Lower Limb Joints: Hip Joint

• The joints of the Lower Limb Include:
  • Hip joint
  • Knee joint
  • Tibiofibular joint
  • Tibiofibular syndesmosis
  • Ankle (talocrural) joint
  • Joints of the foot

Questions to answer about Joints

• Which bones they connect
• Which parts of bones they connect
• What are the articular surfaces
• Which fibrocartilagineus structure joint contains
• Articular capsule
• Which ligaments reinforce the capsule
• Which movements joint allows

Hip Joint (Articulatio Coxae)

• Synovial articulation between the head of the femur and the acetabulum of the pelvic bone (hip bone)
• Multi-axial ball and socket joint designed for stability and weight bearing at the expense of mobility.
• Movements at the joint include flexion, extension, abduction, adduction, medial and lateral rotation and circumduction.

Hip Joint – Articular Surfaces

• Articular surfaces are:
  • Spherical head of the femur
  • Lunate surface of the acetabulum of the pelvic bone

Hip Joint - Acetabulum

• The acetabulum entirely accommodates the hemispherical head of the femur and contributes to the joint stability
• The nonarticulated acetabular fossa contains loose connective tissue
• The lunate surface is a real articular surface and is covered by hyaline cartilage
• The rim of the acetabulum is slightly raised by a fibrocartilaginous collar (the acetabular labrum)
• Inferiorly, the labrum bridges across the acetabular notch as the transverse acetabular ligament and converts the notch into foramen

Hip Joint – Head of Femur

• The head of femur is spherical
• Fovea of the head is located at the top of the head
• The ligament of the head of the femur, a flat band of connective tissue is attached to it, and at the other end to the acetabular fossa
• It carries a small branch of the obturator artery which contributes to the blood supply of the head of the femur

Hip Joint - Capsule

• Synovial membrane is an internal membrane attaching to the margins of the articular surfaces of the femur and acetabulum
  • Also covers the neck of the femur before reflecting into the fibrous membrane
• Fibrous membrane is external, covers the hip joint, is strong, and generally thick

Hip Joint - Ligaments

• Three ligaments reinforce the external surface of fibrous membrane and stabilize the joint
  • Iliofemoral ligament is anterior to the hip joint
  • Pubofemoral ligament is anteroinferior to the hip joint
  • Ischiofemoral ligament reinforces posterior aspect of the fibrous membrane
  • Zona orbicularis – circular fibers encircling the neck of femur
• The fibers of the first three ligaments are oriented in a spiral fashion around the hip joint so that they become tensed when the joint is extended
  • This stabilizes the joint and reduces the amount of muscle energy required to maintain the standing position

Mechanics of the Hip Joint

• Flexion measures 130°
• Extension measures 13°
• Abduction measures 45°
• Adduction is limited
• Lateral rotation measures 13°
• Medial rotation measures 35°
• Circumduction

Knee Joint (Articulatio Genus)

• Largest synovial joint in the human body
• A complex joint consisting of:
  • Articulation between the femur and tibia (weight bearing)
  • Articulation between the patella and femur (allows the pull of the quadriceps femoris muscle to be directed anteriorly over the knee to the tibia without tendon wear)
• Hinge joint allowing mainly flexion and extension
• Weight bearing joint with an efficient "locking" mechanism to reduce the amount of energy required to keep the joint extended when standing

Knee Joint – Articular Surfaces

• Articular surfaces of the bones that contribute to the knee joint are covered with cartilage
  • Two femoral condyles, lateral and medial
  • Superior articular surfaces of tibia
  • Patellar surface of femur
  • Articular surface of patella
• Lateral and medial condyles of the femur are curved and rounded, more antero-posteriorly than from side to side
  • They are connected anteriorly with the patellar surface and divided posteriorly with intercondylar fossa
• Superior articular surfaces of tibia are two cartilage covered articular surfaces that are nearly flat, but slightly concave, and separated by intercondylar area
  • Two fibrocartilaginous structures are attached principally to the periphery of the tibial condyles - menisci which only slightly deepen the concavities of the superior surface of the tibia

Knee Joint - Menisci

• C shaped fibrocartilaginous structures interposed between the corresponding condyles of femur and tibia
  • Medial meniscus
  • Lateral meniscus
• Both menisci are attached at each end to facets on the intercondylar area
  • The medial meniscus is also attached to the capsule around its margin, while the lateral is unattached to the capsule
• Menisci are interconnected anteriorly by a transverse ligament of the knee
  • The lateral is also connected to the tendon of the popliteus muscle
• Patella is located in the tendon of the quadriceps femoris muscle
  • It pushes condyles of femur backwards in flexion because they tend to move forward.

Knee Joint - Capsule

• The synovial membrane of the knee joint attaches to the margins of the articular surfaces and to the superior and inferior outer margins of the menisci
• The fibrous membrane is extensive and is partly formed and reinforced by extensions from tendons of surrounding muscles

Knee Joint - Ligaments

• External ligaments include:
  • Anterior ligaments that consists of Patellar ligament (Medial and lateral retinaculum of patella)
  • Side ligaments that consists: Tibial collateral ligament & Fibular collateral ligament
  • Posterior ligaments: Arcuate popliteal ligament
• Internal, intraarticular ligaments include:
  • Anterior cruciate ligament
  • Posterior cruciate lig.
  • Transverse ligament of knee
  • Meniscofemoral ligaments (anterior and posterior)

Mechanics of the Knee Joint

• Flexion (140-150°)
• Extension
• Medial rotation (5°)
• Lateral rotation (15-20°)
• Maximal rotation in half-flexed knee 35-40°

