Anatomy Flashcards
Anatomical planes
Median:
- midline plane that divides into L and R halves
Sagittal:
- divides into L and R parts
- infinite number of sagittal planes parallel to mid-sagittal plane
Coronal:
- divides into front and back
- aka frontal plane
Transverse:
- divides into top and bottom
- aka horizontal plane, aka axial plane
Levator scapula
spacular elevation
dorsal scapular n.
Rhomboid minor/major
scapular elevation, retraction
dorsal scapular n.
Latissumis dorsum
arm extension, adduction, medial rotation
thoracodorsal n.
Deltoids
arm abduction
axillary n.
Trapezius
upper fibers: scapular elevation, upward rotation
middle fibers: scapular retraction
lower fibers: scapular depression, upward rotation
accessory n.
Intermediate back muscles
serratus posterior superior, serratus posterior inferior
respiratory muscles
Deep/intrinsic intermediate muscles
erector spinae: spinalis, iliocostalis, longissimus
vertebral column and head movements
Shoulder ligaments, muscles
Ligaments:
- acromioclavicular ligament (weak)
- coracoacromial ligament (weak)
- coracoclavicular ligament (strong) <- if torn, you get a 3rd degree shoulder separation
Rotator cuff muscles:
- supraspinatus
- infraspinatus
- teres minor
- subscapularis
Supraspinatus
rotator cuff muscle; initial abduction (0˚-15˚)
suprascapular n.
empty can test
- supraspinatus travels deep to the coracoacromial arch; the proximity of the bones and ligaments of this arch makes the supraspinatus easily injured
- most commonly injured rotator cuff muscle
Infraspinatus
rotator cuff; lateral rotation of arm
suprascapular n.
Subscapularis
medial rotation of arm
upper and lower subscapular n.
Teres minor
lateral rotation
axillary n.
Teres major
medial rotation, extension
lower subscapular n.
Axillary n.
C6, C7 (posterior cord of brachial plexus)
innervates deltoid, teres minor
innervates skin of lateral upper arm
injured in humerus fracture of surgical neck
Axillary foramens
Suprascapular foramen - suprascapular n.
Quadrangular space - axillary n., posterior circumflex humeral a.
Triangular space - circumflex scapular a.
Triangular interval - radial n., profunda brachii a. (mid-shaft humeral fracture)
Pectoralis major
arm adduction, flexion, medial rotation
medial & lateral pectoral n.
Pectoralis minor
shoulder depression, scapular protraction, forced inspiration
medial pectoral n.
Subclavicus
clavicular depression
n. to sublavicus
Serratus anterior
spacular protraction and rotation, holds scapula to thoracic wall
long thoracic n.
winged scapula
Clavipectoral/Deltopectoral triangle
hole in clavipectoral fascia that allows cephalic vein to exit axilla
Veins down arm/forearm
medial cubital vein ==> cephalic v. (lateral) + basilic v. (medial)
basilic v. ==> axillary v. ==> subclavian v.
Axillary artery
starts at 1st rib and ends below teres major
3 parts:
1. 1st rib to superior aspect of pectoralis minor
2. superior aspect of pec minor to inferior aspect
3. inferior aspect of pec minor to teres major
1st part of axillary a.
superior thoracic a.
2nd part of axillary a.
thoraco-acromial a.
lateral thoracic a.
3rd part of axillary a.
subscapular a.
- circumflex scapular a.
- thoracodorsal a.
anterior circumflex humoral a.
posterior circumflex humoral a.
Subclavian artery
above axillary artery:
suprascapular a.
dorsal scapular a.
creates anastamoses with 3rd part of axillary a.
Axillary lymph nodes
[humeral (lateral) + pectoral (anterior) + subscapular (posterior) nodes] ==> central nodes ==> apical nodes
Coracobrachialis
arm flexion
- attaches to coracoid process and midshaft of humerus
musculocutaneous n.
Brachialis
forearm flexion
musculocutaneous n.
Biceps brachii
short and long head (long head tendon more commonly ruptured <- popeye sign)
forearm flexion and supination; accessory muscle for arm flexion
musculocutaneous n.
