Regional Anatomy Flashcards
2 main joints in the knee
- Tibiofemoral joint
2. Patellofemoral joint
When in flexion, the patella stays_____.
The patella stays still but the tibial condyles move
There is ____ change in the distance between the tibial tuberosity and the patella/ But the _____ moves and the ______ unfolds.
- No
- Femur
- Suprapatella pouch (synovial)
Attachments of the capsule (knee)
- Edges of the tibial condyle
- Margins of the patella
Are cruciate ligaments intra-synovial or extra-synovial?
Extra-synovial
Are cruciate ligaments intra-capsular or extra-capsulare?
Intra-capsular
An infrapatella fat (fat pad) is highly innervated/sensitive and is a good space filler. True or false.
True
Tibiofemoral joint is __axial
Uniaxial
What are the two articular surfaces that make up the tibifemoral joint?
- Femoral condyles
- Tibial plateau
What are the main movements of the tibiofemoral joint?
- Flexion-extension in a sagittal plane around a coronal axis
- Some rotation (IR and ER) around vertical axis
What allows for the rotation around a vertical axis of the tibiofemoral joint?
- Longer articular surface on medial femoral condyle (from A to P)
- Screw-home mechanism
What is the screw home mechanism’s function?
Allows for extra stability as it locks the knee into extension
What is the screw-home mechanism?
The discrepancy between the length of surfaces of condyles
How does the screw-home mechanism work in extension?
EXTENSION + MEDIAL ROTATION
Due to the longer medial condyle from anterior to posterior, when knee is extended, there is medial rotation of the femur on a fixed tibia (eg. sit –> stand)
So most stable as locked in extension
How does the screw-home mechanism unscrew in flexion?
Need to unlock to get into flexion
Popliteus will pull lateral condyles –> laterally rotate femur –> unlocks knee –> femur and tibia in sagittal plane –> flex
O: latera femoral epicondyle
I: tibia
What is the normal frontal plane alignment of the knee?
5 degrees anatomical genu valgus
What does genu valgus mean?
- Medial femoral condyle extends further distally
- Shaft of femur inclined laterally
- Femoral condyles in same transverse alignment
What is the benefit of 5 degrees genu valgus?
Brings feet closer to midline for bipedal gait
What is something that can be determined by the alignment of the femoral condyles in the transverse plane?
Orientation of the flexion/extension axis of the knees
- Relative torsion of distal condyles in relation to proximal condyles
Femur torsion= medially rotated
The distal portion of the femoral condyle is ___ flat. Anterior and posterior portions are ____ flat. Why?
More flat = larger radius of curvature
When in extension (standing), the flat portion articulates with the tibial plateau = more stable
When in fexion, the curve part articulate with the plateau = less stable
What is the medial and lateral tibial slope? What is P-line? What is line A-B?
Angle between the line P and line A-B
Line P: line perpendicular to long axis of tibial diaphysis
Line A-B: line from anterior tibial peak to posterior tibial peak.
What is the function of the meniscus?
- Increase congruency (contact area betwene the femoral condyles and the tibial plateau)
- Decreases stress
- Protects articular cartilage
What shape is the tibiofemoral meniscus?
- Semi-lunar shaped (superior view)
- Wedge-shaped (anterior view)
What was the difference between the medial and lateral menisci?
- Thinner longer medially and less mobile = less able to move out of way = covers more tibia plateau = has more tibia plateau to cover (cause longer)
- Thicker laterally (to fill condyle space) and more mobile
What is meniscus made of? Why?
Fibrocartilage
- Able to withstand shear force
- Protects underlying hyaline cartilage (which withstand compression but not shearing)
What are the 5 ligaments of the tibiofemoral joint?
- Tibia collateral (capsular)
- Fibular collateral (extracapsular)
- Anterolateral
- Anterior cruciate
- Posterior cruciate
What is the function of the tibial collateral ligament (TCL)?
Resist valgus
Superficial (longer and stronger) resist valgus throughout flexion
Deep (shorter) reists anterior translation of tibia too
What is the function of the fibular collateral ligament? (FCL)
Resists varus
What is the function of the anerolateral ligament (ALL)?
- Resists tibia IR in 30 degrees flexion
- Anterolateral stability
Where does the fibular collateral ligament (FCL) attach?
Femoral lateral epicondyle –> head of fibula
Where does the anterolateral ligament (ALL) attach?
