Upper Extremity Injuries Flashcards
What are the terminal branches of the brachial plexus (there are 5)? Where do they come from?
MARMU Lateral cord: Musculocutaneous Posterior cord: Axillary, Radial Lateral / medial cord: Median Medial cord: Ulnar
What is the mnemonic for order of progression of brachial plexus? What things are contained (other than the branches which you just did)?
Randy Travis Drinks Cold Beer Roots: C5-T1 Trunks: Upper, Middle, Lower Divisions: 3 posterior to posterior cord, 2 anterior to lateral cord, 1 anterior to medial cord Cords: Lateral, posterior, medial Branches: MARMU
What is the thoracodorsal nerve also called?
Middle subscapular. So you can just remember posterior cord as radial, axillary, and three subscapular nerves (Upper, middle, and lower)
Origin, insertion, innervation, and action of serratus anterior muscle?
Origin: Superolateral 8-9 ribs
Insertion: Medial border of scapula
Innervation: Long thoracic nerve (from roots of C5-C7)
Action: Protracts, rotates, and assists in abduction of scapula
Origin, insertion, innervation, and action of levator scapulae?
Origin: Transverse processes of CV1-4
Insertion: Medial superior border of scapula
Innervation: Dorsal scapular nerve (root of C5)
Action: Elevates and rotates scapula
Origin, insertion, innervation, and action of rhomboid minor?
Origin: Spinous processes of C7/T1
Insertion: Superior medial border of scapula
Innervation: Dorsal scapular nerve (root of C5)
Action: Retracts, elevates, and rotates scapula
Origin, insertion, innervation, and action of rhomboid major?
Origin: Spinous processes of T2-T5
Insertion: Medial border of scapula
Innervation: Dorsal scapular nerve (root of C5)
Action: Retracts, elevates, and rotates scapula
Origin, insertion, innervation, and action of subclavius?
Origin: First rib
Insertion: Inferior clavicle
Innervation: Nerve to subclavius (C5/C6, off same area as suprascapular nerve)
Action: Depress shoulder and stabilize sternoclavicular joint
Origin, insertion, innervation, and action of supraspinatus?
Origin: Supraspinous fossa
Insertion: Superior facet of greater tubercle of humerus
Innervation: Suprascapular nerve (C5/C6, off the upper trunk)
Action: Initiates arm abduction
Origin, insertion, innervation, and action of infraspinatus?
Origin: Infraspinous fossa
Insertion: Middle facet of greater tubercle of humerus
Innervation: Suprascapular nerve (C5/C6, off the upper trunk)
Action: External rotation in neutral position
Origin, insertion, innervation, and action of pectoralis major?
Origin: Medial 1/2 of clavicle, anterior sternum
Insertion: Lateral lip of intertubercular groove of humerus
Innervation: Medial (C8-T1) and lateral (C5-C7) pectoral nerves
Action: Flexion, adduction, and medial rotation of arm
Origin, insertion, innervation, and action of pectoralis minor?
Origin: Ribs 3-5
Insertion: Coracoid process
Innervation: Medial pectoral nerve (C8,T1)
Action: Pulls tip of shoulder down and protracts scapula, mainly stabilization function
Origin, insertion, innervation, and action of subscapularis?
Origin: Subscapular fossa
Insertion: Lesser tuberosity of humerus
Innervation: Upper and lower subscapular nerves (C5, C6)
Action: Internal rotation of arm
Origin, insertion, innervation, and action of teres major?
Origin: lateral scapular border, inferiorly
Insertion: Medial lip of intertubercular groove (pec major inserts on lateral lip)
Innervation: LOWER subscapular nerve (C5, C6)
Action: Internal rotation and adduction of arm. Extends a flexed arm.
Origin, insertion, innervation, and action of teres minor?
Origin: lateral scapular border superior to teres major
Insertion: Inferior facet of greater tubercle
Innervation: Axillary nerve (C5, C6) (along with deltoid)
Action: Chief external rotator of arm at 90 degrees abduction.
