Knee Joint Anatomy PDF

XY2141. ANATOMY. KNEE JOINT, LEG REGION Dr Viktoriia Yerokhina, Lecturer in Medical Sciences [email protected]с.u k  LEARNING OUTCOMES ANAT.35 - Leg ANAT.35.01 - Discuss the anatomy of the knee joint (bones, ligaments, blood supply, actions). ANA...

XY2141. ANATOMY. KNEE JOINT, LEG REGION Dr Viktoriia Yerokhina, Lecturer in Medical Sciences [email protected]с.u k  LEARNING OUTCOMES ANAT.35 - Leg ANAT.35.01 - Discuss the anatomy of the knee joint (bones, ligaments, blood supply, actions). ANAT.35.02 - Name and identify the bones and features of the leg (tibia and fibula) ANAT.35.03 - Review the compartments of the leg, the muscles within each compartment, and describe their functions. Identify the muscles in each compartment. ANAT.35.04 - Summarize the neurovascular structures (arteries, veins, nerves) of the leg. ANAT.35.05 - Discuss the relationship of structures related to bone (e.g. common peroneal nerve to fibula; popliteal artery to femur; the tarsal tunnel and review their clinical importance. ANAT.35.06 - Apply anatomical knowledge to clinical correlations of the leg region, as discussed. * Tarsal tunnel will be mentioned in the lecture ‘Ankle, Foot’ – next  PATELLA – PATELLA Sesamoid bone located in the tendon of the quadriceps femoris. It is part of the knee joint. 1. Base of patella (basis patellae) – wide proximal part 2. Apex of patella (apex patellae) – pointy distal end 3. Articular surface (facies arti cularis) – dorsal surface – is divided into a lateral and a medial facet 4. Anterior surface (facies anterior) – roughened ventral surface – incorporates part of the tendon of the quadriceps femoris.  TIBIA – SHINBONE Weight bearing long bone of the leg which forms the shin. Larger of the 2 bones, located medially. Distal end forms the medial malleolus. Anterior margin and the medial surface are not covered by muscles and are therefore palpable in their entire course.  TIBIA – SHINBONE 1. Condyles of tibia (condyli tibiae) – form the widened proximal end – has two condyles: medial and lateral 1.1 Superior articular surface (facies articularis superior) – articular surface for articulation with the femoral condyles 1.2 Intercondylar eminence (eminentia intercondylaris) – eminence located in the middle of the superior articular surface – comprises the medial and lateral tubercle  TIBIA – SHINBONE 1.3 Anterior intercondylar area (area intercondylaris anterior) – attachment of the anterior cruciate ligament and menisci 1.4 Posterior intercondylar area (area intercondylaris posterior) – attachment of the posterior cruciate ligament and menisci 1.5 Fibular articular facet (facies articularis fibularis) – articulates with the head of the fibula TIBIA – SHINBONE  TIBIA – SHINBONE 2. Shaft (corpus tibiae) – body of the tibia 2.1 Soleal line (linea musculi solei) – origin of the soleus muscle 2.2 Tibial tuberosity (tuberositas tibiae) – insertion of the quadriceps femoris (as the patellar ligament)  TIBIA – SHINBONE Surfaces: 2.3 Medial surface – is palpable as it is not covered by muscles 2.4 Lateral surface 2.5 Posterior surface Borders: 2.6 Anterior border – palpable as it is not covered by muscles 2.7 Interosseous border – attachment of the interosseous membrane of the leg 2.8 Medial border.  TIBIA – SHINBONE 3. Distal end 3.1 Medial malleolus (malleolus medialis) – medial side of the ankle 3.1.1 Malleolar groove – forms the malleolar canal together with the flexor retinaculum 3.1.2 Articular facet – articulates with the talus 3.2 Fibular notch (incisura fibularis) – forms part of the tibiofibular syndesmosis 3.3 Inferior articular surface (facies articularis inferior) – articulates with the trochlea of the talus. TIBIA (SHINBONE)  CLINICAL CORRELATION Osteomyelitis of the upper end of tibia is the commonest site of acute osteomyelitis. Fracture of tibia: commonly fractured at the junction of upper 2/3 and lower 1/3 of its shaft. The lower 1/3 of the tibial shaft is bare area (hence devoid of any muscular attachment) and have low blood supply  fractures in the lower 1/3rd of the shaft of tibia show delayed union or non- union.  Fibular = peroneal FIBULA (CALFBONE) A long bone located on the lateral aspect of the leg. It does not bear any weight of the body and serves only for attachments of muscles. Distal end of the fibula forms the lateral malleolus.  