Lower extremity non-muscle anatomy

Borders and content of the femoral triangle

Borders: sartorius, adductor longus, inguinal ligament, all laying on top of pectineus floor

Contents: femoral nerve, artery, vein

How does blood supply get to femoral head

Via femoral head ligament (aka ligamental teres/foveal ligament) that has an acetabular branch of obturator artery, that goes into fovea of the femur

Transverse acetabular ligament function

Seals off the inferior aspect of femoral head into the acetabulum because the labrum does not wrap all the way around

Iliofemoral ligament

Biggest ligament, prevents hyperextension

Ischiofemoral ligament

prevents hyperextension, screws femoral head into acetabulum

Pubofemoral ligament

limits ABD, tightens during extension and abduction

Screw home mechanism and what reverses it

• The final tibial external rotation that locks the knee into place during the final 10-15 degrees of extension to help stabilize it

• When popliteus m contracts, it unlocks the knee

When is the patella most stable

Knee bent/ flexed so tendons and ligaments are taught

When is the patella least stable

Knee extended, quads relaxed

Gerdys tubercle attachment

IT band, more lateral on tibial head

Tibial tuberosity attachment

Patellar ligament

Patellofemoral joint and facet facts

Patella articulates with the femur, not the tibia, gliding joint

• The medial facet sits deeper on the medial condyle of the femur, so the lateral facet is more easily displaced because it is sitting more shallowly

Tibiofemoral joint and role of meniscus

• Condyloid joint (because of the final external rotation)

• Femur condyles are very round while tibia condyles are shallow, so meniscus increase surface area of contact so net force distributed is decreased

What happens when an intracapsular ligament or meniscus is injured

Swelling occurs

Intracapsular ligaments of knee

• Anterior and posterior cruciate ligament, transverse ligament of knee

Extracapsular ligaments of knee

Medial collateral ligament, lateral collateral ligament

Why is the MCL more commonly injured

Because external forces strike from outside in, versus something hitting between your legs

Why are MCL and medial meniscus commonly injured together

Because they are fused together/connected

If the popliteus was tight, what would it limit

End range knee extension

What happens with popliteus contracts in open chain versus close chain circuits

Open chain: leg in air, tibial internal rotation

Closed chain: leg on the ground, external rotation

What runs through the adductor canal

• Femoral artery and vein

• Saphenous nerve

What area of the meniscus heals the fastest

The outer third area, known as the red zone because it gets the most blood flow

What are the proximal attachment sites of the meniscus

Medial and lateral intercondylar tubercles of tibia

What happens when femoral A and V pass through adductor canal and then adductor hiatus (and what forms these landmark areas)

ADD canal: remain femoral A and V

• Formed by vastus medialis, sartorius, and adductor longus (floor)

ADD hiatus: become popliteal A and V and wrap around the posterior leg

• Formed by ADD magnus

ACL femoral attachment

• Prevents hyperextension

• Attaches to lateral femoral condyle and crosses to medial intercondyle tubercle of tibia

PCL attachment

Medial femoral condyle and crosses to lateral tibia

Femoral N pathway

Obturator N pathway

Sciatic N pathway

Borders and contents of popliteal fossa

Contents: Popliteal A and V, common fibular and tibial N

Borders:

• anterior: biceps femoris and semimembranosus

• posterior: gastrocnemius lateral and medial heads

What veins converge around the femoral triangle

Deep femoral, femoral, great saphenous V

What muscle has an important relationship with the sciatic N

Piriformis, sciatic N runs under it

What nerves are providing motor and sensation to posterior thigh

Motor: sciatic

Sensory: posterior femoral cutaneous

What nerve curves around the lower border of the gluteus maximus muscle

Perforating cutaneous

• Commonly mistaken for hamstring tendinitis

Rami of lumbosacral trunk

L4 and L5

Sacral plexus rami and nerves

L4-S5

• sciatic

• Inferior and superior gluteal

• Nerve to piroformis, quadratus femoris, and obturator internus

• Posterior femoral cutaneous

Lumbar plexus rami and nerves

L1-L5

• obturator (anterior division)

• Femoral

• Lateral femoral cutaneous

Hindfoot bones

Calcaneus and talus

Midfoot bones

navicular, cuboid, cuniform (medial-lateral)

Forefoot bones

metatarsals and phalanges

What motions occur at talocrual joint and what ligaments reinforce it

Dorsiflexion and plantarflexion (Talus is convex moving on the concave joint of fibula and tibia)

Ligaments

• Medial: deltoid ligaments

• Lateral: anterior and posterior talofibular ligament, calcaneofibular ligament

What do the deltoid ligaments (medial ankle) protect against

Eversion

What do the lateral ligaments of the talocrual joint protect against

Inversion (anterior and posterior talofibular ligaments, calcaneofibular ligaments)

What supports the proximal tibiofibular joint

Anterior and posterior ligaments of fibular head

What supports the distal tibiofibular joint

Anterior and posterior tibiofibular ligaments

• relatively horizontal fiber direction to balance forces

What separates the hindfoot from midfoot

Transverse tarsal joint

What separates the midfoot from forefoot

Tarsometatarsal joint

What attaches to the calcaneal tuberosity

Planter aponeurosis

What is the function of the sustentaculum and navicular tuberosity

These serve as hoots/anchor points for tendons, lifting the arch up

What causes a high ankle sprain?

The talus gets wedges between the distal tibia and fibula at the talocrual joint

• The proximal tibiofibula joint would stiffen up to compensate

Why is the lateral ankle more frequently sprained?

More bony prominence but WEAKER ligaments (compared to the medial deltoid ligaments)

• The ankle is more likely to invert + planterflex to cause the sprain

What does the plantar ligament protect against?

Hyperextension

What nerve innervates the dorsal surface of the foot

Deep fibular N

What muscles does the medial plantar N innervate

Abductor hallicus, flexor hallicus brevis, 1st lumbrical, flexor digitorum brevis

What muscles does the lateral plantar N innervate

Adductor hallucis, abductor digiti minimi, flexor digiti minimi, rest of lumbricals , quadratus plantae

• Dorsal (4 between toes) and plantar (last 3 toes) interossei