Triceps brachii
forearm extension
long head also does arm extension and adduction
radial n.
Musculocutaneous n.
C5, C6, C7 (lateral cord of brachial plexus)
pierces coracobrachialis and goes between biceps and brachialis; ends as cutaneous nerve of lateral forearm
coracobrachialis, brachialis, biceps bracii
Radial n.
C5, C6, C7, C8, T1 (posterior cord of brachial plexus)
posterior cord of brachial plexus, travels through triangular interval and goes along radial groove on humerus
innervates triceps brachii, posterior forearm muscles (extensors)
Brachial a.
continuation of axillary artery, from bottom of teres major to cubital fossa (radius neck)
branches into profunda brachii a. (triceps), which passes through triangular interval
profunda brachii a. ==> radial & middle collateral a.
Afferent vs. efferent neurons
Afferent = sensory
- dorsal root ganglion (posterior)
- somatic: pain, touch, proprioception
- visceral: organs
Efferent = motor
- ventral root (anterior)
- somatic: skeletal muscle
- visceral: smooth muscle, cardiac muscle, glands
Spinal nerves & vertebrae
spinal nerves C1-C7 emerge superior to pedicle of corresponding vertebrae
spinal nerves C8, T1-T12, L1-L5, S1-S5, Co emerge inferior to pedicle of corresponding vertebrae
Cauda equina
nerve roots suspended in CSF, below L2
spinal cord ends around L1-L2 (lumbar cistern)
- lumbar punctures ideally between L3-L4 or L4-L5
- anatomical landmark for L4: iliac crest
Brachial plexus
Real Teachers Drink Cold Beer:
- Roots (C5-C8, T1)
- Trunks (superior, middle, inferior)
- Divisions (anterior, posterior)
- Cords (lateral, posterior, medial)
- Branches (musculocutaneous, median, radial, axillary, ulnar)
3 musketeers assassinated 5 rats, 5 mice, and 2 unicorns
- musculocutaneous: C5, C6, C7
- axillary: C5, C6
- radial: C5, C6, C7, C8, T1
- medial: C5, C6, C7, C8, T1
- ulnar: C8, T1
Brachial plexus: Lateral cord
- lateral pectoral n.
- musculocutaneous n.
- lateral root of median n.
Brachial plexus: Medial cord
- median n.
- medial pectoral n.
- ulnar n.
- medial cutaneous n.
Brachial plexus: Posterior cord
- superior subscapular n.
- inferior subscapular n.
- thoracodorsal n.
- axillary n.
- radial n.
Injury to posterior cord would present with:
- atrophy of posterior axillary muscles
- atrophy of shoulder muscles
- inability to extend arm/forearm
- wrist drop
Erb-Duchenne Paralysis
- traction injury to upper trunk of brachial plexus (C5, C6)
- axillary n. completely affected
- adducted shoulder, extended elbow, internally rotated arm, waiter’s tip hand
Klumpke Paralysis
- traction injury to lower trunk of brachial plexus (C8, T1)
- caused by excessive abduction of arm (hanging injury)
- ulnar n. completely affected
- median n. and radial n. also affected
- complete claw hand (4 digits affected) <- opposite actions of lumbricals
Radiculopathy vs. peripheral nerve injuries
Radiculopathy = damage to nerve roots where they leave the spine
- check dermatomes, myotomes, reflexes
Peripheral nerve injuries = damage in peripheries
- check specific nerve functions (motor & sensory)
Cubital fossa contains:
from medial to lateral:
1. ulnar n. (posterior to humerus)
2. median n. (middle of cubital fossa)
3. brachial a.
4. biceps tendon (attaches to radius)
5. radial n. (anterior to humerus)
superior: median cubital v.
Superficial anterior muscles of forearm
- pronator teres
- flexor carpi radialis
- palmaris longus
- flexor carpi ulnaris
median n. innervates all of them except flexor carpi ulnaris, which is innervated by the ulnar n.
Attachment: medial epicondyle of humerus
- golfer’s elbow
Pronator teres
forearm flexion and pronation
median n.
Flexor carpi radialis
wrist abduction and flexion
median n.
