anterior axio-appendicular muscles

Question 1

Answer 1

pec major

• *proximal attachment**
• clavicular head* : anterior surface of medial half of clavicle

sternocostal head : anterior surface of sternum, superior six costal cartilages, oponeurosis of external oblique muscle

Distal attachments : Lateral lip of interbercular sulcus (groove) of humerus

Main actions : Adducts and medially rotates shoulder joint, draws scapula anteriorly and inferiorly

Acting alone, clavicular head flexes shoulder joint and sternocostal head and extends it from the flexed position

Innervation : lateral and medial pec nerves, clavicular head (C5,C6), Sternocostal head (C7, C8, T1)

Question 2

Answer 2

Pectoralis Minor

Proximal Attachment : 3rd-5th ribs near their costal cartilages

Distal attachment : Medial border and superior surface of coracoid process of scapula

Main action : stabilizes scapula by drawing inferiorly and anteriorly against thoracic wall

Innervation : Medial pectoral nerve (C8, T1)

Question 3

Answer 3

subclavius

Proximal attachment : junction of 1st rib and its costal cartilages

Distal attachment : inferior surface of middle third of clavicle

Main action: Anchors and depresses clavicle

Innervation : Subclavian nerve (C5, C6)

Question 4

Answer 4

serrates anterior

proximal attachment : external surfaces of lateral part of 1st-8th ribs

distal attachments : anterior surface of medial border of scapula

main action: protracts scapula and holds it against thoracic wall; rotates scapula. accessory respiration, also helps extend arm with pec minor

Innervation : long thoracic nerve (C5, C6, C7)

-big and powerful