Topic 2 Flashcards
define the functions of ligaments
- act as mechanical constraints (mechanical function)
prevent undesired movement
permit limited desired movement - sensory organs - proprioception
define articular discs and their function
pads of fibrocartilage that are situated between the articular surfaces of some synovial joints
function:
act as shock absorbers
aid mechanical fit between articular surfaces
restrain movement
assist lubrication
permit different movements to occur in the joint
define bursae and their functions
fluid-filled sacs around many
synovial joints
potential rather than actual
spaces
function: to reduce friction as structures slide on one another therefore located between layers of muscles where muscles and tendons overlie bony prominences bursitis
define and demonstrate active movement in joints
active movement
- produced by muscle contraction
can be angular movements
- flexion/ extension transverse axis
- abduction/ adduction anteroposterior axis
or rotational movements
- internal (medial)/
external (lateral) rotation longitudinal axis
define and demonstrate passive movement in joints
passive movement
movement produced by an external force
passive physiological
could also be produced actively
passive accessory
cannot be produced actively
movement of articular surfaces within joint capsule
define close packed position
greatest joint stability is achieved for the least energy
It is the position where
joint surfaces are maximally congruent
the ligaments & capsule are maximally taut
In this position
the joint is resistant to tensile forces that tend to cause separation
little or no joint play is possible
will be a slightly different position for each joint
what are the anatomical features that can limit movement at a joint
ligaments and articular discs
what are the articular surfaces of the hip
acetabulum, acetabular notch, acetabular labrum, ilium, ischium, pubic and head of femur.
describe the acetabulum
• Acetabulum – concave (female) surface • Formed by union of the three component parts of innominate bone • one fifth pubis • two fifths ischium • two fifths ilium • Semilunar shaped area covered with articular cartilage • Acetabular fossa - non- articular area
describe the acetabular notch and labrum
Acetabular notch
• inferior deficiency of the
acetabulum
• transverse ligament
Acetabular labrum • fibrocartilage wedge attached to rim of acetabulum • deepens socket and therefore increases stability
describe head of femur
head of femur – convex (male) surface • 2/3 sphere • covered with articular cartilage, except for small area on head (fovea capitis)
describe the joint capsule and synovial membrane at the hip joint
joint capsule • strong • thickest anteriorly and superiorly • attaches to labrum and surrounding bone on innominate (and to transverse ligament at the notch) • reflected onto neck of femur attaching to intertrochanteric line
synovial membrane • lines internal surface of capsule, covers labrum • cavity communicates with the psoas major bursa
describe the iliofemoral ligament
Iliofemoral • Capsular • located anteriorly, triangular in shape • inferior band limits extension, and external rotation • superior band limits extension, adduction and external rotation • sometimes small deficiency anteriorly – covered by iliopsoas
describe the pubofemoral ligament
Pubofemoral • Capsular • located inferiory and anteriorly • limits abduction, extension and external rotation
describe the ischiofemoral ligament
Ischiofemoral • Capsular • located posteriorly • least well defined • limits extension, abduction and internal rotation
describe the transverse ligament
transverse ligament • completes acetabulum, breaches the acetabular notch - intracapsular
describe the ligamentum teres
ligamentum teres (ligament to head of femur) • from transverse ligament to fovea capitis • no strict mechanical function • recent research indicates a proprioceptive role and a possible source of hip pain (Martin et al 2019) - intracapsular
what is the acetabular fat pad
acetabular fat pad • occupies the acetabular fossa • function – proprioception
where are the two bursae around the hip joint
Greater trochanteric bursa: • sits between the greater trochanter and the Iliotibial band
Iliopectineal bursa: • often referred to as the iliopsoas bursa • lies between the tendon of iliopsoas and the fibrous capsule of the hip
describe the factors that confer stability at the hip joint
articular fit – reasonable congruence • acetabular labrum • strong capsule • functions of muscles- line of pull • bony factors • angle of inclination • angulation of head with shaft • reflects an adaptation to bipedalism • increases stability by increasing contact area of the surfaces
