Role of P‐A line in relation to diaphragm (visceral) and Respiratory Mechanics
Postural Analysis and cavity relationships (respiratory dynamics)
Role of P‐A line in relation to diaphragm (visceral) and Respiratory Mechanics
Respiration Dynamics Role of P‐A line in relation to diaphragm (visceral) and Respiratory Mechanics
Postural Analysis and cavity relationships (respiratory dynamics)
Role of P‐A line in relation to diaphragm (visceral) and Respiratory Mechanics
PA ‐ Line
Function
Complementary to articulation of the atlas‐coccyx line (A‐P). (1) Represents a line of pressure binding the posterior occipito‐atlantal
articulation to 2 D and 2nd rib to maintain the integrity of neck tension.
(2) Strengthens line of abdominal‐pelvic support and directs tension from the articulation of 2‐3 L to the femoral heads.
Special Function
Maintains tension of neck, trunk and legs co‐ordinate with the pressure in the internal cavities of the body, via the D‐L ligaments, which oppose the hip and leg movements in relation to the abdominal muscles and pelvic organs. Role of P‐A line in relation to diaphragm (visceral) and Respiratory Mechanics
PA ‐Line
Line
PA ‐
Represents a line of pressure binding the posterior occipito‐atlantal articulation to 2 D and 2nd rib to maintain the integrity of neck tension. (1)
(1)
PA – strengthens the line of abdomino‐pelvic support (2)
(4)
(2)
(3)
Directs tensions from the articulation of l2/3 to the femoralheads (via the psoas mm and deep abdomino pelvic fascia) (3)
Maintains tension of neck, trunk and legs co‐
ordinate with the pressure in the internal cavities of the body, via the D‐L ligaments, which oppose the hip and leg movements in relation to the abdominal muscles and pelvic organs. (4) It finally passes around the pubic ramus to reunite at the symphesis – thus it is present at key points throughout each of the cavities
Role of P‐A line in relation to diaphragm (visceral) and Respiratory Mechanics
Polgones of forces
“PC – lines” NB . The PC – lines of polygone run on same plane as PA line
Role of P‐A line in relation to diaphragm (visceral) and Respiratory Mechanics
Example of structures relating to lower polygone and function of PA /PC*lines
PC – lines of Lower polygone
PA line and relations
Postural Analysis and cavity relationships
PA – Line under relative compression
PA – Line under relative tension / (stetch)
Postural Analysis and cavity relationships (respiratory dynamics)
The high dome of the diaphragm puts it at a mechanical disadvantage resulting in decreased excursion Most rib movement occurs at the lower ribs (bucket handle) Depressed upper thorax leading to a decrease in movement of the upper ribs, decreased excursion of the thoracic cage and therefore impaired upper lung function Ribs are held in relative expiration so that the diaphragm is held relatively high
The above two factors lead to a relative increase in the thoracic cavity pressure
The high diaphragmatic position and the poor abdominal tone result in a relative decrease in the intrabdominal and pelvic cavity pressures Postural Analysis and cavity relationships (respiratory dynamics)
Shoulders retracted and externally rotated The anterior thorax leads to a decrease in the thoracic kyphosis
The lateral expansion of the lower ribs is decreased The whole extensor apparatus of the spine is tense Dorso ‐ abdominal junction 'opened out', therefore respiration is more efficient than the posterior type The whole thorax is pulled superiorly and anteriorly
The thorax is therefore in relative inspiration, with the diaphragm being lower and more flattened at rest
On inspiration, the thoracic cage moves en masse anteriorly and superiorly
The abdominal pressure is increased by the combined effects of: 1 The lowering of the thoracic diaphragm
2 The increased tension in abdominal muscles due to the anteriorization of the ilia causing an increased distance between the abdominal muscles' origin and insertion 3 The anteriorization of the lower lumbar vertebrae
Postural Analysis and cavity relationships (respiratory dynamics)
Posterior type
Anterior type
Modified of PA line function inducing modified diaphragmatic “function” and effects on posture
Postural Analysis and cavity relationships (respiratory dynamics)
“Optimised cavity relationship where diaphragm, PA and AP lines ,functional curves and polygones are In a state of “dynamic equilibrium”