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
What is the largest sesamoid bone in the body?
Patella
What forms the medial and lateral retinaculae?
Medial formed by tendon of vastus medialis
Lateral formed by tendon of vastus lateralis
Which muscle is called the “kicking muscle” and why? What is a common injury associated with this muscle?
Rectus femoris: efficient in knee extension and hip flexion from position of hip hyperextension
May be avulsed from AIIS during kicking, reducing thigh flexion strength by up to 17%
What is the articularis genu? What are its attachments?
Articular muscle of the knee, derived from vastus intermedius
Attaches to anteroinferior femur and synovial membrane of knee and wall of suprapatellar bursa
Describe the passage of the anterior and posterior divisions of the obturator n.
Obturator n. divides into anterior and posterior divisions as it emerges from obturator canal to enter medial compartment of thigh
Passes anterior and posterior to adductor brevis
Which three muscles insert into the superomedial tibia via pes anserinus?
Sartorius from anterior (flexor) compartment
Gracilis from medial (adductor) compartment
Semitendinosus from posterior (extensor) compartment
What is the function of pes anserinus? What structure performs the converse function?
Common insertion of sartorius, gracilis and semitendinosus which stabilises medial aspect of extended knee
Gluteus maximus and tensor fascia lata similarly stabilise the lateral side via iliotibial tract
What is the adductor hiatus and what structures does it transmit? Where is it located?
Opening between distal attachments of adductor and hamstring parts of adductor magnus
Located just lateral and superior to adductor tubercle
Transmits femoral artery and vein from adductor canal to popliteal fossa
Describe the boundaries and contents of the femoral triangle
Medial wall: lateral part of adductor longus
Lateral wall: sartorius
Base: inguinal ligament
Apex: sartorius overlies adductor longus
Floor: iliopsoas laterally and pectineus medially
Roof: fascia lata, cribiform fascia, subcut tissue, skin
Contents: NAVEL (femoral Nerve, femoral Artery, femoral Vein, Empty space (femoral canal), Lymphatics*)
* Contained in femoral sheath
Where is the adductor canal and what traverses it?
Deep to sartorius, inferiorly from apex of femoral triangle
Major neurovascular bundle (femoral nerve, artery, vein, lymphatics) traverses middle third of the thigh
What is the largest branch of the lumbar plexus?
Femoral n.
Describe the passage of the femoral n.
Originates in abdo within psoas major
Descends posterolaterally through pelvis to midpoint of inguinal ligament
Passes deep to ligament and enters femoral triangle lateral to femoral vessels
Divides into several branches to anterior thigh muscles, also sends articular branches to hip and knee joints, and provides cutaneous branches to anteromedial thigh (anterior cutaneous branches and saphenous n.)
What are the two cutaneous branches of the femoral n.?
Anterior cutaneous branches
Saphenous n. (terminal cutaneous branch)
Describe the passage of the saphenous n.
Descends through femoral triangle, lateral to femoral sheath
Accompanies femoral artery and vein through adductor canal
Becomes superficial by passing between sartorius and gracilis (does not travel through adductor hiatus)
Runs anteroinferiorly to supply anteromedial knee, leg and foot
How does the femoral sheath form and how does it terminate?
Forms from inferior prolongation of transversalis and iliopsoas fascia
Terminates by blending with the adventitia of the femoral vessels
What is the femoral canal and what is its purpose? What is its distal boundary and what are its contents?
Medial subcompartment of the femoral sheath
Allows femoral vein (in adjacent intermediate compartment of femoral sheath) to expand as needed
Extends distally to proximal edge of saphenous opening
Contains loose connective tissue, fat, few lymphatic vessels +/- deep inguinal lymph node (lacunar node)
What is the femoral ring?
Base of the femoral canal
Outline the boundaries of the femoral ring
Lateral: vertical septum between femoral canal (medial compartment of femoral sheath) and femoral vein (intermediate compartment of femoral sheath)
Medial: lacunar ligament
Posterior: superior ramus of pubis, pectineus
Anterior: medial part of inguinal ligament
Closed by femoral septum
Outline the boundaries of the adductor canal
Anterolateral: vastus medialis
Posterior: adductors longus and magnus
Medial and roof: sartorius
What structures are carried in the adductor canal?
Femoral artery
Femoral vein
Saphenous nerve
Nerve to vastus medialis
Between what structures are limb measurements made to determine if shortening is present?
Thigh: between ASIS and distal lateral femoral condyle
Whole limb: between ASIS and medial malleolus
Describe the course of the femoral vein relative to the femoral artery within the thigh
Medial to artery at base of femoral triangle
Posterior to artery at apex of femoral triangle
Posterolateral to artery within adductor canal
Five arteries of the anteromedial thigh
Femoral
Profunda femoris
Medial circumflex femoral
Lateral circumflex femoral
Obturator
Describe the origin, course and distribution of the femoral artery
Origin: continuation of external iliac (distal to inguinal ligament)
Course: bisects femoral triangle, courses adductor canal, terminates as it traverses adductor hiatus to enter popliteal fossa (becomes popliteal artery)
Distribution: anterior and anteromedial thigh
Describe the origin, course and distribution of profunda femoris
Origin: femoral artery 1-5cm inferior to inguinal ligament
Course: between pectineus and adductor longus, descends posterior to adductor longus on medial femur
Distribution: perforating arteries pierce adductor magnus to supply medial, posterior and lateral part of anterior compartments
Describe the origin, course and distribution of the medial circumflex femoral artery
Origin: profunda femoris
Course: posteromedially between pectineus and iliopsoas, enters gluteal region (gives rise to posterior retinacular arteries), terminates into transverse and ascending branches
Distribution: most of blood to head and neck of femur, transverse branch joins cruciate anastomosis, ascending branch joint inferior gluteal
Describe the origin, course and distribution of the lateral circumflex femoral artery
Origin: profunda femoris
Course: laterally deep to sartorius and rectus femoris; divides into ascending, transverse and descending arteries
Distribution: ascending branch supplies anterior gluteal region, transverse winds around femur, descending joins genicular peri-articular anastasmosis
Describe the origin, course and distribution of the obturator artery
Origin: internal iliac typically (20% from inferior epigastric)
Course: through obturator foramen to medial compartment, divides into anterior and posterior branches over adductor brevis
Distribution: anterior branch supplies obturator externus, pectineus, adductors, and gracilis; posterior branches supply muscles attached to ischial tuberosity
What is chondromalacia patellae?
“Runner’s knee”
Softening of the articular cartilage of the patella commonly due to quadriceps imbalance
What finding on XR suggests ossification abnormality of the patella rather than fracture?
BILATERAL bipartite or tripartite patella
When does the patella ossify?
Age 3-6
What nerve and spinal cord segments are tested by the patellar tendon reflex?
Femoral n.
Spinal cord segments L2-4
Which thigh muscle may be transplanted without noticeable loss of its actions on the leg?
Gracilis
Three possible causes of proximal thigh swelling
Femoral hernia
Psoas abscess
Saphenous varix
Are femoral hernias more common in males or females? Why
Females
Due to wider pelvis and smaller inguinal canals and rings
May also occur after multiple pregnancies due to enlargement of femoral ring over time
