Lower Limb Flashcards
What is the fovea?
Central fovea is present in the femoral head for attachment of the ligamentum teres
What is the blood supply of the femoral head?
medial and lateral femoral circumflex artery - medial is most important
-> comes off the profunda femoris
Ligamentum teres - trivial supply
Comes off obturator A
What is the gross anatomy of the neck of the femur?
Greater trochanter
Lesser trochanter
Intertrochanteric line [anterior]
-> marks hip capsule location
Intertrochanteric crest [posterior]
Shentons line (radiological)
What attaches to the greater trochanter?
gluteus medius
gluteus maximus
obturator internus
obturator externus
superior gemelli
inferior gemelli
piriformis
What attaches to the lesser trochanter?
iliopsoas
What is the gross anatomy of the shaft of the femur?
Linea aspera
Adductor tubercle
What attaches to the linea aspera?
adductor muscles
vastus medialis
vastus lateralis
What attaches to the adductor tubercle?
adductor longus
adductor brevis
adductor magnus
What is the gross anatomy of the shaft of the femur?
medial condyle
lateral condyle
-> intercondylar notch
patella notch
What joints are involved with the femur?
Hip joint - acetabulum of pelvis
Knee joint - patella + tibia
What are the ligaments involved with the femur?
ligamentum teres
Where are the primary ossification centers and the fusion dates for the femur?
Primary ossification center is in shaft of femur at week 7.
Secondary ossification centers -
Distal femoral epiphysis - 9 months
used as an indicator of a baby born at term.
femoral head - 2 - 6 months
greater trochanter - 4 years
lesser trochanter - puberty ~8 years
All ossification centers fuse at age 20.
What is the hip joint?
It is a ball and socket synovial joint
What bones make up the hip joint?
The acetabulum of pelvis + femoral head
What is the ossification and fusion dates for the acetabulum of the pelvis?
It is made up of three bones
-ilium
-ischium
-pubis
Seperated by a tri radiate cartilage Y shaped.
Fuses at year 14
Where does the hip joint capsule extend to?
proximally to acetabulum and labrum
distally - to anterior femur to intertrochanteric line, posteriorly down to 2/3 of the femoral neck
What are the ligaments involved with the hip joint?
ischiofemoral
iliofemoral
pubofemoral
What are the menisci/labrum involved with the hip joint?
Acetabular labrum
- reinforced by transverse acetabular ligament
What are the bursa involved with the hip joint?
Anterior and inferior
Where are the fat pads involved with the hip joint?
between the acetabulum and fovea
What is the arterial supply of the hip joint?
medial and lateral circumflex femoral (from the profunda femoris)
ligamentum teres artery (from obturator) trivial supply
What is the nerve supply of the hip joint?
femoral N
obturator N
What are the anatomical variants associated with the hip joint?
developmental dysplasia of the hip
Labrum variation - triangular/round/absent
Os acetabula - accessory ossicle at superior acetabulum
What is the patella?
It is a diamond shaped bone within the quadriceps tendon
What is the osteology / structure of the patella?
Apex is inferior
- continuous with the patella tendon inferiorly and goes to the tibial tuberosity
Has medial and lateral facets
- articulates with patella groove of femur
Where does the patella sit?
within the quadriceps tendon
What is the fusion date and ossification center of the patella?
Begins at 3 years, and is complete at puberty
Has odd ossification due to bipartite and multipartite patella
What bones articulate with the patella?
Patella with medial and lateral facet
Patella groove of the femur
What type of joint is the patella?
It is a synovial joint
Saddle joint
What is the capsule surrounding the patella?
Superiorly, the knee joint capsule will join with suprapatellar bursa
What are the ligaments involved with the patella?
quadriceps tendon (superior)
patellar tendon (inferior to tibial tuberosity)
-> tiny tendon / retaniculum of vastus medialis (which prevents lateral tracking)
What are the bursae involved with the knee joint?
Suprapatellar bursa - continuous with knee joint, communicates with knee joint
Infrapatellar bursa - deep / superficial to knee joint
Prepatellar bursa
What are the fat pads involved with the knee?
