Joints of the Hip Complex

Question 1

Which is the only surface on the hip joint that is weight bearing?

Answer 1

Only the luneat surface is weight bearing, and articular with a rim of cartilage around it

Question 2

What kind of joint is the hip joint & what is the socket called?

Answer 2

The hip joint is aball and socket joint & the fossa is called the acetabumulum

Question 3

Anatomical neck, what occurs here?

Answer 3

Line of growth plate + capsular attachment

Question 4

Attachment of capsule to the hip joint?

Answer 4

Anteriorly attaches to intratrochanteric line

Posteriorly it attaches to the itnratrochanteric crest

Question 5

Ossification centres are what type of epiphysis?

Answer 5

Pressure & Traction epiphyses

• Traction is pull of muscle or ligaments on greater / lesser trochanter
• Pressure = dependent on adequate blood supply to head of femur ( capital epiphysis)

Question 6

What is perthe’s disease

Answer 6

Poor blood supply to head of femur, causing avascular necrosis.

Question 7

Note the orientation of the head of the femur, what is it protected by anteriorly?

Answer 7

Head of the femur is directed upward, medially and forwards. The anterior part protrudes outside the joint space and is protected by the psoas bursa.

Question 8

How is the Psoas Bursa irritated? Clinical Question

Answer 8

The Psoas muscle attaches to the lesser trochanter, lots of hip flexion can irritate the bursa.

Question 9

What induces improved range of motion of the hip joint i.e. thick about the shape of the neck and head?

Answer 9

Femoral head circumference is greater than that of the neck, thus the head can rotate without the neck touching the rim of the acetabulum.

Question 10

What does the trabecular system do in the head of femur? name the two, and describe their action?

Clinical Implications

Answer 10

Trabecular system is designed to resist weight in the hip joint.

Superior system = the Arcuate bundle + medial bundle
It resists vertical forces & bending

Inferior system = MEdial + Lateral ( Bundles) , it resists teh pull of muscles on the lesser and greater trochanters

(in the middle of the inferior system is a point of weakness in osteoporotic pateints and post menopausal women, commonly affects the elderly

Question 11

Femur Neck Angle

Answer 11

In normal its about 125 degrees, babies begin at 150 and reduce 1 degree per year until the end of adolescnce. Pathological

• Decrease = Cox Vara
• Patologycal increase = Cox Valga

Question 12

What is femurs angle of torsion? What happens if the angle of torsion increases, what is the pathology Describe

Answer 12

The femur normally sits 10-15 degrees in front of the horizontal anteriorly.
If this angle increases pathologically, the lower limbs try to compensate, there is medial rotation of tibia, there is stresses on medial part of the knee and when the foot is pronated.

Question 13

Capital Epiphysis Slip

Answer 13

If there is cox vara, this increases the shear forces pushing down on the head of femur

• Normally head of femur sits squarely on the femoral neck
• Increased shear stress and subsequent abnromal movement causes a slip
• The ephysis remains in the acetabulum, whilst the metaphsysis the end of the femur moves in an anterior direction with external rotation.

Question 14

Where does line of gravity pass through the hip joint & what are the implications?

Answer 14

Line of gravity passes behind, so the capsule must be quite enforeced in front

Question 15

Describe the close packed position of the hip

Answer 15

Extension, abduction and medial rotation

Question 16

Describe loose packed position

Answer 16

Flexion, adduction and external rotation of the hip

Question 17

What is the Iliofemoral ligament? What is its function

Answer 17

Located anteriorly. It originates from the ilium, immediately inferior to the anterior inferior iliac spine.The ligament attaches to the intertrochanteric line in two places, giving the ligament a Y shaped appearance. It prevents hyperextension of the hip joint. Re inforces the capusle.

• Stablishes the hip joint in extension, causes joint capsule to tighten.
• Posterior capsule doesnt extend as far distaly, extends to intratrochanteric crest, so this ligament limits movement in extension.

Question 18

Pubofemoral LIgament

Answer 18

Located anteriorly and inferiorly. It attaches at the pelvis to the iliopubic eminance and obturator membrane, and then blends with the articular capsule.

