Human Anatomy Vol 1

Third

costotransverse joint

Head of rib

Neck of rib (cut part)

Concave facet for

articular tubercle

of rib

Flattened facets for

articular tubercles

of 7-9 ribs

Ninth

costotransverse joint

Fig. 13.24: A section through the costotransverse joints from the
third to the ninth inclusive. See the convex facets on tubercles of
3rd-6th ribs and flattened facets on tubercles of 7th-9th ribs

F19.13.25: The axes of movement (AB and CD) of a

vertebrosternal rib. The interrupted lines indicate the position of

the rib in inspiration

The articular surfaces of the seventh to tenth ribs
are flat, permitting up and dovrn gliding movements
or bucket-handle movements of the lower ribs. When
the neck of seventh to tenth ribs moves upwards,
backwards and medially, the result is increase in
infrasternal ang1e. This causes increase in transverse
diameter of thorax (Fig. 13.26).

BONES AND JOINTS OF THORAX

FIg" 13.26: The axes of movement (AB) of a vertebrochondral

rib. The interrupted lines indicate the position of the rib in

inspiration

For explanation of the terms 'pump-handle' and

'bucket-handle' movemettts, see'Respiratory Move-

ments'.

Costochondlol Joints

Each rib is continuous anteriorly with its cartilage, to

form a primary cartilaginous joint. No movements are

permitted at these joints.

Chondlosternol Joints

The first chondrosternal joint is a primary cartilaginous

joint, it does not permit any movement. This helps in

the stability of the shoulder girdle and of the upper

limb.

The second to seventh costal cartilages articulate with

the sternum by synovial joints. Each joint has a single

cavity except in the second joint where the cavity is

divided in two parts. The joints are held together by

the capsular and radiate ligaments.

lnlelchondtol Joints

The fifth to ninth costal cartilages articulate with one

another by symovial joints. The tenth cartilage is united

to the ninth by fibrous tissue.

The movements taking place at the various joints

described above are considered under 'Respiratory

Movements'.

!nterverlebrol Joints

Adjoining vertebrae are connected to each other at three

joints. There is a median joint between the vertebral