Week 4: Hip & Thigh Muscles 2 Flashcards
Describe the action, innervation, and common blood supply of the anterior thigh compartment:
Action:
- Knee extension
- Hip flexion (rectus femoris)
Innervation: Femoral (L2-L4)
Blood supply: Deep femoral
Describe the action, innervation, and common blood supply of the posterior thigh compartment:
Action:
- Knee flexion
- Hip extension (except short head biceps femoris) +/- leg rotation
Innervation: Tibial (L4-S3)
- Short head of biceps femoris = common fibular
Blood supply: Deep femoral
Describe the action, innervation, and common blood supply of the medial thigh compartment:
Action: Adduction
Innervation: Obturator (L2-L4)
- Pectineus = femoral nerve
- Adductor magnus = obturator + tibial
Blood supply: Obturator + deep femoral
Describe the origin, insertion, position, and function of the sartorius:
Origin: ASIS
Insertion: Tibia, part of the pes anserinus
Position: Long, ribbon like, passes inferio-medially
Function:
- Flexion
- Abduction
- Lateral rotation of the Hip
- Knee flexion
Describe the origin, insertion, position, and function of the rectus femoris:
Origin:
- Straight head: AIIS
- Reflected head: groove above the acetabular rim
Insertion: Base of patella via the quadriceps tendon and into the tibia via the patellar ligament
Position: Runs straight down the thigh, anterior to the hip and knee joints
Function:
- Knee extension
- Hip flexion
Describe the origin, insertion, position, and function of the vastus lateralis:
Origin: Femur via an aponeurosis which attaches to inter-trochanteric line and along the lateral lip of linea aspera, lateral IMS
Insertion:
- Superolateral border of patella via quadriceps tendon and to tibia via patellar ligament
- Lateral border of tibia via lateral patellar retinaculum
Position:
- Anterior to knee joint
- High pennation angle, large cross sectional area, short fibres
Function:
- Knee extension (powerful)
Describe the origin, insertion, position, and function of the vastus medialis:
Origin: Medial lip linea aspera, distal ½ intertrochanteric line, medial IMS
Insertion:
- Superomedial border patella via quadriceps tendon, and tibial tuberosity via patellar ligament
- Medial condyle of tibia via medial patellar retinaculum
Position: Large muscle composed of two parts - longus and obliquus
Function:
- Knee extension
- Stabilisation of patella (against lateral displacement)
Describe the origin, insertion, position, and function of the vastus intermedius:
Origin: Femoral shaft from one lip of the linea aspera to the other, lateral IMS
Insertion: Upper border of patella via quadriceps tendon to tibial tuberosity via patellar ligament
Position: Deep to rectus femoris
Function: Knee extension
Describe how the muscles of the quadriceps femoris group converge and insert distally:
- Converge onto the quadriceps tendon
- Insert into the patella and patellar retinaculum - VM and VL
- Insert into the tibial tuberosity via the patellar ligament/tendon – results in leg extension
Describe the architecture of the vastus medialis:
- High pennation angle, large cross sectional area, short fibres
- Fibres tend to be directed down and forwards although the lowest fibres are almost horizontal
What are thought to be the specific functional roles of VMO?
- Knee extension
- Stabilising the patella i.e. preventing lateral displacement, and is often the first to weaken with injury
What structures (bony and soft tissue) are most important for maintaining patellar stability?
- Vastus medialis – but also the functional interplay of all surrounding muscles
- Patellar retinaculum
- Patella ligament - prevents patella from moving superiorly
- Limb alignment and joint geometry - patella and trochlear of femur
What is the common origin of the hamstring muscles (except the short head of biceps femoris)?
Ischial tuberosity
- Semitendinosus and biceps femoris long head arise from a common tendon, semimembranosus attaches more laterally
What is the origin of the biceps femoris short head?
Lateral lip linea aspera (midshaft to bifurcation), lateral intermuscular septum
Describe the characteristics of the semitendinosus:
Distal tendon of this muscle is long and relatively thin
What is the distal insertion of semitendinosus?
Upper part of the medial surface of tibia as part of the pes anserinus
Describe the architecture of the semitendinosus:
- Cross-sectional area: Intermediate
- Fascicle direction: Long fibres, low pennation angle
Describe the function of the semitendinosus:
- Hip extension, knee flexion - passes posterior to the hip and knee joints
- Medial rotation of flexed knee – due to its insertion onto tibia and line of pull
- Large excursion – designed for range rather than force production
Describe the characteristic of the semimembranosus:
Characterised by its extensive membranous proximal aponeurosis
What are the distal insertions of semimembranosus?
- Posteromedial aspect of medial condyle of tibia
- Some fibrous expansions to knee joint capsule e.g. oblique popliteal ligament
Describe the architecture of the semimembranosus:
- Cross-sectional area: Intermediate
- Fascicle direction: Long fibres, low pennation angle
Describe the functions of the semimembranosus:
- Hip extension, knee flexion – crosses posterior to hip and knee joints
- Medial rotation of flexed knee - attachment on tibia and line of pull
Describe the merge of the long and short head of the biceps femoris:
The muscle bellies of these 2 heads merge in the distal, lateral thigh to form a common round tendon of insertion
Describe the distal insertions of the biceps femoris:
- Lateral aspect of head of fibula
- Lateral condyle of tibia