Lateral femur –> anterolateral tubercle (Gerdy’s tubercle)
When does the anterolateral ligament (ALL) tighten?
In flexion and internal rotation of tibia
Where does the anterior cruciate ligament (ACL) attach?
Attach to anterior tibia
What are the 2 bands of the ACL?
- Posterolateral band (PLB)- largest, tighest in extension
2. Anteromedial band (AMB)- tightens in flexion
What does the Anterior cruciate ligament (ACL) resist?
- Anterior translation of tibia on femur
- Posterior translation of femur on tibia
- Rotation stability
- Valgus
- End of range extension
What does the Anterior cruciate ligament (ACL) allow?
10 degrees internal and external rotation in 30 degrees flexion
What are some injuries of the ACL?
- Often non contact
- Large valgus moment and tibia ER
- Adolescence
- pivoting sports
- females 3-5 x
The slope of the tibial plateau has a direct relationship with anterior tibial translation during the transition from non-weightbearing to weightbearing conditions. Why?
Increase tibial slope = increase shear force
ACL prevents tibia from translating anteriorly and femur from translating posteriorly.
What does the posterior cruciate ligament (PCL) resist?
- Posterior translation of tibia on femur
What are some common injuries of the PCL?
- Dashboard (eg. car injury- knee hits dashboard)
- Hyperflexion or hyperextension
What is a PCL sag test?
PCL deficiency = posterior shift of tibia on femur at 90 degrees flexion
What is the patellofemoral joint? Articulations?
Patella –> patella surface of the distal femur
In extension, is there contact between the patella and femur?
Little contact
In flexion, is there contact between the patella and femur?
Femur moves underneath patella –> Patella and patellar surface come in contact (intercondylar area)
Which way does the patella usually dislocate? Why?
Laterally due to the pull of the quadriceps (moves proximally and increases contact)
More flat = more dislocations
Translations of the patella in 0-30 degrees flexion
Glides medially
Translations of the patella in 30-90 degrees flexion
Glides laterally
Rotations of the patella in knee flexion
Tilts laterally
How is the line of action and moment arm of the quadriceps group changed with the presence of a patella?
Patella = more strength in quads
It deflects the quads = increased moment arm = more effective = more strength
What are 10 structures found in anterior thigh compartment
- Sartorius
- Quadriceps femoris
- Rectus femoris (RF)
- Vastus lateralis (VL)
- Vastus intermedius (VI)
- Vastus medialis longus (VML)
- Vastus medialis obliquus (VMO)
- Quadriceps tendon
- Patella tendon
- Tibial tuberosity
All the quads attach inferiorly on the______?
Tibial tuberosity
Rectus femoris has ________ fibres
Bipennate
Vastus intermedius has a _____ line of action.
Vertical
Action of vastus lateralis
Lateral pull
Action of vastus medialis obliquus
Horizontal action
- Only muscle that can offset the lateral pull of the pther quad muscles
- if knee problems exist, work on VMO as an active component to stabilise patella in medial direction
Tibial tuberosity IS OR ISN’T quite vulnerable to 2nd ossification (before being ossified)
IS
What are 4 structures found in the posterior thigh compartment?
- Semimebranosus
- Semitendionsus
- Biceps femoris long head
- Biceps femoris short head
Action of biceps femoris long head
Hip extension
Knee flexion
Tibial ER
Action of bicpes femoris short head
Knee flexion
Tibial ER
Action of semimebranosus and semitendinosus
Hip extension
Knee flexion
Tibial IR
What are 2 structures of the posterior leg?
- Gastrocnemius
2. Plantaris
Action of gastrocnemius. Insertion?
Crosses knee joint = knee flexion
Inserts on femoral condyles
Function of popliteus
Screw home mechanism is medial rotation of femur on tibia.
Popliteus will laterally rotate femur on tibia to unlcok the extended knee.
Where does popliteus attach?
Medial tibia –> Lateral femoral condyle
Which structures are found in the medial thigh knee? What 3 muscles does it consist of?
Pes anserinus:
- Sartorius
- Gracilis
- Semitendinosus
What are 4 structures that are found in the lateral thigh and knee?
- Tensor fascia latae
- Iliotibial band
- Biceps femoris long head
- Biceps femoris short head
What is the Iliotibial band (ITB)?
Thickening of TFL (ligament/tendon)
What is tensor fascia latae (TFL)?
Small muscle which attaches inferiorly to the long thick strip of fascia, known as the iliotibial band (ITB).