Infrapatellar fat pads (hoffa’s)
Suprapatellar fat pads
What are the muscles involved with the knee?
In quadriceps tendon
Infrapatellar tendon inferiorly
Vastus medialis attaches to medial facet to stop lateral dislocation
What are the arteries supplying the knee?
paired superior and inferior genucleate arteries - these make the patella anastomoses
What are the anatomical variations associated with the patella?
bipartite patella
multipartite patella
wiberg classification of facet changes - type 1, 2, 3
absent patella
dorsal patella defect
What is the tibial plateau?
it is the proximal articular surface of the tibia
What are the parts of the tibial plateau?
Has 2 parts
- the articular surfaces
- medial and lateral tibial plateau; attachments for medial and lateral meniscus
intercondylar eminence
- medial and lateral projections
- attachment of cruciate ligaments
tibial tuberosity
- is anterior
- attachment for the patellar tendon
What joint is the tibial plateau part of?
Part of the knee hinge joint
Synovial
articulating surfaces are the medial condyle of femur + medial tibial plateau + lateral condyle of femur and lateral tibial plateau
What are the ligaments associated with the tibial plateau?
Anterior cruciate ligament
(anterior - drifts lateral, inserts posterior)
Posterior cruciate ligament
Medial collateral ligament
Lateral collateral ligament
Where do the medial and lateral meniscus attach?
Medial meniscus - attaches to the medial collateral ligament
Lateral meniscus - attached to popliteus
What are the ossification centers and fusion dates for the tibial plateau?
Tibial shaft - primary @ 7 weeks gestation
Proximal tibial epiphysis (secondary) - at 9 months gestation (same as femur)
Distal tibial epiphysis (secondary) - is at one year
Medial malleolus (secondary) - is at 2 years
Tibial tuberosity (secondary) - grows from tibial epiphysis at year 10, all fuse at 16- 18
What are the joints associated with the tibial plateau?
intimately related with knee - synovial joint
What are the variants associated with the tibial plateau?
tibial tuberosity may have seperate ossification center
What is the fibula?
It is the bone lateral to tibia which is part of the ankle joint
but not part of the knee joint
What are the parts of the fibula?
Head
- styloid process
Neck
- relation: common peroneal nerve
Shaft
Distally
- lateral malleolus
- facet for tibia
- facet for talus
What are the joints associated with the fibula?
Proximal tibio fibular joint
- synovial joint
- anterior + posterior proximal tibiofibular ligament
Distal tibio fibular joint
- fibrous joint
- anterior and posterior distal tibiofibular ligament
Also part of ankle joint
- synovial joint
anterior talofibular
calcaneofibular
posterior talofibular
What are the ossification centers and fusion dates for the fibula?
Shaft - at 7 weeks gestation (same as tibia, and femur)
Distal fibular epiphysis / lateral malleolus (secondary) - at 1 year, same as tibia
Proximal fibular epiphysis - at 3-4 years (same as patella)
What are the ligaments associated with the fibula?
Interosseous membrane
- between tibia and fibula
- anterior tibial A + deep peroneal N on anterior surface
Anterior + posterior tibiofibular ligaments
- proximal and distal
Ankle joint
- anterior talofibular, middle calcaneofibular, posterior talofibular
What are the muscles associated with the fibula?
peroneus longus
peroneus brevis
peroneus tertius
-> gives origin to all 3
What are the important relations of the fibula?
Neck of fibula - common peroneal N wraps around it
interosseous membrane - between tibia + fibula, has deep peroneal N + anterior tibial A running down it
What type of joint is the knee joint?
It is a modified hinge joint
Synovial joint
What are the bones involved in the knee joint?
femur - femoral condyles
tibia - tibial condyles
patella
What is involved with the knee joint capsule?
Synovial membrane is attached to the femoral + tibial condyles
Superiorly - communicates with the suprapatellar bursa
popliteus and cruciate ligaments are extrasynovial
What are the ligaments involved with the knee joint?