Palmaris longus
wrist flexion
median n.
Flexor carpi ulnaris
wrist adduction and flexion
ulnar n.
Intermediate & deep anterior muscles of forearm
Intermediate:
- flexor digitorum superficialis
Deep:
- flexor digitorum profundus
- flexor pollicis longus
- pronator quadratus
all innervated by median n. (or anterior interosseous branch of median n.), except for digits 4-5 of flexor digitorum profundus (ulnar n.)
Flexor digitorum superficialis
flexion of digits 2-5 at PIP
median n.
Flexor digitorum profundus
flexion of digits 2-5 at DIP (attach to lumbricals)
- the only muscle that flexes the DIP joints
digits 2-3: anterior interosseous n.
digits 4-5: ulnar n.
Flexor pollicis longus
thumb IP flexion
anterior interosseous n.
Pronator quadratus
forearm pronation
anterior interosseous n.
Median n.
C5, C6, C7, C8, T1 (from lateral and medial cords of brachial plexus)
passes under flexor retinaculum (carpal tunnel)
- palmar branch passes superior to flexor retinaculum <- not affected in carpal tunnel syndrome
sensory: lateral palm + lateral 3.5 digits
motor: anterior forearm flexors (except flexor carpi ulnaris and digits 4-5 of flexor digitorum profundus)
Dupuytren’s disease
abnormal thickening of palmar aponeurosis, causing flexion of MCP joints (4th and 5th digits most commonly affected)
Thenar muscles
- abductor pollicis brevis
- flexor pollicis brevis
- opponens pollicis
all innervated by median n.
Hypothenar muscles
- abductor digiti minimi
- flexor digiti minimi
- opponens digiti minimi
- palmaris brevis (wrinkles skin of medial palm)
all innervated by ulnar n.
Lumbricals
connect from flexor digitorum profundus; do MCP flexion and PIP/DIP extension
- claw hand if nerve lesion affects lumbricals
lateral digits 1-2: median n.
medial digis 3-4: ulnar n.
Deep palm muscles
- abductor pollicis
- palmar interossei
- dorsal interossei
all innervated by ulnar n.
Abductor pollicis
abduction of thumb
ulnar n.
Palmar interossei
adduction of digits 2, 4, 5
ulnar n.
Dorsal interossei
Abduction of digits 2, 4, 5
ulnar n.
Tenosynovitis (Trigger finger)
inflammation of synovial sheaths; fingers stuck in flexion
Carpal tunnel
median n. affected
intermediate/deep flexor tendons travel beneath flexor retinaculum:
- flexor pollicis longus
- flexor digitorum superficialis
- flexor digitorum profundus
Tinel’s sign (tapping), Phalen maneuver (wrist flexion for 60s)
Anterior interosseous n. syndrome (AINS)
median n. lesion affecting lateral flexor digitorum profundus and flexor pollicis longus
OK sign is flattened
Pope’s hand
flexor digitorum profundus (lateral) and flexor digitorum superficialis affected
digits 1-2 don’t flex when trying to make a fist
Supracondylar fracture of humerus
most common pediatric elbow fracture
- FOOH
compression of medial n. and brachial a. ==> weak forearm flexors and pronators
Nursemaid’s elbow
radial head subluxation (partial dislocation) at proximal radio-ulnar joint
annular ligament slips over head of radius
Ulnar n.
C8, T1 (from medial cord of brachial plexus)
passes over flexor retinaculum, under Guyon’s canal (ulnar tunnel)
- deep branch goes to palm
- superficial branch goes to digits
sensory: medial palm/dorsum + medial 1.5 digits
motor: flexor carpi ulnaris and digits 4-5 of flexor digitorum profundus
Ulnar claw
loss of medial lumbricals (4-5)
MCP extension + IP flexion
Ulnar paradox: ulnar claw is less severe in proximal lesions (elbow) than distal lesions (wrist) because the IP joints are left intact in proximal lesions
Guyon’s canal syndrome
caused by direct pressure on ulnar n. near wrist (bicyclists)
Anterior forearm/palm arteries
Brachial a. ==> radial a. (lateral) + ulnar a. (medial)
- Radial a. passes by flexor carpi radialis tendon and goes to supply deep palmar arch + lateral 1.5 digits
- Common interosseous a. branches off of ulnar a.
