Enhance your knowledge with our comprehensive guide and curated study materials.
The hip joint is a ball-and-socket synovial joint between the head of femur and the acetabulum of hip bone.
It is designed for stability and weight-bearing, not excessive mobility like the shoulder.
Functions: Supports body weight in standing, walking, and running; provides locomotion while maintaining equilibrium.
Structural Type: Synovial joint (ball and socket variety).
Functional Type: Diarthrosis (freely movable).
Acetabulum:
Cup-shaped cavity on lateral surface of hip bone.
Formed by ilium (2/5), ischium (2/5), and pubis (1/5).
Articular surface covered with hyaline cartilage, horseshoe-shaped (lunate surface).
Non-articular part is the acetabular fossa filled with fat and ligamentum teres.
Head of Femur:
More than half a sphere covered with cartilage except at the fovea capitis femoris, where ligament of head attaches.
The strength of the hip joint depends on strong ligaments and surrounding muscles.
Attached above to acetabular margin and below to neck of femur (anteriorly to intertrochanteric line, posteriorly above intertrochanteric crest).
Encloses the joint completely.
Very strong and dense, particularly anteriorly.
Strongest ligament of the body.
Attachment:
Apex → anterior inferior iliac spine.
Base → intertrochanteric line.
Function:
Prevents hyperextension of hip during standing.
Maintains upright posture with minimal muscle effort.
Attachment:
From iliopubic eminence and obturator crest → blends with capsule and iliofemoral ligament.
Function:
Limits over-abduction and extension.
Attachment:
From ischial part of acetabular rim → spirals superolaterally to attach to greater trochanter.
Function:
Limits internal rotation and extension of hip.
Attachment:
Apex → fovea on head of femur.
Base → margins of acetabular notch and transverse acetabular ligament.
Contains:
Small artery to head of femur (from obturator artery).
Function:
Provides vascular supply and minimal mechanical support.
Fibrocartilaginous rim attached to acetabular margin, deepening the cavity and increasing stability.
Bridges the acetabular notch, converting it into a foramen for the obturator vessels and nerves to enter.
Iliopsoas tendon and bursa.
Femoral nerve, artery, and vein.
Pectineus and rectus femoris.
Obturator internus, gemelli, and quadratus femoris.
Sciatic nerve.
Gluteus minimus and reflected head of rectus femoris.
Obturator externus.
Primary sources:
Medial circumflex femoral artery — main supply to head and neck of femur.
Lateral circumflex femoral artery.
Superior and inferior gluteal arteries.
Obturator artery (via artery in ligamentum teres in children).
Clinical note:
The retinacular branches from medial circumflex femoral artery are easily damaged in neck of femur fractures, causing avascular necrosis of the head.
Supplied by Hilton’s Law (nerves supplying muscles acting on joint also supply the joint):
Femoral nerve (anterior).
Obturator nerve (inferior).
Nerve to quadratus femoris (posterior).
Superior gluteal nerve (superior).
| Movement | Muscles Involved | Range / Notes |
|---|---|---|
| Flexion | Iliopsoas (chief), rectus femoris, sartorius | Up to 120° |
| Extension | Gluteus maximus, hamstrings | Up to 20° |
| Abduction | Gluteus medius, minimus, tensor fasciae latae | 45° |
| Adduction | Adductor longus, brevis, magnus, gracilis | 30° |
| Medial rotation | Gluteus medius (anterior fibers), tensor fasciae latae | 35° |
| Lateral rotation | Piriformis, obturator internus, gemelli, quadratus femoris | 45° |
| Circumduction | Combination of all movements | Circular movement |
Incision through gluteus maximus exposes the capsule.
Removal of gluteus medius and minimus reveals ligaments and joint capsule.
Synovial membrane lines capsule and reflects onto neck of femur.
Note the iliofemoral ligament as thickened anterior part of capsule.
Congenital Dislocation of Hip:
Present at birth; due to shallow acetabulum.
Limb appears shortened and externally rotated.
Trendelenburg’s sign positive.
Traumatic Dislocation:
Usually posterior, from dashboard injury.
Limb is shortened, flexed, adducted, and medially rotated.
Fracture Neck of Femur:
Common in elderly (especially females).
Leads to avascular necrosis of head due to torn retinacular vessels.
Avascular Necrosis (AVN):
Death of femoral head due to disrupted blood supply.
Presents with pain and limited motion.
Coxa Vara:
Decrease in angle between neck and shaft (<125°).
Causes limb shortening and limp.
Coxa Valga:
Increase in neck-shaft angle (>135°).
Associated with cerebral palsy or postural deformity.
Trendelenburg’s Sign:
Positive when gluteus medius/minimus are weak (superior gluteal nerve palsy).
Pelvis drops on the opposite side when standing on one leg.
Referred Pain:
Pain from hip joint felt in knee joint (via obturator and femoral nerves).
Synovial joint – condylar variety.
Functionally a complex joint consisting of three joints in one:
Lateral femorotibial joint
Medial femorotibial joint
Femoropatellar joint
Cavity divided by menisci (intra-articular fibrocartilaginous discs).
Femur: Medial and lateral condyles.
Tibia: Medial and lateral condyles with intercondylar area.
Patella: Articulates with patellar surface of femur.
The knee joint is stabilized by five extracapsular and two intracapsular ligaments, along with menisci.
