Ch. 25: Joints of Lower limb: hip and knee

Question 1

What type of joint is the hip? How is the socket made deeper? what is the arterial supply?

Answer 1

• synovial joint, ball and socket
• articulation b/w head of femur and acetabulum of os coxa
• socket made deeper by:

1. transverse acetabular ligament
2. acetabular labrum

• the synovial lining surrounds all non-articular elements of the joint, providing a bursa for obturator externus posteriorally
• arterial supply: lat/med. femoral circumflex aa, superior/inferior gluteal aa. obturator a.

Question 2

where is the capsule of the hip joint attached to?

Answer 2

superiorly: brim of acetabulum near labrum and tasverse acetabular ligament
inferiorly: anteriorly to intertrochanteric line and jn. of neck of femur with trochanters; posteriorally possesses a free (unattached) border around femoral neck

Question 3

what are the two laminae fibers making up the capsule of the hip joint?

Answer 3

1. superficial lamina : longitudinally oriented fibers which limit movment of the lib in a specific direction

• Iliofemoral ligament
• pubofemoral ligament
• ischiofemoral ligament

2. Deep lamina: “circularly” arranged fibers (zona orbicularis) which provide a “screw home” effect between the head of the femur and acetabulum; greatly enhances hip joint stability

Question 4

What is the iliofemoral ligament? where does it attach?

Answer 4

• in position of an inverted y anteriorally = “Y ligament”
• one of the strongest ligaments in the body - when you are standing and leaning back, the head of femur rests on this ligament
• attaches superiorly to the AIIS and inferioraly to the intertrochanteric line and anterior inferior portion of the greater trochanter
• is tightest in full extension

Question 5

Where is the pubofemoral ligament? what does it do?

Answer 5

• forms the medial/inferior portion of the capsule
• attaches medially to the brim of pubic portion of acetabulum and laterally to the neck of femur near lesser trochanter
• limits abduction; becomes tight in extension

NOTE: a gap exists between the ilio and pubofemoral ligaments anteriorally and inferioraly; this is covered by the psoas major and its bursa (iliopectineal bursa)

Question 6

What does the ischiofemoral ligament do? where is it located?

Answer 6

• becomes tight in extension
• attached posteriorly to ischial portion of acetabulum, laterally to neck of femur

*fibers composing this ligament spiral in their course; forms posterior free margin of capsule - pulls head of femur into cap during extension

Question 7

what is an intracapsular ligament found in the hip joint?

Answer 7

Ligamentum teres captis femoris (round lig. of the head of the femur)

• arises from edges of acetabular notch and transverse acetabular ligament
• attaches to fovea capitis of femur
• limits adduction

Question 8

what elements limit range of motion in the hip joint?

Answer 8

1. capsular and intracapsular ligs
2. soft tissue
3. opposite limb

NOTE: lateral rotation of the thigh at the hip joint is greater than medial rotation and is more powerful of the two motions

Question 9

what is the structure of the knee joint? how does its structure give it stability?

Answer 9

• true synovial joint; modified hinge (does allow some rotation)
• joint b/w femoral and tibial condyles and femur with patella
• expanded roller surface and expanded tibial plateau = joint stability

Question 10

general characteristics of the knee joint capsule and its attachments?

Answer 10

1. attached superiorly to the condyles and intercondylar fossa of hte femur, inferiorly to the margins of the tibial condyles
2. thickest posteriorly where it is reinforced by ligamentous expansions of muscular attachments
3. laterally is buttressed by IT tract; anteriorly by expansions of fascia lata
4. has small openings (mainly posteriorally) which provide communication v/w muscular bursae and synovial cavity of the joint

Question 11

What are the (three) important ligaments of the knee joint?

Answer 11

1. lateral and medial patellar retinacula: expansion of vastus lateralis/medialis
2. oblique popliteal ligament: expansion of semimembranosus tendon superolaterally toward the lateral femoral condyle
3. arcuate popliteal lig: expansion of attachment of biceps femoris muscle in fibular head; arches superiorly and medially over popliteus muscle

Question 12

flexors at hip joint?

Answer 12

iliopsoas

sartorsius

tensor fascia latae

pectineus

adductor longus

adductor brevis

adductor magnus - anterior part

gracilis

Question 13

adductors of hip joint?

Answer 13

adductor longus, brevis, magnus

gracilis

pectineus

obturator externus

Question 14

lateral rotators of hip

Answer 14

obturator externus/internus

piriformis

quadratus femoris

gluteus maximus

Question 15

extensors of hip

Answer 15

hamstrings: semitendinosus, membranosus, biceps femoris long head

adductor magnus- posterior part

gluteus maximus

Question 16

abductors acting at hip joint

Answer 16

gluteus medius, minimus, tensor fascia latae

Question 17

medial rotators at hip

Answer 17

gluteus medius, minimus

tensor fascia latae

Question 18

What are three important extracapsular ligaments at the knee?

Answer 18

1. ligamentum patellae: goes across from of patella from quadriceps tendon to tibial tuberosity
2. medial (tibial) collateral ligament - attached to medial meniscus [larger ligament]
3. lateral (fibular) collateral ligament - “pencil like” to lateral meniscus

NOTE; both lateral and medial get tight in extension/hyperextension

Question 19

What makes up the synovium of the knee joint?

Answer 19

• lines interior of joint (except for articular surfaces and cruciate ligaments)

* Infrapatellar synovial fold: divides joint space into lateral and medial tibiofemoral compartments

*Suprapatellar bursae: extension of synovial cavity beneath the quad tendon

Question 20

why is the cartilate of kneee joint important?

Answer 20

“menisci”

• lateral= lunar, medial=semi-lunar
• help cushio joint and stabilize articulation by deepning the articulation surfaces

Question 21

what is the purpose of the anterior cruciate ligament? what about the posterior cruciate ligament

Answer 21

Anterior: prevents posterior displacement of femur when foot is firmly fixed

Posterior: prevents forward displacement of femur when foot is firmly fixed

Question 22

what do the meniscofemoral ligaments do?

Answer 22

• keep menisci from being trapped during knee flexion; stabilize knee during posterior translation of lateral femoral condyle

Question 23

what muscles do extension and lateral rotation of hip joint?