Week 3

Question 1

Hip features

Answer 1

Bares 2/3 of body weight.
Multiaxial ball and socket joint.
Femur sits snuggly into actabelum.

Question 2

Hip ligaments

3

Answer 2

1. Iliofemoral (strongest).
2. Pubofemoral.
3. Ischiofemoral (weakest).

1. limits resistances, prevents from doing the split.
3. Limits hip adduction.

Question 3

Femur Blood supply

Answer 3

Femur head: Retinacular Arteries.
Throcanteric and Cruciate anastomosis.

Retinacular arteries independently feed femoral head.

External iliac > femoral > deep femoral > lateral + medial circumflex > retinacular arteries.

Question 4

NOFF

Answer 4

Neck of Femur Fracture.
External rotation of limb.
Typically results in hip arthroplasty.

Question 5

Psoas Major

Answer 5

Major hip flexor.
Originates in transverse process of lumbar vertebrae. Inserts into Lesser Trochanter of femur.

Question 6

Hip Abductors

Answer 6

Gluteus Medius.
Gluteus Minimus.
Tensor Fascia Latae.

Gluteus medius + minimus Internal rotators

Superior Gluteal (L4-S1)

Question 7

Trendelenburg Gait

Answer 7

Lesion to Superior Gluteal.
Weak abductors - hip drop on contralateral side.

Question 8

Lateral Rotators

Hip

(6)

Answer 8

Piriformis.
Obturator Externus.
Obturator Internus.
Superior Gemelli.
Inferior Gemelli.
Quadratus Femoris.

Innervated by Sacral Plexus.

Question 9

Posterior Thigh Muscles

Answer 9

Biceps Femoris*.
Semitendinosus.
Semimembranosus.
Adductor Magnus (Hamstring part).

Common Origin & innervation = Ischial Tuberosity + tibial (sciatic).

** Biceps femoris shorthead origin + innervation =Linea Aspera + common fibular nerve.
* Function = Extend hip and flex knee.

Question 10

Posterior Thigh Muscle function

Answer 10

Extend hip and Flex knee.

Question 11

Hip Flexion & Extension Muscles + Innervation

Summary

Answer 11

Flexion (L2-L3):
Ilioposas, Pectinenus, Sartious, Rectus Femoris.
Lumbar Plexus + Femoral Nerve.
Extension (L4-L5):
Gluteus Maximus, Hamstrings.
Inferior Gluteal + tibial + lumbosacral plexus.

Question 12

Hip Adduction and Abduction Muscles + Innervation

summary

Answer 12

Adduction (L2-L3):
Adductor Longus, Adductor Brevis, Adductor Magnus*, Pectinenus, Gracilis.
Obturator Nerve (exc. 1/2 AM & pectinenus)
Abduction (L4-L5):
Gluteus Medius, Gluteus Minimus, Tensor Fascia Latae.
Superior Gluteal nerve.

Question 13

Osteoporosis

Answer 13

Osteopenia so severe that risk of fracture is signifcant.
Defined as 2.5 std below the mean peak bone mass. Osteopenia is 1-2.5 std.

Senile (aging) and Postmenopausal are most common.

Net deficient of 0.7% of bone mass per year. Menopause is 2% cortical and 9% medullary bone.

Question 14

Osteoporosis Pathogenesis

Answer 14

Age: Elderly Osteoblast have reduced proliferative effects and diminished biosynthetic potential.
Reduced physical activity: Mechanical forces stimulate normal bone remodelling.
Genetics: LRP 5 mutuation, rare.
Hormonal: Estrogen deficiency results in increased bone resorption and formation but the latter does not keep up.

Decreased estrogen may increase secretion of inflammtory cytokines from monocytes. Stimulating:
Osteoclast recruitment and activiting via increasing RANKL.
Diminishing expression of OPG (suppresses osteoclastogenesis + bone resorption).
Prevent osteoclast apoptosis.

Question 15

Osteoclast function.

Answer 15

Osteoclast bind to bone via avB3 intergrin. Forms “ceiling zone”, osteocyte has proton pump therefore can create a acidic environment in vivo, and secrete lysosomal and Cathespin K to the bone beneath ceiling zone.

Osteoblast regulate osteoclast maturation via RANKL. Osteoblast also produces OPG, that binds to RANKL inhibiting binding to osteocyte.

Question 16

Bisphosphonates

Answer 16

Enzyme resistant analogue of pyrophosphate, which inhibit bone mineralization.
R1 chain affects mode of action.
R2 chain affects pharmacokinetics.

ADR: Osteonecrosis of the jaw.

Non-N containing: Etidronate, not potent.

N-containing: Alendronic acid, very potent. Inhibit enzyme, Farnesyl Pyrophosphate Synthase. Inhibiting GTP binding proteins such as Rab, Rho, Rac.

Question 17

Coxibs Drug Family

Answer 17

COX-2 inhibitors.
Celecoxib - selective anti-inflammatory.

Question 18

Cushing Syndrome

Answer 18

Excess cortisol production.
Can be caused by steroid withdrawal. Have to ween patients off.

Question 19

Sacral Plexus

L4-S4

Some Irish Sailor Pesters Polly

Answer 19

Superior Gluteal (L4-S1).
Inferior Gluteal (L5-S2).
Sciatic (L4-S3).
Posterior Femoral cutaneous (S1-S3).
Pudenal (S2-S4).

Question 20

Lumbar Plexus

T12-L4

I, I Get Leftovers On Friday

Answer 20

Iliohypogastric (T12-L1).
Ilioinguinal (L1).
Lateral Cutaneous of Thigh (L2-L3).
Obturator (L2-L4).
Femoral (L2-L4).