Lower Limb Bones & Joints

these boots were made for walking

Femur

Anterior

• the most proximal portion of the head of the femur has a small dimple called the fovea for the ligament of head of femur

• below the neck are the greater and lesser trochanters, with the intertrochantic line spanning between them, which are important attachment sites for the muscles of the hip and thigh

• the distal end of the anterior femur features the medial and lateral condyles that articulate with the tibia, and the medial and lateral epicondyles above them

• between the medial and lateral condyle is the patellar surface of the femur which articulates with the patella

Posterior

• the lesser trochanter is seen more clearly from the posterior view, weparated from the greater trochanter by the intertrochanteric crest

• the intertrochanteric crest (posterior) and intertrochanteric line (anterior) mark the transition between the neck and the shaft of the femur

• on the medial surface of the greater trochanter is the crescent shaped depression called the trochanteric fossa

• below the lesser trochanter are 3 small bony ridges called the pectineal line, spiral line, and gluteal tuberosity, which converge inferiorly to form the linea aspera that runs along the entire shaft of the femur

• at the distal end of the femur, the linea aspera diverges into 2 ridges: the medial and lateral supracondyler lines

• the posterior view provides a better view of medial and lateral condyles, which are separated on the posterior surface by the intercondylar fossa

some pics :)

Patella

• a flat, triangular bone embedded within the quadriceps tendon that functions to protect the knee joint and improve the leverage of the quadriceps muscles when straightening the leg

• divided into base (superior), apex (inferior), anterior surface, and posterior/articular surface

• the base is the thick, broad top edge where the quadriceps tendon attaches

• the apex is the pointed, downward facing bottom tip that anchors the patellar ligament

• the anterior surface is rough, convex, and sits just beneath the skin

• the articular surface is smooth, and contains the medial and lateral facets that glide within the femoral trochlear groove

some pics :)

Knee Joint

• the knee joint is a complex synovial joint that connects the femur, tibia, and fibula for form 2 articulations

  • the tibiofemoral joint between the tibia and femur

  • the patellofemoral joint between the patella and femur

• the lateral and medial condyles of the femur articulate with the tibial plateau inferiorly, forming the tibial femoral joint

• anteriorly, the patellar surface of the femur articulates with the articular surface of the patella, forming the patellofemoral joint

• the joint capsule itself is divided into tow parts: an outer fibrous layer and an inner synovial membrane that encloses the articular cavity

  • the articular capsule forms several pouches (the bursae)

Bursae

• the knee bursae are small, fluid filled sacs that reduce friction and accommodate gliding of muscles and tendons as they cross bony prominences

• two groups of bursae are associated with the knee joint

  • bursae around the patella

  • non patellar bursae

    • consists of a group of superficial bursae including the inferior subtendinous bursa of the biceps femoris muscle located on the lateral side of the joint between the tendon of biceps femoris and the fibular collateral ligament and the anserine bursa, found on the medial side cushioning the space between the tibial collateral ligament and the tendinous expansions of the sartorius, gracilis, and semitendinous muscles

• as many as 14 bursae may be present, including the subtendinous bursae of the iliotibial tract found between the tibia and distal part of the iliotibial tract

Extracapsular Ligaments & Popliteus Muscle

• the extracapsular ligaments of the knee are found outside the capsule

• they are the patellar ligament, fibular and tibial collateral ligaments, and oblique and arcuate popliteal ligaments

• the patellar ligament is a continuation of the quadriceps tendon that extends from the patella to the tibial tuberosity and helps keep the patella in its proper position

• the articular capsule extends posteriorly between the intercondylar line of the femur to the posterior border of the tibial plateau

  • it is strengthened posteriorly by the arcuate and oblique popliteal ligaments, medially by the tibial collateral ligament, and laterally by the fibular collateral ligament

  • the popliteus muscle provides additional stabilization to to the knee joint as it ascends superolaterally across the posterior aspect. Its tendon enters the lateral part of the articular capsule, deep to the arcuate popliteal ligament, thus making it an intracapsular structure