Origin, insertion, innervation, and action of latissimus dorsi?
Origin: Spinous processes of T6-LV5, sacrum, iliac crest
Insertion: Intertubercular groove
Innervation: Thoracodorsal (C6-C8), also called middle subscapular
Action: Extends, adducts, and medially rotates humerus
What are the origin, insertion, innervation, and action of the biceps brachii?
Origin: Long head from superglenoid tubercule, short head from coracoid process
Insertion: Radial tuberosity of radius
Innervation: Musculocutaneous nerve (C5-C7)
Action: Flexor of forearm, major supinator of forearm, minor flexor of arm through short head
What are the origin, insertion, innervation, and action of the coracobrachialis?
Origin: coracoid process
Insertion: medial mid-shaft humerus
Innervation: Musculocutaneous nerve (C5-C7)
Action: flexor of arm
What are the origin, insertion, innervation, and action of the brachialis?
Origin: Anterior humeral shaft
Insertion: tuberosity of ulna
Innervation: Musculocutaneous nerve (C5-C7)
Action: flexor of arm
What are the origin, insertion, innervation, and action of the deltoid?
Origin: Spine of scapula, acromion, lateral 1/3 of clavicle
Insertion: Deltoid tuberosity
Innervation: Axillary nerve (C5,C6), same as teres minor
Action: Abduction, flexion, and extension of arm. Can also rotate internally / externally.
What muscles does the median nerve innervate proximal to the wrist?
Palmaris longus
FCR, FDS, FDP (lateral 1/2), FPL
Pronator quadratus
Pronator teres
What muscles does the median nerve innervate distal to the wrist?
LOAF
L - lumbricals (1st/2nd)
OAF = thenar muscles
O = opponens pollicis
A = ABductor pollicus brevis (adductor by ulnar nerve)
F = Flexor pollicis brevis (superficial head)
What nerve innervates brachioradialis?
RADIAL nerve
-> the only flexor of the forearm innervated by non-musculocutaneous.
What muscles does radial nerve innervate other than brachioradialis?
Anconeus
ECRL / ECRB
Supinator
All other useless extensors of the wrist
What muscles does the ulnar nerve innervate proximal to the wrist?
Flexor carpi ulnarus
Flexor digitorum profundus (medial 1/2)
What muscles does the ulnar nerve innervate distal to the wrist?
Adductor pollicius DEEP head of flexor pollicis brevis Dorsal / palmar interossei Medial two lumbricals Hypothenar muscles (adductor, opponens, flexor)
What are the borders of the quadrangular space?
Medial: Long head of triceps
Lateral: Humeral shaft
Inferior: Teres major
Superior: Teres minor
What are the contents of the quadrangular space?
Axillary nerve
Posterior circumflex humeral artery
What are the borders of the triangular space and what is the content?
Lateral: Long head of triceps
Superior: Teres minor
Inferior: Teres major
Contents: Circumflex scapular artery
What are the borders and contents of the triangular interval?
Superior: Teres major
Medial: Long head of triceps
Lateral: Shaft of humerus
Contents: Radial nerve and profunda brachii artery (deep brachii)
What is injured in Erb’s palsy and how will the arm look?
Think Erb-dUchenne palsy -> Upper trunk traction / tear = C5/C6
Loss of suprascapular nerve, musculocutaneous nerve, axillary nerve
Unable to flex, supinate, abduct, or externally rotate arm:
Extended arm, held at side, internally rotated, in pronation = Waiter’s tip
What is the mechanism of action of Erb’s palsy in infants and adults?
Infants - Pulling laterally on neck during delivery injuries the opposite side (upper trunk separates). Most common
Adults - trauma which separates head from shoulder during fall
What nerves are affected in Klumpke’s Palsy?
kLumpke’s = Lower trunk tear or traction = C8-T1
Affects especially the ulnar nerve, as well as the distal median nerve (proximal flexors affected less than distal hand muscles)
What is the cause of Klumpke’s palsy mechanically and what defect is typically seen?
