Thoracic cavity surrounded by thoracic wall contains the thymus, heart, lungs, distal part of
trachea, most of esophagus.
Skeleton of thoracic wall forms osteocartilaginous thoracic cage.
Contains 12 thoracic vertebrae and intervertebral discs, 12 pairs of ribs, and sternum.
Thoracic vertebrae have
costal facets on bodies for articulation with heads of ribs [joint of head of rib, along with
adjacent intervertebral disc]
facets on transverse processes for articulation with tubercles of ribs (except inf. 2)
superior demifacet art. w/ head of own rib;
inferior demifacet art. w/ head of inf. rib
Ribs – 12 pairs (1-7 = true, 8-10 = false, 11-12 = floating; unattached ant., end b/w muscles)
Head = 2 articular facets + crest
Tubercle art. w/ transverse process
Shaft – costal groove on inf. surface, lodges intercostal vessels and nerves
has one art. facet, is broadest, shortest, most curved
scalene tubercle (anterior scalene m.), groove of subclavian a. (ant.) and vein. (post.)
has has tuberosity for serratus ant.
has single art. facet
have single art. facet, no neck or tubercle
Manubrium (T3-T4)– jugular notch, 2 clavicular notches (sternoclavicular joints)
manubriosternal joint (symphysis) – forms sternal angle [of Louis]
Body (T5-T9) – costal notches 2-7, xiphisternal joint (synchondrosis); cartilagenous,
ossified by age 40.
Xiphoid process (T10) – ossified by age 40
Radiate lig. - head of rib to body of vertebrae sup. and inf.
Radiate sternocostal ligaments – costal cartilage to sternum
Intraartciular lig. - manubrium to body
Lateral costotransverse lig. - tubercle to tip of transverse process
Superior costotransverse lig. - neck to transverse process superior to it
Sternocostal joints (1-7)
– cartilagenous (synchondrosis)
2-7 – synovial
superior aperture = inlet (bounded by T1, first pair of ribs, sup. border of manubrium)
inferior aperture = outlet (bound by T12, costal cartilages ribs 7-12, xiphisternal joint)
closed by diaphragm, which allows structures to pass through.
Inspiration – increase vertical, transverse, anteroposterior diameters, and intrathoracic volume.
Anteroposterior diameter - costovertebral joints cause ribs 2-6 to rise like pump handles
Pectoralis major and scalene muscles are accessory respiratory muscles.
Intercostal nerves = ant. rami of T1-T12 (upper = T1-T6, lower = T7-T12)
11 pairs + 12
Dorsal rami of these nerves supply muscles, bones, joints, and skin of back