11. Shoulder muscles Flashcards
Identify
- Trapezius muscle
- Deltoid muscle
- Latissimus dorsi muscle
Identify 1. O & I
Insertion (distal): Superior fibers of the trapezius muscle insert into ___
Middle fibers insert into the medial margin of the acromion and posterior border of the scapular spine.
Inferior fibers converge to end in an aponeurosis inserted into the scapular spine.
- Trapezius muscle
→ the posterior border of the lateral third of the clavicle
Identify 1. O & I
Insertion (distal): Superior fibers of the trapezius muscle insert into the posterior border of the lateral third of the clavicle.
Middle fibers insert into (1)____ & (2) ____
Inferior fibers converge to end in an aponeurosis inserted into the scapular spine.
Trapezius muscle
- the medial margin of the acromion
- posterior border of the scapular spine.
Identify 1. O & I
Insertion (distal): Superior fibers of the trapezius muscle insert into the posterior border of the lateral third of the clavicle.
Middle fibers insert into the medial margin of the acromion and posterior border of the scapular spine.
Inferior fibers converge to end in an aponeurosis inserted into ____
Trapezius muscle
→ the scapular spine.
Identify 1. Action
The upper and lower fibers of the trapezius muscle → rotate the scapula for full abduction of the upper extremity.
The upper fibers → (1)____ and (2)____ when a weight is being carried by the shoulder or hand.
Central fibers → run horizontally and (3)____
Lower fibers → draw the scapula downward
-
Trapezius muscle
(1) elevate the shoulder
(2) brace the shoulder girdle
(3) retract the shoulder.
Identify 1. Action
The upper and lower fibers of the trapezius muscle → ___
The upper fibers → elevate the shoulder and brace the shoulder girdle when a weight is being carried by the shoulder or hand.
Central fibers → run horizontally and ____
Lower fibers → draw the scapula downward.
- Trapezius muscle
→ retract the shoulder.
Identify 1. Innervation
- Trapezius muscle
Motor supply is from the accessory nerve (CN XI).
Proprioceptive fibers are from the 3rd and 4th cervical nerves.
Identify 1. Does this muscle receive innervation from brachial plexus?
The trapezius, in contrast to the other shoulder muscles, does not receive nerve fibers from the brachial plexus.
→ Motor supply is from the accessory nerve (CN XI). Proprioceptive fibers are from the 3rd and 4th cervical nerves.
The trapezius can be tested by having a patient elevate the shoulder against resistance (the upper portion of the contracting muscle can be felt).
→ This tests the integrity of ____ innervating this muscle.
the accessory nerve (CN XI)
Identify
- Latissimus dorsi muscle
- Teres major muscle
- Thoracolumbar fascia
Identify
- Levator scapulae muscle
- Splenius capitis muscle
Identify 1. O & I
Origin (proximal): Latissimus dorsi muscle spinous processes of the lower 6 thoracic vertebrae
Insertion (distal): the intertubercular groove of the humerus.
Identify 1.
Insertion (distal): The fibers of the latissimus dorsi muscle converge as the muscle curves around the lower border of the teres major and twists on itself.
→ They end as a tendon that inserts into the ___
- Latissimus dorsi muscle
→ intertubercular groove of the humerus.
Identify 1. Action?
- Latissimus dorsi muscle
→ Extends, adducts, and medially rotates the humerus (arm).
Identify 1. Innervation?
- Latissimus dorsi muscle
→ Thoracodorsal nerve (C6-C8).
With the upper extremity fixed, the latissimus dorsi ____ when the arms are stretched above the head, as when reaching up while climbing.
elevates the trunk
Latissimus dorsi muscle
→ The blood supply is by (1)____, a branch of (2)___
- the thoracodorsal artery
- the subscapular artery (which arises from the axillary artery).
Identify
- Levator scapulae muscle
- Splenius capitis muscle
Identify 1. O & I
Origin (proximal): Levator scapulae muscle arises from the transverse processes of the first 4 cervical vertebrae.
Insertion (distal): Inserts into the superior portion of the medial (vertebral) border of the scapula.
Identify 1. Action
- Levator scapulae muscle
→ Action:
- Elevates the superior angle of the scapula and tends to draw it medially.
- Rotates the scapula so that the glenoid cavity is tilted inferioly.
- When the scapula is held in a fixed position, the levator scapulae bends the neck laterally and rotates it slightly toward the same side.
Identify 1. Direct actions with scapula?
- Levator scapulae muscle
Elevates the superior angle of the scapula and tends to draw it medially.
→ Also rotates the scapula so that the glenoid cavity is tilted inferioly
Identify 1. Action with neck?
- Levator scapulae muscle
→ When the scapula is held in a fixed position, the levator scapulae bends the neck laterally and rotates it slightly toward the same side.
Identify 1. Innervation?
- Levator scapulae muscle
Innervation: By the 3rd and 4th cervical nerves from the cervical plexus and by a branch from the dorsal scapular nerve (C5) to the muscle’s lower fibers.