Yoga as Therapeutic Exercise: A Practical Guide for Manual Therapists

5

Chapter

Preparatory practice for the yoga art of breathing

Basic anatomy and physiology of respiration Basic anatomy and physiology of respiration

Basic anatomy and physiology of respiration Basic anatomy and physiology of respiration

the right side during inhalation. Due to the mobility

of the liver this difference can be balanced with

practice. During normal exhalation the diaphragm

relaxes; the dome moves upwards a few centime-

ters, and the lungs go into passive rebound.

The accessory muscles of inspiration are the ster-

nocleidomastoid, scalenus anterior, medius, and

posterior (some fibers of which are attached to the

fascia covering the top of the lungs), serratus ante-

rior, pectoralis minor, and erector spinae.

In inspiration the air is drawn into the lungs

through active expansion of the thoracic cavity. The

diaphragm is contracted and moved downwards a few

centimeters. This causes 75% of air intake in normal

breathing. Raising the side ribs at the beginning of

inhalation can enhance movement of the diaphragm.

The intercostal muscles raise the ribs, resulting in

the remaining 25% of the air intake. Combining both

actions, normal breathing can become quite deep

yet still be very subtle. The breathing techniques

we explain later in this chapter are based on this.

This subtle, conscious, deep breathing is different

from forced breathing using the accessory muscles

of respiration. These accessory muscles are not very

active in normal, quiet respiration.

The muscles of expiration

Normal, quiet exhalation is passive. The diaphragm

relaxes and moves a few centimeters towards the

head. The costal cartilages and the ribs are depressed

through the transversus thoracis muscle and the

internal intercostal muscles. In this way the space is

reduced and air moves out of the lungs. The activ-

ity of all the abdominal muscles and the latissimus

dorsi muscle causes forced exhalation. As forced

inhalation, this is not relevant to our approach to

breathing techniques. These accessory muscles are

rather used in a balanced, mindful way to improve

and stabilize the sitting postures for the breathing

techniques.

The thoracic cage

The thoracic vertebrae, the ribs, and the sternum form

the thoracic cage, the skeleton of the chest (Figure

5.4). This protects the thoracic organs; the respiratory

muscles are also attached to the thoracic cage.

The ribs and their movements with

inhalation and exhalation

There are 12 pairs of ribs. The upper seven ribs,

the true ribs, are directly connected to the sternum

by separate costal cartilages. The eighth to twelfth

ribs are the false ribs. The costal cartilages of the

eighth, ninth, and tenth ribs are fused, forming the

costal arch and connected to the costal cartilage of

the seventh rib. Ribs 11 and 12, the floating ribs,

are connected just to the thoracic vertebrae, but not

the sternum. All other ribs are also connected to

the thoracic vertebrae. The costovertebral joints are

between the head of the rib, the vertebral body, and

the intervertebral disc. The costotransverse joint

is between the costal tubercle and the tip of the

transverse process. The many different joint planes

throughout the different segments of the thoracic

spine and the corresponding ribs lead to rib move-

ments in different planes around different axes and

therefore to a very complex movement pattern of

the ribs during inhalation and exhalation. The three

main movement directions can be summarized as

follows: (1) elevation of the lower ribs increases the

transverse diameter of the thorax; (2) elevation

of the upper ribs increases the anteroposterior

diameter of the thorax and raises it; (3) elevation

of the middle ribs increases both diameters. Ribs 11

and 12 move like callipers to create more space in

the lower thorax (Kapandji 2008).

Clavicle

Manubrium

of sternum

Ribs

Costal cartilages

Body of sternum

Xiphoid process

of sternum

Rib 12 Rib 11

1 2 3 4 5 6 7 8 9

10

T1

C7

T12

L1

Figure 5.4 The thoracic cage.