CHEST
Trunk Upper part of trunk being called
Chest Chest walls
More general Skin Superficial fascia Deep fascia Extrinsic muscles More front
Pectoralis major
Pectoralis minor More lateral Serratus anterior More back Rhomboid Major Minor Serratus posterior Superior Inferior Levator scapulae More particular Framework Front chest Sternum Side chest Ribs Back chest Thoracic vertebra Thoracic wall proper Ribs
Spaces between ribs Intercostal space Anteriorly 9 intercostal spaces
Posterior 11 intercostal spaces
Intercostal muscles
External intercostal
From
Posteriorly tubercle of rib to Continuous with posterior fibres of superior costotransverse ligament
costochondral junction
External or anterior intercostal membrane Fibres direction Downward , forward and medially
Internal intercostal From Lateral border of sternum Superior costotransverse ligament To Angle of rib Continuous with internal intercostal membrane Fibres Backwards , laterally Transversria thoracis
Parts
Subcostalis Intercostalis intimi Sternocostalis Nerve supply
Intercostal nerves
Anterior primary Rami of t1 to t11 Upper two supply upper limb Lower 5 supply abdominal wall Anterior primary Rami of t12 forms Subcostal nerve Course Runs in costal groove Ends near sternum Relations Passes below Neck of rib Costal groove Lies below posterior intercostal vessels Above downwards VAN posterior part of groove Nerve lies beneath pleura With endothoracic fascia and internal intercostal membrane Near sternum Nerve crosses infront of internal thoracic artery And sternocostalis muscle Pierces External and internal intercostal muscle
Branches Muscular branches Sensory branches Lateral cutaneous branch. Anterior cutaneous branch
Intercostal arteries Each intercostal space has a artery Posterior intercostal arteries
First and second arise from superior intercostal artery
Which arises from costocervical trunk of subclavian artery 3- 11 arise from descendng thoracic aorta
Course and relations
Actions of intercostal muscles
Chest cavity