Thorax
the upper part of the trunk, is a cage composed of bones and cartilages, which affords protection for several very vital organs; the heart with its trunk vessels and the respiratory organs.
Thoracic vertebra
Sternum – breast bone
Ribs or costae – 12 pairs
Costa cartilages – 12 pairs
The skeleton of the thorax includes
Costovertebral
– between a rib and the body of a vertebra
Costotrasverse
– between a rib and a transverse process of a vertebra
Sternocostal or costosternal
– between a rib cartilage and the sternum
Costochondral
– between a rib and its costal cartilage
Interchondral
– between the adjacent anterior margins of costal cartilages of 6th to 10th ribs.
Sternoclavicular
– between the sternum and the clavicle
Manubriosternal
– between the manubrium and the body of the sternum
Xiphisternal
– between the body of the sternum and its xiphoid process.
Sternum
– flat bone
Sternum parts
Manubrium
Body or gladiolus
Xiphoid process
Manubrium
O Jugular notch (suprasternal notch)
O Clavicular notches
O Costal notches – complete and half
Ribs (costae)
– 12 pairs O Dorsal extremity or vertebral extremity (end) O Body or shaft with an angle O Ventral extremity or sternal extremity
The Sternum
– is a long bone that lies vertically in the midline of the anterior chest wall.
Manubrium
– the upper part and represents the handle of the sword.
Clavicular notches
– depression on the upper surface of the manubrium.
The body or gladiolus
– extends from the manubrium to the xiphoid process and is the largest part of the sternum.
Sternal angle
– (angle of Louis or Ludwig) is marked by a prominent transverse ridge at the junction of the manubrium and the body of sternum.
Xiphoid process
– inferior part of the bone
Costal notches
- are niches on the lateral margins of the sternum
Ribs
– long, curved, flat bones that form the posterior wall, lateral walls and part of the anterior wall of the thorax.
Head
– slightly expanded posterior end.
Neck
– slightly constricted part connecting the head to the body
Tubercle
– small prominence on the dorsal surface at the junction of the neck and body.
The body
long flat, curved part that extends from the neck around the chest wall. At its lower margin there is a groove- the costal groove – fror an intercostal artery, vein and nerve.
Angle of a rib
is a prominence in front of the neck where the rib becomes bent anteriorly.
The ventral or sternal extremity
– anterior end that articulates with its costal cartilage.
The first rib
has 2 grooves running transversely on its upper anterior surface for the subclavian artery and vein.
The 1st, 10th, 11th and 12th ribs
have a single articular surface on the head, not two.
The 11th and 12th ribs
have no tubercles.
True ribs
– upper seven pairs
False ribs
– lower five pairs
Vertebrosternal
– upper seven pairs
Vertebrochondral
– 8 th, 9th and 10th pairs
Vertebral ribs
– 11th and 12th pairs
Costal Cartilages
– flat plates of cartilages similar in shape to the adjacent rib.
Costal arch
– curved formed by the anterior margins of the 7th, 8th, 9th and 10th costal cartilages on each side and the rounded tip of the xiphoid process.
Costochondral joints
Located at the anterior, or sternal, end of a rib and the adjacent costal cartilage.
Sternocostal or costosternal joints
sliding synovial joints (except the 1st which is cartilagionous)
Formed by the sternal (anterior) end of a costal cartilage articulating with a costal notch on the lateral margin of the sternum. (upper 7)
Interchondral joints
Located between adjacent anterior margins of the 7th, 8th, 9th and 10th costal cartilages and the rib cartilage above each one.
Sternoclavicular joints
gliding joints
Between the sternal end of the clavicle and clavicular notch of the sternum
Manubriosternal joint
cartilaginous joint
Between the inferior margin of the manubrium and the upper margin of the body of the sternum, at the sternal angle.
Xiphesternal or xiphosternal joint
cartilaginous joint
Located between the inferior end of the body of the sternum and the xiphoid process of the sternum.
Cervical ribs
– and extra rib may be present on one or both sides above the first rib.
Lumbar ribs
– short extra rib that may be present below the 12th rib.
Absence of ribs
– one or more ribs may be absent on one or both sides.
Forked ribs
– the anterior or sternal end of a rib may divide into two parts.
Pectus excavatum
– the sternum may be depressed so that it lies closer to the thoracic vetrebrae than usual.
Pigeon chest
– prominent sternum may be present.
Jugular notch
Sternal Angle
Xiphisternal joint
Costal Arch
Landmarks – Prominences of the Bones of the Chest
Sternum
Sternoclavicular joints
The ribs
Costal cartilages
Radiography of the Thorax