Surrounds the joint completely except anteriorly (where replaced by patella and ligamentum patellae).
Attached above to the margins of the articular surfaces of the femoral condyles and below to the tibial condyles.
Strengthened posteriorly by oblique popliteal ligament and laterally by arcuate popliteal ligament.
Continuation of quadriceps tendon below the patella to the tibial tuberosity.
Acts as an anterior reinforcement of the capsule.
Patellar retinacula on both sides support it, formed by expansions of vasti.
Broad, flat band from medial femoral epicondyle to medial tibial condyle.
Firmly attached to medial meniscus.
Function: Resists valgus (abduction) stress.
Cord-like structure from lateral femoral epicondyle to head of fibula.
Separated from lateral meniscus by tendon of popliteus.
Function: Resists varus (adduction) stress.
Expansion from semimembranosus tendon, reinforces posterior capsule.
Y-shaped; arises from fibular head and spreads upward to strengthen the posterolateral part of the capsule.
Anterior Cruciate Ligament (ACL):
From anterior intercondylar area of tibia → posterior part of inner surface of lateral femoral condyle.
Prevents anterior displacement of tibia on femur.
Posterior Cruciate Ligament (PCL):
From posterior intercondylar area of tibia → anterior part of medial femoral condyle.
Prevents posterior displacement of tibia on femur.
Both are intracapsular but extrasynovial.
Medial meniscus: C-shaped, less mobile, attached to tibial collateral ligament → prone to injury.
Lateral meniscus: Circular, more mobile, separated from fibular collateral ligament by popliteus tendon.
Functions:
Increase congruence of articular surfaces.
Absorb shock.
Aid in joint lubrication and proprioception.
Connects anterior horns of medial and lateral menisci.
Lines the capsule except posteriorly where reflected by cruciate ligaments.
Extensions:
Suprapatellar bursa (extends upward for 5 cm or more).
Infrapatellar pad of fat (separates it from ligamentum patellae).
Infrapatellar synovial fold extends backward to intercondylar fossa.
Alar folds on either side of the patella.
There are 12 bursae around the joint — 4 anterior, 4 medial, and 4 lateral.
Subcutaneous prepatellar bursa
Subcutaneous infrapatellar bursa
Deep infrapatellar bursa
Suprapatellar bursa
Bursa beneath lateral head of gastrocnemius
Between fibular collateral ligament and biceps femoris
Between fibular collateral ligament and popliteus tendon
Between popliteus tendon and lateral tibial condyle
Bursa beneath medial head of gastrocnemius
Anserine bursa (between sartorius, gracilis, semitendinosus, tibia, and tibial collateral ligament)
Beneath tibial collateral ligament
Beneath semimembranosus tendon
Ligamentum patellae and anterior bursae.
Patellar plexus of nerves.
Middle: Popliteal artery and vein, tibial nerve.
Posterolateral: Lateral head of gastrocnemius, plantaris, and common peroneal nerve.
Posteromedial: Medial head of gastrocnemius, semimembranosus, semitendinosus, gracilis, and popliteus.
Sartorius, gracilis, semitendinosus, great saphenous vein, saphenous nerve.
Biceps femoris, popliteus tendon.
Genicular branches of:
Femoral artery
Popliteal artery
Lateral circumflex femoral artery
Recurrent branches from anterior and posterior tibial arteries
Together form the genicular anastomosis.
Derived from:
Femoral nerve (via saphenous branch)
Tibial nerve
Common peroneal nerve
Obturator nerve
Follows Hilton’s law (nerves supplying muscles acting on the joint also supply the joint).
Strip surrounding structures to display capsule, collateral, cruciate, and popliteal ligaments.
Observe menisci, synovial folds, and bursae during deep dissection.
The knee is primarily a hinge joint with slight rotation, allowing:
Flexion
Extension
Slight medial and lateral rotation (only when the joint is flexed)
Range: Up to 135°
Muscles producing flexion:
Biceps femoris
Semitendinosus
Semimembranosus
Sartorius
Gracilis
Gastrocnemius (weak flexor)
Limitation: By tension of quadriceps tendon and anterior cruciate ligament.
Range: Up to 0° (full extension)
Muscles producing extension:
Quadriceps femoris (chief extensor)
Assisted by tensor fasciae latae
Limitation: By posterior capsule, oblique popliteal ligament, and cruciate ligaments.
Range: About 10°
Muscles producing medial rotation:
Popliteus
Semitendinosus
Semimembranosus
Gracilis
Sartorius
Range: About 30°
Muscle producing lateral rotation:
Biceps femoris
When the knee is extended, rotation is prevented by tightness of ligaments, especially the cruciate and collateral ligaments.
Definition: A mechanism that converts the knee into a rigid, weight-bearing joint during the last stage of extension.
Mechanism:
During the last 10°–15° of extension, the medial femoral condyle continues to glide, while the lateral condyle stops early due to its shorter articular surface.
This results in medial rotation of the femur on the tibia (in fixed tibia position).
The joint becomes locked — stable for weight-bearing with minimal muscular effort.
Muscle responsible: Quadriceps femoris (especially vastus medialis) brings the joint into the locked position.
Ligaments involved: Cruciate and collateral ligaments become taut, adding passive stability.
Definition: The process of initiating flexion by undoing the locking.
Mechanism:
Brought about by popliteus muscle.
