Thigh musculature, Knee and ankle osteology Lower Extremity Thigh musculature, Knee and ankle osteology

Objectives Describe the gross anatomy for each system (circulatory, muscular, nervous, and skeletal) in the lower extremity. Integrate the systems to discuss the lower extremity stability and mobility functions. Analyze common injuries in the lower extremities. For each muscle, describe how the attachment sites result in an action around a joint. For each muscle, identify the innervation (peripheral nerve and nerve roots). Pulled from syllabus

There are 4 genicular arteries that supply the hip joint True False B

Gluteus medius is an internal rotator when the hip is flexed True False A

R Gluteus Medius L Gluteus Medius R Gluteus Minimus L Gluteus Minimus Your patient has trendelenburg gait when body weight is shifted to the R Leg. Which muscle is probably weakest? R Gluteus Medius L Gluteus Medius R Gluteus Minimus L Gluteus Minimus A

Soft spots Femoral Triangle Adductor Canal Borders: Problems? Femoral triangle borders: lateral – Sartorius superior – inguinal ligament medial – adductor longus floor – iliopsoas laterally, pectineus medially roof – fascia latae contains femoral nerve, artery, vein (VAN) Problems: femoral hernia – more common in women than men -> loop of small intestine pushed into femoral sheath Adductor canal borders: anterior – VMO posterior – adductor longus & magnus roof – Sartorius spans from apex of femoral triangle to adductor hiatus contains femoral artery, femoral vein, saphenous nerve (branch of femoral, ends before hiatus)

Adductors Large moment arm for adduction Small moment arm for internal hip rotation Obturator nerve Shaft bends anteriorly – creates a moment arm for adductors around long axis of femur moment arm gets larger as hip is flexed (pg. 417 Neumann) Describe all muscles involved in internal rotation: glut med and min TFL adductors medial hamstrings Superficial Layer: Pectineus -> pectineal line of femur Adductor Longus -> linea aspera Gracilis -> pes anserine Middle Layer: Adductor brevis -> between pectineus and longus Deep Layer: Adductor magnus hamstring part -> adductor tubercle (palpated) adductor part -> entire length of posterior femur

Clinical Relevance Groin injury or “pulled groin” Gracilis muscle transplant Groin injury or “pulled groin” strain, stretching, or tearing of proximal attachment of flexors or adductors usually in sports that require quick starts or extreme stretching Gracilis muscle used in grafts not very effective – can be used to repair forearm muscles or for nonfunctional external anal sphincter to significantly improve quality of life

Your patient has damage to the obturator nerve Your patient has damage to the obturator nerve. Which muscle would be unaffected? Adductor longus Adductor brevis Pectineus Hamstring portion of adductor magnus Adductor portion of adductor magnus D

Tibial plateau – flat, rotates around femoral condyles Interosseous membrane – criss cross pattern, strong membrane, attachment site for posterior tib extensor hallucis longus Opening for anterior tibial artery

Genu valgus and varus will change amount of force through each condyle Healthy knee xray features joint space (menisci don’t show on xray) equal spaces Note how unstable the knee joint is

To provide stability, ligaments are essential! MCL – broad, expansive, attached to medial meniscus, medial epicondyle -> medial condyle of tibia LCL – thick and cord-like, lat epicondyle -> fibular head ALL – new ligament found in 2013 – lateral femoral epicondyle -> gerdy’s tubercle deep to IT band, but fibers attach to epicondyle ACL & PCL next slide

https://www.youtube.com/watch?v=RTV5Yo3E7VQ ACL from anterior intercondylar eminence -> posterior inner part of lateral condyle PCL posterior intercondylar eminence -> anterior inner part of medial condyle Video Knee menisci medial meniscus – half moon shape lateral meniscus – circular Anchored to tibia anteriorly and posteriorly by horns -> intercondylar eminence Menisci provide cushion for large amounts of force triple joint contact area during walking, forces crossing the knee are typically 2-3 times body weight, maximally reaches up to 9 times body weight Lateral meniscus is more mobile – typically damaged with ACL Medial meniscus is anchored by MCL – can be damaged with MCL Patella tracking – knee biomechanics group!! https://www.youtube.com/watch?v=RTV5Yo3E7VQ

Bursae & Bursitis Prepatellar Infrapatellar Suprapatellar Pes anserine Superficial Deep Suprapatellar Pes anserine MCL Iliotibial Locations of bursae prepatellar – superficial to patella infrapatellar – superficial and deep to patellar ligament suprapatellar – deep to quad tendon pes – deep to pes anserine MCL – deep to MCL iliotibial – deep to IT band near insertion Bursitis inflammation or irritation of synovial sacs pain occurs during movement the bursae is supposed to protect (pes bursitis = pain while contracting pes muscles) furthermore, using those muscles will continue to inflame the bursa MRIs of prepatellar bursitis

What’s wrong with this picture? Nothing The ligaments shown are wrong The patella is out of place The knee doesn’t bend that way There is a ligament missing C, E