FIBULA (CALFBONE) 1. Head (caput fibulae) – insertion of the biceps femoris – attachment of the fibular collateral ligament, arcuate popliteal ligament and anterior and posterior ligaments of the head of the fibula – origin of the soleus and fibularis longus 1.1 Apex of head of fibula (apex capitis fibulae) 1.2 Articular facet (facies articularis capitis fibulae) – articulates with the tibia 2. Neck (collum fibulae) – common fibular nerve runs around the neck  FIBULA (CALFBONE) 3. Shaft (corpus fibulae) Surfaces: 3.1 Lateral surface 3.2 Medial surface 3.3 Posterior surface Borders: 3.4 Anterior border 3.5 Posterior border 3.6 Interosseous border – attachment of the interosseous membrane of the leg 3.7 Medial crest.  FIBULA (CALFBONE) 4. Lateral malleolus (malleolus lateralis) 4.1 Articular facet (facies articularis malleoli lateralis) – articulates with the talus 4.2 Malleolar fossa (fossa malleoli lateralis) 4.3 Malleolar groove (sulcus malleolaris) FIBULA (CALFBONE)  INTEROSSEOUS MEMBRANE OF LEG A tough fibrous sheet of CT that spans the distance between facing interosseous borders of the tibial and fibular shafts. There are two apertures in the interosseous membrane: at the top and at the bottom, for vessels to pass between the anterior and posterior compartments of the leg. Inferior aspect of the interosseous membrane: anterior and posterior tibiofibular ligaments  KNEE JOINT (ARTICULATIO GENUS) Most complicated synovial joint in the human body. A complex and compound bicondylar joint in which three bones and two menisci articulate. Has 12 articular ligaments and many associated bursae. Movements are possible in two axes, but these movements are limited when the knee is in full flexion and full extension.  TYPE, SHAPE AND ARTICULAR SURFACES OF THE KNEE JOINT Type: both complex (indicates the presence of an articular disc or meniscus) and compound (articulations of more than two bones) 1. Femoropatellar joint 1.1 Shape: plane 1.2 Articular head: patellar surface of the femur 1.3 Articular fossa: articular surface of the patella 2. Femorotibial joint 2.1 Shape: combination of the hinge and pivot joints 2.2 Articular head: condyles of the femur 2.3 Articular fossa: condyles of the tibia Three primitive joints included in the knee joint A. Medial and lateral femorotibial joints; B. Patellofemoral joint.  Radiograph of the knee joint A. AP view; B. lateral view; C. sky view.  ARTICULAR CAPSULE 1. Fibrous capsule – originates below the epicondyles of the femur – attaches to the circumference of the articular surfaces of the tibia and patella 2. Synovial membrane – lines the internal surface of the fibrous layer – does not cover the cruciate ligaments 2.1 Infrapatellar synovial fold 2.1.1 Alar folds – project dorsally from the ventral part of the joint 2.2 Infrapatellar fat pad – fat pad between the fibrous and synovial layers.  ARTICULAR CAPSULE 3. Synovial bursae and articular recesses – approximately 20 bursae and 2 recesses are located in the vicinity of the knee joint Communicating with the knee joint: 3.1 Suprapatellar recess 3.2 Suprapatellar bursa 3.3 Subpopliteal recess 3.4 Gastrocnemiosemimembranosus bursa Not communicating with the knee joint: 3.5 Anserine bursa 3.6 Subcutaneous prepatellar bursa 3.7 Subcutaneous infrapatellar bursa  L M LIGAMENTS 1. Collateral ligaments: 1.1 Tibial (medial) collateral ligament – runs from the medial epicondyle of the femur to the tibia – is attached firmly to the medial meniscus 1.2 Fibular (lateral) collateral ligament – runs from the lateral epicondyle of the femur to the head of the fibula  L M LIGAMENTS 2. Ventral ligaments: 2.1 Medial and lateral patellar retinacula – hold the patella in the shallow patellar surface of the femur 2.2 Patellar ligament (ligamentum patellae) – insertion of the quadriceps femoris between the patella and the tibial tuberosity.  