- Ulnar a. goes to supply superficial palmar arch + medial 3.5 digits
Posterior forearm/hand blood supply
Common interosseous a. (from ulnar a.) ==> anterior interosseous a. + posterior interosseous a.
- posterior interosseous a. ==> dorsal arch
- radial a. comes from anterior forearm and passes through anatomical snuffbox
Basilic v. + cephalic v. ==> dorsal venous arch
- cephalic venipuncture
Superficial posterior forearm muscles
- brachioradialis
- extensor carpi radialis longus
- extensor carpi radialis brevis
- extensor digitorum
- extensor digiti minimi
- extensor carpi ulnaris
all innervated by branches of radial n.
Attachment: lateral epicondyle
- tennis elbow
Brachioradialis
forearm flexion in midpronated position
radial n.
Extensor carpi radialis longus & brevis
wrist extension and abduction
extensor carpi radialis longus: radial n.
extensor carpi radialis brevis: deep branch of radial n.
Extensor digitorum
extension of digits 2-5
posterior interosseous n. (from deep branch of radial n.)
Extensor digiti minimi
extension of 5th digit
posterior interosseous n.
Extensor carpi ulnaris
wrist extension and adduction
posterior interosseous n.
Deep posterior forearm muscles
- supinator
- adductor pollicis longus
- extensor pollicis brevis
- extensor pollicis longus
- extensor indicis
all innervated by branches of radial n.
Supinator
forearm supination
deep branch of radial n.
Adductor pollicis longus
thumb base extension and abduction
posterior interosseous n.
Extensor pollicis brevis
thumb MCP extension
posterior interosseous n.
Extensor pollicis longus
thumb MCP and IP extension
posterior interosseous n.
Extensor indicis
digit 2 extension
posterior interosseous n.
Anatomical snuffbox
FOOH: scaphoid fracture leads to swelling and pain in anatomical snuffbox
- most common fractured carpal bone
- radial a. injury ==> avascular necrosis of proximal scaphoid
cephalic v. passes superficial to snuffbox
radial a. passes through snuffbox
Lunate dislocation
rare; lunate is displaced and rotated volarly (90˚)
carpal tunnel compression ==> median n. compression
DeQuervain tenosynovitis
overuse of abductor pollicis longus and extensor pollicis brevis (forceful gripping)
- inflammation of compartment 1 (most lateral), inferior to extensor retinaculum
Finkelstein’s test (ulnar adduction + thumb flexion)
Radial n.
passes through triangular interval to radial groove (posterior arm), then lateral forearm (along radius)
Radial n. ==> deep branch + posterior interosseous n. + superficial branch (sensory to dorsum of lateral hand)
Saturday night palsy
compression of radial n. at triangular interval
triceps brachii affected (elbow extension)
Midshaft humerus fracture
wrist drop, lateral dorsal hand sensory loss
triceps/elbow extension not affected, posterior arm/forearm sensation intact
Radial head fracture / Compression between supinator heads
deep branch of radial n. compressed
no wrist drop:
- extensor carpi radialis longus stays intact
- extensor carpi radialis brevis affected
UE dermatomes & myotomes
Dermatomes:
C4 - skin over shoulder tip
C5 - upper lateral arm
C6 - thumb
C7 - index finger
C8 - pinky finger
T1 - medial elbow
T2 - skin of axilla
Myotomes:
C5 - shoulder abduction
C6 - elbow flexion
C7 - elbow extension
C8 - finger flexion
T1 - finger abduction/adduction
C4 dermatome
skin over shoulder tip
C5 dermatome/myotome
Derm: upper lateral arm
Myotome: shoulder abduction
C6 dermatome/myotome
Derm: thumb
Myotome: elbow flexion
C7 dermatome/myotome
Derm: index finger
Myotome: elbow extension
C8 dermatome/myotome
Derm: pinky finger
Myotome: finger flexion
T1 dermatome/myotome
Derm: medial elbow
Myotome: finger abduction/adduction
T2 dermatome
skin of axilla
UE tendon reflexes
C5-6 roots - biceps reflex
C6 roots - brachioradialis reflex
C7 - triceps reflex
Lumbar plexus innervates
anterior compartment of thigh (femoral n.)
medial compartment of thigh (obturator n.)
