6.2 Hip & thigh: bones & muscles

Question 1

During development, how is the lower limb rotated & how does that compare with that of the upper limb?

Answer 1

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!

Question 2

What regions does the lower limb divide into?

Answer 2

Gluteal region
Thigh region
Leg

*on the basis of major joints, component bones & superficial landmarks

Question 3

Where does the gluteal region span?

Answer 3

Gluteal region lies posterolateral and extends from iliac crest above to gluteal fold below

Question 4

Where does the thigh region span?

Answer 4

Anteriorly - extends from inguinal ligament (free inferior edge of external oblique) above to knee joint

Posteriorly - gluteal fold to knee joint

Question 5

Where does the leg region span?

Answer 5

knee joint to ankle joint

Question 6

Which three bones constitute the hip bone?

Answer 6

Superior: ilium
Inferior: ischium
Anterior: pubis

all 3 fuse by adulthood at the acetabulum which articulates with the head of the femur

Question 7

What is on the outer surface of the ilium?

Answer 7

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.

Question 8

What’s on the inner surface of the ilium?

Answer 8

Iliac fossa: gives attachment to iliacus muscle (iliacus forms part of the posterior abdominal wall)

Question 9

Where does the iliac crest begin and end and what is below it?

Answer 9

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.

Question 10

What does the spine of the ischium demarcate?

Answer 10

The ischium has a spine posteriorly demarcating notch above (greater sciatic notch) and below (less sciatic notch) where neurovascular structures run through from pelvis

Question 11

What arises from the ischial tuberosity?

Answer 11

Ischial tuberosity is the origin of the hamstrings and bears weight when you sit

Question 12

What does the ischial ramus meet?

Answer 12

It projects forwards to meet the inferior pubic ramus

Question 13

What is the pubis?

Answer 13

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

Question 14

What angle does the femoral neck form with the shaft?

Answer 14

120 degrees - has functional and fractural ramifications

Question 15

What are the features of the femur?

Answer 15

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.

Question 16

What are the muscles of the gluteal region responsible for?

Answer 16

• 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.

Question 17

What are the major flexors of the hip & where do they arise?

Answer 17

Psoas major and iliacus which arise from the posterior abdominal wall

Iliopsoas insert into the lesser trochanter of femur.

Question 18

What are the compartments of muscles in the thigh and what are they separated by?

Answer 18

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.

Question 19

What are the compartments of muscles in the leg?

Answer 19

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.

Question 20

What muscles are seen on the lateral view of the hip & thigh?

Answer 20

Gluteus maximus
Tensor fascia lata
Iliotibial tract

Question 21

LATERAL & POSTERIOR HIP & THIGH: Gluteus maximus

Answer 21

‘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’

Question 22

LATERAL HIP & THIGH: Tensor fascia lata

Answer 22

‘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.

Question 23

LATERAL HIP & THIGH: Iliotibial tract

Answer 23

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

Question 24

What muscles are seen on the posterior view of the hip & thigh?

Answer 24

Superficially:
-gluteus maximus

Deep:

• gluteus medius & minimus
• piriformis
• obturator internus
• quadratus femoris

Question 25

POSTERIOR HIP & THIGH: Gluteus medius/minimus

Answer 25

‘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

Question 26

POSTERIOR HIP & THIGH: piriformis, obturator internus & quadratus femoris

Answer 26

‘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)

Question 27

What contracts to prevent/minimise pelvic tilt?

Answer 27

Gluteal muscles contract on opposite side of leg in swing phase

Question 28

What muscles (+ tendon, ligament) are seen on the superficial anterior view of the thigh?

Answer 28

• iliopsoas
• pectineus
• sartorius
• rectus femoris
• vastus lateralis
• vastus medialis
• quadriceps tendon
• patellar ligament

Question 29

What is the function of the iliopsoas?

Answer 29

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!)

Question 30

What is the significance of the sartorius muscle?

Answer 30

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’

Question 31

What is the function of the pectineus muscle?

Answer 31

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.