LIGAMENTS 3. Dorsal ligaments: 3.1 Oblique popliteal ligament – one of the insertions of the semimembranosus 3.2 Arcuate popliteal ligament – forms an arch above the tendon of the popliteus LIGAMENTS  LIGAMENTS 4. Intra-articular ligaments: 4.1 Anterior cruciate ligament (ACL) – runs from the medial surface of the lateral condyle of the femur ventromedially to the anterior intercondylar area of the tibia 4.2 Posterior cruciate ligament (PCL) – runs from the lateral surface of medial condyle of the femur caudally to the posterior intercondylar area of the tibia  LIGAMENTS 4. Intra-articular ligaments: 4.3 Transverse ligament of knee – connects both menisci ventrally; not covered by synovial membrane (the only true intraarticular ligament of the human body) 4.4 Anterior and posterior meniscofemoral ligament – weak ligaments around the posterior cruciate ligament. Anterior view  MENISCI Menisci - are crescent-shaped wedges of fibrocartilage that provide increased stability to the femorotibial articulation 6. Medial meniscus – C-shape semicircle attaches to the anterior and posterior intercondylar area firmly attached medially to the articular capsule and laterally to the tibial collateral ligament, which limits its mobility 7. Lateral meniscus – O-shaped, almost forms a complete circle attaches to the anterior and posterior intercondylar area not attached to the capsule  more mobile than the medial meniscus.  MOVEMENTS 8. Flexion: 0–150° 9. Extension: 0° 10. Rotations – is possible only in flexed knees 10.1 Internal rotation: 5–10° 10.2 External rotation: approximately 40°  3 MOST COMMON INJURIES OF KNEE JOINT TORN ACL (anterior cruciate ligament) – its weaker than posterior one TORN medial meniscus TORN MCL (medial collateral ligament) – its weaker than lateral  Mnemonic: three C UNHAPPY TRIAD OR O’DONOGHUE TRIAD Unhappy triad: simultaneous injury of the: tibial (medial) collateral ligament, anterior cruciate ligament, medial meniscus (cartilage) (medial meniscus is attached to the MCL) Can occur when a football player’s shoe is planted firmly on the turf and the knee is struck from the lateral side.  GENU VARUM AND GENU VALGUM Mechanical axis of the lower extremity runs from the midpoint of the femoral head and the midpoint of the ankle joint. Physiologically, this line passes through the midpoint of the knee joint. Genu valgum - valgus (lateral) misalignment of the knee, resulting in a knocked knee deformity. Genu varum - varus (medial) misalignment of the knee, resulting in a bowleg deformity.  POPLITEAL ARTERY - ARTERIA POPLITEA Popliteal artery is a direct continuation of the femoral artery. It occupies the popliteal fossa together with the vein of the same name (it runs laterally and posteriorly). Upon reaching the leg region, the artery enters the cruropopliteal canal and gives off its two terminal branches - anterior and posterior tibial arteries. Popliteal artery gives off five genicular arteries.  NERVE SUPPLY OF THE KHEE JOINT Knee joint receives innervation from the femoral nerve, via the saphenous nerve and muscular branches. Joint also receives contributions from the tibial and common fibular (peroneal) nerves, and the posterior division of the obturator nerve.  MUSCLES OF THE LEG Muscles of the leg are organised into three groups: anterior, lateral and posterior groups. Anterior group is innervated by the deep fibular nerve. Lateral group is innervated by the superficial fibular nerve. Posterior group is innervated by the tibial nerve.  MUSCLES OF THE LEG Anterior group 1.2 Tibialis anterior (m. tibialis anterior) 1.2 Extensor digitorum longus (m. extensor digitorum longus) 1.3 Extensor hallucis longus (m. extensor hallucis longus) Lateral group 2.1 Fibularis longus (m. fibularis longus) 2.2 Fibularis brevis (m. fibularis brevis) Posterior group, superficial 3.1 Triceps surae (m. triceps surae) layer 3.2 Plantaris (m. plantaris) Posterior group, deep layer 3.3 Popliteus (musculus popliteus) 3.4 Tibialis posterior (m. tibialis posterior) 3.5 Flexor digitorum longus (m. flexor digitorum longus) 3.6 Flexor hallucis longus (m. flexor hallucis longus)  MUSCLES OF THE LEG. ANTERIOR GROUP 1.1 Tibialis anterior (anterior tibial) 1.2 Extensor digitorum longus (long extensor of the toes) 1.3 Extensor hallucis longus (long extensor of big toe) Consists of three muscles that are located ventrally to the interosseous membrane of the leg. Common innervation from the deep fibular nerve and Function: extensors of the leg. Tibialis anterior helps to maintain both the longitudinal and transverse arches of the foot.  