Medial collateral ligament
- is attached to the medial meniscus
lateral collateral ligament
anterior cruicate ligament
posterior cruciate ligament
ACL + PCL are intra capsular but extra synovial
Quadriceps tendon (which contains patella)
Patella tendon
What are the menisci associated with the knee joint?
Medial meniscus
- attached to medial collateral ligament
Lateral meniscus
- attached to popliteus, but is seperate to lateral collateral ligament
Both menisci have an anterior and posterior horn.
Also; anterior meniscofemoral ligament + posterior menisofemoral ligament
What are the bursa associated with the knee joint?
suprapatellar bursa (continuous with knee capsule)
semimembranousus bursa (under medial head of gastrocnemius)
What are the fat pads involved with the knee joint?
infrapatellar (hoffa’s) fat pad
suprapatellar fat pad
What are the nerves involved with the knee joint?
Femoral N
Obturator N
tibial N
common peroneal N
What are the arteries involved with the knee joint?
Knee anastomosis
Genuclear arteries
Superior + inferior, medial and lateral
(from popliteal artery)
What is the anatomical variation of the knee joint?
posterior synovial diverticulum - can become bakers cyst
patella variants - bipartite, multipartitie, absence, wilbergs, classification of facets, dorsal patella defect
What are the core relations of the knee joint?
The popliteal fossa
POPLITEAL ARTERY is the most deep structure in the knee joint
What are the variants associated with the popliteal artery?
Trifurcation of the popliteal A (no tibioperoneal trunk)
High origin anterior tibial
high origin posterior tibial
Very long tibioperoneal trunk (gives low origin of peroneal A and posterior tibial)
entrapped by gastrocnemius medial head
What are the osseous variants associated with the knee?
Flabella (sesamoid bone in the medial head of gastroc)
inferior lateral patella tendon (sesamoid)
benign fibrous cortical defect
What are the meniscal variants associated with the knee?
discoid meniscus
meniscofemoral ligaments
transverse ligament absence
meniscocruciate ligament
meniscal osscile
What type of the joint is the ankle joint?
distal tibiofibular (fibrous)
synovial hinge joint - ankle mortice
What are the articular surfaces / bones involved with the ankle joint?
tibia
fibula
talus
What type of joint is the ankle joint?
Two types of joints
Distal tibiofibular joint (fibrous)
Ankle Mortice Joint (synovial hinge joint)
What are the articular surfaces/ bones involved with the ankle joint?
tibia
fibula (with talar facet)
talus (trochlear surface)
What are the ligaments involved with the ankle joint?
Distal tibiofibular joint; it is a fibrous joint
Interosseous membrane - important as all force is transmitted through the interosseous membrane when injuries occur
Anterior + posterior tibiofibular ligaments
Medially - deltoid ligament; from tibia medial malleolus to insert onto talus, sustenaculum tali of calcaenus, navicular tuberosity
Laterally - distal fibula ligament
- anterior talofibular ligament
- middle calcaneofibular ligament
- posterior talofibular ligament
What is the movement of the ankle joint?
The distal talofibular ligament is very strong, allows for hinge like movement of the ankle mortis
Where does the joint capsule of the ankle run?
Will line the articular margins, except the talar neck
What are the arteries supplying the ankle joint?
anterior tibial A/ dorsalis pedis A
posterior tibial A posterior to medial malleolus
What is the nerve supply to the ankle joint?
hilton’s law - peroneal N and tibial N
What are the important relations for the ankle joint?
The great saphenous vein runs anterior to the medial malleolus with the saphenous N
Small saphenous vein runs posterior to lateral malleolus with sural nerve
behind tarsal tunnel underneath flexor retinaculum- tom dick and very naughty harry
underneath extensor retinaculum - tom has a nasty diseased foot
What are the anatomical variations associated with the ankle joint?
can be a ball and socket joint
What are the ossification dates / fusion centers for the ankle joint?
Tibia
- shaft: 7 weeks gestation
- distal tibia: at 1 year
- medial malleolus (secondary) - at two years
Fibula
- shaft: at 7 weeks gestation
- lateral malleolus: at one year (same as distal tibia)
Talus
- at six months gestation
Calcaneus
- at three months gestation
What runs underneath the flexor retinaculum in the tarsal tunnel?