Intracapsular Ligaments

• the intracapsular ligaments of the knee are located within the joint capsule

• the cruciate ligaments of the knee extend between the intercondyer fossa of the femur and the intercondyler areas of the tibia, crossing each other to form an X shape

  • the cruciate ligaments prevent the femur and tibia from sliding forwards or backwards

  • the posterior cruciate ligament (PCL) is shorter, thicker, and stronger that the anterior cruciate ligament (ACL)

  • the ACL prevents anterior dislocation of the tibia on the fixed femur

  • the PCL prevents posterior dislocation of the tibia on the fixed femur

• the collateral ligaments are strong ligaments on either side of the knee that prevent excessive medial or lateral movement and stabilize the hinge motion of the knee,

  • the lateral collateral ligament (LCL) is a cord like ligament that is broader than the MCL and joins the distal femur to the head of the fibula

  • the medial collateral ligament (MCL) joins the distal femur to the proximal tibia

Intracapsular Menisci

• the intracapsular menisci are paired, crescent shaped fibrocartilaginous structures located between the articular surfaces of the tibia and femur

• they are supported by several accessory ligaments including the anterior and medial meniscotibial liagments, medial meniscofemoral ligaments, posterior meniscofemoral ligaments, and transverse ligament of the knee

knee joint pics cont’d

knee joint pics cont’d

more pics :)

and some more :)

Tibia

• the tibia articulates proximally at the knee joint with the distal end of the femur, which rests on the tibial plateau formed by the medial and lateral tibial condyles

• the tibial tuberosity is a large, roughened prominence on the anterior proximal tibia which serves as the attachment point for the patellar ligament (and indirectly for the tendon of the quadriceps femoris muscle)

• the body/shaft has 3 surfaces (medial, lateral, posterior) which are separated by 3 borders (anterior, interosseous, medial)

• the posterior surface of the tibia has a ridge called the soleal line which gives attachment to the soleus muscle

• the distal end of the tibia has a projection called the medial malleolus which articulates with the talus; its medial surface can be palpated as the medial ‘knob’ of the ankle

Fibula

• the head of the fibula forms the large proximal end and has 2 main landmarks: the apex (styloid process) which projects proximally from its posterior surface, and a small medially oriented articular surface for the lateral condyle of the tibia, which contributes to the superior tibiofibular joint

• the body of the fibula forms a long thin shaft, with 3 surfaces (medial, lateral, posterior) seperated by 3 ill-defined borders (anterior, posterior, medial)

• the medial surface of the fibula has an interosseous crest, which is connected to the interosseous border of the tibia via the interosseous membrane of the leg to form the middle tibiofibular joint

• the distal end of the fibula articulates with the tibia to form the inferior tibiofibular joint before expanding into the lateral malleolus which constitutes the lateral ‘knob’ of the ankle

• the lateral malleolus articulates with the body of the talus, along with the medial malleolus of the tibia, to form the talocrural joint

joints between tibia and fibula (& interosseous membrane)

• superior tibiofibular joint → plane synovial joint between proximal tibia and fibula

• middle tibiofibular joint → fibrous joint attached by the interosseous membrane

• inferior tibiofibular joint → syndesmosis between distal tibia and fibula. Secures the ankle mortise (the socket that holds the talus bone) and provides stability during weight bearing movement using the anterior inferior tibiofibular ligament located at the front of the ankle, the posterior inferior tibiofibular ligament located at the back of the ankle, the inferior transverse ligament which spans horizontally across the posterior aspect, and the interosseous membrane

• the tibia and fibula are the two bony pillars of the leg, anchoring several muscles and joined by the interosseous membrane of the leg at the middle tibiofibular joint

• the interosseous membrane spans between the interosseous crests of the tibia and fibula and separates the muscles of the anterior and posterior compartment of the leg

• distally, it is continuous with the interosseous ligament of the tibiofibular syndesmosis and has numerous perforations for the passage of small vessels

superior tib fib joint pics :)

inferior tib fib joint & tib fib together labelled :)

some pics :)

