Muscles of Scapular Region

Deltoid

Muscle	Origin	Insertion	Nerve Supply	Action
Deltoid	Anterior fiber: §  Lateral third of anterior border of clavicle Middle fiber: §  Lateral border of acromion process Posterior fiber §  Lower lip of the crest of the spine of scapula	§  Deltoid tuberosity of the humerus	§  Axillary nerve	Anterior fiber: §  Flexion & medial rotation of the arm Posterior fiber: §  Extension & lateral rotation of the arm Middle fiber: §  Abduction of the arm from 15 to 90 degree

Teres Major

Muscle	Origin	Insertion	Nerve Supply	Action
Teres Major	§  Lower 1/3 lateral border & inferior angle of scapula (dorsal surface)	§  Medial lip of the bicipital groove	§  Lower subscapular nerve (C5 & 6)	§  Extension, adduction & medial rotation of the arm

Rotator Cuff Muscles

Rotator Cuff Muscles

• The rotator cuff is the group of muscles and their tendons that acts to stabilize the shoulder. 
• the 4 muscles of rotator cuff are:

• Subscapularis
• Supraspinatus 
• Infraspinatus
• Teres Minor

Teres Minor

Muscle	Origin	Insertion	Nerve Supply	Action
Teres Minor	§  Upper 2/3 lateral border of scapula (dorsal surface)	§  Lower impression on the greater tuberosity	§  Axillary nerve (C5 & 6)	§  Adduction & lateral rotation of the arm §  Help to stabilize the shoulder

Subscapularis

Muscle	Origin	Insertion	Nerve Supply	Action
Subscapularis	§  Medial 2/3 of subscapular fossa	§  Lesser tuberosity of the humerus	§  Upper & lower subscapular nerve (C5 & 6)	§  Adduction & medial rotation of the arm §  Help to stabilize the shoulder

Supraspinatus

Muscle	Origin	Insertion	Nerve Supply	Action
Supraspinatus	§  Medial 2/3 of supraspinous fossa	§  Highest impression on the greater tuberosity	§  Suprascapular nerve	§  Initiate the abduction of the arm (from 0 to 15 degree) §  Help to stabilize the shoulder

Infraspinatus

Muscle	Origin	Insertion	Nerve Supply	Action
Infraspinatus	§  Medial 2/3 of infraspinous fossa	§  Middle impression on the greater tuberosity	§  Suprascapular nerve	§  Lateral rotation of the arm §  Help to stabilize the shoulder