Sacral plexus innervates
gluteal muscles (superior/inferior gluteal n.)
anterior/lateral leg and foot (common fibular n.)
posterior leg and foot (tibial n.)
Lateral cutaneous n. of thigh
branch of lumbar plexus, passes under inguinal ligament
supplies skin of lateral thigh
Meralgia paresthetica:
- compression of lateral cutaneous n. (low-waisted jeans)
Lymphatics of LE
Superficial inguinal nodes:
- along inguinal ligament and great saphenous v.
- drain into external iliac nodes (higher up in hip region)
Deep inguinal nodes:
- associated with femoral vessels (within femoral triangle)
- drain into external iliac nodes
Popliteal nodes:
- along popliteal a., receives lymph along small saphenous v.
- drain into inguinal lymph nodes
Anterior thigh muscles
- iliopsoas: iliacus, psoas major
- sartorius
- tensor fascia lata (attaches to iliotibial tract)
- quadriceps femoris: rectus femoris, vastus lateralis, vastus medialis, vastus intermedius
all innervated by femoral n.
Iliopsoas
primary hip flexor:
- iliacus (attaches to iliac crest)
- psoas major (attaches to vertebrae T12-L5)
iliacus innervated by femoral n.
psoas major innervated by lumbar plexus
Sartorius
tailor’s muscle; flexion and lateral rotation of thigh and leg (criss cross apple sauce)
- attaches to anterior superior iliac spine (lateral)
- crosses thigh diagonally and goes all the way down to superficial pes anserinus (goose’s foot), on medial side of knee
femoral n.
Tensor fascia lata
thigh abduction, medial rotation, flexion
femoral n.
Quadriceps femoris
thigh flexion and leg extension:
- rectus femoris
leg extension:
- vastus lateralis
- vastus medialis
- vastus intermedius
femoral n.
Femoral triangle contains:
VAN (medial to lateral):
1. femoral ring
2. femoral v.
2. femoral a.
3. femoral n.
Femoral ring contains lymphatics, is a potential site for femoral hernia
Femoral canal opens up to saphenous opening, through which great saphenous v. enters femoral triangle and becomes femoral v.
Femoral sheath becomes adductor canal, which connects femoral triangle with popliteal fossa
Femoral n.
largest branch of lumbar plexus
- passes between iliacus and psoas major muscles
innervates all anterior thigh muscles except psoas major
branches into anterior cutaneous n. and saphenous n. (skin of medial leg and foot)
Femoral a.
From femoral triangle, continues through adductor canal and becomes popliteal a.
Branch: Deep femoral a. (posterior)
- lateral and medial circumflex femoral a. (loop around proximal femur, supplying hip)
- perforating branches (supply posterior thigh)
Medial thigh muscles
- obturator externus
- gracilis
- pectineus
- adductor longus
- adductor brevis
- adductor magnus
- adductor minimus
all innervated by obturator n. except for pectineus (femoral n.) and hamstring portion of adductor magnus (sciatic n.)
Obturator externus
thigh lateral rotation (attaches to obturator foramen)
obturator n.
Gracilis
thigh adduction, leg flexion and internal rotation
- attaches to pubis
- goes all the way down to superficial pes anserinus (goose’s foot), on medial side of knee
obturator n.
Pectineus
thigh adduction
- attaches to superior pubic ramus
obturator n. and femoral n.
Adductors
thigh adduction:
- adductor longus
- adductor brevis
thigh adduction and extension:
- adductor magnus
all innervated by obturator n.
hamstring part of adductor magnus: tibial n. (sciatic n. branch)
Obturator n.
branch of lumbar plexus, passes through obturator canal
innervates all muscles of medial thigh except pectineus and hamstring part of adductor magnus
innervates skin of upper medial thigh
Hip joint ligaments & blood supply
Hip & femoral ligaments: limit hip extension
- pubofemoral ligament
- iliofemoral ligament
- ischiofemoral ligament (deep)
Femoral head:
- transverse acetabular ligament
- ligament of the head of the femur (contains artery of ligament of head)
Lateral and medial circumflex femoral a.