Ankle (Talocrural) Joint

• the talocrural joint is a synovial hinge joint formed by the articular surfaces of the distal parts (malleloi) of the tibia and fibula and the body of the talus

• it is supported by a complex set of strong ligaments to provide stabilization and manage the weight of the body

• the ligaments are divided into 2 groups: the medial (tibial) and lateral (fibular) collateral ligaments

Medial Tibial Collateral Ligaments

• the medial collateral ligament (aka deltoid ligament) is a strong band that reinforces the medial aspect of the joint and prevents dislocations of the ankle joint

  • the ligament has a proximal attachment on the medial malleolus of the tibia, and fans out from there to insert onto the navicular bone, calcaneus, and talus

  • it consists of 4 parts: the tibionavicular ligament extending from the tibia to the navicular, the tibiocalcaneal ligament extending from the tibia to the calcaneus, and the anterior and posterior tibiotalar ligaments extending from the tibia to the talus

Lateral Fibular Collateral Ligaments

• the lateral collateral ligament is a strong compound ligament that reinforces the lateral aspect of the ankle joint

  • the ligament has a proximal attachment on the fibula and a distal attachment on the calcaneus and talus

  • the lateral collateral ligament is comprised of 3 distinct bands: the anterior talofibular ligament nd posterior talofibular ligament that extend from the fibula to the talus, and the calcaneofibular ligament that extends from the fibula to the calcaneous

some pics :)

Tarsals & Tarsal Joints

Tarsal Bones

• Talus

• Calcaneus

• Navicular

• Medial Cuneiform

• Intermediate Cuneiform

• Lateral Cuneiform

• Cuboid

Divisions of the Foot

• hindfoot includes the calcaneus and the talus

• midfoot includes the navicular, cuboid, and cuneiform bones

• forefoot includes metatarsals and phalanges

The Tarsals

• the tarsal bones act as important attachment points for muscles of the leg and foot and aid in maintaining the arches of the foot

• the talus forms the connecting bone between the leg and foot, and articulates with the tibia and fibula superomedially and superolaterally to form the talocrural joint, articulates with the calcaneus inferiorly to form the subtalar joint, and articulates with the navicular inferiorly to form the talocalcaneonavicular joint

• the talus contributes to the medial longitudingal arch of the foot

• the calcaneus (heel bone) is the largest of the tarsal bones and articulates with the talus, navicular, and cuboid to form the subtalar, talocalcaneonavicular, and calcanduocuboid joints

• the calcaneus participates in the formation of both the medial and lateral longitudinal arches

• the navicular is boat shaped and located proximal to the 3 cuneiform bones, distal to the talus, and medial to the cuboid

• it contributes to the formation of the calcaneonavicular, cuboideonavicular, and talocalcaneonavicular joints

• navicular bone contributes to the formation of the lateral longitudinal arch of the foot

• the cuneiform bones are wedge shaped bones that articulate with the navicular posteriorly and their respective metatarsal anteriorly, and with each other

• they contribute to the formation of the tarsometatarsal, cuneonavicular, cuneocuboid, and intercuneiform joints

• the cuneiform joints contribute to the formation of the medial longitudinal arch and the transverse arch of the foot

Tarsal Joints

Subtalar Joint → talus to calcaneus

Calcaneocuboid Joint → calcaneus to cuboid

Talonavicular Joint → talus to navicular

Tarsometatarsal Joints → medial, intermediate, lateral cuneiform and cuboid to metatarsal bones

some pics :)

Metatarsals & Joints

Metatarsalphalangeal Joints → metatarsals to proximal phalanges

Tarsometatarsal Joints → metatarsals to tarsals

Intermetatarsal Joints → metatarsals to metatarsals

• the metatarsals are labeled 1-5 starting with the one beneath the big toe (medial) to lateral

• each metatarsal has a proximal base that articulates with the tarsals, a shaft, and a distal head that articulates with the phalanges

