Benish Islam Lecturer / coordinator Surgical IPMS/KMU Thoracic Wall Benish Islam Lecturer / coordinator Surgical IPMS/KMU

Structure Of thoracic Wall

Sternum Manubrium Body of sternum: Manibriusternal joint Xipibhisternal joint Sternal angle Xiphoid process

Ribs Total 12 pair of ribs True ribs: upper 7 False: 8,9,10th ribs Floating ribs: 11,12 ribs Typical rib:Costal Groove,head,neck, tubercle shaft,angle Atypical rib: 1st rib

Thoracic outlet Opening at root of neck. Oesophagus , trachea and blood vessels pass through it Thoracic outlet

Endothoracic fascia Loose connective tissue Separate parietal pleura from thoracic wall Endothoracic fascia

Intercostal muscles (3 types) External intercostal muscle: Fibers directed downward and forward From inferior border of rib above to superior border of rib below Aponerosis: Ant.(external) intercostal membrane

2. Internal intercostal muscle Intermediate layer Fibers directed downward and backward From subcostal groove of rib above to upper border of rib below Aponeurosis: post. (internal) intercostal membrane

3.Innermost Intercostal muscle Deepest layer Corresponds to transversus abdominis in abdominal wall Croses more than one intercostal space Related to endothoracic fascia. Blood vessels,nerves pass between intermediate and deepest layer.

Respiration mechanism: Action Supply Inter costal nerves Intercostal Arteries and veins: Post. Intercostal arteries Ant. intercostal veins

Diaphragm

Origin of diaphragm Thin muscular tendinous septum,separate chest cavity above from abdominal cavity. Sternl part:arises from post. Surface of xiphoid process Costal Part:arise from deep surface of lower six ribs and costal cartilage. Verterbral part:arises from vertebral column nd arcuate ligament. Inserted into central tendon Rt.dome: upper border of 5th rib Lt. dome: lower border of5th rib

Diaphragm Muscle of Inspiration Muscle of Abdominal Straining Nerve/Action Function Motor nerves: rt,lt. phrenic nerves C3,4,5 Sensory nerves: Phrenic nerve and lower six intercostal nerves Action:On contraction, diaphragm pulls down central tendon and inc. vertical diameter of thorax. Muscle of Inspiration Muscle of Abdominal Straining Weight lifting muscle Thoracoabdominal pump

3 major opening in diaphragm

Anterior view of thorax

Lines of orientation

Posterior chest wall

Surface Anatomy

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