Tibialis posterior
Digitorum (flexor digitorum longus)
Artery (posterior tibial artery - about to become medial and lateral planar A)
Vein (posterior tibial vein)
Nerve (tibial N - about to beocme medial and lateral plantar N)
Hallucis longus (flexor hallucis longus)
What runs in the lateral malleolus?
peroneus longus (deep)
peroneus brevis
What runs underneath the extensor retinaculum?
Tibialis anterior (anterior tibial A, Dorsalis Pedis A, deep peroneal N)
Hallucis longus (extensor hallucis longus)
Artery - Dorsalis Pedis A
Nerve - common peroneal N
Digitorum longus (extensor digitorum longus)
Fibularis tertius (peroneus tertius)
What is the subtalar joint?
It is the joint between the talus and calcaneus
- it involves two joins
the talocalcaneal joint (posterior)
and the talocalcaneal navicular joint (anterior)
What are the articular surfaces involved with the talocalcaneal joint?
Talus - posterior facet on inferior surface
Calcaneus - posterior facet on superior surface
Talocalcaneonavicular joint
- talus:
- anterior and middle facets
- found on inferior surface of calcaneus
Calcaneus
- anterior and middle facets
- on superior surface of talus
Sustenaculum tali
- articulates with middle facet of talus
Spring ligament
- calcaneonavicular ligament
- socket for talar head
- sustenaculum tali to navicular
What are the ligaments involved with the subtalar joint?
spring ligament (plantar calcaneonavicular ligament)
- runs from sustenaculum tali to navicular
Medial, lateral and posterior talocalcaneal ligament
Talocalcaneal osseous ligament - between talocalcaneal joint and TCN joint
What are the ossification centers and fusion dates for the subtalar joint?
talus - 6months
calcaneus - 3 months
What is the lisfranc joint?
synovial joint
involving the metatarsals + tarsals
- 1st, 2nd, 3rd metatarsal articulate with the medial, lateral and intermediate cuneiforms
- 4th and 5th metatarsal ariculate with cuboid
What is the lisfranc ligament?
from the medial cuneiform to the 2nd metatarsal base
- crucial for stability of foot
What are the knee menisci?
Two structures which sit on the tibial plateau
Medial and lateral menisci
Intercondylar region between them
What is the structure of each knee menisci?
Each menisci has an anterior horn + posterior horn
Both anterior horns are joined by transverse meniscal ligament
Both posterior horns attach to posterior intercondylar area
What is the gross anatomy of each menisci?
The medial menisicus is C shaped. Larger. and attaches to the medial collateral ligament
The lateral meniscus is smaller, nearly a complete ring and the posterior horn blends with the popliteus
What are the articulating structures and bones involved with the menisci?
Tibial condyles
- intercondylar eminence
- both medial and lateral posterior horns will attach to intercondylar eminence
Femoral condyles
What is the function of the menisci?
To act as shock absorbers
What are the ligaments involved with the menisci?
- transverse meniscal ligament (joins the anterior horns)
- anterior meniscofemoral ligament
- posterior meniscofemoral ligament (tendon of popliteus, blends with posterior horns) + medial collateral ligament (blends with medial menisci)
What are the attachments of the menisci?
anterior horn of both menisci are attached by the transverse meniscal ligament
posterior horn of both are attached to the intercondylar area of tibial plateau
medial meniscus is attached to the medial collateral ligament
lateral meniscus is attached to the popliteus
What is the arterial supply of the menisci?
Only the outer 1/3 is vascular. Supplied by medial and lateral genucleate arteries. comes off popliteal A.
inner 2/3 is avascular. Which relies on diffusion and heals slowly
What is the nerve supply of the menisci?
tibial nerve branches
What are the anatomical variants associated with the menisci?
discoid menisci
abberant insertion of anterior horn of medial menisci
meniscal ossicle
What are the cruciate ligaments?
