MSK Anatomy

eesohbel's version from 2015-08-08 22:57

Rotator Cuff and Elbow

Question Answer
Which Muscles form the Rotator Cuff?Supraspinatus
Teres minor
Abducts the arm initiallySupraspinatus
Laterally rotates the armInfraspinatus and Teres minor
Adducts the armTeres minor and subscapularis
Medially rotates the armSubscapularis
Most common rotator cuff injurySupraspinatus
Failed empty can testSupraspinatus
What is the innervation of the Rotator Cuff?C5-C6
Pain near medial epicondyleGolfer's elbow (from repetitive flexion)
Pain near lateral epicondyleTennis elbow (from repetitive extension
olecranon bursitisgoose egg on elbow
trouble initiating abduction of arminjury to supraspinatus muscle


Question Answer
Wrist bonesSo Long To Pinky Here Comes The Thumb, Scaphoid Lunate Triquetrum Pisiform Hamate Capitate Trapezoid Trapezium (moving away from thumb)
What is the most commonly fractured carpal bonescaphoid and is prone to avascular necrosis
Dislocation of lunatecan cause carpal tunnel syndrome. median nerve damage
Fall on outstretched handscan damage hook hook of hamate and cause ulnar nerve injury
carpal tunnel syndromeentrapment of median nerve in carpal tunnel

Mnemonics Upper Extremity

Question Answer
Nerves damaged in humerus fracture (superior to inferior)ARM (axillary, radial, median)
axillarysurgical neck of humerus
radialmid-shaft of humerus/ head of radius
mediansupracondyle of humerus
Mnemonic for muscles innervated by radial nerve (C5-C8)BEST (brachioradialis, extensor, supinator, triceps brachii)

Upper extremity nerve injuries

NerveStupid shit you did to fuck it upMotor deficitSensory deficitSigns/Shit you should absolutely associated with this injury
Axillary nerveFracture of surgical neck, dislocation of humerus, intramuscular injections, anterior shoulder dislocationDeltoid paralysis (can't abduct arm)Loss of sensation of shoulderFlattened deltoid/circumflex arteries
Radial nerve in spiral grooveMidshaft fracture of humerusPoor extension (wrist, fingers at MCPs), supination, thumb extension and abductionPosterior arm, dorsal hand and thumbWrist drop
Radial nerve in axillaCompressed b/c you don't know how to use crutchesPoor extension (wrist, fingers at MCPs), supination, thumb extension and abductionPosterior arm, dorsal hand and thumbWrist drop
Radial nerve (deep branch)Subluxation of radius (nursemaid's elbow).Cannot supinateNoneArm held flexed and pronated Annular ligament is torn
Recurrent branch of median nerveSuperficial laceration of palmUnopposable thumbNoneApe hand (unopposable thumb)
Ulnar nerve (distal)Trauma to heel of hand, fracture of hook of hamateAbduction and adduction of fingers (including thumb), extension of 4th and 5th fingersMedial 1.5 fingers and hypothenar eminenceUlnar claw
Median nerve (distal)Carpal tunnel, dislocated lunateCarpal tunnel syndrome (poor lateral finger flexion, wrist flexion)Lateral 3.5 fingersulnar deviation of wrist upon wrist flexion
Median nerve (proximal)Fracture of supracondylar humerusOpposition of thumbLateral 3.5 fingers + thenar eminenceApe hand (unopposable thumb)
Anterior interosseus nerveCompressed in deep forearmCan't do pincer graspNoneWeakness of the pincer movement of the thumb and index finger
Ulnar nerve (proximal)Repeated minor trauma, fracture of medial epicondyle of humerusMedial finger and wrist flexionMedial 1.5 fingers and hypothenar eminenceRadial deviation of wrist upon wrist flexion
Lower trunk of brachial plexus
Compression by cervical rib, Pancoast's tumor (Thoracic outlet syndrome)Nothing permanentMedial side of forearm and handKlumpke's palsy (total claw hand); Atrophy of thenar/hypothenar eminences and interosseous muscles, disappearance of radial pulse upon moving head toward opposite side
Upper trunk of brachial plexus C5-C6 rootsBlow to shoulder, trauma during deliveryAbductors, lateral rotators, bicepsNoneErb's palsy (Limb hands by side, medially rotated. Forearm pronated)
Musculocutaneous nerveUpper trunk compressionFlexion of arm at elbowSensation of lateral forearmCan't bend your arm. Sucks to be you.
Long thoracicaxillary node dissection after masectomy, stab woundscannot abduct arm above horizontalnothingWinged scapula damage to serratus anterior