It laterally rotates the femur on the tibia (or medially rotates tibia when non-weight bearing), thus freeing the joint for flexion.
Popliteus is called the "key of the knee joint."
Locking saves energy during prolonged standing by maintaining joint stability with minimal muscle effort.
Unlocking is necessary for walking, squatting, and all flexion activities.
Identify menisci, cruciate ligaments, and collateral ligaments within the joint cavity.
Observe the popliteus tendon entering the posterior capsule below the lateral condyle.
Trace the suprapatellar bursa and infrapatellar pad of fat for clinical correlations (bursitis, effusion).
ACL tear: Common in athletes; occurs with sudden deceleration or pivoting.
Clinical sign: Anterior drawer test positive — tibia moves anteriorly.
PCL tear: Due to dashboard injury; tibia displaced posteriorly.
Clinical sign: Posterior drawer test positive.
Collateral ligament injury:
Medial collateral ligament (MCL) more frequently injured (often with ACL and medial meniscus — “unhappy triad”).
Medial meniscus tear more common due to its firm attachment to MCL.
Symptoms: Locking of knee, pain, clicking, and swelling.
Diagnosis: MRI or McMurray’s test.
Treatment: Arthroscopic repair or meniscectomy.
Inflammation of prepatellar bursa due to chronic kneeling.
Presents with anterior knee swelling.
Inflammation of subcutaneous infrapatellar bursa, seen in people who kneel frequently.
Fluid-filled swelling in the popliteal fossa due to herniation of synovial membrane through posterior capsule.
Common in chronic arthritis.
Increased Q-angle; knees close together and ankles apart.
Due to rickets or ligament weakness.
Decreased Q-angle; knees apart and ankles close together.
Seen in children with vitamin D deficiency.
Excess synovial fluid collects in suprapatellar pouch → causes swelling above the patella.
Seen in traumatic or inflammatory arthritis.
Pain from hip or spine may be felt in the knee due to shared nerve pathways (obturator and femoral nerves).
Surgical substitution of articular surfaces in severe osteoarthritis; restores mobility and relieves pain.
Synovial hinge joint (ginglymus variety).
Formed between lower ends of tibia and fibula and the superior (trochlear) surface of talus.
Allows movements only in one plane: dorsiflexion and plantar flexion.
Tibia and fibula form a deep socket or mortise that grips the trochlea of talus.
Tibia: Inferior surface and medial malleolus.
Fibula: Medial surface of lateral malleolus.
Talus: Superior, medial, and lateral surfaces of the body of talus.
Encloses the joint, thin in front and behind, strong on sides.
Anteriorly: Attached close to articular margins.
Posteriorly: Attached above articular margins of tibia and below to talus.
Strong, triangular ligament on the medial side.
Apex: Attached to tip of medial malleolus.
Base: Spreads downward to talus, calcaneus, and navicular bone.
Superficial part: Tibionavicular and tibiocalcanean fibers.
Deep part: Anterior and posterior tibiotalar fibers.
Crossed by tendons of tibialis posterior and flexor digitorum longus.
Function: Prevents over-eversion; very strong, so usually causes avulsion fracture rather than rupture.
Consists of three distinct bands:
Anterior talofibular ligament: From anterior margin of lateral malleolus → neck of talus.
Posterior talofibular ligament: From posterior aspect of lateral malleolus → posterior process of talus.
Calcaneofibular ligament: From tip of lateral malleolus → lateral surface of calcaneus.
Function: Prevents inversion; weaker than the deltoid ligament.
Anteriorly:
Tendons of tibialis anterior, extensor hallucis longus, and extensor digitorum longus.
Anterior tibial vessels and deep peroneal nerve.
Posteriorly:
Tendons of gastrocnemius (via Achilles), tibialis posterior, flexor digitorum longus, and flexor hallucis longus.
Posterior tibial vessels and tibial nerve.
Medially: Deltoid ligament, posterior tibial tendons, and vessels.
Laterally: Lateral ligament, peroneal tendons, and peroneal retinacula.
| Movement | Range / Axis | Muscles Involved |
|---|---|---|
| Dorsiflexion | 20° | Tibialis anterior (chief), Extensor hallucis longus, Extensor digitorum longus, Peroneus tertius |
| Plantar flexion | 50° | Gastrocnemius, Soleus, Plantaris, Tibialis posterior, Flexor hallucis longus, Flexor digitorum longus |
Axis: Passes transversely through the malleoli.
Stability: Maximum in dorsiflexion due to the wider anterior part of talus fitting tightly in the mortise.
Derived from:
Anterior tibial artery
Posterior tibial artery
Peroneal artery
These arteries form periarticular anastomoses around the joint
Volume 2, BD Chaurasia’s Human …
.
From deep peroneal nerve (anterior) and tibial nerve (posterior)
Volume 2, BD Chaurasia’s Human …
.According to Hilton’s law, these are the same nerves that supply muscles moving the joint.
Identify extensor and peroneal retinacula, flexor retinaculum, and the tendons within synovial sheaths.
Define medial and lateral ligaments, and note the thin anterior and posterior capsule
Volume 2, BD Chaurasia’s Human …
.Commonest injury: Lateral ankle sprain.
Mechanism: Forced inversion during plantar flexion.
Ligaments involved: Anterior talofibular and calcaneofibular ligaments.