Two ligaments in the knee joint - which stabilise the knee joint
Sit in the knee joint
Are intracapsular but extra synovial
What are the attachments and insertions of the anterior cruciate ligament?
Originates at the anterior intercondylar area of femur,
Inserts at the posterior part of the lateral condyle of the femur
What are the attachments and insertions of the posterior cruciate ligament?
origin at the posterior part of the intercondylar area of femur
inserts at the medial femoral condyle
What are the functions of the anterior and posterior cruciate ligaments?
Anterior cruciate ligament - function is to stop the femur sliding backwards on the tibia
Posterior cruciate ligament - function is to stop the femur sliding forwards on the tibia
What is the common femoral artery?
It is a continuation of the external iliac artery under the inguinal ligament
Originates at the mid inguinal point
What is the origin, course and termination of the common femoral artery?
Origin: continuation of the external iliac artery underneath the inguinal ligament.
Course: femoral triangle, adductor canal, adductor hiatus, and then enters popliteal fossa
Terminates: at the superior margin of the popliteal fossa and becomes the popliteal artery
What are the branches of the common femoral artery?
profunda femoris
- medial and lateral circumflex femoral artery
- 4 perforating branches
- descending geniuclear artery
- superficial/ external pudendal artery
- superior circumflex iliac artery (deep circumflex iliac artery comes directly off the external iliac A)
What are the relations of the common femoral artery?
femoral vein runs medial to the entire course of the femoral artery
femoral nerve runs lateral to the femoral artery in the femoral triangle
femoral nerve origin is in mid inguinal point
What is the obturator artery?
Branch of the anterior division of the internal iliac artery.
Supplies the medial thigh
What is the gross anatomy - origin, course, termination?
Origin - comes off the anterior division of the internal iliac A (also gives off the internal pudendal A, inferior gluteal A)
Courses- through the pelvis, crossed by the vas deferens.
Runs into the obturator foramen with the obturator N and obturator V
Leaves pelvic cavity, runs down medial and adductor thigh.
How does the obturator artery terminate?
When leaving the pelvis, gives anterior + posterior branches around the obturator foramen
What are the branches of the obturator artery?
In pelvis - gives branches to ilium, psoas, iliacus
anastomoses with the iliolumbar A
in medial thigh - branches to anterior and posterior divisions
What are the relations of the obturator artery?
Runs with the obturator N and V in the obturator foramen
runs along adjacent to pubis, so can be damaged in a pelvic fracture
What are the muscles / ligaments / fascia involved with obturator artery?
because it runs the obturator foramen - will be intimately related to the obturator fascia
What are the variations associated with the obturator artery?
Obturator artery - inferior epigastric artery anastomosis dominance
obturator artery can be replaced by the inferior epigastric artery
obturator artery replaces the inferior epigastric artery
What is the origin of the popliteal artery?
It is a continuation of the superficial femoral artery
At the adductor hiatus
What is the course of the popliteal artery?
Courses through the popliteal fossa, most posterior structure, posterior to knee capsule
goes through the soleus fibrous arch and splits into the anterior tibial A + tibioperoneal trunk
What is the termination of the popliteal artery?
TERMINATES AS:
Anterior tibial artery
- will run in anterior compartment of the interosseous membrane
- intimately related to the deep peroneal N
tibioperoneal trunk (posterior tibial A)
- will run with the tibial N
- divides again to give the peroneal A + true posterior tibial A
What are the branches of the popliteal A?
anterior tibial A
posterior tibial A
peroneal A
genuclear Arteries-superior medial and lateral
inferior medial and lateral genuclear A
What are the relations of the popliteal A?
- popliteal artery is the deepest structure in the popliteal fossa, followed by the popliteal vein and then the tibial N
- anterior tibial A - with deep peroneal N on interosseous membrane, anterior tibial A becomes dorsalis pedis
- posterior tibial A will descend with the tibial nerve
- peroneal N - will supply lateral compartment but not run into it
What are the anatomical variants associated with the popliteal artery?