Upper extremity HY

Question Answer
clawing of the ring and little fingersulnar nerve lesion
wasting of the hypothenar eminenceulnar nerve lesion
wasting of the dorsal interosseus musclesulnar nerve lesion
wasting of thenar eminencemedian nerve
wrist dropradial nerve
flexors at the elbowmusculocutaneous
deltoidaxillary nerve
wrist abductionmedian nerve
wrist adductionulnar nerve
finger adduction/abductionulnar nerve
flexion/opposition of thumbmedian nerve
loss of arm abduction greater than 15 degreesaxillary nerve
loss of sensation over thenar eminencemedian nerve
loss of sensation over hypothenar eminenceulnar nerve
muscles of median nerve in the handopponens pollicis, abductor pollicis brevis, flexor pollicis brevis
muscles of ulnar nerve in the handopponens digiti minimi, abductor digiti minimi, flexor digiti minimi
sensory role of musculocutaneouslateral forearm
sensory role of radialposterior surface of arm, forearm, lateral hand
Flexion of thumbmedian nerve
Abduction of thumbradial
Adduction of thumbulnar


Question Answer
unhappy triadACL, MCL and medial meniscus (However, lateral meniscus more common)
prepatellar bursitishousemaid's knee. Can be caused by repeated trauma or pressure from extensive kneeling
baker cystpopliteal fluid collection commonly related to chronic joint disease

Lower extremity nerve injuries

NerveHow to fuck it upMotor DeficitSensory Deficit
FemoralPelvic fracture.Thigh flexion
Leg extension
Anterior thigh
Medial leg
Obturatorpelvic surgeryThigh adductionMedial thigh
Superior glutealPosterior hip dislocation
Thigh abduction
Trendelenburg sign! (hip drops when standing on good foot)
lesion is contralateral to the side of the hip that drops, ipsi to extremitity on which patient stands
Inferior glutealPosterior hip dislocation.Hip extension
Can't jump, climb stairs, rise from seated position.
Sciatic NerveIntervertebral disc herniation
Spinal stenosis
Extend hip
Flex knee
Posterior thigh
Gluteus bootyus
Lower leg except medially
TibialKnee trauma.Invert and plantarflex the Foot
Flex Toe flexion
Can't stand on toes!
Sole of foot loss of sensation
(Back of calf)
Remember TIP
Tibial Inverts and Plantarflexes if injured can't step on TIPtoes
Common peroneal (Fibular)Trauma to lateral leg, fibula neck fracture.Foot eversion and dorsiflexion
Extend toe extension
Foot drop!
affects tibialis anterior muscle
Lateral Lower leg
Dorsal foot loss of sensation
Remember PED
Peroneal Everts and Dorsiflexes

HY Lowers

Question Answer
adduction of the thighobturator nerve
abduction of the thighsuperior gluteal and femoral nerves
flexion of the thighpsoas, iliacus, satorius and tensor fascia lata
extension of the thighgluteus maximus and inferior gluteal nerve
extension of the legquadriceps
landmark for pudenal nerve blockischial spine
knee extensionfemoral nerve
knee flexionsciatic nerve
hip adductionobturator
hip abductionsuperior gluteal
fracture at neck of fibuladamage peroneal nerve