Medial sprains: Rare; occur during over-eversion causing tear of deltoid ligament
Volume 2, BD Chaurasia’s Human …
.Rare due to the deep socket-like mortise formed by tibia and fibula.
Usually associated with fracture of malleoli.
Pott’s fracture: Twisting injury causing fracture of both malleoli with dislocation of foot.
Performed between tendons of extensor hallucis longus and tibialis anterior, with the ankle slightly plantar-flexed
Volume 2, BD Chaurasia’s Human …
.Slight plantar flexion prevents ankylosis (joint stiffness)
Volume 2, BD Chaurasia’s Human …
.Dorsiflexors lift the foot during the swing phase to clear the ground.
Plantar flexors raise the heel during push-off, propelling the body forward.
The ankle’s hinge action is essential for smooth gait
Volume 2, BD Chaurasia’s Human …
.Bony mortise (tibia and fibula gripping talus).
Ligaments: Deltoid, lateral ligaments, interosseous tibiofibular ligament.
Retinacula: Inferior extensor and peroneal retinacula
The tibia and fibula articulate at three joints:
Superior tibiofibular joint
Middle tibiofibular joint
Inferior tibiofibular joint
These joints together maintain the stability and alignment of the leg and ankle during locomotion.
Synovial joint (plane type).
Head of fibula → small, flat facet.
Lateral condyle of tibia → corresponding flat facet.
Fibrous capsule enclosing the joint.
Strengthened by anterior and posterior tibiofibular ligaments, directed forwards and laterally.
Slight gliding or rotatory movements, aiding adjustment of lateral malleolus during ankle motion.
Occasionally communicates with knee joint cavity through the popliteal bursa.
Inferior lateral genicular branch of the popliteal artery.
Nerve to popliteus
Recurrent genicular nerve
Fibrous joint formed by the interosseous membrane connecting tibia and fibula shafts.
Extends between the interosseous borders of both bones.
Fibers directed downwards and laterally.
Upper large opening → for anterior tibial vessels.
Lower small opening → for perforating branch of peroneal artery.
Anteriorly: Tibialis anterior, extensor digitorum longus, extensor hallucis longus, peroneus tertius, deep peroneal nerve, anterior tibial vessels.
Posteriorly: Tibialis posterior, flexor hallucis longus.
Anterior and posterior tibial arteries.
Nerve to popliteus.
Provides muscle attachment surface.
Binds tibia and fibula firmly.
Resists downward pull on fibula by attached muscles (except biceps femoris, which pulls fibula upward).
Syndesmosis (fibrous joint) between the lower ends of tibia and fibula.
Interosseous tibiofibular ligament — main bond of union.
Anterior tibiofibular ligament — fibers directed downward and laterally.
Posterior tibiofibular ligament — stronger than the anterior; lower part forms the inferior transverse tibiofibular ligament, a thick band extending from the malleolar fossa of fibula to the posterior border of tibia.
Perforating branch of peroneal artery
Malleolar branches of anterior and posterior tibial arteries.
Deep peroneal, tibial, and saphenous nerves.
Slight gliding and lateral rotation of the fibula during dorsiflexion of the ankle.
Superior joint: Remove muscles around head of fibula; define popliteus tendon; open the joint.
Middle joint: Remove anterior and posterior muscles from interosseous membrane; examine its surface and openings.
Inferior joint: Identify anterior, posterior, and inferior transverse ligaments; expose interosseous ligament using articulated bones.
The inferior tibiofibular joint provides critical support to the ankle mortise.
Ligament rupture at this joint can cause widening of ankle mortise → instability and chronic pain.
Syndesmotic injuries (“high ankle sprains”) result from forced dorsiflexion with external rotation.
The strength of the interosseous and tibiofibular ligaments is vital for maintaining ankle joint integrity
Volume 2, BD Chaurasia’s Human …
.The joints of the foot form a complex interlocking system that allows both stability for weight-bearing and flexibility for locomotion. The main functional joints are the subtalar (talocalcanean) and talocalcaneonavicular joints.
Synovial plane joint between the talus and calcaneus.
Concave facet on the inferior surface of the talus.
Convex facet on the superior surface of calcaneus (middle one-third).
Fibrous capsule enclosing the joint.
Lateral and medial talocalcanean ligaments — reinforce the sides.
Interosseous talocalcanean ligament — thick and strong, occupies the sinus tarsi; it is the chief bond of union between the two bones.
Cervical ligament — located lateral to the sinus tarsi, passes upward and medially from the calcaneus to the neck of the talus.
The sinus tarsi (tarsal canal) separates the posterior talocalcanean articulation from the anterior and medial ones.
Functionally, the talocalcanean joint and the talocalcaneonavicular joint act together and are often referred to as the subtalar joint complex.
The talocalcanean joint participates in:
Inversion of foot – turning sole medially.
Eversion of foot – turning sole laterally.
Limiting factors:
Eversion limited by interosseous ligament (taut during eversion).
Inversion limited by cervical ligament (taut during inversion).
Modified ball-and-socket synovial joint.
Head of talus → spherical and forms the ball.
Socket → formed by:
Posterior surface of navicular bone.
Upper surface of spring ligament (plantar calcaneonavicular ligament).
Anterior articular surface of calcaneus.
Medial limb of bifurcate ligament (laterally).
Spring ligament (plantar calcaneonavicular ligament):
Extends from sustentaculum tali to navicular bone.
