ESSAY 6 - THORAX

WHAT IS THE SKELETON OF THE THORAX?

THORACIC SKELETON (RIB CAGE) FORMS THE BONY FRAMEWORK OF THE CHEST

IT PROTECTS THE HEART, LUNGS, AND GREAT VESSELS AND AID IN RESPIRATION

COMPONENTS OF THORAX

1. THORACIC VERTEBRAE (T1–T12) WITH COSTAL FACETS.

2. 12 PAIRS OF RIBS (TRUE, FALSE, FLOATING).

3. STERNUM (MANUBRIUM, BODY, XIPHOID PROCESS).

COSTOVERTEBRAL JOINTS

RIB HEADS + VERTEBRAL BODIES,

SYNOVIAL PLANE JOINTS

COSTOTRANSVERSE JOINTS

RIB TUBERCLES + TRANSVERSE PROCESSES

SYNOVIAL PLANE

STERNOCOASTAL JOINTS

COSTAL CARTILAGES + STERNUM

(RIB 1 = SYNCHONDROSIS; RIBS 2-7 = SYNOVIAL).

INTERCHONDRAL JOINTS

BETWEEN COSTAL CARTILAGES 6-10

FLEXIBLE

MANUBRIOSTERNAL JOINT

SECONDARY CARTILAGINOUS (SYMPHYSIS)

ALLOWS SLIGHT MOVEMENT.

XIPHISTERNAL JOINT

PRIMARY CARTILAGINOUS (SYNCHONDROSIS)

OSSIFIES WITH AGE

FUNCTION 1 - PROTECTION

PROTECTS LUNGS , HEARTS AND VESSELS

FUNCTION 2 - SUPPORT

SHOULDER GIRDLE & UPPER LIMBS

FUNCTION 3 - ATTACHMENT

ATTACHMENT FOR MUSCLES OF RESPIRATION, UPPER LIMBS, BACK AND ABDOMEN

INHALATION

EXTERNAL INTERCOSTALS CONTRACT → RIBS ELEVATE → THORACIC VOLUME INCREASES → AIR IN

EXHALATION

PASSIVE → RIBS RETURN → THORACIC VOLUME DECREASES → AIR OUT

WHAT IS THE BIOMECHANICS OF THE THORAX?

RIBS AND JOINTS ALLOW EXPANSION AND CONTRACTION OF THE CHEST CAVITY