Anatomy - Shoulder and Brachial Plexus Flashcards
What muscles are involved in shoulder flexion?
Pectoralis major and anterior part of deltoid.
What muscles are involved in shoulder extension?
Latissimus dorsi and posteriore part of deltoid.
What muscles are involve in shoulder adduction?
- Pectoralis major
- Latissimus dorsi
- Teres major
What muscles are involve in shoulder abduction?
Supraspinatus and deltoid
What muscles are involve in shoulder medial/internal rotation?
- Pectoralis major
- Latissimus dorsi
- Teres major
- Subscapularis
What muscles are involve in shoulder lateral rotation?
- Infraspinatus
- Teres minor
- Supraspinatus
What is the lateral border of the axilla?
Axillary fascia
What is contained within the axilla?
- Cords of the brachial plexus and branches
- Axillary artery
- Axillary vein
- Adipose tissue with nodes
What are the muscular borders of the axilla?
Anterior - Pectoralis major - Pectoralis minor Median - Serratus anterior (and 4th rib) Posterior - Subscapularis - Latissimus dorsi - Teres major
Pectoralis Major: Origin
Origin:
- Clavicular; sternal half of clavicle
- Sterno-costal; sternum and costal cartilages 1-7
- Abdominal; rectus sheath
Pectoralis Major: Insertion
Humerus
Pectoralis Major: Action on the arm, shoulder girdle and thoracic cage
Arm: adduction, internal rotation
Shoulder girdle: ante version of scapula
Thoracic cage: elevates the ribcage (inspiration)
What is the shoulder girdle?
Scapula and clavicle.
Pectoralis Major: Innervation
Pectoral nerves from brachial plexus.
Pectoralis Minor:
Origin, insertion, action on shoulder girdle and thorax and nerve supply.
Origin: Ribs 3-5
Insertion: coracoid process of scapula
Shoulder girdle: Depression (anterior pulling of scapula)
Thorax: elevation (inspiration)
Innervation: pectoral nerves from brachial plexus
What is the origin of the serratrus anterior?
Superior: ribs 1-2
Middle: ribs 2-4
Inferior: ribs 5-9
What is the insertion of the serratus anterior?
Scapula.
Superior: superior angle
Middle: medial margin
inferior: lower angle
What is the action of the serratus anterior on the shoulder girdle?
With fixed scapula, Keeps scapula close to thoracic cage (*failure leads to wing scapula)
Superior: elevation
Middle: depression
Inferior: depression and tilts scapula to allow arm elevation
What is the action of the serratus anterior on the thorax?
With fixed scapula elevates the thoracic cage: inspiration
What is the nerve supply of the serratus anterior?
Long thoracic nerve from brachial plexus.
Subscapularis: origin, insertion, action and innervation.
Origin: subscapularis fossa
Insertion: lesser tubule of humerus
Action: medial rotation
Innervation: subscapular nerves
What are the five divisions of the brachial plexus?
Roots, Trunks, Divisions, Cords and Terminal Branches.
What are the roots of the brachial plexus?
C5, C6, C7, C8, T1.
What are the trunks of the brachial plexus?
Superior, middle and lateral trunk.