Lesions of Menisci

• Lesion of the medial meniscus happens 20 times more often
• "Unhappy triad" consists of:
  • Rupture of the tibial collateral ligament
  • Rupture of the medial meniscus
  • Rupture of the anterior cruciate ligament

Tibiofibular Joints

• The tibia and fibula are connected with their proximal and distal ends
• Proximal ends are connected by superior tibiofibular joint
• Distal ends are connected by the tibiofibular syndesmosis
• Interosseus membrane of leg is tough fibrous sheet of connective tissue that attaches to the interosseous margins of tibia and fibula

Superior Tibiofibular Joint

• Small, plane synovial joint between lateral condyle of the proximal end of tibia and head of fibula
• Articular surfaces are comprised of
  • Articular facet of head of fibula (fibula)
  • Fibular articular facet (tibia)
• Both articular facets are flat and circular
• Ligaments that reinforce the capsule consist of the:
  • Anterior ligament of fibular head
  • Posterior ligament of fibular head
• Movements: the joint allows very little movements

Tibiofibular Syndesmosis

• Located between fibular notch at the distal end of tibia and lateral malleolus of fibula
• Fibrous joint of syndesmosis type where the two bones are firmly connected by Anterior and Posterior tibiofibular ligaments

Ankle (Talocrural) Joint

• Synovial joint involving the talus of the foot and the distal ends of the tibia and fibula of the leg
• Mainly allows hinge-like dorsiflexion and plantar flexion of the foot
• Distal ends of tibia and fibula together make socket for expanded talus of the foot

Ankle Joint – Articular Surfaces

• Distal ends of the tibia and fibula make a socket with articular surfaces
• Inferior articular surface of the tibia forms the roof of the socket
• Articular facet of the medial malleolus is on the Medial side of the socket
• Articular facet of the lateral malleolus is on the Lateral side of the socket
• The articular surface of the talus is like a short half-cylinder (trochlea of the talus)
• The curved upper surface (superior facet of the talus) articulates with the inferior articular surface of the tibia and ends of half-cylinder (medial malleolar facet and lateral malleolar facet) articulate with medial and lateral malleoli
• Articular surfaces are covered by hyaline cartilage

Ankle Joint - Capsule

• The articular cavity is enclosed by the capsule composed of:
  • Synovial membrane: attaches around the margins of the articular surfaces
  • Fibrous membrane: covers the synovial membrane and is also attached to the adjacent bones
• Medial collateral ligament consists of four parts (also referred to as deltoid ligament)
  • Tibionavicular ligament
  • Tibiocalcaneal ligament
  • Anterior tibiotalar ligament
  • Posterior tibiotalar ligament
• Lateral collateral ligament also has parts
  • Anterior talofibular ligament
  • Posterior talofibular ligament
  • Calcaneofibular ligament

Mechanics of the Ankle Joint

• Plantar flexion measures 45°
• Dorsal flexion measures 25°

Intertarsal Joints

• Numerous synovial joints between individual tarsal bones mainly invert, evert, supinate and pronate the foot
• Major joints of the foot include:
  • Subtalar joint
  • Transverse tarsal joint
    • Talocalcaneonavicular joint
    • Calcaneocuboid joint

Subtalar Joint

• Between the large posterior calcaneal articular facet on the inferior surface of the talus, and the corresponding posterior talar articular surface on the calcaneus
• Allows gliding and rotation, and is involved in inversion and eversion of the foot
• Ligaments that stabilize the joint
  • Lateral talocalcaneal ligament
  • Medial talocalcaneal ligament
  • Posterior talocalcaneal ligament
  • Talocalcaneal interosseous ligament
• The articular cavity is enclosed by synovial membrane, which is covered by a fibrous membrane

Transverse Tarsal Joint

• A complex joint (talocalcaneonavicular joint) in which the head of the talus articulates with the calcaneus and plantar calcaneo-navicular ligament.
  • The articular surface for the cuboid on the anterior surface of the calcaneus and corresponding facet on the cuboid bone form the Calcaneocuboid joint
• Allows gliding and rotation movements included in the inversion and eversion of the foot, as well as pronation and supination of the foot.

Inversion & Eversion

• Inversion: movement of the sole towards the median plane
• Eversion: movement of the sole of the foot away from the median plane
• Pronation: natural movement of the foot that occurs during foot landing while running or walking - the foot moves inward
• Supination: the foot roles outward

Long Plantar Ligament

• Longest ligament in the sole of the foot
• Attaches posteriorly to the calcaneus, anteriorly to the cuboid bone
  • More superficial fibers extend to the bases of the metatarsal bones
• Strongest ligament of the foot, it supports the calcaneocuboid joint resisting depression of the lateral arch of the foot

Tarsometatarsal and Other Joints

• Joints between metatarsal bones and adjacent tarsal bones are plain joints and allow limited sliding movements
• Other joints of the foot include
  • Metatarsophalangeal joints
  • Interphalangeal joints

Tarsal Tunnel

• Formed in the posteromedial side of the foot, behind the medial malleolus
• Tendons of tibialis posterior m, flexor digitorum longus, flexor hallucis longus, tibial nerve, posterior tibial artery and veins pass through the tunnel.
  • Flexor retinaculum overlies the tunnel.

Arches of the Foot

• Longitudinal arch
  • Supported by the long plantar ligament and tendon of the flexor hallucis longus muscle
• Transversal arch
  • Supported by the tendon of the peroneus (fibularis) longus muscle
• 3 points of foothold makes up the "resting triangle"