Thorax 3 - GA Flashcards
What are the main muscles of inspiration?
→ external intercostal muscle
→ scalene muscles
What are the origins of the external intercostal muscles?
originates from the sharp inferior costal border of one rib
What are the insertions of the external intercostal muscles?
insert along the outer lip of the superior border of the immediate rib below
What is the innervation for external intercostal muscles?
intercostal nerves
What are the different parts of the scalene muscles?
→ anterior
→ middle
→ posterior
What is the origin of the anterior scalene muscle?
anterior tubercles of transverse processes of cervical vertebrae C3-C6
What is the insertion of the anterior scalene muscle?
scalene tubercle of 1st rib
What innervates the anterior scalene muscle?
anterior rami of 4th-6th cervical nerves
What is the origin of the middle scalene muscle?
posterior tubercles of transverse processes of C2-C7
What is the insertion of the middle scalene muscle?
superior surface of 1st rib
What innervates the middle scalene muscle?
anterior rami of 3rd-8th cervical nerves
What is the origin of the posterior scalene muscle?
posterior tubercles of transverse processes of C4-C6
What is the insertion of the posterior scalene muscle?
external surface of 2nd rib
What innervates the posterior scalene muscle?
anterior rami of 4th-6th cervical nerves
What do the external intercostal muscle do?
contraction moves ribs up + out
What do the scalene muscles do?
contraction raises 1st + 2nd ribs up in deep inspiration
What are the muscles of expiration?
→ internal intercostal muscles
→ abdomen muscles
What are the origins of the internal intercostal muscles?
inferior border of the ribs
What are the insertions of the internal intercostal muscles?
superior borders of the ribs immediately below
What innervates the internal intercostal muscles?
intercostal nerves
What do the internal intercostal muscles do?
→ depresses ribs at their costovertebral joints
→ moves ribs down + in
What are the different abdomen muscle involved in expiration?
→ rectus abdominis
→ transversus abdominis
→ internal oblique
→ external oblique
What do the abdominal muscles do in expiration?
→ helps move ribs down + in expiration
→ assists in forced expiration e.g. coughing + sneezing
What artery is the main supply for the thorax? Where does it stem from?
thoracic arteries, stem from the respective subclavian arteries
What does the internal thoracic artery split off into?
→ pericardiacophrenic artery
→ perforating branches of the internal thoracic arteries
→ musculophrenic artery
→ superior epigastric artery
What does the pericardiacophrenic artery supply?
pericardium + diaphragm
What do the perforating arteries of the internal thoracic arteries supply?
→ pectoralis major
→ breast
→ overlying skin
What does the musculophrenic artery supply?
→ intercostal muscles
→ diaphragm
→ abdominal muscles
How do the veins relate to the thoracic arteries?
accompanying veins of the same name run alongside the arteries to drain them
How is the pectoral region divided?
→ superficial part : consisting of skin, fascia + breast tissue
→ deeper part : 3 muscles of the anterior thorax
What are the 3 muscles of the pectoral region?
→ pectoralis major
→ pectoralis minor
→ subclavius
What is the origin of the pectoralis major?
medial half of clavicle + anterior surface of sternum, costal cartilages 1-7, aponeurosis of external oblique
What is the insertion of the pectoralis major?
lateral lip of inter tubercular sulcus of humerus
What innervates the pectoralis major?
medial + lateral pectoral nerves
What is the action of the pectoralis major?
adduction, medial rotation + flexion of the humerus at the shoulder joint
What is the origin of the subclavius?
rib 1 at junction between rib + costal cartilage
What is the insertion of the subclavius?
groove on inferior surface of middle third of clavicle
What innervates the subclavius?
nerve to subclavius
What is the action of the subclavius?
pulls clavicle medially to stabilise sternoclavicular joint + depresses tip of shoulder
What is the origin of the pectoralis minor?
anterior surfaces of the 3rd, 4th, 5th ribs + deep fascia overlying the related intercostal spaces
What is the insertion of the pectoralis minor?
coracoid process of scapula
What innervates the pectoralis minor?
medial pectoral nerves
What is the action of the pectoralis minor?
depresses tip of shoulder + protracts scapula
What are the key features of the breast tissue?
→ suspensory ligaments of breast → adipose tissue → lactiferous sinuses → lactiferous ducts → lobules of mammary gland → areola → nipple
What is the innervation for the breast?
→ lateral cutaneous branches of 4th + 5th intercostal nerve
What is the arterial blood supply for the breast?
→ pectoral branches of thoracoacromial artery
→ lateral mammary branches of lateral thoracic artery
→ medial mammary branches of perforating branch of internal thoracic artery
What is the lymphatic drainage for the breast?
→ interpectoral nodes → anterior axillary nodes → superficial lymph vessels of thoracic wall → infraclavicular nodes → parasternal nodes
What is the venous drainage for the breast?
→ internal thoracic vein + lateral thoracic vein ??
What are the 2 main classes of back muscles?
→ extrinsic
→ intrinsic
What are extrinsic back muscles?
muscles where the area of origin + area of insertion are different
What are intrinsic back muscles?
area of insertion + are of origin are both in the back
How are back muscles further classified?
→ superficial
→ intermediate
→ deep
What innervates extrinsic back muscles?
anterior spinal nerve rami
What innervates intrinsic back muscles?
posterior spinal nerve rami