6.2 Hip & thigh: bones & muscles Flashcards
During development, how is the lower limb rotated & how does that compare with that of the upper limb?
Lower limb is medially rotated, whilst upper limb is laterally rotated, hence the flexor compartments are on the posterior aspect of LL and anterior aspect of UL.
- Flexors on anterior of UL & big thumb laterally is optimal for manipulative function.
- Combined strength of anterior extensors on bone propels body forwards!
What regions does the lower limb divide into?
Gluteal region
Thigh region
Leg
*on the basis of major joints, component bones & superficial landmarks
Where does the gluteal region span?
Gluteal region lies posterolateral and extends from iliac crest above to gluteal fold below
Where does the thigh region span?
Anteriorly - extends from inguinal ligament (free inferior edge of external oblique) above to knee joint
Posteriorly - gluteal fold to knee joint
Where does the leg region span?
knee joint to ankle joint
Which three bones constitute the hip bone?
Superior: ilium
Inferior: ischium
Anterior: pubis
all 3 fuse by adulthood at the acetabulum which articulates with the head of the femur
What is on the outer surface of the ilium?
The gluteal surface which gives attachments to the gluteal muscles
There are 3 gluteal lines (posterior, anterior and inferior) that delineate the attachment of the 3 gluteal muscles.
What’s on the inner surface of the ilium?
Iliac fossa: gives attachment to iliacus muscle (iliacus forms part of the posterior abdominal wall)
Where does the iliac crest begin and end and what is below it?
Begins at the ASIS (anterior superior iliac spine) and ends at the PSIS (posterior superior iliac spine).
Below each of these is a corresponding inferior iliac spine.
What does the spine of the ischium demarcate?
The ischium has a spine posteriorly demarcating notch above (greater sciatic notch) and below (less sciatic notch) where neurovascular structures run through from pelvis
What arises from the ischial tuberosity?
Ischial tuberosity is the origin of the hamstrings and bears weight when you sit
What does the ischial ramus meet?
It projects forwards to meet the inferior pubic ramus
What is the pubis?
Body of the pelvis with superior and inferior pubic ramus divided by obturator foramen.
Pubic crest lies above/superior to body.
Pubic tubercle lies lateral where pubic crest ends if you run along it
What angle does the femoral neck form with the shaft?
120 degrees - has functional and fractural ramifications
What are the features of the femur?
Proximal end of shaft has greater and lesser trochanters which are joined anteriorly by the intertrochenteric line (rough surface) and posteriorly by the intertrochenteric crest (smooth, clearly delineates where neck stops and shaft begins).
The lesser trochanter is situated posteromedially.
Posteriorly, there is also the linea aspera, which has lots of muscle insertions and ends in adductor tubercle. Linea aspera splits into medial and lateral supracondylar lines due to the medial & lateral femoral condyles.
What are the muscles of the gluteal region responsible for?
- Extension: gluteus maximus
- Rotation: piriformis, obturator internus, gemelli, quadratus femoris
- Abduction: gluteus medius & gluteus minimus
…of the thigh at the hip joint.
Also minimises pelvic tilt in the swing phase of locomotion.
What are the major flexors of the hip & where do they arise?
Psoas major and iliacus which arise from the posterior abdominal wall
Iliopsoas insert into the lesser trochanter of femur.
What are the compartments of muscles in the thigh and what are they separated by?
Medial (adductor) compartment with muscles acting mostly on hip.
Anterior (extensor) compartment with muscles extending knee and flexing hip.
Posterior (flexor) compartment with muscles that act on hip & knee because they span both joints.
The compartments are delineated by the femur, encircling layer of deep fascia, IO membrane and intermuscular sepia.
What are the compartments of muscles in the leg?
Muscles in the anterior compartment dorsiflex the foot and extend the toes
Muscles in the posterior compartment plantarflex the foot and flex the toes.
Muscles in the lateral compartment evert the foot.
What muscles are seen on the lateral view of the hip & thigh?
Gluteus maximus
Tensor fascia lata
Iliotibial tract
LATERAL & POSTERIOR HIP & THIGH: Gluteus maximus
‘posterior fibres of deltoid’
- extensor
- lateral rotator of hip joint
ORIGIN: arises most medially on the ilium posterior to posterior gluteal line across to the dorsum of the sacrum
INSERTION: some deep fibres insert into gluteal tuberosity on posterior aspect of proximal shaft & some into iliotibial tract
45deg angle of fibres
works best b/w flexed and standing positions of thigh ‘end of lecture + stairs’
LATERAL HIP & THIGH: Tensor fascia lata
‘anterior fibres of deltoid’
- flex
- medially rotate
- abduct
From iliac crest to superior/anterior aspect of iliotibial tract. It extends from pelvis above down to be continuous with deep fascia of thigh. Act like compression stockings, are a very dense layer that limits outward bulging of muscles, compress veins when muscles contract to aid in venous return.
LATERAL HIP & THIGH: Iliotibial tract
Extends from iliac crest to proximal tibia, it is the further thickening laterally of the tensor fascia lata.
= the shared aponeurosis/aponeurotic tendon of 2 muscles, shared insertion for gluteus maximus and tensor fascia lata
Functionally, it is an important stabiliser of lateral side of extended leg (anti-gravity, maintains extension)
and stabilises hip joint from lateral displacement
What muscles are seen on the posterior view of the hip & thigh?
Superficially:
-gluteus maximus
Deep:
- gluteus medius & minimus
- piriformis
- obturator internus
- quadratus femoris
POSTERIOR HIP & THIGH: Gluteus medius/minimus
‘middle fibres of deltoid’
- medial rotators
- abductors
Fan-shaped
ORIGIN: posterior surface of ilium
INSERTION: antero-lateral aspect of greater trochanter, passes in front of axis for rotation of hip joint
POSTERIOR HIP & THIGH: piriformis, obturator internus & quadratus femoris
‘rotator cuff muscles of hip joint’ - short fixators
Piriformis & obturator internus arise in pelvis
Quadratus femoris is directly posterior to hip joint, only in gluteal region, from gluteal tuberosity and greater tuberosity.
*obturator internus is characterised by gamelli (2 helper muscles either side of obturator internus)
What contracts to prevent/minimise pelvic tilt?
Gluteal muscles contract on opposite side of leg in swing phase
What muscles (+ tendon, ligament) are seen on the superficial anterior view of the thigh?
- iliopsoas
- pectineus
- sartorius
- rectus femoris
- vastus lateralis
- vastus medialis
- quadriceps tendon
- patellar ligament
What is the function of the iliopsoas?
The iliacus and psoas major have a conjoined tendon of insertion and leave abdomen by passing beneath inguinal ligament heading to lesser trochanter.
- flexes hip OR flexes trunk on extended lower limb
- maintains lumbar lordosis (important postural significance!)
What is the significance of the sartorius muscle?
It divides the muscles into ones above and below sartorius (most are below & are quadriceps)
Runs from anterior/superior iliac spine to proximal tibia
‘dog poo muscle’
What is the function of the pectineus muscle?
Pectineus is in transition, lies partly in anterior and partly in medial/adductor compartment. Therefore it flexes and adducts the hip.
Dual action = dual nerve supply.