Supports the head of the talus, forming part of the socket.
Contains elastic fibers → acts as a “spring” maintaining medial longitudinal arch.
Dorsal talonavicular ligament: Supports the joint dorsally.
Interosseous talocalcanean ligament: Supports it posteriorly.
Medial limb of bifurcate ligament: Supports the joint laterally.
Inversion and eversion of the foot (along with subtalar joint).
During these movements:
The talus acts as a pivot, remaining relatively fixed within the ankle mortise.
The calcaneus and navicular bones move around the head of talus.
These joints together permit complex “supination and pronation” movements essential for walking on uneven ground.
The combined talocalcanean and talocalcaneonavicular joints allow the foot to:
Adapt to uneven surfaces.
Maintain balance during locomotion.
Absorb shocks during heel strike and propulsion.
Subtalar dislocation: Rare; occurs due to severe inversion or eversion injury.
Flat foot (pes planus): Weakening of the spring ligament causes depression of medial arch and downward displacement of talar head.
Sinus tarsi syndrome: Pain and tenderness due to inflammation in the interosseous ligament area.
Synovial saddle-type joint, but functionally behaves as a plane joint.
Anterior surface of calcaneus – slightly convex.
Posterior surface of cuboid – slightly concave.
Together form a stable but flexible articulation forming the lateral part of the transverse tarsal joint.
Fibrous capsule – completely encloses the joint.
Dorsal calcaneocuboid ligament – strengthens dorsum.
Plantar calcaneocuboid ligament (short plantar ligament) – very strong, lies deep to long plantar ligament.
Long plantar ligament – extends from calcaneus to bases of 2nd–4th metatarsals, forming a tunnel for the tendon of peroneus longus.
Gliding movements occur, contributing to inversion and eversion of the foot.
Motion occurs around an oblique axis, continuous with that of the talocalcaneonavicular joint.
From peroneal and dorsalis pedis arteries.
Lateral plantar nerve and superficial peroneal nerve.
Formed by the combination of:
Talocalcaneonavicular joint (medially) and
Calcaneocuboid joint (laterally).
Functionally acts as one continuous joint line, providing rotational mobility of the foot.
Compound synovial joint.
Derived from the two constituent joints (same as above).
The interosseous talocalcanean ligament and bifurcate ligament (connecting calcaneus to cuboid and navicular) are key stabilizers.
The main site for inversion and eversion of the foot.
Acts as a transverse hinge between hindfoot and forefoot, adjusting the foot to uneven ground.
Movement occurs about an oblique axis passing from the back of the heel to the front of the foot.
Passes obliquely from the posterolateral calcaneus through the sinus tarsi to the dorsum of the navicular bone.
Sole faces medially and upward.
Associated movements:
Adduction of forefoot.
Supination (raising of medial border).
Joints involved:
Talocalcanean joint.
Talocalcaneonavicular joint.
Calcaneocuboid joint.
Muscles producing inversion:
Tibialis anterior – chief muscle during dorsiflexion.
Tibialis posterior – chief muscle during plantar flexion.
Assisted by flexor hallucis longus and flexor digitorum longus.
Sole faces laterally and upward.
Associated movements:
Abduction of forefoot.
Pronation (raising of lateral border).
Joints involved:
Talocalcanean joint.
Talocalcaneonavicular joint.
Calcaneocuboid joint.
Muscles producing eversion:
Peroneus longus
Peroneus brevis
Peroneus tertius
Inversion helps lift the medial side during walking on uneven surfaces.
Eversion stabilizes the foot on lateral tilt and prevents ankle inversion injuries.
Together, these movements give the foot its adaptive and spring-like quality.
Remove extensor tendons on dorsum to expose the talonavicular and calcaneocuboid joints.
Identify bifurcate ligament dividing into:
Calcaneonavicular limb (medial).
Calcaneocuboid limb (lateral).
Display short and long plantar ligaments and peroneus longus tendon tunnel beneath them.
Observe spring ligament beneath the head of talus, supporting the medial arch.
Note movement demonstration: passive inversion and eversion by manipulating calcaneus.
Flat Foot (Pes Planus):
Collapse of medial arch due to weakness of spring ligament or tibialis posterior.
Club Foot (Talipes Equinovarus):
Congenital inversion and adduction deformity of foot.
Eversion Injury:
May rupture deltoid ligament or fracture medial malleolus.
Inversion Injury:
Commonest ankle trauma; damages lateral ligament complex.
The forefoot contains numerous small synovial joints between the tarsal, metatarsal, and phalangeal bones.
Together, they provide flexibility, stability, and shock absorption during walking.
There are five main synovial cavities in the foot:
Ankle joint cavity — communicates freely with the superior tibiofibular joint in some individuals.
Subtalar (talocalcanean) joint cavity — separate from others, lies between talus and calcaneus.
Talocalcaneonavicular + anterior intertarsal joints — continuous with midtarsal (transverse tarsal) joint cavity.
Tarsometatarsal + intermetatarsal joints — interconnected, allowing limited gliding movement.
Metatarsophalangeal + interphalangeal joints — independent small synovial cavities.
Note: All cavities are lined by synovial membrane and surrounded by strong fibrous capsules.
Synovial condyloid joints.
Heads of metatarsals → convex.
Bases of proximal phalanges → concave.
