Shoulder Muscles

Where is the subscapularis located?

Anterior side of scapula, covering the anterior surface of scapula. Deep to Pectoralis minor (obliquely across) and pectoralis major

What actions does the Teres Minor m do?

lateral rotator of shoulder joint (like infraspinatus m)

You throw a ball. What muscle helps your arm to decelerate after throwing?

the infraspinatus.

Actions of the Supraspinatus m? What muscle finishes this action?

Abduction (initiates the first 30 degrees of abduction. The deltoid completes the rest of the abduction.

What are the actions of the Teres major?

Adduction, extension, and medial rotation (same as Latissimus Dorsi)

Why is the Deltoid considered the "Jumping Jack" muscle?

Because it's middle fibers are responsible for abduction - or raising arm in Jumping Jack

Is the Latissimus Dorsi an antagonist or synergist to the Pectoralis Major?

Both! Antagonist in that it performs extension, while the pectoralis major performs flexion. Synergist in that both the pectoralis major and the latissimus dorsi perform adduction and medial rotation.

What shoulder muscles perform Flexion?

Corachobrachialis, Deltoid, Pectoralis Major, Biceps Brachii

What is the small anterior arm muscle not included with the intrinsic shoulder muscles (though it is one) that is only a synergist to primary movers?

Coracobrachialis

What shoulder muscles perform Adduction, including horizontal adduction?

Coracobrachialis (horizontal), Latissimus Dorsi, Teres Major, Pectoralis Major, Triceps Brachii

What is Coracobrachialis located?

Deep and medial to the Short head of the Biceps Brachii

What shoulder muscles perform Extension?

Deltoid, Latissimus Dorsi, Teres Major, Triceps Brachii

What are the intrinsic shoulder muscles that insert on the humerus?

Deltoid, Rotator Cuff: (Supraspinatus, Infraspinatus, Teres Minor, Subscapularis), and Teres Major

What is the triangle of auscultation used for?

For clinicians to listen for lung sounds

What actions go into the "Handcuff position" What muscles make these actions?

Glenohumeral adduction, Extension, and medial rotation. Latissimus Dorsi and Teres major

What actions does the coracobrachialis perform?

Horizontal adduction assists in flexion and adduction.

Compression of the Suprascapular nerve (by a heavy backpack) would weaken which actions of the shoulder joint?

IT would weaken the actions of abduction of arm (first 30 degrees) and lateral rotation of arm).

What is the Teres Minor nickname? Why?

Infra's little helper, because acts as synergist to the infraspinatus muscle.

Muscles that cause movement to the humerus must cross the shoulder and _______ on the humerus

Insert

What is the location of the Serratus Anterior muscle relative to scapula and rib cage? Where is the Teres Minor?

It is anterior to scapula and posterior to rib cage. The Teres minor is just anterior to the scapula (on it's anterior fossa), and is just posterior to the serratus anterior m.

What actions does the Deltoid perform? What is so special about the Deltoid

It is considered "Jack of all trades" muscle! Primary abductor of arm, anterior flexion, posterior extension, and rotations.

In the Rotator cuff, why is there only one muscle that performs medial rotation? Which muscle is it?

It is the subscapularis m. that performs medial rotation. This is because it is the only muscle of the Rotator cuff that is on the anterior side of the scapula, and attaches to the LESSER tubercle of the humerus. The other 3: Teres minor, supra and infra spinatus attach to the greater tubercle of the humerus and are located posteriorly - so do lateral rotation.

Where is the Latissimus Dorsi located? What does it form

It's the widest back muscle. It forms the posterior border of axilla.

What is Teres Major's nickname? Why?

Lat's little helper because it performs same action as the Latissimus Dorsi m., and is it's synergist.

Where is the Triangle of Auscultation?

Lateral border: Medial scapula Medial border: Trapezius Inferior Border: Latissimus Dorsi

What shoulder muscles perform Medial Rotation?

Latissimus Dorsi, Teres Major, Subscapularis, Pectoralis Major

What three muscle insertions take place on the intertubercular (sulcus) groove on the humerus?

Latissimus Dorsi, Teres Major, and Pectoralis Major

If your subscapular nerve got compressed, what actions of the shoulder joint would weaken?

Medial rotation, adduction and extension.

Where is Teres Major m. located?

On posterior scapula, deep to the triceps long head.

What is the origin and insertion of the coracoabrachialis? Innervation?

Origin: Coracoid process of scapula Insertion: medial proximal humerus Innervation: Musculocutaneous

What is the origin and insertion of Latissimus Dorsi?

Origin: covers distal 1/2 of back Insertion: Intertubercular groove on anterior humerus (medial to the pectoralis major M. insertion on intertubercular groove)

What is the origin and insertion of subscapularis?