MUSCLES OF THE LEG. LATERAL GROUP 2.1 Fibularis longus (Long peroneal muscle) 2.2 Fibularis brevis (Short peroneal muscle) Consits of two fibular muscles that originate on the lateral surface of the fibula. Both muscles run behind the lateral malleolus in a common tendinous sheath. Innervated by the superficial fibular nerve. Common function: eversion of the foot. Fibularis longus maintains the longitudinal and transverse arches of the foot. ANTERIOR AND LATERAL GROUPS OF MUSCLES OF THE LEG  MUSCLES OF THE LEG. POSTERIOR GROUP Superficial layer 3.1 Triceps surae: 1. Medial head of gastrocnemius 2. Lateral head of gastrocnemius 3. Soleus 3.2 Plantaris Consists of one muscle, triceps surae, which is made up of the soleus and the two-headed gastrocnemius. Variably, a rudimentary muscle plantaris, can also be found in the superficial layer. TENDOCALCANEUS (TENDOACHILLIS) Tendocalcaneus (Achilles tendon) is a conjoint tendon of insertion of gastrocnemius and soleus (triceps surae). It is the thickest and strongest tendon in the body and is about 15 cm long. It acts as a prime mover of plantar flexion of the foot at the ankle joint.  ANCIENT GREEK MYTHOLOGICAL FIGURE ACHILLES The name Achilles tendon comes from the ancient Greek mythological figure Achilles, whose mother held him by the heel when she dipped him in the River Styx to make him invulnerable. The tendon is the only part of his body that was still vulnerable. Troy, 2004 Brad Pitt – Achilles  CLINICAL CORRELATION Achilles tendon ruptures often result from indirect trauma related to sports and exercise and primarily affect men between the ages of 30–50 years. Pre-existing degenerative conditions and certain drugs (e.g., local glucocorticoid injections) have been linked with an increased risk of complete or partial Achilles tendon rupture. Patients may experience a sudden onset of sharp pain in the tendon at the back of the ankle, usually accompanied by a popping or snapping sound or sensation. Both conservative and surgical treatments are recommended.  MUSCLES OF THE LEG. POSTERIOR GROUP – DEEP LAYER Deep layer 3.3 Popliteus 3.4 Tibialis posterior (Posterior tibial) 3.5 Flexor digitorum longus (Long flexor of the toes) 3.6 Flexor hallucis longus (Long flexor of big toe) Consists of four muscles. Tendons of these muscles (except the popliteus) run behind the medial malleolus through the malleolar canal under the flexor retinaculum in three separate tendon sheaths. Act as flexors of the foot and toes and have a common innervation from the tibial nerve. MUSCLES OF THE LEG. POSTERIOR GROUP  BLOOD SUPPLY OF THE LEG Popliteal artery is a direct continuation of the femoral artery carrying blood further down the lower limb. Popliteal artery then splits into the anterior and posterior tibial arteries that travel all the way towards the foot. Anterior tibial artery is the main blood supply for the anterior compartment of the leg. Posterior tibial artery supplies the posterior and lateral sides of the calf and sole. In addition, it supplies a large number of leg muscles via its important branch, the fibular artery.  VEINS OF THE LEG They can be divided into two groups – deep and superficial: Deep veins are located underneath the deep fascia of the lower limb, accompanying the major arteries. Superficial veins are found in the subcutaneous tissue. They eventually drain into the deep veins.  VEINS OF THE LEG Superficial veins: long (great) and short (small/leser) saphenous veins Deep veins Anterior tibial vein Drains the anterior aspect of the leg and foot Posterior tibial vein Drains the posterior aspect of the leg and foot Fibular veins (peroneal veins) Drain the lateral aspect of the leg  CLINICAL CORRELATION Chronic venous disease/disorders (CVD): spectrum of disorders caused by venous dysfunction; ranges from telangiectasia to venous ulceration Chronic venous insufficiency (CVI): advanced CVD including edema, skin changes, and venous ulceration Varicose veins: type of CVD characterised by cylindrical dilation (diameter > 3 mm) and tortuosity of superficial veins.  NERVES OF THE LEG – MAIN BRANCHES Sciatic nerve terminates at the apex of the popliteal fossa by dividing into the tibial nerve and the common peroneal nerve. A cutaneous branch from both the tibial and common peroneal nerve unites to form the sural nerve.  CLINICAL CORRELATION TIPPED: tibial nerve injury versus peroneal nerve injury TIP: Tibial nerve Inverts and Plantarflexes the foot; injury leads to an inability to walk on the TIPtoes PED: Peroneal nerve Everts and Dorsiflexes the foot; injury leads to foot drop. SURFACE ANATOMY REFERENCES