Where does the ITB attachment inferiorly?
Gerdy’s tubercle
What is the function of the ITB?
Resists varus forces
In standing, the anterior tibia is under tension or compression?
Tension
In standing, the posterior tibia is under tension or compression? Why?
Compression.
- The posterior muscle bulk is greater
What is a tibial stress fracture? How does it occur?
Repeated loading with insufficient time for recovery
Where do 90% of tibial stress fractures occur? Why?
Posteriomedial
- The junction between the proximal 2/3 and the distal 1/3
- It is the narrowest part of bone
Where is another common area for a tibia stress fracture other than posteromedial tibia? Better or worse?
Anterior cortex
Worse and can have serious consequences
- poor blood supply.
- bone responds to compression force to stimulate bone to produce bone cells
so when bone breaks = less compression stimulus = less ability to heal
What is the degree of external tibial torsion?
20-40 degrees
What is external tibial torsion?
The distal parts are laterally rotated with respect to condyles
How many tarsals, metatarsals, phalanges?
7 tarsals
5 metatarsals
5 phalanges
Explain a heel strike?
When walking,
Land on lateral heel but weight is medially –> Foot pronates –> weight goes to 1st/2n MTP and hallux
What 2 bones make up the hindfoot?
- Calcaneus
2. Talus
What bones make up the midfoot?
All tarsal bones except calcaneus and talus
What bones make up the forefoot?
Metatarsals and tarsals
What bones make up the 1st ray?
1st MT and medial cuneiform
What bones make up the 2nd ray?
2nd MT and intermediate cuneiform
What bones make up the 3rd ray?
3rd MT and lateral cuneiform
What bone make up the 4th ray?
4th MT
What bone makes up the 5th ray?
5th MT
Why is a navicular stress fracture not ideal?
Central zone of hypovascularity
How does a navicular stress fracture occur?
Medial and lateral compressive forces though 1st and 2nd ray (both sides of the navicular)
What are the 3 functions of the arches of the foot?
- Shock absorption (weight bearing)
- Energy return wen locomotion (spring back)
- Protection for neurovascular structure and intrinsic foot muscles (4 layers)- won’t be compressed
What bones does the medial longitudinal arch consist of?
- Talus
- Calcaneus
- Navicular
- Medial cuneiform
- 1st MT
Which bones does the lateral longitudinal arch consist of?
- Calcaneus
- Cuboid
- 5th MT
What bones does the transverse arch consist of?
From medial to lateral
- Head of talus
- Cuneiforms
- Cuboid
Which longitudinal arch is longer? Medial or lateral?
Medial
What are 4 passive structures that support the arches of the foot?
- Plantar aponeurosis (Medial calcaneal tuberosity to metatarsal phalangeal joints, thickening of the fascia)
- Long plantar ligament
- Short plantar ligament
- Spring ligament (support the head of talus)
How is calcaneus specialised for weight bearing?
- Thin cortical shell around sparse trabecular bone
- Trabecular bone –> shock absorption. Bone marrow and blood –> Hydrodynamic shock absorber
- Calcaneal fat pad returns 70% energy into locomotion
What are 3 extrinsic active structures that support the arches of the foot? Attachments?
- Tibialis anterior (coming down over the medial aspect will attach to medial cuneiform and base of first metatarsal. On medial inferior aspect)
- Tibialis posterior (coming down under the foot, most of the insertion on navicular and medial cuneiform so many connections widely spread)
- Fibularis longus
(comes down on the lateral malleolus, under the cuboid and crosses the sole of the foot on plantar aspect and insert onto the same bones as tibialis anterior)
What is 1 intrinsic active strcuture that supports the arches of the foot?
Abductor hallucis longus
How many bones articulate with the tibia distally?
2 bones
- Fibula
- Talus
What ligament resists the talus when it is forced down medially?
Spring ligament
What is the plantar fascia?
1Plantar fascia is a very specialised structure. Very tough structure, twice the tensile strength of other plantar ligaments very rich in proprioception.
Arises: Medial calcaneal tuberosity
Inserts: Onto capsules of all MTP joints
What tenses the plantar fascia?
When you go into MTP extension and when gastrocnemius and soleus pull superiorly on calcaneus, plantar flexing it.
Plantar fascia functions to hold the foot rigid for push off
What is the ankle joint also known as?
Talocrural joint
What articulates in the talocrural joint?
