Muscles: Shoulder & Arm

Question 1

Trapezius

Answer 1

Originates at the occipital bone; nerve = accessory nerve. Extends down through thoracic spine 12.
Stabilizes scapula in 3 planes: elevates, retracts, and depresses.

Question 2

Sternocleidomastoid

Answer 2

Nerve= Accessory nerve; flexes head; rotates head to opposite side; side bends head to same side. Runs from mastoid process to medial clavicle.

Question 3

Splendius capitis

Answer 3

Prime mover for head extension; allows lateral flexion & rotation of cervical spine. Inserts at mastoid process. One of 3 muscles that forms floor of posterior triangle of neck.

Question 4

Deltoid

Answer 4

Inserts at deltoid tuberosity; nerve = axillary nerve; used for shoulder abduction, shoulder flexion, internal rotation, shoulder extension & external rotations