- from deep branch of femoral a.
Femoral head fracture
Posterior dislocation is most common (eg, a dashboard injury):
- adduction and internal rotation of extremity
If accompanied by anterior dislocation:
- abduction and external rotation of extremity
Trochanteric femoral fracture
Not typically associated with dislocations
Greater trochanteric fracture:
- pain, especially with abduction and extension
- no deformity may be apparent, but pressure through greater trochanters will result in pain
Lesser trochanteric fracture:
- pain occurs during flexion and internal rotation
Gluteus muscles
- gluteus maximus
- gluteus medius
- gluteus minimus
- tensor of fascia lata
all innervated by superior gluteal n. except for gluteus maximus (inferior gluteal n.)
Gluteus maximus
hip extension (standing up from seated position), lateral rotation
- attaches to ilium
- attaches to iliotibial tract (along with tensor fascia lata) and gluteal tuberosity
inferior gluteal n.
Gluteus medius/minimus
hip abduction, medial rotation
- attach to ilium
- attach to lateral surface of greater trochanter of femur
superior gluteal n.
Trendelenburg sign
hip drop on contralateral side due to superior gluteal n. lesion (gluteus medius/minimus)
Tensor of fascia lata
thigh abduction, flexion, lateral rotation
superior gluteal n.
Superior/inferior gluteal n.
branch of sacral plexus
Superior gluteal n.:
- gluteus medius
- gluteus minimus
Inferior gluteal n.:
- gluteus maximus
passes through greater sciatic foramen:
- superior gluteal n. passes above piriformis
- inferior gluteal n. passes below piriformis
Hip external rotator muscles
- piriformis
- obturator internus
- superior/inferior gemellus (stabilize obturator internus tendon)
- quadratus femoris
Piriformis syndrome
Piriformis comes through greater sciatic foramen, potentially entrapping sciatic n.
- sciatic-like symptoms: pain in buttock, wallet sign
Causes:
- trauma to region
- muscle strain ==> fibrosis/scarring around nerve
- variation in sciatic n.
Posterior thigh muscles (hamstrings)
- biceps femoris (long/short heads)
- semitendinosus
- semimembranosus
- hamstring part of adductor magnus
innervated by sciatic n. (tibial n. and common fibular n. branches)
proximal attachment: ischial tuberosity
Biceps femoris
Long head of biceps femoris: medial
- thigh extension, leg flexion
- tibial n.
Short head of biceps femoris: lateral
- leg flexion
- common fibular n.
Semitendinosus
thigh extension, leg flexion and medial rotation
tibial n.
Semimembranosus
thigh extension, leg flexion and medial rotation
tibial n.
Sciatic n.
passes through greater sciatic formamen, below piriformis
innervates posterior thigh, leg, foot
innervates skin of lateral leg, dorsum, sole of foot
branches into common fibular n. (lateral) and tibial n. (medial, through popliteal fossa)
Popliteal fossa contains:
From medial to lateral:
1. popliteal a. (from femoral a.)
2. popliteal v. (branches into small saphenous v., superficial to popliteal fascia)
3. tibial n. (from sciatic n.)
4. common fibular n. (from sciatic n.)
Common fibular n.
comes from sciatic n., branches into deep fibular n. and superficial fibular n.
- deep fibular n.: anterior leg
- superficial fibular n.: lateral leg
Common fibular n. lesion:
- fibular neck fracture
- paralysis of all anterior and lateral leg compartments ==> foot drop (inability to dorsiflex + inversion of foot)
- sensory loss to dorsum and lateral leg
Popliteal a.