Traction / forced abduction of arm -> i.e. catching a treebranch in adulthood or forcing arm upward during delivery of an infant
Total claw hand is seen: loss of medial and lateral lumbricals
- > extension and MCP joints and flexion and PIP and DIP joints
- > wrist is also extended (loss of FCU)
What is thoracic outlet syndrome and what causes it?
Compression of lower trunk of the brachial plexus (like Klumpke’s palsy) also with involvement of subclavian vessels
Causes: Pancoast tumor, cervical rib (rib growing from C7)
What are the symptoms of thoracic outlet syndrome?
Due to lower trunk involvement -> Klumpke’s palsy
Ischemia, pain, and edema of upper extremities due to compression of subclavian vessels in arms
What causes medial vs lateral scapular winging?
Medial - absent pull of serratus anterior towards chest wall -> medial border protrudes. Due to long thoracic nerve dysfunction.
Lateral - absent retraction and elevation by trapezius - shoulder droops down. Due to CN11 dysfunction
Which way will fragments be pulled in clavicle fracture?
Medial fragment is pulled posterosuperiorly by SCM
Lateral fragment is pulled inferolaterally by pec major and weight of arm.
What are the muscles of the rotator cuff?
SITS: Supraspinatus Infraspinatus Teres Minor Subscapularis
What tests are used to assess supraspinatus and infraspinatus?
Supraspinatus - positive empty can test
Infraspinatus - Weakness to external rotation at neutral position
Where is teres minor commonly injured, and how is the muscle tested?
Tested by external rotating during 90 degrees of abduction
Commonly injured by compression of axillary nerve as it runs through quadrangular space
Which way does the shoulder typically dislocate and how does it happen?
Usually an anterior dislocation
Secondary to trauma, seizures, or electrocution
Which nerve is typically injured in shoulder dislocation and what are the symptoms?
Typically the axillary nerve
-> deltoid / teres minor wasting with paresthesias
What are the clinical features of pectoralis major tear?
Ecchymosis, pain, and weakness with adduction, flexion, and internal rotation of humerus
What are the primary nerves affected in proximal, medial, and distal humerus fractures?
ARM: From proximal to distal
A - axillary
R - radial
M - median
What are the symptoms / complications of proximal humerus fractures?
Pain, decreased range of motion, axillary nerve damage: deltoid atrophy
Complications: avascular necrosis of humeral head
What will be the symptoms of a mid-shaft fracture of the humerus?
Radial nerve -> wrist drop, loss of elbow, wrist, and finger extension
Decreased grip strength -> extension of wrist needed to maximally activate finger flexors
Loss of sensation over posterior arm / forearm and dorsal hand (lateral 3 and 1/2 fingers except tips)
What type of fracture do kids often get when playing on monkeybars / trampolines?
Supracondylar fractures
What are the two types of supracondylar fractures, and which is most common? How do you tell them apart?
Extension - most common - line of humerus will be anterior to capitulum on X-ray
Flexion - line of humerus will be posterior to capitulum (end of humerus) on X-ray -> indicates arm was flexed during injury
What nerves are injured in extension type supracondylar fractures? What direction will injure each?
Extension type: Humerus is displaced anteriorly -> damage nerves anterior to elbow.
Anteromedial -> median nerve is injured
Anterolateral -> radial nerve is injured
What nerve is injured in flexion type supracondylar fractures? How do you check the integrity of this after surgery?
Rarer -> ulnar nerve
-> make the patient fan their fingers out then make a fist -> responsible for interosseous muscles as well as medial FDP
How do you check the integrity of the median nerve post supracondylar fracture repair?
Make them make an A-ok sign -> flexion of 1st and 2nd digits
What is the cause of nursemaid’s elbow? How will the patient present?