Capsular ligament — encloses the joint.
Plantar ligament (plate) — thick fibrocartilaginous structure on plantar side, limits hyperextension.
Collateral ligaments — strong, on either side of the joint.
Deep transverse metatarsal ligament — connects the plantar ligaments of all MTP joints (except first), maintaining the transverse arch.
Flexion and extension (chief).
Abduction and adduction (slight).
Range greatest at the first MTP joint (for push-off during walking).
Flexion: Flexor digitorum longus, flexor digitorum brevis, lumbricals, interossei.
Extension: Extensor digitorum longus and brevis.
Abduction: Dorsal interossei (away from 2nd toe).
Adduction: Plantar interossei (toward 2nd toe).
Synovial hinge joints.
Head of proximal phalanx → pulley-shaped.
Base of distal phalanx → correspondingly concave.
Capsular ligament — encloses the joint.
Collateral ligaments — strong, stabilize laterally.
Plantar ligament — fibrocartilaginous thickening that limits hyperextension.
Only flexion and extension.
Flexion more extensive than extension.
Flexion: Flexor digitorum longus, flexor digitorum brevis, flexor hallucis longus (for great toe).
Extension: Extensor digitorum longus, extensor digitorum brevis, extensor hallucis longus.
Hammer Toe: Hyperextension at MTP and flexion at PIP joint due to imbalance between flexors and extensors.
Claw Toe: Hyperextension at MTP and flexion at both IP joints, commonly in neuropathic foot.
Hallux Valgus: Lateral deviation of great toe at the first MTP joint with medial deviation of first metatarsal.
Bunion: Inflammation and swelling of the bursa over the first MTP joint in hallux valgus.
Remove skin and superficial fascia from the dorsum and sole of forefoot.
Identify tendons of long and short flexors and extensors entering toes.
Note fibrous flexor sheaths enclosing tendons on plantar side.
Observe deep transverse metatarsal ligament connecting plantar plates.
Demonstrate MTP and IP joints by gently flexing and extending the toes.
Display bursa and synovial sheaths to understand friction-reducing mechanisms.
MTP and IP joints maintain foot grip, adapt to terrain, and ensure smooth toe-off in walking and running.
Their coordinated motion supports the longitudinal and transverse arches of the foot.
Gait is the rhythmic, alternating movement of the limbs and trunk that results in forward progression of the body.
Each complete sequence of limb movement is called a gait cycle or stride.
Each gait cycle has two main phases:
Period when the foot is on the ground bearing body weight.
Sub-phases:
Heel strike (initial contact):
Heel touches the ground.
Muscles: Tibialis anterior (controls foot lowering).
Foot flat (loading response):
Entire foot contacts ground; weight transferred to limb.
Muscles: Quadriceps stabilize knee; gluteus medius prevents pelvic drop.
Mid-stance:
Body passes over supporting limb; opposite limb in swing.
Muscles: Soleus and gastrocnemius control forward tibial movement.
Heel off (terminal stance):
Heel rises as body moves forward.
Muscles: Gastrocnemius and soleus (plantar flexors) propel body.
Toe off (pre-swing):
Toes push off; limb prepares for swing.
Muscles: Flexor hallucis longus, flexor digitorum longus.
Period when foot is off the ground and limb moves forward.
Acceleration (initial swing):
Hip flexors (iliopsoas) and knee flexors (hamstrings) advance limb.
Mid-swing:
Foot clears ground; dorsiflexors (tibialis anterior) lift forefoot.
Deceleration (terminal swing):
Hamstrings slow down limb before heel strike.
One gait cycle = time between two successive heel strikes of the same foot.
The alternating pattern of stance and swing ensures continuous movement.
Seen in painful conditions (arthritis, fracture, soft-tissue injury).
Shortened stance phase on affected side to reduce pain.
Cause: Paralysis of gluteus medius/minimus (superior gluteal nerve).
Sign: Pelvis drops on the opposite side when standing on affected limb.
Person lurches toward affected side to maintain balance.
Cause: Paralysis of dorsiflexors (deep peroneal nerve lesion).
Sign: Toes drag during swing; patient lifts knee high to clear foot.
Cause: Bilateral hip abductor weakness or congenital hip dislocation.
Sign: Side-to-side trunk movement, resembling duck walk.
Cause: Upper motor neuron lesion.
Sign: Affected limb stiff; swung outward in semicircle during walking.
Cause: Cerebellar or sensory pathway lesions.
Sign: Unsteady, broad-based, irregular steps (“drunken gait”).
Cause: Basal ganglia disorder (Parkinson’s disease).
Sign: Short, shuffling steps, stooped posture, reduced arm swing, difficulty starting or stopping.
Cause: Tabes dorsalis or sensory neuropathy.
Sign: Patient stamps feet to know ground contact (loss of proprioception).
Cause: Tight Achilles tendon or spastic plantar flexors.
Sign: Walking on toes with heels elevated.
Cause: True or apparent limb shortening.
Sign: Pelvic dip on shorter side; compensatory circumduction of long limb.
Mnemonic: 🧠 “MAP Tightens Joint”
M – Medial condyle of femur continues to glide (longer surface).
A – Anterior cruciate ligament becomes taut.
P – Posterior cruciate ligament tightens too.
Tightens Joint – Collateral ligaments also tense up → knee becomes stable.
