5.3 Lower Limb Exam : Medial Thigh Muscles (Adductors) & Superficial Pes Anserinus

Medial thigh compartment - Layer Organization

Superficial layer: Pectineus, Adductor longus, Gracilis. Middle layer: Adductor brevis. Deep layer: Adductor magnus

Pectineus - Origin and Insertion

Origin: Pecten pubis (pectineal line) and adjacent superior pubic ramus. Insertion: Pectineal line on posterior surface of proximal femur (inferior to lesser trochanter)

Pectineus - Actions

Adduction and flexion of thigh at hip joint

Pectineus - Specificity and Topography

Most superior and anterior muscle of medial compartment; forms the medial portion of the floor of the femoral triangle

Adductor longus - Origin and Insertion

Origin: External surface of body of pubis (inferior to pubic crest and lateral to symphysis). Insertion: Middle third of linea aspera of femur

Adductor longus - Actions

Adduction of thigh at hip joint; assists in hip flexion and rotation

Adductor longus - Specificity and Topography

Forms the medial boundary of the femoral triangle (Scarpa's triangle); lies superficial to adductor brevis and magnus

Gracilis - Origin and Insertion

Origin: External body of pubis and inferior pubic ramus (ischiopubic ramus). Insertion: Proximal medial surface of tibia (superficial pes anserinus)

Gracilis - Actions

Adduction of thigh at hip; flexion of leg at knee; medial rotation of flexed knee

Gracilis - Specificity and Biomechanics

Most superficial and medial muscle of medial compartment; the ONLY adductor muscle crossing two joints (hip and knee)

Adductor brevis - Origin and Insertion

Origin: External surface of body and inferior ramus of pubis. Insertion: Pectineal line and upper third of linea aspera of femur

Adductor brevis - Actions

Adduction and medial rotation of thigh at hip joint; assists in hip flexion

Adductor brevis - Specificity and Layer

Sole muscle forming the middle (intermediate) layer of adductor compartment; situated deep to pectineus/adductor longus and superficial to adductor magnus

Adductor magnus - Origin and Insertion

Origin: Adductor part from ischiopubic ramus; Hamstring part from ischial tuberosity. Insertion: Gluteal tuberosity, linea aspera, medial supracondylar line, and adductor tubercle

Adductor magnus - Actions

Adductor part: Powerful hip adduction and flexion. Hamstring part: Hip extension

Adductor magnus - Specificity and Hiatus

Deepest and largest adductor; forms the adductor hiatus between its aponeurotic and tendinous parts for passage of femoral vessels to popliteal fossa

Superficial pes anserinus - Tendon Composition

Sartorius (anterior), Gracilis (middle), Semitendinosus (posterior) [Mnemonic: S-G-T / Say Grace before Tea]

Superficial pes anserinus - Bony Insertion Site

Medial and anteromedial surface of the proximal tibia, immediately inferomedial to the tibial tuberosity

Superficial pes anserinus - Exam Trap and Compartment Origins

Unites tendons from three separate functional compartments (Anterior: Sartorius; Medial: Gracilis; Posterior: Semitendinosus); all three act as knee flexors and internal rotators of the flexed knee

Deep pes anserinus - Constituent Muscle and Origin

Formed exclusively by the semimembranosus tendon originating from the ischial tuberosity

Deep pes anserinus - Insertions and Expansions

Posterior aspect of the medial tibial condyle and the oblique popliteal ligament reinforcing the posterior knee capsule

Deep pes anserinus - Topographical Location and Relations

Located on the posteromedial aspect of the knee, positioned deep to the medial collateral ligament (MCL)

Deep pes anserinus - Actions

Flexion of the knee, medial (internal) rotation of the flexed knee, and posterior capsule stabilization

Deep pes anserinus vs Superficial pes anserinus - Exam Trap

Superficial is anteromedial and tri-muscular (Sartorius, Gracilis, Semitendinosus); Deep is posteromedial and mono-muscular (Semimembranosus only)