• the metatarsals play a vital role in forming the arches of the foot

1st Metatarsal

• thickest and shortest metatarsal

• articulates proximally with the medial cuneiform

• the base features a tuberosity medially and acts as the attachment for the tibialis anterior and the fibularis longus, and laterally as the attachment for the 1st dorsal interosseous muscle

• the shaft articulates proximally with the 1st proximal phalanx has two grooved facets where the two sesamoid bones articulate on the plantar surface

2nd Metatarsal

• the longest metatarsal

• has 4 articular facets at the base that articulate with the medial, intermediate, and lateral cuneiforms and third metatarsal

• it articulates with the 2nd proximal phalanx distally

• the 1st dorsal interosseus muscle attaches to the medial shaft and the 2nd dorsal interosseus muscle attaches to the lateral shaft

3rd Metatarsal

• has a triangular base that articulates proximally with the lateral cuneiform

• medially it has 2 facets that articulate with the 2nd metatarsal and laterally it has 1 facet that articulates with the 4th metatarsal

• the head articulates with the 3rd proximal phalanx

• the medial shaft is the attachment for the 2nd dorsal interosseus muscle and the 1st plantar interosseus muscle

• the lateral shaft is the attachment for the 3rd dorsal interosseus muscle

4th Metatarsal

• smaller than the 3rd and has 3 articular facets at the base

• proximally it has a quadrilateral facet that articulates with the cuboid

• there is an oval facet medially that articulates with the third metatarsal and a facet on the lateral surface that articulates with the 5th metatarsal

• distally, the head articulates with the 4th proximal phalanx

• the medial shaft is the attachment for the 3rd dorsal interosseous and 2nd plantar interosseus muscles

• the lateral shaft is the attachment for the 4th dorsal interosseous muscle

5th Metatarsal

• the 5th metatarsal has a tuberosity lateral to the base which can be seen and felt on the lateral border of the foot

• the base articualtes with the cuboid proximally by a triangular surface and medially with the 4th metatarsal

• the head articulates with the 5th proximal phalanx

• the dorsal base is the attachment for the fibularis tertius muscle

• the tuberosity is the attachment for the fibularis brevis muscle

• the plantar base is the attachment for the flexor digiti minimi brevis muscle

• the medial shaft is the attachment for the 4th dorsal interosseus and the 3rd plantar interosseus muscle

some pics :)

Phalanges & Joints

Metatarsophalangeal Joints → metatarsals to proximal phalanges

Proximal Interphalangeal Joints → proximal phalanges to middle phalanges

Distal Interphalangeal Joints → middle phalanges to distal phalanges

• the phalanges are divided into proximal, middle, and distal (with the exception of the hallux/big toe that only has proximal and distal) and each phalange has a proximal base, shaft, and distal head

• the proximal phalanges are concave to allow for articulation with the metatarsal heads and the heads are trochlear (pulley shaped)

• the shafts of the proximal phalanges are convex dorsally and concave on the plantar aspect

• the small, middle phalanges are broader than the proximal phalanges

• the distal phalanges consist of a broad base for articulation with the middle phalanges as well as a non articular head, and a rough crescent shaped tuberosity on the plantar surface of the heads to support the pads (pulps) of the toes

Muscle Attachments

• Proximal Phalanges

  • the lumbricals attach to the medial aspects of the 4 lateral phalanges

  • the interossei attach to both sides of the 2nd, 3rd, & 4th phalange

• Middle Phalanges

  • the flexor digitorum brevis attaches to the plantar aspect of the base

  • the extensor digitorum brevis attaches to the dorsal aspect of the base

• Distal Phalange of the Hallux

  • the flexor hallucis longus attaches to the plantar aspect of the base

  • the extensor hallucis longus attaches to the plantar aspect of the base

• Distal Phalanges (lateral 4)

  • the flexor digitorum longus attaches to the plantar aspect of the base

  • the extensor digitorum longus attaches to the plantar aspect of the base

some pics :)