- continuation from femoral a., comes through adductor hiatus into popliteal fossa
- superior genicular a. branch wraps around knee joint
- after passing through popliteal fossa, branches into anterior tibial a. (goes down anterior leg) and posterior tibial a. (goes down posterior leg and to tarsal tunnel)
At risk in knee dislocation or distal fracture of femur
Knee joint
- patellar tendon: continuation of quadriceps tendon (rectus femoris), attaches to tibial tuberosity
- lateral/medial menisci
Ligaments:
- fibular/lateral collateral ligament (LCL)
- tibial/medial collateral ligament (MCL)
- anterior cruciate ligament (ACL) <- Lachman (anterior drawer) test
- posterior cruciate ligament (PCL)
Varus force = away from midline
- LCL and lateral meniscus damaged
Valgus force = towards midline
- MCL and medial meniscus damaged
Terrible triad = ACL + MCL + medial meniscus
Anterior leg muscles
- tibialis anterior
- extensor hallucis longus
- extensor digitorum longus
- fibularis tertius (not everyone has)
innervated by deep fibular n.
tendons pass under superior/inferior extensor retinaculum to reach dorsal foot
Tibialis anterior
dorsiflexion, inversion of foot
- attaches to base of first metatarsal and cuneiform
deep fibular n.
Extensor hallucis longus
great toe extension, foot dorsiflexion
deep fibular n.
Extensor digitorum longus
extension of lateral 4 digits, foot dorsiflexion
deep fibular n.
Fibularis tertius
dorsiflexion and eversion
- distal part of extensor digitorum longus
deep fibular n.
Deep fibular n.
comes from common fibular n. (sciatic n.)
innervates anterior leg muscles
innervates skin between great/2nd toe
Deep fibular n. lesion: ski boot syndrome
- anterior leg muscles affected ==> foot drop, steppage gait
- sensory loss between great/2nd toes
Dorsal arteries
anterior tibial a. (from popliteal a.) ==> dorsalis pedis a. ==> deep plantar a. (deep plantar arch)
Dorsal veins
great saphenous v. (branch that goes into femoral n.) is anterior to medial malleolus
small saphenous v. is posterior to lateral malleolus
Lateral leg muscles
- fibularis longus
- fibularis brevis
innervated by superficial fibular n.
pass under fibular retinaculum (on lateral side of foot)
Fibularis longus
eversion and plantarflexion
- after passing through fibular retinaculum, tendon crosses underneath foot ==> attaches at base of first metatarsal and medial cuneiform
superficial fibular n.
Fibularis brevis
eversion and plantarflexion
- after passing under fibular retinaculum, tendon attaches to tuberosity of fifth metatarsal
superficial fibular n.
Superficial fibular n.
branch of common fibular n. (sciatic n.)
innervates lateral leg muscles
innervates skin of dorsum and toes (except between great/2nd toes)
Superficial fibular n. lesion:
- lateral leg muscles affected ==> no foot drop, but plantarflexion/eversion affected
- sensory loss to dorsum of foot
Superficial posterior leg muscles
- gastrocnemius (medial/lateral heads)
- soleus
- plantaris
innervated by tibial n.
Gastrocnemius
plantarflexion, knee flexion
- superior attachment is at femur
- attaches to calcaneal tendon (Achilles tendon)
tibial n.
Soleus
plantarflexion
- attaches to calcaneal tendon
tibial n.
Plantaris
plantarflexion, knee flexion
- superior to soleus muscle
- attaches to calcaneal tendon
tibial n.
Deep posterior leg muscles
- popliteus
- tibialis posterior
- flexor digitorum longus
- flexor hallucis longus
innervated by tibial n.
Popliteal
unlocks knee by laterally rotating femur on tibia, weakly flexes knee
tibial n.
Tibialis posterior
inversion, plantarflexion
tibial n.
Flexor digitorum longus
plantarflexion, flexion of toes 2-5
tibial n.
Flexor hallucis longus
plantarflexion, flexion of great toe
tibial n.
