Posterior Axio-Appendicular (Extrinsic & Intrinsic Shoulder) Muscles

Question 1

Trapezius

Answer 1

Proximal Attachment: Occipital Bone - Superior Nuchal Line & External Occipital Protuberance. Nuchal Ligament & C7-T12

Distal Attachment: Clavicle (Lateral) - Posterior Border, Acromion (Scapula), Spine (Scapula)

Innervation: CN XI - Spinal Accessory Nerve,
Ventral Rami of C3-C4 Spinal Nerves (Pain & Proprioception)

Action: Upper fibers–> Scapula Elevation & Upward Rotation
Middle Fibers–> Scapula Retraction
Lower Fibers–> Scapula Depression & Upward Rotation

Question 2

Latissimus Dorsi

Answer 2

Proximal Attachment: T7-T12 - Spinous Processess, Thoracolumbar Fascia, Ilium - Iliac Crest, Ribs 9-12

Distal Attachment: Humerus - Floor of Intertuberculer Groove (IT Groove)

Innervation: Thoracodorsal Nerve (C6, C7, & C8)

Action: Shoulder Extension, Adduction, and Medial Rotation/IR

Question 3

Teres Minor

Answer 3

Proximal Attachment: Scapula - Middle Part of the Lateral Border

Distal Attachment: Humerus- Greater

Innervation: Axillary Nerves (C5 & C6)

Action: Shoulder Lateral Rotation and Holds Humeral Head in Glenoid Cavity of Scapula

Question 4

Infraspinatus

Answer 4

Proximal Attachment: Scapula - Infraspinous Fossa

Distal Attachment: Humerus - Greater Tubercle

Innervation: Suprascapular Nerve (C5, C6)

Action: Shoulder Lateral Rotation and Holds Humeral Head in Glenoid Cavity of Scapula

Question 5

Supraspinatus

Answer 5

Proximal Attachment: Scapula - Supraspinous Fossa

Distal Attachment: Humerus - Greater Tubercle

Innervation: Suprascapular Nerves (C4, C5, C6)

Action: Shoulder Abduction and Holds Humeral Head in Glenoid Cavity of Scapula

Question 6

Levator Scapulae

Answer 6

Proximal Attachment: C1-C4 - Transverse Processes

Distal Attachment: Scapula - Medial Border from Superior Angle to Base of Spine

Innervation: Dorsal Scapular Nerve (C4 & C5), Ventral Rami of C3-C4 Spinal Nerves

Action: Scapula Elevation & Downward Rotation

Question 7

Teres Major

Answer 7

Proximal Attachment: Scapula - Posterior Surface of Inferior angle

Distal Attachment: Humerus - Medial Lip of Intertubercular groove

Innervation: Lower Subscapular Nerve (C5 & C6)

Action: Shoulder Adduction, Extension, Medial Rotation

Question 8

Rhomboid Minor

Answer 8

Proximal Attachment: Nuchal Ligament, C7-T1- Spinous Processes

Distal Attachment: Scapula - Medial Border @ Base of Spine

Innervation: Dorsal Scapular Nerve (C4 & C5)

Action: Scapula Retraction & Downward Rotation

Question 9

Deltoid

Answer 9

Proximal Attachment: Clavicle (Lateral) Anterior Border
Scapula - Acromion and Spine

Distal Attachment: Humerus - Deltoid Tuberosity

Innervation: Axillary Nerve (C5 & C6)

Action: Anterior Fibers - shoulder Medial Rotation and Flexion
Middle Fibers: shoulder abduction
Posterior Fibers: Shoulder Extension and Lateral Rotation

Question 10

Rhomboid Major

Answer 10

Proximal Attachment: T2-T5 - SPinous Processes

Distal Attachment: Scapula - Medial Border from Base of Spine to Inferior Angle

Innervation: Dorsal Scapular Nerve (C4 & C5)

Action: Scapula Retraction & Downward Rotation

Question 11

Subscapularis

Answer 11

Proximal Attachment: Scapula - Subscapular Fossa

Distal Attachment: Humerus - lesser tubercle

Innervation: Upper and Lower Subscapular Nerves (C5, C6, C7)

Action: Shoulder Medial Rotation and Holds Humeral Head in Glenoid Cavity of Scapula