Talus + tibia/fibula
1 tarsal bone articulates with 2 bones of leg
What kind of joint is the talocrural joint? What movement does it produce?
Synovial hinge joint
Dorsiflexion and plantarflexion
Pronation of the foot is a combination of____?
Dorsiflexion
Eversion
Abduction
“flat feet”
The tarsal bones are more mobile = good = usually unsure surface
Supination of the foot is a combination of ___?
Plantarflexion
Inversion
Adduction
What plane is DF/PF in?
Sagittal plane
What plane is adduction/abduction of the foot in?
Transverse plane
What plane is inversion/eversion of the foot in?
Coronal plane
Tarsal bones are more mobile in supination or pronation? Why?
Pronation.
Used on unsteady surface
Explain the movements of the foot in gait (Landing –> pushing off)
Land on posterolateral heel –> pronate foot to transfer weight to the anterior/medial side for shock absorption (adaptation of –> midstance –> supination –> ridged –> push off
Is the distal tibiofibular joint a synovial joint or not?
No- is a syndesmosis
Is the distal radioulnar joint a synovial joint or not?
Yes- synovial gliding joint
Distal tibiofibular joint is supported by what ligaments? Why is the stability of this joint so important?
- Anterior tibiofibular ligament
- Posterior tibiofibular ligament
- Interosseous membrane
Forms the superior part of the talocrual joint (dome of the talus + tibia and fibula)
The dome of the talus is widest anteriorly. What could that mean?
So when you are in planter flexion –> narrowest part articulating with tibia and fibula
When you are is dorsiflexion –> widest part articulating with tibia and fibula
Therefore, dorsiflexion –> closed pack.
What type of movement is pronation and supination of the foot?
Triplanar
What is the subtalar joint?
Talus and calcaneus
Separates vertical leg & talus with rest of the foot at 90 degrees = links movement
How many articulations are there in the subtalar joint? What/where are they?
3 articulations
- Anterior
- Middle
- Posterior
What movements does the subtalar joint allow?
Supination and pronation
What is function of the subtalar joint?
Translates movements from foot to the leg (vice versa)
When a foot pronates, does it IR or ER the tibia?
Tibial IR
When a foot supinates, does it IR or ER the tibia?
Tibial ER
When a foot supinates, does it IR or ER the tibia?
Tibial ER
What is the transverse tarsal?
Talonavicular + calcaneocuboid
The joint between the rearfoot and the midfoot
What are some joints of the foot? Starting from intertarsal –> DIP.
Intertarsal TMT MTP PIP DIP
The joint capsule is continuous with the ______ and _____ subtalar joint capsule.
Anterior & middle
Talocalanonavicular joints surrounded by ____ large capsule
1
Name 16 ligaments in the foot
- Anterior talofibular (ATFL)
- Calcaneofibular (CFL)
- Posterior talofibular (PTFL)
- Talocalcaneal interosseous
- Dorsal calcaneonavicular (Bifurcate)
- Dorsal calcaneocuboid (Bifurcate)
- Cervical
- Deltoid
- Posterior tibiofibular
- Spring
- Anterior tibiotalar
- Posterior tibiotalar
- Tibiocalcaneal
- Tibionavicular
- Short plantar
- Long plantar
What is a closed-pack position?
Both articular surfaces are at maximal congruency = max. stability and energy transfer
When are the tarsal joints in a closed-packed position?
Full supination (inversion)
When are the metatarsaophalangeal joints in a closed-packed position?
Extension
When are the interphalangeal joints in a closed-packed position?
Extension
What muscle groups are found in the anterior compartment (foot/leg)?
Dorsiflexors
Invertors
What muscle groups are found in the posterior compartment (foot/leg)?
Plantar flexors
Evertors
What muscle group is found in the lateral compartment (foot/leg)?
Evertors
What nerve innervates the anterior compartment (foot/leg)?
Deep fibular nerve L4,L5, S1
What nerve innervates the posterior compartment (foot/leg)?
Tibial nerve L4,L5,S1,S2
What nerve innervates the lateral compartment (foot/leg)?
Superficial fibular nerve L4,L5,S1
Action of tibialis anterior
Strong dorsiflexor (forward of axis- agonist) Inversion (midfoot)
Action of tibialis posterior
Inversion (large moment arm- agonist) Weak plantarflexor (posterior to axis)
Action of fibularis tertius
Plantarflexion
Eversion