Trifurcation of popliteal artery (no tibioperoneal trunk) o Peroneal a. from anterior tibial.
o High origin of anterior tibial artery
o High origin of posterior tibial artery
o Very long tibioperoneal trunk, giving a low origin of post tib. / peroneal a.
o Anterior tibial artery getting a branch from tibioperoneal trunk
o Hypoplastic infrapopliteal vessels
o Popliteal artery trapped by medial head of gastrocnemius (aberrant origin gastroc)
What is the arterial supply of the foot?
Doralis pedis artery
which is a continuation of the anterior tibial artery
Related to the deep peroneal N which runs emerges between extensor digitorum longus + extensor hallucis longus
What is the course of the dorsalis pedis artery?
Comes off the anterior tibial artery
Courses between Extensor hallucis longus and extensor digitorum longus
Terminates as the arcuate artery (gives the dorsal metatarsal arteries, anastomoses with the deep plantar arch)
What are the branches of the dorsalis pedis artery?
medial and lateral plantar artery
What is the arterial supply of the plantar foot?
posterior tibial A
comes off the tibioperoneal A distal to the popliteal fossa
What is the course of the posterior tibial artery?
Comes off the tibioperoneal A distal to the popliteal fossa,
Runs posterior to the medial malleolus (TDAVNH)
Terminates as the medial and lateral plantar arteries
What are the branches of the lateral plantar artery?
Lateral plantar artery comes off the posterior tibial A.
It becomes the plantar arterial arch of the foot and subsequently the plantar metatarsal artery
** arcuate artery of dorsalis pedis + lateral plantar A will anastomose
What are the anatomical variants associated with the arterial supply of the foot?
The peroneal A from the tibioperoneal trunk can replace the dorsalis pedis
What is the major venous drainage of the lower limb?
The great and small saphenous veins
What is the course of the great saphenous vein?
dorsal venous arch of foot (medially)
Runs anterior to medial malleolus
posterior to medial femoral condyle
penetrates the saphenous opening of femoral triangle
Drains into femoral vein in femoral triangle
What is the course of the small saphenous vein?
Dorsal venous arch of foot - laterally
Courses posterior to lateral malleolus (with sural N)
RUns into popliteal fossa
Empties into popliteal vein
What are the relations of the great saphenous vein and the small saphenous vein?
Great saphenous vein
- runs anterior to medial malleolus
- runs with saphenous nerve
Small saphenous vein
- runs posterior to lateral malleolus
- runs with sural nerve
What are the anatomical variants associated with the small saphenous vein and the great saphenous vein?
great saphenous vein
duplication
accessory saphenous vein
abnormal course - can course posterior to medial malleolus
duplication
vein of giacomini - can run into thigh rather than popliteal fossa
What is the femoral N?
femoral nerve is the nerve to the anterior compartment of the thigh
except tensor fascia lata which is supplied by superior gluteal N
What is the origin of the femoral N?
Comes from L2, L3, L4
From the lateral border of psoas - lumbar plexus
Posterior division of anterior ramii in lumbar plexus
What is the course of the femoral N?
emerges from the lumbar plexus, on the lateral border of psoas muscle
goes under the inguinal ligament
into the femoral triangle
most lateral structure
does not run in the femoral sheath
What is the termination of the femoral N?
Divides into the anterior and posterior divisions
Terminal continuation as the saphenous nerve
Sensory - cutaneous innervation to medial foot
Saphenous N courses with the great saphenous vein
What does the femoral N innervate?
Motor
- quadriceps (anterior thigh)
- iliacus
- sartorius + pectineus
Sensory
- saphenous nerve (medial foot)
- quadriceps (anterior thigh)
What are the branches of the femoral N?
Superficial and deep division
Superficial (4)
2 sensory - medial /intermediate cutaneous N of thigh
2 deep - Sartorius and pectineus
Deep (4)
motor to quadriceps
What are the relations to the femoral N?
It is the most lateral structure to run in the femoral triangle. Does not run in the femoral sheath.
Saphenous N runs through the adductor hiatus with the femoral A
Saphenous N runs with the great saphenous vein
What are the anatomical variants associated with the femoral N?
femoral N is as 2-3 seperate slips within the psoas
What is the obturator N?