Male Sexual Response

Question Answer
Erectionparasympathetic fibers via the pelvic nerve
Emissionsympathetic fibers via the hypogastric nerve
Ejaculationmediated by visceral and somatic nerve (ie pudenal)
Point and ShootErection (PNS) and Emission (Sympathetic)
ordererection, emission, ejaculation
bicylist what willl be damaged in erectal dysfunctionpudenal
spinal cord injuryusually parasympathetic aka pelvic nerve


Question Answer
intraabdominal pressure exceeds urethral sphincter pressurestress
loss of urethral supportstress
leaking with sneezing, coughing, laughing, liftingstress
detrusor overactivityurge
overwhelming frequent need to empty bladderurge
impaired detrusor contractilityoverflow
bladder outlet obstructionoverflow
constant involuntary dribbling of urineoverflow
incomplete emptyingoverflow
treatment for urge incontinenceantimuscarinic (M3 receptor) meds --> decrease IP3 --> decrease Ca release --> relaxation
urge continencegive oxybutinin (muscaranic anatongist)
outflow incontinence (BPH)zosin, but give finasteride to shrink the prostate
someone who cannot pee after surgery or atonic bladder (urinary retention)bethanechol (muscarinic agonist)
stress incontinencegive alpha agonist

Defecation Reflex

Question Answer
damage to pelvic splanchnic nerves (ps)blocks defecation reflex
damage to internal anal sphincter (damaged sym)fecal incontinence
damage to external anal sphincterpudenal nerve
damage to rectumblocks contract of external anal sphincter

Signs of lumbrosacral radiculopathy

Question Answer
L3-L4weakness of knee extension, decreased patellar reflex (femoral nerve)
L4-L5weakness of dorsiflexion, difficulty in heel walking (peroneal nerve)
L5-S1weakness of plantar flexion, difficulty in toe-walking, decreased achilles reflex (tibial nerve)

Neurovascular pairing

axillalong thoraciclateral thoracic
surgical neck of humerusaxillaryposterior circumflex
midshaft of humerusradialdeep brachial
digital humerusmedianbrachial
popliteal fossatibialpopliteal
posterior to medial malleolustibialposterior tibial

Arteries of the Lower extremities

Question Answer
Common Iliac bifurcates intoExternal and Internal Iliac
FemoralPopliteal and Posterior tibial (Posterior leg)
Anterior tibial arteryAnterior Leg Compartment
Dorsalis PedisAnterior foot
Posterior TibialFibular artery aka Peroneal
avascular necrosis of femoral headmedial circumflex femoral artery


Question Answer
Flattened DeltoidAxillary nerve
Wrist DropRadial nerve in Spiral groove or Axilla
Arm held flexed and pronatedDeep branch of the Radial nerve
Claw hand (Extended MCP, Flexed IP in 4th/5th fingers)Ulnar nerve
Hypothenar wastingUlnar nerve
Ape hand (Unopposable thumb)Recurrant branch of Median
Hand of Benediction when making a fist (Can't flex fingers 2+3)Median
Carpal Tunnel (numb first 3.5 fingers)Median
Can't bend armMusculocutaneous
Weak pincers of thumb and index fingerAnterior Interosseus Nerve
Winged ScapulaLong thoracic (Nothing connecting to Serratus)
Waiter's Tip (Arm by side, medial rotated and pronated)Erb Duchenne Palsy (C5-C6)
C5-C6Paralysis of Lat. Rotator, Abductors and Biceps
Claw hand, Ulnar atrophy, Lose radial pulse with head turnKlumpke palsy (C8-T1)
Anterior shoulder injury damages which nerve and artery?Axillary nerve
Posterior Circumflex artery
Mid shaft of humerusRadial nerve
Surgical Neck of humerusAxillary nerve
Can't kick a ballFemoral nerve
Can't climb up stairsInferior gluteal n.
Trendelenberg gait (hip drops on on good foot)Superior gluteal N.
muscles affected in trendelenburg gaitgluteus medius and minimus
Herniated DiscSciatic N.
Foot DropFibular (Common Peroneal): Common and deep
Can't stand on Toes (decreased plantar flexion)Tibial
Fracture of neck of FibulaCommon Fibular
Habitual leg crossingCommon Peroneal (Fibular)
saturday night palsy or injury from crutchesradial nerve injury (wrist drop)
anterior dislocation of hipobturator nerve
supracondyl humerus fracturemedian
midshaft break of humerus arterybrachial artery
loss of forearm pronationmedian
cannot adduct abduct fingersulnar nerve
weak external rotation of armaxillary
unable to abduct beyond ten degreesaxillary
Psoas abscessfever, back pain, inguinal mass and difficulty walking
Psoas sighnpain when hip is extended
supracondylar fracture of the femur blood supplypopliteal artery
dislocated lunate compresses what nervemedian nerve
sciatic nerveL4-S3
mc ligament in ankle sprainanterior talofibular ligament


