Thorax - Bony Structures Anatomy

Thorax - Bony Structures

• The thorax is a complex skeletal framework, composed of bones, muscles, fascia and neurovasculature
• It forms a protective cavity for vital organs like the heart and lungs
• It has two major openings, the superior and inferior thoracic apertures
• The superior aperture connects to the neck, bordered by the manubrium of the sternum, first rib pair and the vertebrae
• The inferior aperture is almost entirely closed by the diaphragm, separating it from the abdominal cavity

Thoracic Skeleton

• The thoracic skeleton consists of the sternum, ribs, costal cartilages, and thoracic vertebrae
• The sternum is a flat bone located in the center of the anterior thoracic wall
• It's made up of three parts: manubrium, body, and xiphoid process
• The manubrium is the superior part, and has a suprasternal notch
• The body is the middle portion and largest
• The xiphoid process is the smallest part at the inferior part of the sternum
• Ribs: 12 pairs of ribs, either true, false or floating
• True ribs attach directly to the sternum via costal cartilage
• False ribs attach indirectly or not at all to the sternum, usually connecting to costal cartilage of other ribs
• Floating ribs do not attach to the sternum at all but attach to the thoracic vertebrae

Intercostal Space

• Spaces between ribs
• Contain internal and external intercostal muscles (and sometimes internal and innermost intercostal muscles)
• Contain intercostal blood vessels and nerves

Typical Ribs

• Each rib is somewhat like a curved strut
• The head is a projection on the posterior end of the rib, and has an upper and lower facet
• The neck is a constricted portion, just lateral to the head
• A knob-like structure, the tubercle, is at the posterior surface of the ribs' neck
• The body or shaft is the main part of the rib, slightly curved
• Articulation of rib with thoracic vertebrae: the head and the tubercle articulate

Ribcage (including costal cartilage)

• Ribs and costal cartilage form the rib cage
• Sternum, ribs, costal cartilage, and thoracic vertebrae make up the cage
• Ribs have costal cartilages and attach directly to the sternum, called true ribs (1-7)
• Remaining ribs, false ribs, attach indirectly to the sternum or not at all,
• The 11th and 12th pairs are floating ribs (vertebrochondral)

Joints of the Thoracic Cage

• Intervertebral joints (T1-T12): Symphysis
• Costovertebral joints: synovial plane joint(s)
• Costochondral joints: primary cartilaginous joint
• Interchondral joints: synovial plane joint
• Sternocostal joints: primary cartilaginous joints
• Sternoclavicular joints: saddle type of synovial joint
• Manubriosternal joints: secondary cartilaginous joint
• Xiphisternal joints: primary cartilaginous joint

Explore the intricate bony structures of the thorax, including the thoracic skeleton, sternum, ribs, and major apertures. This quiz covers the protective functions of the thoracic cavity and its vital role for the heart and lungs. Delve into the anatomy and functions of these crucial components of the human body.