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39 Cards in this Set

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  • Back
What nerve roots form the superior trunk of brachial plexus?
C5, C6
What nerve roots form the middle trunk of the brachial plexus?
C7
What nerve roots form the inferior trunk of the brachial plexus?
C8, T1
How is the axillary nerve formed?
It's the superior branch of the posterior cord
Muscles innervated by the axillary nerve
Deltoid and teres minor
Muscles innervated by the musculocutaneous nerve
Biceps, brachial, choracobrachial
Muscles innervated by the radial nerve
Triceps and extensor muscles on the posterior compartments of arm and forearm
Muscles innervated by the ulnar nerve
Flexor carpi ulnaris, medial part of the flexor digitorus profundus, lumbricals 3 and 4, palmar interosseous, dorsal interosseous, adductor pollicis, abductor digiti minimi, flexor digiti minimi, opponens digiti minimi
Muscles innervated by the median nerve
Flexor muscles of the forearm except flexor carpi ulnaris and medial part of flexor digitorus profundus, lumbricals 1 and 2, abductor pollicis brevis, opponens pollicis brevis, flexor pollicis brevis.
Actions of the axillary nerve
Abduct shoulder (deltoid), lateral roation of the shoulder (teres minor)
Actions of the musculocutaneous nerve
Flexes elbow (biceps, chorachobrachial), supination (biceps brachii)
Actions of the radial nerve
Extends digits, wrist and elbow. Supination.
Actions of the ulnar nerve
Flexes wrist and digits 4 and 5. Abducts and adducts digits 2, 3, 4, 5.
Actions of the median nerve
Flexes wrist and digits, pronation; abduction, opposition and flexion of the thumb
Clinical features of injury of the upper trunk of the brachial plexus
C5, C6 are injured due to adduction traction of the arm and hyperextension of the neck (fall on shoulder or pull baby by the neck). Results in Erb-Duchene paralysis damaging axillary, musculocutaneous, suprascapular and phrenic nerves. Loss of shoulder and anterior arm muscles. Arm is medially rotated and adducted, forearm is extended and pronated (waiter's tip)
Clinical features of injury of the lower trunk of the brachial plexus
C8, T1 are injured by a sudden abduction upward pull of the arm (pull baby by the arm). Results in thoracic outlet syndrome damaging median and ulnar nerves as well as T1 sympathetics. Loss of muscles of forearm and hand and Horner's syndrome (ptosis, miosis, anhydrosis)
Long thoracic nerve injury
Paralysis of the serratus anterior. No abduction of the arm past the horizontal position. Can't push (winging of the scapula)
Axillary nerve injury
Injured by fracture at the surgical neck of humerus or anterior dislocation of the shoulder. Cant abduct the shoulder to the horizontal plane, cant lateral rotate shoulder (teres minor). Sensory loss at the shoulder.
Radial nerve injury at the axilla
Shoulder dislocation or pressure on the floor of the axilla. No extension of the elbow, wrist or digits. Weak supination. Sensory loss of posterior arm, posterior forearm and posterolateral hand. "Wrist drop"
Radial nerve injury at the arm
Midshaft fracture of the humerus. No extension of the wrist or digits. Sensory loss on the posterior forearm and posterolateral hand. "Wrist drop"
Radial nerve injury at the wrist
Sensory loss on the lateral part of the dorsum of the hand.
Median nerve injury at the elbow
Supracondylar fracture of the humerus. Weak flexion of the wrist with ulnar deviation upon flexion. No flexion of digits 1 and 2, thenar muscles and lumbricals 1 and 2. Sensory loss on lateral palm and fingers 1, 2 and 3. Flattening of the thenar eminence (ape hand) and index and middle fingers cant make a fist.
Median nerve injury at the wrist
Slashing of the wrist (suicide attempt). Loss of thenar muscles and lumbricals 1 and 2. Sensory loss on lateral palm and fingers 1, 2 and 3. Flattening of the thenar eminence (ape hand) and index and middle fingers cant make a fist.
Ulnar nerve injury at the elbow
Fracture of the medial epicondyle of the humerus. Hand deviates radially when flexed (injured flexor carpis ulnaris), no flexion of ring and little fingers (injured flexor digitorus profundus and lumbricals 3, 4), abduction and adduction of the fingers is lost (injured palmar and dorsal interosseous), no adduction of the thumb, no mevement of little finger. Sensory lost on lateral half of ring finger and little finger. "Claw hand".
Ulnar nerve injury at the wrist
Slashing of the wrist (suicide attempt). Loss of abduction and adduction of the digits, loss of hypothenar muscles and lumbricals 3, 4. Sensory loss on lateral half of digit 4 and 5. "Claw hand".
Musculocutaneous nerve injury
Loss of elbow flexion and weak suppination. Loss of sensation on lateral aspect of the forearm.
Branches of the brachiocephalic trunk
Left subclavian and left common carotid arteries
Branches of the subclavian artery
Internal thoracic artery (continuous with superior epigastric and inferior epigastric which provide colateral circulation in postductal coarctation of the aorta), vertebral artery.
Branches of the axillary artery
Thoracoacromial, lateral thoracic (mammary gland), subscapular (collateral to shoulder), posterior and anterior humeral circumflex arteries.
Branches of the brachial artery
Deep brachial artery (together with radial nerve at midshaft of humerus), ulnar artery and radial artery at the cubital fossa.
Branches of the ulnar artery
Common interosseous artery and superficial palmar arch
Branches of the radial artery
Deep palmar arch
Rotator cuff muscles
Subscapularis, Infraspinatous, Teres minor, Supraspinatous. "SITS"
What are the joints of the elbow and what is the function of each?
Humeroulnar and humeroradial permit flexion and extension. The radioulnar permits pronation and supination.
Wrist and hand joints
Radiocarpal joint (between the distal radius and scaphoid/lunate carpal bones), ulnocarpal joint, midcarpal joint (between proximal and distal carpal bones), carpometacarpal joints.
What are the carpal bones
From lateral to medial. Proximal row: scaphoid, lunate, triquetrum, pisiform. Distal row: trapezium, trapezoid, capitate, hamate.
What are the structures in the carpal tunnel?
Flexor digitorum superficialis (4 tendons), flexor digitalis profundus (4 tendons), flexor pollicis longus and median nerve.
Fracture of the scaphoid bone
Results in avascular necrosis of the proximal head of the scaphoid.
Lunate bone dislocation
Results in median nerve compression in the carpal tunnel