Lecture 3: The Muscular System
of the Lower Limb
General
Os coxae (ilium, ischium and pubis)
Different bones at different levels therefore muscles will originate at different levels
There are different relationships between the muscles of the hip joint
Muscles work on the joints that they cross
They do not work in isolation
The muscle direction and the fibre direction determine the action
Hip muscle
Psoas major and iliacus
Pass the hip anteriorly
Share a common insertion: iliopsoas muscle
The psoas lies superomedial
The iliacus lies inferomedial
Origin
Psoas major
Lumbar discs and transverse processes
Bodies of T12-L5
Iliacus: iliac fossa
The muscles join under the inguinal ligament (anterior to femoral head)
Insertion: lesser trochanter of the femur
Action
Flexion and lateral rotation (powerful flexor)
Stabilises the hip joint
Innervation
Psoas by the Anterior rami of L1-L3
Iliacus by the branches of the femoral nerve
, Gluteal muscles
Tensor fasciae latae
Origin: lateral aspect of the iliac crest (posterior to ASIS)
Insertion: iliotibial tract (thickened band-like structure on the lateral side of the leg
made of fascia)
Action: stabilises the knee in extension
Innervation: superior gluteal nerve
Gluteus maximus
Origin
Behind the gluteal line
Fascia of the gluteus medius and erector spinae
Dorsal surface of the sacrum
Coccyx lateral margin
Sacrotuberous ligament
Insertion
Posterior aspect of the iliotibial tract
Gluteal tuberosity of the proximal femur
Action
Hip extension
Lateral rotation
Abduction
Laterally stabilises the hip and knee joint
Innervation: Inferior gluteal nerve (L5-S2)
Gluteus medius
Origin: external surface of the ilium (between the anterior and posterior gluteal lines)
Insertion: lateral surface of the greater trochanter
Action:
Abduction and medial rotation
Maintain the horizontal pelvic plane
Innervation: superior gluteal nerve (L4-S1)
Gluteus minimus
Deep gluteus medius and maximus
Origin: external surface of the ilium (between the anterior and inferior gluteal lines)
Insertion: anterolateral surface of the greater trochanter
Action
Abduction and medial rotation
Maintains the horizontal pelvic plane
Innervation: superior gluteal nerve
of the Lower Limb
General
Os coxae (ilium, ischium and pubis)
Different bones at different levels therefore muscles will originate at different levels
There are different relationships between the muscles of the hip joint
Muscles work on the joints that they cross
They do not work in isolation
The muscle direction and the fibre direction determine the action
Hip muscle
Psoas major and iliacus
Pass the hip anteriorly
Share a common insertion: iliopsoas muscle
The psoas lies superomedial
The iliacus lies inferomedial
Origin
Psoas major
Lumbar discs and transverse processes
Bodies of T12-L5
Iliacus: iliac fossa
The muscles join under the inguinal ligament (anterior to femoral head)
Insertion: lesser trochanter of the femur
Action
Flexion and lateral rotation (powerful flexor)
Stabilises the hip joint
Innervation
Psoas by the Anterior rami of L1-L3
Iliacus by the branches of the femoral nerve
, Gluteal muscles
Tensor fasciae latae
Origin: lateral aspect of the iliac crest (posterior to ASIS)
Insertion: iliotibial tract (thickened band-like structure on the lateral side of the leg
made of fascia)
Action: stabilises the knee in extension
Innervation: superior gluteal nerve
Gluteus maximus
Origin
Behind the gluteal line
Fascia of the gluteus medius and erector spinae
Dorsal surface of the sacrum
Coccyx lateral margin
Sacrotuberous ligament
Insertion
Posterior aspect of the iliotibial tract
Gluteal tuberosity of the proximal femur
Action
Hip extension
Lateral rotation
Abduction
Laterally stabilises the hip and knee joint
Innervation: Inferior gluteal nerve (L5-S2)
Gluteus medius
Origin: external surface of the ilium (between the anterior and posterior gluteal lines)
Insertion: lateral surface of the greater trochanter
Action:
Abduction and medial rotation
Maintain the horizontal pelvic plane
Innervation: superior gluteal nerve (L4-S1)
Gluteus minimus
Deep gluteus medius and maximus
Origin: external surface of the ilium (between the anterior and inferior gluteal lines)
Insertion: anterolateral surface of the greater trochanter
Action
Abduction and medial rotation
Maintains the horizontal pelvic plane
Innervation: superior gluteal nerve
