Shoulder Anatomy
Medial Border of Scapula
Levator Scaupulae
Rhomboid Minor
Rhomboid Major
- O: Transverse processes of C1-C4
- I: Upper part of medial border of scapula
- N: Dorsal scapuar nn (C5)
- A: Elevates medial scapular
Rhomboid Minor
- O: Spinous process of C7 - T1
- I: Medial border of scapula
- N: Dorsal scapular nn (C5)
- A: Retracts scapula
Rhomboid Major
- O: Spinous process of T2 - T5
- I: Inferior angle + Medial border of scapula
- N: Dorsal scapular nn (C5)
- A: Retracts scapula
Lateral Border of Scapula
Long Head of Triceps
Teres Minor
Teres Major
- O: Infraglenoid tubercle of scapula
- I: Olecranon process of ulna
- N: Radial nn (C7, C8)
- A: Extends Elbow
Teres Minor
- O: Lateral border of scapula
- I: Inferior part of greater tuberosity of HH
- N: Axillary nn (C5, C6)
- A: Stabilizes HH + ER (weak) shoulder
Teres Major
- O: Inferior angle of scapula
- I: Medial lip of bicipital groove of HH
- N: Lower subscapular nn (C5, C6)
- A: Adducts + IR shoulder
Fossa Muscles
Supraspinatus
Infraspinatus
Subscapularis
- O: Supraspinatus fossa
- I: Superior part of greater tuberosity of HH
- N: Suprascapular nn (C5, C6)
- A: Stabilizes HH + Abducts (weak) shoulder
Infraspinatus
- O: Infraspinatus fossa
- I: Middle part of greater tuberosity of HH
- N: Suprascapular nn (C5, C6)
- A: Stabilizes HH + ER (weak) shoulder
Subscapularis
- O: Subscapularis fossa
- I: Lesser tuberosity + medial lip of bicipital groove of HH
- N: Upper + Lower Subscapular nn (C5, C6)
- A: Stabilizes HH + IR shoulder
Coracoid Mucles
Pectoralis Minor
Coracobrachialis
Short Head of Biceps Brachii
- O: Ribs # 3, 4, 5
- I: Coracoid process of scapula
- N: Medial pectoral nn (C8, T1)
- A: Protracts scapula. If scapula fixed, elevated ribs
Coracobrachialis
- O: Coracoid process of scapula
- I: Upper, Med, half of humerus
- N: Musculocutaneous nn (C5, C6, C7)
- A: Flex + adducts (weakly) shoulder
Short Head of Biceps Brachii
- O: Coracoid process of scapula
- I: Biceps tendon = Bicipital tuberosity of radius
- N: Musculocutaneous nn (C5, C6)
- A: Flex (weakly) shoulder + flex elbow + supinates forearm
Miscellaneous
Long Head of the Biceps Brachii
Serratus Anterior
Trapezius
Deltoid
- O: Superior Glenoid Fossa
- I: Radial Tuberosity
- N: Musculocutaneous nn (C5, C6)
- A: Elbow Flexion, shoulder flexion
Serratus Anterior
- O: Ribs # 1-8 + ANT Intercostal membrane
- I: Anterior medial border of scapula
- N: Long thoracic nn (C5, C6, C7)
- A: Laterally Rotates (Upward Rotate Inferior Ang) + Protracts scapula
Trapezius
- O: Superior Nuchal Line + external protuberance of skull + SP of C1-T12
- I: Lateral Clavicle + Acromion + Spine of Scapula
- N: Spinal Accessory nn (CN XI) (C1-C5)
- A: Laterally rotates + elevates + retracts scapula. If scapula is fixed, extends + laterally Flex neck
Deltoid
- O: Spine of Scapula + Acromion + Clavicle
- I: Deltoid tuberosity
- N: Axillary nn (C5, C6)
- A: Abducts arm (ANT = flex + IR) (POST = extend + ER)