It prevents excessive abduction and extension.

• They blend with the capsule and not directly to the femur

Question 19

Ischiofemoral

Answer 19

Located posteriorly. It originates from the ischium of the pelvis and attaches to the greater trochanter of the femur. It prevents excessive extension of the femur at the hip joint.

Question 20

Labrum? Function of the labrum? And pathology?

Answer 20

Labrum is like a fat pad, which increases in surface area for head of femur , making the socket deeper and increases stability by applying a negative pressure (suction effect)

When there is posterior dislocation of the hip, bits of it can break off and lodge elsewhere

Question 21

Ligament of head of femur? Purpose? Pathology?

Answer 21

It is a direct extension of a brach of the obturator artery to supply blood to femoral head during development. Altough it regresses after puverty disruption to joint can cause it to bleed.

Question 22

Retinaculum what is it?

Answer 22

Fibres from the hip joint capsule, supplied by retinacular vessels, susceptible to neck of femur fracture injuries.

Question 23

What is the illiopsoas & what is its purpose?

Answer 23

Illiopsoas is a combination of the illiacus muscle and the psoas major at its inferior end, it is the primary hip flexor

Question 24

What is the primary extensor of the hip?

Answer 24

The gluteus maximus

Question 25

Adductor especially aductor longus

Answer 25

Attaches to the pubic bone, its inflammation can cause osteitis pubis

Question 26

Abductor Muscles? WHat do they do? What is the tendellenburg Gait

Answer 26

Gluteus medius & gluteus minimus ( deep to gluteus maximums) they maintain the position of the pelvis and prevent if from fallign away on the weight bearing leg during walking - When these muscles are weak trendelenburg gait results and pelvis is tilted towards the side where you lift your leg.

Question 27

Cuff Fixator muscles?

Answer 27

They attach to the greater trochanter form the acetabulum, improves stability. Like rotator cuffs of the shoulder. Also involved in lateral rotation.

Question 28

HIltons Law

Answer 28

Read

Question 29

Femoral Nerve

Answer 29

Supplies muscles around femur

Question 30

Obturator Nerve? Origin roots? WHere can pain in the hip refer to?

Answer 30

arises from L2,3,4 also supplies medial thigh, anterior divsion of the obturator extends to hip joint and can be irritated in arhtirtic changes.

This pain may be referred to skin of medial thigh or even as far down as the knee

Question 31

How can pain refer to the ihp

Answer 31

L2-3 ( hip flexion)

L4-5 ( hip extension)

Question 32

Femoral Artery? What does it do?

Answer 32

Takes blood supply from the hip to the back of the knee

Question 33

Profunda Femoris

Answer 33

Major blood supply to thigh, gives off lateral femoral circumflex, and medial femoral circumflex

Question 34

Retinacular vessels

Answer 34

Are branches of the medial and lateral circumflex, which pass through retinacular fibres of the capusle and supply the neck of the femur, go to teh head of the femur and form a ring around the joint.

This is susceptible to neck of femur fractures

Question 35

Fracture of neck of femur

Answer 35

Disrupts blood supply

Hip will become externally rotated, limb is shortened due to muscle spasm of the illiopsoas + gluteal muscles

Question 36

Sciatic Nerve where does it run

Answer 36

It runs posteriorly, femoral artery runs anteriorly

Question 37

Posterior dislocation of hip joint, commonly in car accidents. Describe what happens? What is the clinical implicatiosn

Answer 37

The joint dislocates posteriorly, it is associated with fractured posteiror lip of acetabulum, it endangers teh sciatic nerve. Rearticularisation immediately is important. occurs in loose packed position - flexed, adduction, external rotation

Question 38

Congenital dysplasia in acetabulum? clinical implications

Answer 38

Causes a shallow acetabulum, treated by keeping the legs in an abducted position. untreated causes teh formation of a false joint, tredelenburg gait, shortened limb.

Question 39

Osteoarthritis

Answer 39

Wearing away of cartilage, osteophytic changes protect