Posterior Thigh and Popliteal Fossa PDF

The posterior thigh and popliteal fossa  Outline A bit of revision The femur and pelvis revisited The muscles – Hamstrings The nerves and vascular structures The clinical significance of the region Summary  Aims To study: – The bones associated...

The posterior thigh and popliteal fossa  Outline A bit of revision The femur and pelvis revisited The muscles – Hamstrings The nerves and vascular structures The clinical significance of the region Summary  Aims To study: – The bones associated with the posterior thigh, their alignment and relationship. – The muscles of the posterior compartment their relationship and action. – The nerves and vascular structures of the region. – Introduce the clinical importance of the region.  The femur Longest, strongest, biggest bone in body. The structures of the posterior thigh and popliteal fossa overlie the femur.  Pelvis Many of the structures of the posterior thigh and popliteal fossa arise in the gluteal area / pelvis.  Posterior fascial compartment Boundaries – Lateral intermuscular septum. – Adductor magnus – Deep fascia Contents – Hamstrings – Nerves – Vascular structures  Posterior fascial compartment. Common properties: – Common action Knee flexion, hip extension (most of them). – Common innervation Sciatic nerve (tibial portion). – Common blood supply Profunda femoris Muscles Hamstrings – Semimembranosus – Semitendinosus – Biceps femoris Long head Short head – (Vertical fibres of adductor magnus can also act like a hamstring causing hip extension but no knee flexion). Semimembranosus Origin: Superior lateral quadrant of ischial tuberosity. Insertion: Posterior surface of medial tibial condyle. Action: Knee flexion, hip extension, medial knee rotation. Antagonists: Knee extensors, hip flexors. Innervation: Tibial portion of sciatic nerve L5, S1, S2. Semitendinosus Origin: Medial facet of ischial tuberosity. Insertion: Medial tibial condyle. Action: Knee flexion, hip extension, medial knee rotation. Antagonists: Knee extensors, hip flexors. Innervation: Sciatic (tibial portion) L5, S1, S2. Biceps femoris (long head) Origin: Medial facet of ischial tuberosity. Insertion: Head of fibula, LCL ligament, Lateral tibial condyle. Action: Knee flexion, hip extension, lateral knee rotation. Antagonists: Knee extensors, hip flexors. Innervation: Sciatic (tibial portion) L5, S1, S2. Biceps femoris (short head) Origin: Linea aspera, lateral supracondylar line. Insertion: Head of fibula, LCL ligament, Lateral tibial condyle. Action: Knee flexion, lateral knee rotation. Antagonists: Knee extensors. Innervation: Sciatic (common peroneal portion L5, S1, S2. Pes anserinus Bursa on medial side of knee. (looks like a gooses foot!) Overlying the bursa are tendons inserting to medial side of knee. – Sartorius – Gracilis – SemiTendinosus Posterior to the bursa is SemiMembranosus Say Grace before Tea (Mother). This muscle assortment assists with stabilising medial knee and pelvis. Hip motion Hip flexion is limited by flexiblity of hamstrings (amongst other things). Should be able to flex hip > 70° Adverse tension in sciatic nerve will also restrict hip flexion. As will tight hip ligaments. Nerves Sciatic nerve: – Arises from sacral plexus. – L4, L5, S1, S2, S3. Sciatic nerve Has 2 distinct portions: – Tibial – Common peroneal Variation where they split. Usually mid thigh – Can be more proximal or distal Sciatic nerve 2 Motor action: – All hamstrings are innervated by tibial portion of sciatic nerve. EXCEPT! Short head of biceps femoris. Cutaneous (sensory) innervation Posterior femoral cutaneous nerve Arises from sacral plexus (S1 - S3) Vascular supply Femur and hamstrings are supplied with blood by profunda femoris artery. Posterior compartment is drained by the profunda femoris vein, assisted by lymphatics. Popliteal fossa Diamond shaped space posterior to the knee. Boundaries: – Medial and lateral heads of gastrocnemius (plantaris) – Biceps femoris – Semimembranosus / tendinosus  Popliteal fossa 2 Floor: – Posterior surface of femur – Knee joint capsule – Oblique popliteal ligament – Popliteus muscle Ceiling: – Deep fascia and adipose tissue – Embedded in adipose tissue: Part of posterior femoral cutaneous nerve Small saphenous vein  Popliteal fossa 3 Significance – Pulse palpable and dopplerable – May present with a popliteal (Bakers) cyst in various knee pathologies or arthritis. – We can inject things in there LA Popliteal fossa 3 Contents – Tibial nerve – Popliteal artery – Popliteal vein – Common peroneal nerve – Lymph vessels and nodes Popliteal fossa 4 Popliteal fossa 5  Summary You should now be able to: – Identify the hamstrings and know their functions. – Identify major nerves within the posterior thigh and popliteal fossa, what they innervate or cutaneous areas they serve. – Identify major vascular structures. – Have a rudimentary understanding of the clinical significance of the area and the impact of some injuries / conditions.  Look forward Bus for Leicester leaves 9.00 sharp. For next week: – Read around general issues. – Muscular structure and function. – Vascular structures and nerves. Next week: – Am, lecture, me; The knee. – Pm, Leicester, Gluteal region