Tibial n.
passes through popliteal fossa ==> posterior leg ==> tarsal tunnel (medial) ==> foot
innervates posterior leg muscles
branches into sural n. and medial calcaneal n., which innervate the skin of:
- sural n.: posterolateral leg, lateral foot, little toe
- medial calcaneal n.: medial/sole of heel
Tarsal tunnel
Tom, Dick, and A Very Nervous Harry: anterior to posterior
1. Tibialis posterior
2. flexor Digitorum longus
3. posterior tibial Artery (palpate posterior to medial malleolus for pulse point)
4. posterior tibial Vein
5. tibial Nerve
6. flexor Hallucis longus
Tarsal tunnel syndrome: compression of tibial n.
- caused by flat feet, ankle sprain swelling, synovial sheath inflammation
Plantar aponeurosis
protects internal structure of foot, supports arch of foot
- attached to calcaneal tuberosity
- can stretch and fall ==> flat foot
plantar fascitis ==> formation of calcaneal spur
Medial & lateral plantar n.
tibial n. enters foot posterior to the medial malleolus
- innervates skin of heel
tibial n. branches into medial plantar n. and lateral plantar n.
- medial plantar n.: more sensory (skin of 3.5 medial toes)
- lateral plantar n.: more motor (skin of 1.5 lateral toes)
First (most superficial) layer of foot
Medial plantar n.:
- abductor hallucis
- flexor digitorum brevis
Lateral plantar n.:
- abductor digiti minimi
Second layer of foot
Medial plantar n.:
- 1st lumbrical (flexion of MTPs, extension of IPs)
Lateral plantar n.:
- 2nd-4th lumbricals
- quadratus plantae (flexion of toes 2-5)
Third layer of foot
Medial plantar n.:
- flexor hallucis brevis
Lateral plantar n.:
- flexor digiti minimi
- adductor hallucis (transverse & oblique heads)
Fourth (deepest) layer of foot
Lateral plantar n.:
- dorsal interosseous (abduction)
- plantar interosseous (adduction)
Medial & lateral plantar a.
branches from posterior tibial a.
- lateral plantar a. forms deep plantar arch
Foot arches
pes cavus = high arches
pes planus = flat footed
Talus fracture
talus = ankle joint bone that articulates with tibia and fibula
fractures at neck of talus often interrupt blood supply ==> osteonecrosis
Ankle sprains
In plantarflexion, the gap between the fibula and talus widens ==> higher risk of sprain on lateral side of ankle (inversion)
Anterior talofibular ligament
- most common lateral ligament sprain
- attaches to fibula and neck of talus
Deltoid ligament
- strong eversion sprain
Potts fracture
Forced eversion ==> bimalleolar/trimalleolar fracture
- bimalleolar: deltoid malleolus, medial malleolus
- trimalleolar: deltoid malleolus, medial malleolus, distal tibial fracture
Herniated discs
herniated discs affect the lower numbered vertebrae:
- Herniated disc between L4 and L5 ⇒ spinal nerve L5 would be affected
- Herniated disc between C5 and C6 ⇒ spinal nerve C6 would be affected
LE dermatomes & myotomes
Dermatomes:
L1 - over inguinal ligament
L2 - lateral thigh
L3 - lower medial thigh
L4 - medial great toe
L5 - medial digit 2
S1 - little toe
S2 - back of thigh
S3 - lower butt cheek (gluteal fold)
S4/S5 - perineum
Myotomes:
L1/L2 - hip flexion
L3/L4 - knee extension
L4/L5 - foot and toe dorsiflexion
S1/S2 - foot and toe plantarflexion
L1 dermatome/myotome
Derm: skin over inguinal ligament
Myotome: hip flexion
L2 dermatome/myotome
Derm: lateral thigh
Myotome: hip flexion
L3 dermatome/myotome
Derm: lower medial thigh
Myotome: knee extension
L4 dermatome/myotome
Derm: great toe
Myotome: foot dorsiflexion
L5 dermatome/myotome
Derm: 2nd toe
Myotome: toe dorsiflexion
S1 dermatome/myotome
Derm: pinky toe
Myotome: plantarflexion
S2 dermatome/myotome
Derm: back of thigh
Myotome: plantarflexion
S3 dermatome
skin over gluteal fold (butt cheek)
S4/S5 dermatome
perineum
LE tendon reflexes
L3, L4 - patellar/knee reflex
S1, S2 - Achilles reflex