Key Point:
During final stage of extension, femur medially rotates on tibia (or tibia laterally rotates when foot is free), producing the locked position.
Purpose:
Allows the body to stand erect without continuous quadriceps contraction.
Mnemonic: 🗝️ “POP Laterally”
POP – Popliteus muscle initiates movement.
Laterally – Causes lateral rotation of femur (or medial rotation of tibia).
Key Point:
Popliteus “unlocks” the knee by releasing tension in cruciate and collateral ligaments so flexion can begin.
| Process | Movement | Muscle | Effect |
|---|---|---|---|
| Locking | Medial rotation of femur | Quadriceps (esp. vastus medialis) | Stability in extension |
| Unlocking | Lateral rotation of femur | Popliteus | Initiates flexion |
Inability to lock → quadriceps weakness.
Inability to unlock → popliteus paralysis (posterior knee injury).
Locking mechanism provides energy-efficient standing posture; essential for erect bipedal gait.
Type: Ball-and-socket synovial joint.
Strongest ligament: Iliofemoral ligament (of Bigelow) — prevents hyperextension.
Chief flexor: Iliopsoas.
Chief extensor: Gluteus maximus.
Chief abductor: Gluteus medius.
Chief adductor: Adductor longus.
Main blood supply: Medial circumflex femoral artery.
Nerve supply: Femoral, obturator, and nerve to quadratus femoris.
Clinical note: Fracture neck of femur → avascular necrosis of femoral head.
Type: Condylar synovial joint (modified hinge).
Ligaments: Two cruciate (ACL, PCL) and two collateral (MCL, LCL).
Strongest ligament: Posterior cruciate ligament.
Weakest part: Anterior aspect (no capsule).
Menisci: Fibrocartilaginous; medial meniscus fixed (commonly torn).
Locking mechanism: Medial rotation of femur during final extension.
Unlocking muscle: Popliteus.
Blood supply: Genicular anastomosis.
Nerve supply: Femoral, tibial, common peroneal, obturator nerves.
Clinical note: “Unhappy triad” — injury to ACL, MCL, and medial meniscus.
Type: Synovial hinge joint.
Axis: Transverse line joining tips of malleoli.
Movements: Dorsiflexion and plantar flexion.
Stable position: Dorsiflexion (wider anterior talar surface engaged).
Strong ligament: Deltoid (medial) ligament.
Common injury: Lateral ligament sprain due to inversion.
Main stabilizer: Inferior transverse tibiofibular ligament.
Clinical note: Pott’s fracture — twisting injury causing bimalleolar fracture.
Superior: Plane synovial joint (slight gliding).
Middle: Fibrous interosseous membrane (no movement).
Inferior: Syndesmosis (strong fibrous joint).
Main ligament: Interosseous tibiofibular ligament.
Function: Maintains ankle mortise stability.
Clinical note: High ankle sprain = injury to inferior tibiofibular ligaments.
Subtalar joint: Between talus and calcaneus — for inversion/eversion.
Talocalcaneonavicular joint: Modified ball-and-socket type.
Calcaneocuboid joint: Saddle-type; forms lateral part of transverse tarsal joint.
Plantar calcaneonavicular (spring) ligament: Supports medial arch; maintains talar head position.
Long and short plantar ligaments: Support lateral arch.
Movements: Inversion (tibialis anterior & posterior) and eversion (peronei).
MTP joints: Condyloid type → flexion, extension, slight abduction/adduction.
IP joints: Hinge type → flexion and extension.
Deep transverse metatarsal ligament: Maintains transverse arch.
Clinical note:
Hallux valgus → lateral deviation of great toe.
Hammer/claw toe → imbalance of long flexors and extensors.
Medial longitudinal arch: Higher and more elastic.
Bones: Calcaneus, talus, navicular, 3 cuneiforms, medial 3 metatarsals.
Key ligament: Spring ligament.
Key muscle: Tibialis posterior.
Lateral longitudinal arch: Flatter, more rigid.
Bones: Calcaneus, cuboid, 4th & 5th metatarsals.
Key ligament: Long plantar ligament.
Transverse arch: Across metatarsal bases; maintained by peroneus longus tendon.
Stance phase: 60% of cycle (foot in contact with ground).
Swing phase: 40% (foot in air).
Locking of knee: Medial rotation of femur during last phase of extension.
Unlocking: Lateral rotation of femur by popliteus.
Trendelenburg gait: Superior gluteal nerve lesion.
Foot drop: Deep peroneal nerve lesion.
Waddling gait: Bilateral abductor weakness.
Ataxic gait: Cerebellar disorder.
Parkinsonian gait: Short, shuffling steps.
Hilton’s Law: Nerves supplying muscles acting on a joint also supply the joint.
Menisci: Absorb shock, improve congruence.
Spring ligament: Supports talar head and medial arch.
Popliteus: “Key of the knee joint.”
Iliofemoral ligament: “Y-shaped ligament of Bigelow.”
Locking–Unlocking Mnemonics:
Locking → MAP tightens joint
Unlocking → POP laterally (popliteus)
Case: A 65-year-old woman falls and cannot stand; her limb appears shortened and laterally rotated.
Diagnosis: Fracture of the neck of femur.
Explanation: Fracture disrupts retinacular branches of the medial circumflex femoral artery → avascular necrosis of femoral head; lateral rotation by short lateral rotators.
