Muscles of the Shoulder Joint Flashcards
Where are the Origins of the Pectoralis Major?
Clavicle, sternum and cartilage of ribs 1-6
Where is the Insertion of the Pectoralis Major?
Humerus
What joint does the Pectoralis Major cross?
Glenohumeral/Shoulder Joint
What are the Actions of the Pectoralis Major?
Shoulder horizontal flexion, shoulder adduction, shoulder medial rotation
Where is the Origin of the Teres Major?
Lateral border of the scapula near the inferior angle
Where is the Insertion of the Teres Major?
Humerus (proximal, anterior)
What joint does the Teres Major cross?
Shoulder
What are the Actions of the Teres Major?
Medial rotation, adduction and extension of the shoulder joint
Where are the Origins of the Latissimus Dorsi?
Via the thoracolumbar fascia (TLF) from spinous processes of T6–T12, lumbar and sacral vertebrae and iliac crest. Also the lower 3–4 ribs and bottom (inferior) edge of the scapula
What is the TLF?
TLF is a sheet of ligamentous connective tissue covering the lumbar spine and Sacro-Iliac joint. It is primarily made of collagen so has no contractile properties.
Where is the Insertion of the Latissimus Dorsi?
Top of the Humerus
What joint does the Latissimus Dorsi cross?
Shoulder Joint
What are the Actions of the Latissimus Dorsi when the Origin is fixed?
Adducts and extends the arm. Assists in medial rotation of the arm. Depresses the shoulder girdle via the insertion on the humerus
What is the Action of the Latissimus Dorsi when the Insertion is fixed?
Tilts the pelvis forwards
Where is the Origin of the anterior head of the Deltoid?
Clavicle
Where is the Origin of the medial head of the Deltoid?
Acromion process of the scapula
Where is the Origin of the posterior head of the Deltoid?
Spine of the scapula
Where is the Insertion of the Deltoid?
Lateral surface of the humerus (nearly halfway round)
What joint does the Deltoid cross?
Shoulder
What are the Actions of the Anterior fibres of the Deltoid?
Shoulder flexion and assist in horizontal flexion and medial rotation
Which Deltoid fibres abduct the shoulder?
All, but emphasis on medial
What are the Actions of the Posterior fibres of the Deltoid?
Shoulder extension and assist in lateral flexion and horizontal flexion
