Musculoskeletal: Anatomy - Anterior and medial regions of thigh Flashcards
List the four muscles of the anterior thigh. Which of these are hip flexors and which are knee extensors?
Hip flexors:
1. Pectineus
2. Iliopsoas: iliacus, psoas major, psoas minor
3. Sartorius
Knee extensors:
4. Quadriceps femoris: rectus femoris, vastus lateralis, vastus medialis, vastus intermedius
Proximal and distal attachment, innervation, and main actions of pectineus
Proximal: superior ramus of pubis
Distal: pectineal line of femur (inferior to lesser trochanter)
Innervation: femoral n. (L2, L3)
Action: hip adduction and flexion (assists medial rotation)
Proximal and distal attachment, innervation, and main actions of psoas major
Proximal: sides of T12-L5 vertebrae and discs, transverse processes of lumbar vertebrae
Distal: lesser trochanter
Innervation: anterior rami of lumbar nerves (L1, L2, L3)
Action: hip flexion and stabilisation, maintenance of posture
Proximal and distal attachment, innervation, and main actions of psoas minor
Proximal: sides of T12-L1 vertebrae and discs
Distal: pectineal line and iliopubic eminence via iliopectineal arch
Innervation: anterior rami of lumbar nerves (L1, L2)
Action: hip flexion and stabilisation
Proximal and distal attachment, innervation, and main actions of iliacus
Proximal: iliac crest, iliac fossa, ala of sacrum, anterior sacro-iliac ligaments
Distal: tendon of psoas major, lesser trochanter, and femur distal to it
Innervation: femoral n. (L2, L3)
Action: hip flexion and stabilisation
Proximal and distal attachment, innervation, and main actions of sartorius
Proximal: ASIS
Distal: superior part of medial surface of tibia
Innervation: femoral n. (L2, L3)
Action: hip flexion, abduction and lateral rotation; knee flexion (medially rotating leg when knee is flexed)
Proximal and distal attachment, innervation, and main actions of rectus femoris
Proximal: AIIS and ilium superior to acetabulum
Distal: via quadriceps tendon to base of patella, indirectly via patellar ligament to tibial tuberosity
Innervation: femoral n. (L2, L3, L4)
Action: knee extension, stabilises hip joint and assists iliopsoas to flex hip
Proximal and distal attachment, innervation, and main actions of vastus lateralis
Proximal: greater trochanter, lateral lip of linea aspera
Distal: via quadriceps tendon to base of patella, indirectly via patellar ligament to tibial tuberosity, also attaches via lateral patellar retinacula
Innervation: femoral n. (L2, L3, L4)
Action: knee extension
Proximal and distal attachment, innervation, and main actions of vastus medialis
Proximal: intertrochanteric line, medial lip of linea aspera
Distal: via quadriceps tendon to base of patella, indirectly via patellar ligament to tibial tuberosity, also attaches via medial patellar retinacula
Innervation: femoral n. (L2, L3, L4)
Action: knee extension
Proximal and distal attachment, innervation, and main actions of vastus intermedius
Proximal: anterolateral shaft of femur
Distal: via quadriceps tendon to base of patella, indirectly via patellar ligament to tibial tuberosity
Innervation: femoral n. (L2, L3, L4)
Action: knee extension
Why is the sartorius so-named?
Its four actions produce the cross-legged sitting position used by tailors
What is the chief flexor of the thigh?
Iliopsoas
Proximal and distal attachment, innervation, and main actions of adductor magnus
Proximal: adductor part from inferior pubic ramus and ischial rambus, hamstring part from ischial tuberosity
Distal: adductor part to gluteal tuberosity, linea aspera and medial supracondylar line; hamstring part to adductor tubercle
Innervation: adductor part by obturator n. (L2-4) and branches of posterior division, hamstring part by tibial part of sciatic n. (L4)
Action: hip adduction, in isolation adductor part flexes and hamstring part extends hip
Proximal and distal attachment, innervation, and main actions of adductor longus
Proximal: body of pubis inferior to pubic crest
Distal: middle third of linea aspera
Innervation: obturator n. (L2-4) and branch of anterior division
Action: hip adduction
Proximal and distal attachment, innervation, and main actions of adductor brevis
Proximal: body and inferior ramus of pubis
Distal: pectineal line and proximal linea aspera
Innervation: obturator n. (L2-4) and branch of anterior division
Action: hip adduction, some flexion
Proximal and distal attachment, innervation, and main actions of obturator externus
Proximal: margins of obturator foramen and obturator membrane
Distal: trochanteric fossa
Innervation: obturator n. (L3-4)
Action: lateral rotation of hip, steadies head of femur in acetabulum
Proximal and distal attachment, innervation, and main actions of gracilis
Proximal: body and inferior ramus of pubis
Distal: superior part of medial surface of tibia
Innervation: obturator n. (L2-3)
Action: hip adduction (assists with medial rotation), knee flexion
Three compartments of the thigh. Which nerves innervate each?
- Anterior (flexor; largest, includes femur): femoral n.
- Medial (adductor): obturator n.
- Posterior (extensor): tibial portion of sciatic n.
Where do the intermuscular septa attach in the thigh?
From fascia lata to linea aspera
Which muscle is a transitional muscle between anterior and medial compartments?
Pectineus: receives dual innervation from femoral and obturator n., both adducts and flexes thigh
What is the longest muscle in the body?
Sartorius
What is the great extensor of the leg?
Quadriceps femoris