It is the nerve to the medial thigh. except for pectineus which is supplied by the femoral N
What is the origin of the obturator N?
Comes from the anterior division of the anterior ramii
L2 L3 L4
From medial border of psoas (lumbar plexus)
What is the course of the obturator N?
Arises medial to psoas,
behind common iliac vessels
courses through the obturator canal, enters thigh
Split into anterior and posterior divisions by adductor brevis
What is the termination of the obturator N?
anterior and posterior divisions by adductor brevis
anterior
- medial - adductor longus / brevis / gracillis
- sensory - medial thigh
posterior
- adductor magnus, obturator externus
What does the obturator N supply?
Motor to adductor muscles / medial thigh
Sensory to medial thigh
What are the relations with the obturator N?
psoas, emerges from the medial margin
runs through obturator foramen with the obturator A and obturator V
divided into anterior and posterior divisions - adductor brevis
Referred pain from ovarian pathology?
Can be from the obturator N
due to ovaries sitting in the bifurcation of the common iliac vessels, and obturator N sits posterior to the common iliac vessels
What innervates the obturator internus?
Obturator internus is innervated by the nerve to obutrator internus
The obturator externus is innervated by the obturator N
What is the sciatic nerve?
Nerve to the leg.
Biggest and longest nerve in the body!
What is the gross anatomy of the sciatic N?
Origin: L4-L5, S1, S2, S3 of sacral plexus
What is the course of the sciatic N?
through the greater sciatic foramen
emerges below piriformis
runs posterior to acetabulum, femoral head
Divides in mid thigh to tibial and common peroneal N
What is the termination / branches of the sciatic N?
tibial N
- nerve to the posterior compartment of the leg, intrinsic muscles of the foot (except first 2 dorsal interossei which are deep peroneal N)
common peroneal N
- nerve to the lateral compartment (superficial peroneal N)
- nerve to the anterior compartment (deep peroneal N)
What does the sciatic N innervate?
Posterior thigh
- hamstrings: biceps femoris/semimembranosus/semitendinosus
Motor
- distal to knee
Sensory
- distal to thigh
What are the relations of the sciatic nerve?
Piriformis - should emerge below it
Acetabulum - courses immediately posterior to it
Runs in psoterior thigh compartment
What are the anatomical variants associated with sciatic nerve?
division of sciatic into common peroneal/tibial
sciatic N emerges from superior to piriformis
sciatic N emerges from belly of piriformis
sciatic n emerges inferior to piriformis
sciatic artery
abnormally high bifurcation of sciatic n
abnormally low bifurcation of sciatic N - in popliteal fossa or below
What are the nerves which emerge directly from the sacral plexus?
nerve to piriformis (S1, S2)
perineal branch of S4
perforating cutaneous nerve (S2, S3)
posterior femoral cutaneous nerve (S1, S2, S3)
pelvic splanchic (parasympathetics)
pudendal nerve (S2, S3, S4)
What are the branches of the sciatic N?
anterior division:
tibial N - to flexors (L4, L5, S1, S2, S3)
nerve to obturator internus - (L5, S1, S2)
nerve to quadratus femoris - (L4, L5, S1)
posterior division:
common peroneal N - to extensors
superior gluteal N (L4, L5, S1)
inferior gluteal N (L5, S1, S2)
What structures leave the greater sciatic foramen?
Superior gluteal N and vessels
Inferior gluteal N and vessels
Sciatic N
Piriformis
Posterior femoral cutaneous N
Perforating cutaneous N
N to quadratus femoris
N to obturator internus
Pudendal nerve
Internal pudendal Artery
What structures enter the lesser sciatic foramen?
internal pudendal A
pudendal N
N to obturator internus
What structures leave the lesser sciatic foramen?
internal pudendal V
tendon to obturator internus
What is the pudendal N?
It is the nerve to the perineum
S2-S4 origin - sacral plexus
What is the course of the pudendal N?
