Pectoralis Major Attachments.
Orig (2 parts)
Orig. Clavicular Head:
Anterior surface of medial half of Clavicle.
Anterior surface of sternum.
Insert. Lateral lip of intertubercular sulcus of humerus.
Innervation and action of pectoralis major.
Medial and Laterla Pectoral Nerves.
Actions: Flexion, Adduction, and medial rotation
Clavicular head: Flexion of extended arm.
Attachments, Innervation and Action of pectoralis minor
Orig: Anterior surface of superior borders of ribs 3-5
Insert: Corocoid process of scapula
Medial Pectoral nerve/s
Pulls top of shoulder down.
Protracts Scapula (Pulls scapula forward and pushes arms forward.)
What is the purpose of the twisting motion of the pectoralis major?
Twisting keeps things from crushing us.
What is the cartilage structure of the joints connecting ribs and vertebra?
Fibrocartilage disc in the joint.
Hyaline cartilage over bones.
Describe the innervation path to both Pectoralis major and minor.
Lateral Pectoral Nerve goes to P. Major only.
Medial Pectoral Nerve goes to both P. Major and Minor.
of Subclavius Muscle
1. Attachments--Orig. 1st rib at junction of rib and costal cartilage,
Insert. Groove of inferior surface of Middle 1/3 of clavicle
2. Innervation--Nerve to the subclavius
3. Action--Anchors clavicle (Pulls tip of shoulder down, pulls clavicle medially.)
1. Attachment--Ribs, Medial boarder of scapula
2. Innervation--Long Thoracic Nerve (Nerve on the outside of the muscle. ) C5-7 (5, 6, 7, Spread your wings and go to heaven.)
3. Action--Protracts the scapula and holds it againg the thoracic wall. (Runs under scapula to vertebral edge. Holds scapula down.)
Winging scapula causes
Weak serratus anterior
Damage to long thoracic nerve. (Also causes innability to raise arms above 90 degrees.)
A: orig, insert
A: Orig. Anterior surface of superior borders of ribs 3-5
Insert. Corocoid porcess of scapula.
N. Medial Pectoral Nerve.
F: Pulls top of shoulder down.