Question Answer
C2Face & scalp
C5Around clavicles, lateral arm (ant & post) (sup. of abducted limb)
C6Lateral forearm, thumb (ant. & post)
C7Middle three fingers (ant. & post.)
C8Little finger, medial hand & middle stream of posterior forearm (inf. of abducted limb)
T1Ulnar end to Tricep
T2Tricep , axilla to 2nd ICS
T33rd & 4th ICS
T4Nipple level (4th & 5th ICS)
T5Infra-mammary fold (5th & 6th ICS)
T6Xiphoid process level
T10Umbilicus level
T12Pubic bone area
L1Inguinal ligament area
L2Deep pocket (upper thigh)
L3Lateral thigh to Medial knee
L4Lateral knee (+ knee cap) to Medial ankle + great toe
L5Lateral calf to Dorsum of foot, big toe
S1Lateral foot then way up to posterior lateral bum
S2Posterior centre of mid-calf to middle part of one bum
S3Perianal area
S4Perianal area (closer to ur asshole)
S5Perianal area (closest to ur asshole)
Loss of S2 through S4loss of anocutaneous rellex symptom of cauda equina syndrome
Loss of S1 and S2sensory loss over posterior leg and thigh
L5 lesionsensory loss over anterior leg
L3 and L4weakness over anterior thigh
L2 lesiongluteal region inferior to the iliac crests

Structures perforating diaphram

Esophagus, vagusT10
Aorta, thoracic duct, azygous veinT12


Question Answer
Cribiform plateCN 1
Optic canal of sphenoidCN II, Opthalmic a., Central Retinal Vein
Superior orbital fissure of sphenoidCN III, IV, V1, VI, Opthalmic v.
Foramen rotundum of sphenoidCN V2
Foramen ovale of sphenoidCN V3
Foramen spinosum of sphenoidMiddle meningeal artery
Internal auditory meatus of temporal/occipitalCN VII, VIII
Jugular foramen of temporal/occipitalCN IX, X, XI, internal jugular v.
Hypoglossal canal of temporal/occipitalCN XII
Foramen magnum of temporal/occipitalCN XI, brain stem, vertebral arteries

Nerve Injury

Question Answer
superomedial buttocksuperior gluteal nerve aka Trendelenberg gait
superomedial, inferomedial and inferolateralsciatic nerve
where to give buttock injectionssuperolateral or anterolateral
anesthesia during childbirthone form is pudenal nerve block
Where to palpate during pudenal nerve blockischial spines
Complete perianal and genital anesthesiapudenal nerve, genitofermoral and ilioinguinal nerves


Clinical Reflexes:
Question Answer
S1achilles reflex
L3, L4patellar reflex
C5biceps reflex
C6brachioradialis reflex
C7, C8triceps reflex (triceps brachii via radial nerve)

Jaw Injury

Question Answer
mandibular fractureinferior alveolar and mental nerves. Branches off of V3.

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