Origin is S2 - S4
Courses through the greater sciatic foramen
Does a U turn to enter through the lesser sciatic foramen
enters the perineum
runs along wall of obturator internus
is in lateral wall of ischioanal fossa / pudendal canal
terminates by dividing into branches of skin + skeletal muscle of perineum
How does the pudendal nerve terminate?
inferior rectal N
perineal N
dorsal N of penis / clitoris
What does the pudendal N innervate?
external anal sphincter
external urethral sphincter
skin of perineum
lower anus
What are the relations to the pudendal N?
internal pudendal A
runs inferior to pirifromis
goes thru both greater and lesser sciatic foramen
courses in pudendal canal (alcocks canal on wall of ischiorectal fossa)
What is the tibial nerve?
It is the nerve to the posterior compartment to the leg
What is the origin of the tibial nerve?
Is a terminal branch of the sciatic nerve - divides in the lower half of the thigh
- L4, L5 and S1, S2, S3 (anterior divisions of the anterior ramii)
What is the course of the sciatic N?
Runs through the popliteal fossa.
It is the most superficial structure (popliteal V and then popliteal A is deeper)
under soleal arch (with posterior tibial A)
runs posterior to medial malleolus, under the flexor retinaculum
Through the tarsal tunnel
becomes medial and plantar nerves
What is the termination of the tibial N?
as the medial and lateral plantar N
+ sural N
What does the tibial N innervate?
Motor
to posterior compartment of the thigh
- gastrocnemius
- soleus
- plantaris
Sensory
sural N (with small saphenous vein)
- lateral foot
What are the relations to the tibial N?
Most superificial structure in the popliteal fossa
under soleal arch (runs with post tib A)
in tarsal tunnel, TDAVNH
sural nerve - runs with short saphenous vein
What is the common peroneal nerve?
Is the nerve to the anterior compartment (Deep peroneal N)
and lateral compartment (superficial peroneal N)
What is the origin of the common peroneal N?
One of the terminations of the sciatic N in the thigh
L4 L5 S1 S2 S3
What is the course of the common peroneal N?
Through the popliteal fossa
Wraps around the neck of the fibula
(i.e. enters the lateral leg compartment)
Divides into the deep and superficial peroneal nerve component
Divides in peroneus longus
How does the common peroneal nerve terminate?
Superficial peroneal nerve
- nerve to lateral leg compartment
- innervates peroneus longus + brevis
- sensory: does all the foot dorsum (except 1st webspace which is deep peronal nerve)
Deep peroneal nerve
- nerve to anterior leg compartment
- runs with anterior tibial A, on the interosseous membrane
- innervates tibialis anterior, extensor digitorum longus, extensor hallucis longus, peroneus tertius
- runs under extensor retinaculum
- THANDF
- sensory - 1st webspace only
What are the relations to the common peroneal nerve?
leaves the popliteal fossa laterally, can be mistaken for biceps femoris tendon
common peroneal N - wraps around neck of fibula
- plunges into peroneus longus
deep peroneal nerve - runs with anterior tibial artery on interosseous membrane
superficial peroneal nerve - runs into lateral leg compartment
What is the clinical significance of casting when consdering the deep peroneal N?
neck of fibula - common peroneal nerve is endangered in fracture
or from compression from too tight cast which causes foot drop when DPN is affected
What are the boundaries of the femoral triangle?
Superiorly - inguinal ligament
medially - adductor longus
laterally - sartorius
inferiorly - the adductor canal (transmits saphenous N and femoral A)
roof - fascia lata
floor - iliopsoas, pectineus, adductor longus
What are the contents of the femoral triangle?
femoral artery
femoral vein + great saphenous vein
femoral N and branches - not in the femoral sheath
What are the boundaries of the popliteal fossa?
medially - semitendinosus + semi membranosus
laterally - biceps femoris tendon
Inferiorly - 2 heads of gastroc
floor - capsule of knee joint
roof - fascia lata
What are the contents of the popliteal fossa?
popliteal artery
- and tibioperoneal trunk
popliteal vein
- and small saphenous vein
tibial nerve
- and sural nerve
common peroneal nerve
plantaris
Please remember to revise normal foot bone variants!
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