Origin: the subscapular fossa of spinous Insertion: the lesser tubercle of the humerus

Origin and insertion of the supraspinatus?

Origin: the supraspinous fossa of the scapula Insertion: the greater tubercle of the humerus

What is the innervation to the Pectoralis major? Deep or superficial?

Pectoral Nerve (both medial and lateral). Deep

What is the innervation to the Pectoralis minor?

Pectoral Nerve (medial)

what muscles does Coracobrachialis act as a synergist to?

Pectoralis Major

What thorax muscles make up the Axillary Borders?

Pectoralis Major: Anterior Thorax, forms anterior borders of axillary Latissimus Dorsi: Posterior Thorax, forms posterior border of axillary

Where is the Teres Minor located?

Posterior side of scapula, lateral and inferior to the infraspinatus.

Where is the infraspinatus located?

Posterior, Deep to the deltoid and trapezius. Inferior to spine of scapula.

Where is the supraspinatus m. located?

Posterior, Deep to the trapezius and deltoid, in the supraspinous fossa of the scapula

What actions does the Latissimus Dorsi do?

Powerful adductor, medial rotator, and extensor of arm.

What actions does the Pectoralis Major make?

Powerful flexor, adductor, and medial rotator of arm.

What is the action of the infraspinatus m?

Primary lateral rotator (I.E holding ball and bringing it back behind ear in order to throw)

What muscles make up the Rotator Cuff?

SITS Supraspinatus Infraspinatus Teres Minor Subscapularis

What is the innervation to the Subscapularis M.?

Subscapular nerve

What is the innervation to the Teres Major?

Subscapular nerve

What shoulder muscles perform Abduction?

Supraspinatus, Deltoid

Where is the Rotator Cuff located?

Surrounding the proximal humerus

What shoulder muscles perform Lateral Rotation?

Teres minor, infraspinatus, Deltoid

Simon says: perform bilateral shoulder abduction to 90 degrees of your trunk. What is the primary muscle that performed this action?

The Deltoid. The supraspinatus only first 30 degrees of abduction.

Someone's tickling you. You immediately pull your elbows towards your sides to cover up. What is the primary muscle responsible for this move?

The Pectoralis Major M.

What does the Suprascapular nerve innervate?

The Supraspinatus m. and infraspinatus m.

What is the innervation to the Latissimus Dorsi? Deep or superficial to muscle?

The Thoracodorsal Nerve. Deep to muscle

What does the Axillary nerve innerviate?

The deltoid and Teres Minor

Which cartilage structure of the joint assists the rotator cuff in stabilizing the ball-and-socket joint?

The glenoid labrum

What action does Teres Minor preform?

The primary lateral rotator

What is the most commonly injured Rotator cuff muscle? Why?

The supraspinatus m. Because tendon can easily be ripped due to placement on the greater tubercle of humerus and b/c it goes under the acromion process

What function does the Rotator Cuff have as a group?

To stabilize the head of the humerus in the glenoid cavity

Where is the deltoid located? How does it look?

Visible both anterior ad posterior, it is the delta (triangle) shaped muscle of shoulder.

Coracobrachialis

What muscle is this?

Deltoid

What muscle is this?

Infraspinatus

What muscle is this?

Latissimus Dorsi

What muscle is this?

Pectoralis Major M.

What muscle is this?

Subscapularis

What muscle is this?

Supraspinatus

What muscle is this?

Teres Major

What muscle is this?

Teres Minor

What muscle is this?

What m is the Teres major fused with in it's insertion?

the Latissimus Dorsi

Where is the Pectoralis Major located and what shape? What does it form?

It is on anterior thorax, superficial to the Pectoralis Minor and deep to the breast tissue. It is convergent shaped. It forms the anterior border of the axilla.

What are the origins and insertions of Teres Major?

Origin: Inferior part of lateral border of scapula Insertion: Intertubercular groove of humerus (aka intertubercular sulcus).

What is the origin and insertion of the infraspinatus m?

Origin: Infraspinous fossa of the scapula. Insertion: Greater tubercle of Humerus

Origin and insertion of Pectoralis Major?

Origin: Medial 2/3 of clavicle, manubirum and body of sternum, and the costal cartilages up to the 6th rib. Insertion: Intertubercular groove on anterior humerus

What is the origin and insertion of the Deltoid?

Origin: Spine of scapula, Acromion Process, and lateral 1/3 of Clavicle Insertion: Deltoid tuberosity of Humerous

What is the origin and insertion of the Teres Minor m?

Origin: Superior part of lateral border of scapula Insertion: Greater tubercle fo humerus

The origin of the Deltoid is also the insertion for what muscle?

The Trapezius