Case: A young athlete experiences pain in the groin after excessive kicking.
Diagnosis: Strain of iliopsoas or rectus femoris.
Explanation: These are primary hip flexors; sudden contraction during kicking leads to muscle strain near origin.
Case: Patient with posterior dislocation of the hip has loss of dorsiflexion and extension of knee.
Diagnosis: Injury to sciatic nerve.
Explanation: Hip dislocation may stretch or tear the sciatic nerve → paralysis of hamstrings and all muscles below knee.
Case: A patient complains of pain and locking of the knee while walking.
Diagnosis: Medial meniscus tear.
Explanation: Medial meniscus is fixed to MCL and less mobile → prone to tear during rotation when flexed.
Case: After a football tackle, a player shows valgus strain with swelling in knee.
Diagnosis: Unhappy Triad Injury.
Explanation: Simultaneous rupture of ACL, MCL, and medial meniscus from lateral impact on flexed knee.
Case: A person cannot initiate knee flexion after posterior knee trauma.
Diagnosis: Injury to popliteus muscle.
Explanation: Popliteus unlocks the knee by laterally rotating femur; injury prevents initiation of flexion.
Case: Elderly patient has pain behind knee after walking; swelling in popliteal fossa.
Diagnosis: Baker’s cyst (popliteal cyst).
Explanation: Herniation of knee joint synovial membrane through posterior capsule.
Case: A patient complains of knee instability when descending stairs.
Diagnosis: Tear of anterior cruciate ligament (ACL).
Explanation: ACL prevents forward displacement of tibia; tear causes “anterior drawer sign” positive.
Case: Following a dashboard injury, the tibia moves backward abnormally.
Diagnosis: PCL tear.
Explanation: Posterior cruciate ligament prevents posterior tibial displacement; “posterior drawer sign” positive.
Case: A runner complains of pain below the patella; swelling over front of knee.
Diagnosis: Prepatellar bursitis (Housemaid’s knee).
Explanation: Inflammation of subcutaneous prepatellar bursa due to prolonged kneeling.
Case: Pain over medial ankle with swelling after eversion injury.
Diagnosis: Deltoid ligament tear or avulsion fracture.
Explanation: Deltoid ligament is very strong; excessive eversion avulses medial malleolus.
Case: Severe pain on outer ankle after inversion injury.
Diagnosis: Lateral ligament sprain (ankle sprain).
Explanation: Inversion strain tears anterior talofibular and calcaneofibular ligaments.
Case: Patient complains of pain and tenderness over lateral malleolus after a twisting fall.
Diagnosis: Pott’s fracture.
Explanation: External rotation of foot fractures both malleoli and dislocates ankle.
Case: A person walking on uneven surface twists ankle repeatedly with pain at ankle joint.
Diagnosis: Syndesmotic injury (high ankle sprain).
Explanation: Tear of interosseous tibiofibular ligament → widening of ankle mortise and instability.
Case: A person complains of chronic pain in heel, worse after rest.
Diagnosis: Plantar fasciitis.
Explanation: Inflammation of plantar aponeurosis at calcaneal attachment; causes “first step” heel pain.
Case: A shopkeeper develops a bony spur at calcaneal tuberosity.
Diagnosis: Calcaneal spur.
Explanation: Chronic traction by plantar aponeurosis → ossification at attachment.
Case: A patient develops flattening of the medial border of foot.
Diagnosis: Flat foot (pes planus).
Explanation: Weakness of spring ligament and tibialis posterior → collapse of medial arch.
Case: Newborn presents with plantar flexed, inverted, and adducted foot.
Diagnosis: Congenital talipes equinovarus (clubfoot).
Explanation: Deformity due to abnormal intrauterine positioning or muscle imbalance.
Case: Pain and tenderness over lateral side of foot after eversion sprain.
Diagnosis: Peroneal tendon strain.
Explanation: Overuse of peroneus longus and brevis during excessive eversion.
Case: A person has high-stepping gait with inability to dorsiflex foot.
Diagnosis: Common peroneal nerve injury at fibular neck.
Explanation: Paralysis of dorsiflexors → foot drop; compensated by exaggerated hip and knee flexion.
Case: Patient shows pelvis drooping on one side while walking.
Diagnosis: Positive Trendelenburg sign.
Explanation: Weakness of gluteus medius/minimus (superior gluteal nerve palsy).
Case: A child walks on toes with heels off the ground.
Diagnosis: Equinus gait.
Explanation: Spastic contraction or contracture of calf muscles (gastrocnemius, soleus).
Case: A diabetic patient develops ulcer on ball of foot with clawing of toes.
Diagnosis: Neuropathic foot (Charcot foot).
Explanation: Loss of protective sensation and muscle imbalance → deformity and pressure ulcers.
Case: Elderly patient complains of instability while walking in dark.
Diagnosis: Sensory ataxia.
Explanation: Loss of proprioceptive input from posterior columns → stamping gait.
Case: Elderly woman with osteoarthritis reports difficulty rising from sitting.
Diagnosis: Quadriceps weakness.
Explanation: Quadriceps extend the knee and stabilize patella; weakness prevents smooth standing.
These 25 clinicoanatomical cases comprehensively integrate the applied anatomy of hip, knee, ankle, and foot — ideal for viva and theory discussion.
Get the full PDF version of this chapter.
Continue with Google