Muscles and Neurovascular Structures around the Knee PDF

Muscles and Neurovascular Structures around the Knee Ngozi Onuegbu PhD PT4050/PT7001  Knee Joint Type of joint: Hinge joint Articulating surfaces: Femur, tibia, patella Functions: Flexion, extension, stability during movement Muscles of the Knee Flexors: Hamstrings (Biceps Femori...

Muscles and Neurovascular Structures around the Knee Ngozi Onuegbu PhD PT4050/PT7001  Knee Joint Type of joint: Hinge joint Articulating surfaces: Femur, tibia, patella Functions: Flexion, extension, stability during movement Muscles of the Knee Flexors: Hamstrings (Biceps Femoris, Semitendinosus, Semimembranosus), Gastrocnemius Extensors: Quadriceps (Rectus Femoris, Vastus Lateralis, Vastus Medialis, Vastus Intermedius) Internal Rotators: Semitendinosus, Semimembranosus, Popliteus External Rotators: Biceps Femoris Hamstrings Neurovascular Structures of the Knee Main Nerves Femoral Nerve: Supplies quadriceps (extensors) Sciatic Nerve: Divides into Tibial Nerve (posterior compartment of the leg) and Common Peroneal Nerve (anterior and lateral compartments of the leg) Saphenous Nerve: Cutaneous branch of femoral nerve Neurovascula r Structures of the Knee Blood Supply Arteries: Popliteal artery, genicular arteries Veins: Popliteal vein, small saphenous vein  Anterior Muscles (Knee Extensors) Quadriceps Femoris Group: The quadriceps femoris is the primary extensor of the knee joint and consists of four muscles: Quadriceps (Group): Vastus Lateralis Origin: Greater trochanter and linea aspera of femur Insertion: Tibial tuberosity via the patellar ligament Action: Knee extension, patella stability Nerve supply: Femoral nerve (L2-L4) Blood supply: Lateral circumflex femoral artery Clinical Relevance: Vastus lateralis tightness or imbalance compared to the vastus medialis can contribute to patellar tracking problems and patellofemoral pain syndrome. Quadriceps (Group): Vastus Medialis Origin: Medial lip of linea aspera of femur Insertion: Tibial tuberosity via the patellar ligament Action: Knee extension, patella stability Nerve supply: Femoral nerve (L2-L4) Blood supply: Femoral artery, Profunda femoris artery Clinical Relevance: Weakness of the vastus medialis, particularly the vastus medialis obliquus (VMO), is often implicated in patellar instability and patellofemoral pain. Quadriceps (Group): Vastus Intermedius Origin: Anterior and lateral surfaces of the femoral shaft Insertion: Tibial tuberosity via the patellar ligament Action: Knee extension, patella stability Nerve supply: Femoral nerve (L2-L4) Blood supply: Lateral circumflex femoral artery Clinical Relevance: Dysfunction of the quadriceps muscles, especially after injury or surgery, can lead to atrophy, affecting knee stability and mobility The Vastus intermedius lies deep to the Rectus femoris Quadriceps (Group): Rectus Femoris Origin: Anterior inferior iliac spine (AIIS) and superior acetabular rim. Insertion: Tibial tuberosity via the patellar ligament. Action: Flexes the hip and extends the knee. Nerve supply: Femoral nerve (L2-L4). Blood supply: Lateral circumflex femoral artery Clinical Relevance: Frequently strained in activities requiring powerful hip flexion, like sprinting or kicking. Posterior Muscles (Knee Flexors) Hamstrings Group: The hamstrings are the primary knee flexors and also assist in hip extension: Hamstrings Group: Biceps Femoris (Long Head and Short Head) Origin: Long head – ischial tuberosity; Short head – linea aspera. Insertion: Head of the fibula. Action: Flexes the knee, extends the hip, and externally rotates the knee. Nerve supply: Sciatic nerve (L5-S2). (Long head: Tibial division; short head: common peroneal division) Clinical Relevance: The biceps femoris is frequently injured in sprinting activities due to its role in hip extension and knee flexion. Hamstrings Group: Semitendinosus Origin: Ischial tuberosity. Insertion: Pes anserinus (medial surface of the tibia). Action: Flexes the knee and extends the hip; internally rotates the tibia. Nerve supply: Sciatic nerve (L5-S2). Clinical Relevance: Often involved in hamstring strains; contributes to medial knee stability. Hamstrings Group: Semimembranosus Origin: Ischial tuberosity. Insertion: Posterior part of the medial tibial condyle. Action: Flexes the knee, extends the hip, and internally rotates the tibia. Nerve supply: Sciatic nerve (L5-S2). Clinical Relevance: Important in providing medial stability to the knee joint. Semimembranosus lies deep to the Semitendinosus and Biceps femoris  Gastrocnemius Origin: Medial (Medial head) and lateral (lateral head) condyles of the femur. Insertion: Calcaneus via the Achilles tendon. Action: Flexes the knee and plantarflexes the ankle. Nerve supply: Tibial nerve (S1-S2). Clinical Relevance: A key muscle in lower limb propulsion, frequently involved in calf strains.  Popliteus Origin: Lateral femoral condyle. Insertion: Posterior surface of the tibia above the soleal line. Action: Unlocks the knee by rotating the femur on the tibia; flexes the knee. Nerve supply: Tibial nerve (L4-S1). Clinical Relevance: Plays a crucial role in knee stability, especially in controlling knee rotation during walking. Clinical Relevance of the Knee Neuromuscular structures The balance of muscle strength between the anterior and posterior compartments of the knee is crucial for joint stability. Imbalances, particularly between the quadriceps and hamstrings, can lead to injury or contribute to conditions such as anterior cruciate ligament (ACL) injuries, patellofemoral pain syndrome, and tendinopathies Common Conditions and Injuries Ligament tears (e.g., ACL, PCL) Meniscal injuries Patellofemoral pain syndrome Knee osteoarthritis Bursitis Tendon injuries (e.g., patellar tendinopathy) Questions References De Maeseneer M, Shahabpour M, Lenchik L, Milants A, De Ridder F, De Mey J, Cattrysse E. Distal insertions of the semimembranosus tendon: MR imaging with anatomic correlation. Skeletal Radiol. 2014 Jun;43(6):781-91 Kenhub (n.d.) Hip Anatomy and Knee Anatomy Diagrams. Available at: https://www.kenhub.com (Accessed: 14 September 2024). McMinn, R.M.H. (2019) Last’s Anatomy: Regional and Applied. 13th edn. Elsevier Health Sciences. Moore, K.L., Dalley, A.F. and Agur, A.M.R. (2018) Clinically Oriented Anatomy. 8th edn. Wolters Kluwer. Muscolino, J.E. (n.d.) The Muscular System Manual: The Skeletal Muscles of the Human Body. Available at: https://www.learnmuscles.com (Accessed: 14 September 2024). Netter, F.H. (2019) Atlas of Human Anatomy. 7th edn. Elsevier.Physiopedia (n.d.) Hip and Knee Anatomy Overview. Available at: https://www.physio-pedia.com (Accessed: 14 September 2024). Rehab My Patient (n.d.) Anatomy of the Hip and Knee. Available at: https://www.rehabmypatient.com (Accessed: 14 September 2024). Standring, S. (2020) Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 42nd edn. Elsevier.