Knee rotation and the locked position Full extension & 10 degrees external rotation All ligaments taught, maximal joint contact

Clinical Relevance Genu varum & genu valgum Patellofemoral syndrome Patellar dislocation Bursitis & popliteal cysts Knee replacement Genu varum leads to medial condyle osteoarthritis Genu valgum leads to lateral condyle osteoarthritis gait repeatability is the same in patients with knee osteoarthritis as in normal individuals* Patellofemoral syndrome “runner’s knee” abnormal tracking can cause degenerative trauma strengthening VMO supposedly helps – seen research that suggests otherwise hint hint: another potential topic! Patellar dislocation more common in women, larger q-angle (quadriceps angle) femur is shaped to prevent lateral dislocation (lateral condyle extends farther anteriorly than medial, deeper groove laterally Bursitis & popliteal cysts prepatellar bursa most commonly aggravated

O’Donoghue Triad MCL, ACL, and lateral meniscus often torn together – “unhappy, terrible triad”, “blown knee” Still often considered MCL, ACL, medial meniscus but it has been found that lateral meniscus is more often affected and medial meniscus tears are always accompanied by lateral meniscus damage as well. valgus force to knee Symptoms: Pain in affected knee Stiffness and swelling in affected knee Catching or locking of the knee in affected knee Instability of the knee with twisting or side-to-side movements(The sensation of the knee "giving out"). Inability to move the knee through its full range of motion

Your patient suffered a lateral blow to the knee with the foot planted while playing soccer. Which of the following is least likely to have suffered damage? ACL PCL MCL Medial meniscus Lateral meniscus B

While rollerblading, your patient ran into a short wall While rollerblading, your patient ran into a short wall. Which of the following is most likely damaged? ACL PCL MCL Medial meniscus Lateral meniscus B

Quadriceps Rectus Femoris Vastus Lateralis Vastus Medialis Vastus intermedius ¾ quads pull the patella laterally Innervated by femoral nerve VL is large, linea aspera -> quad tendon strong and pulls laterally VM is smaller with angled muscle fibers, linea aspera -> quad tendon weaker, often too weak to counteract VL VI fills space under VL and VM – larger than it looks, anterior & lateral shaft of femur -> quad tendon

Clinical Relevance Contusions Avulsion fractures Hematomas Charley horse Contusions “hip pointer injury” – contusion of iliac crest bleeding from ruptured capillaries into soft tissues (muscles, tendons, connective tissue) Avulsion fractures often confused as a contusion tendon rips off part of the attachment site from the bone Sartorius or rectus femoris common avulsion fractures in “hip pointer injuy” Hematomas blood clot (hema – blood; toma – mass) contusions large enough to clot Charley horse acute cramping of a muscle from ischemia, nocturnal leg cramps, contusion

Hamstrings Biceps Femoris Semitendinosus Semimembranosus Long head Short head (not a hamstring) Semitendinosus Semimembranosus Biceps Femoris Long head fused with semitendinosus proximally ischial tuberosity -> fibular head distally, splits around the LCL tibial nerve Short head (not a hamstring) fused with long head distally lateral intermuscular septum, linea aspera -> fibular head common fibular nerve Semitendinosus ischial tuberosity -> pes anserine (medial tibia) very superficial distally, half the muscle is strong, cordlike tendon possibly for energy efficiency?? Possibly to primarily act on the hip?? Semimembranosus ischial tuberosity -> medial condyle of tibia, partially attaches to medial meniscus proximally, half the muscle is thin membranous type tendon possibly for energy efficiency?? Possibly to primarily act on the knee?? Hint hint: potential topic for final essay

What is the muscle highlighted on the left? Biceps femoris long head Biceps femoris short head Semitendinosus Semimembranosus A

What is the muscle highlighted on the right? Biceps femoris long head Biceps femoris short head Semitendinosus Semimembranosus D

Popliteal fossa Task: Borders: Identify each of the numbers Superomedial Superolateral Inferomedial Inferolateral Floor Roof Identify each of the numbers Pass this in for participation points Considerations for popliteal fossa – prescribing wheelchairs, sitting for long periods at a time

Break

Ankle joint Hinge joint with 3 articular surfaces: Medial surface of fibula -> talus Inferior tibia -> trochlea of talus Lateral surface of medial malleolus -> talus

Ligaments – ankle joint Deltoid ligament 4 parts Fibular collateral ligaments 3 Tibiofibular ligaments Deltoid – strong, fibrous, resists eversion; bony structure helps as well anterior tibiotalar tibionavicular tibiocalcaneal posterior tibiotalar Fibular – very strong, resists inversion; high mobility; often stretched, torn, or breaks fibula (like our cadaver!) anterior talofibular calcaneofibular posterior talofibular Anterior and posterior talofibular – resist separation of the ankle joint

Clinical relevance Eversion and inversion sprains and fractures Deltoid ligament and fibular collateral ligaments are so strong, they will often break bones before tearing