forearm - innervates skin of anterolateral aspect of forearm muscle
Which muscle is least likely to undergo atrophy in chronic carpal tunnel syndrome
Flexor pollicis longus (located on anterior forearm, receives innervation before the median nerve passes through the carpel tunnel)
Pronator quadratus is innervated by
Anterior interosseous branch of median nerve
Deformity when median nerve is damaged at elbow
hand of benediction d
Which injury is most likely to result in wrist drop
Humoral shaft fracture - radial nerve tightly bound in spiral groove of humerus
How many sensory branches does the radial nerve give rise to
4
Damage with superficial branch of radial nerve
Purely sensory
What is flexor digitorum profundus medial half innervated by
Ulnar nerve
Which area does the ulnar nerve provide cutaneous innervation to
Medial one and a half fingers