Annular ligament around radial head gets caught in the radiohumeral joint when the extended, pronated arm is tugged
Patient will present in pain with arm pronated and slightly flex
How can you fix nursemaid’s elbow?
- Supinate elbow
- Hyperflex the forearm
- > will slip back into position
What are the symptoms of medial vs lateral epicondylitis?
Medial - Golfer’s elbow -> pain with resisted wrist flexion / pronation
Lateral - Tennis elbow -> pain with resisted wrist extension
What is messed up which requires Tommy John surgery and how is it diagnosed?
Ulnar collateral ligament
Valgus force onto lateral elbow causes gapping of medial elbow. Medial elbow will be constantly in pain.
What typically causes a biceps tear and what signs and symptoms will be present?
Excessive eccentric biceps contraction (i.e. lifting furniture) which causes biceps tendon to detach from radial tuberosity
Tests: Hook test (positive if you can’t feel biceps tendon on palpation), reverse popeye deformity (biceps contracts higher up in arm since it isn’t attached distally)
What typically causes a triceps tear and what sign is seen on X-ray?
Excessive eccentric tension on triceps i.e. lifting weight -> triceps detach from olecranon
Flake sign seen on X-ray
-> calcifications at end of triceps (olecranon)
What is the name for the proximal and distal ulnar nerve entrapments?
Proximal - Cubital Tunnel Syndrome -> compression posteriorly around medial epicondyle
Distal - Ulnar Tunnel Syndrome (in Guyon’s canal) -> compression of ulnar nerve as it travels through distal wrist and hand
What is the cause of Guyon canal syndrome?
Classically seen in cyclists due to pressure from handlebars. Also can happen if you break your hamate
(This is ulnar tunnel syndrome)
What are the symptoms of the ulnar nerve intrapments?
Sensory deficits over medial 1.5 fingers, loss of interossei, and clawing of fingers 4/5 (FCU is preserved but lumbricals are not)
Positive Tinel’s sign at elbow for cubital tunnel syndrome, or wrist for Guyon canal.
What is a Greenstick fracture and who gets it?
Common pediatric fracture
-> fracture extends partway through the width of the bone
-> half broken, half bent
(bent like a green twig)
What is a torus fracture?
A compression fracture seen in pediatrics, typically in the radius or ulna
-> immature skeleton is SOFT and compresses (buckles) on itself. Will heal with immobilization.
Also called a buckle fracture
What makes up the roof, floor, ulnar wall, and radial wall of the carpal tunnel?
Roof - transverse carpal ligament
Floor - proximal carpal row (scaphoid, lunate, triquetrum, pisiform)
Ulnar wall: pisiform and hook of hamate
Radial wall: scaphoid and trapezium
Ulnar and radial walls are the most lateral bones from each row
What are the contents of the carpal tunnel?
Median nerve and 9 flexor tendors:
4 FDP
4 FDS
1 Flexor pollicis longus
What is the mnemonic for remembering the carpal bones of the hand?
Some Lovers Try Positions That They Cannot Handle
Scaphoid Lunate Triquetrum Pisiform
Trapezium Trapezoid Capitate Hamate
What are common causes of carpal tunnel syndrome? What is one test for CTS which you haven’t heard before?
- Pregnancy - progesterone swells the synovium (edema)
- Repetitive activity
- Endocrine causes: i.e. acromegaly, myxedema
Remember: Durkan’s test -> press on median nerve for 30 sec
What typically causes a scaphoid fracture and how can you tell when it has happened?
Falling on outstretched hands
Anatomical snuffbox will be palpable
Why is it important to recognize scaphoid fracture early?
80% of blood flow to scaphoid is retrograde = poor blood supply
Can cause non-union of scaphoid (fracture never heals) or avascular necrosis -> predisposes to arthritis very early in life
What bone may be dislocated to cause carpal tunnel syndrome? When should this be fixed?
Lunate -> drops right in the carpal tunnel.
Bone looks like a moon. Needs to be relocated quickly or will cause permanent damage
