3.1 Superficial Back and Shoudler Girdle

What are the superfical back muscles?

Hint: TLLR

Trapezius, Latissimus dorsi, Levator scapulae, Rhomboids

Anterior chest muscles - Nerve innervates: (PPD)

Pectoralis major:

Pectoralis minor:

Deltoid:

medial and lateral pectoral nerve

medial pectoral nerve

axillary nerve

Scapular muscles - Nerve innervates: (SITS)

Rotator Cuff muscles:

• Supraspinatus:

• Infraspinatus:

• Teres Muscles:

• Subscapularis:

Suprascapular nerve (C5-C6)

Suprascapular nerve (C5-C6)

Axillary nerve (C5-C6)

Upper and lower subscapular nerve (C5-C7)

Scapular muscles - Nerve innervates:

Teres major:

Serratus Anterior:

lower subscapular nerve (C5-C7)

long thoracic nerve (C5-C7)

What are the anterior chest mucles called?

Hint: PPD

Pectoralis major, Pectoralis minor, and Deltoid

What are the scapular muscles of the rotator cuff called?

Hint: SITS

Supraspinatus, Infraspinatus, Teres minor, Subscapularis

What scapular muscles are known to be the rotator cuff muscles?

Hint: SITS

Supraspinatus, Infraspinatus, teres minor, subscapularis

what group of muscles holds the head of the humerus + glenoid cavity

rotator cuff muscles (SITS)

Superficial back muscles - Nerve innervates: (TLLR)

Trapezius:

Laterissimus Doris:

Levator scapula:

Rhomboid major:

Rhomboid minior

Spinal accessory nerve, Thoracodorsal nerve (C6–C8), Dorsal scapular nerve (C5)

Teres major acts similarly to which muscle?

Latissimus dorsi

Does teres major stabilize the glenohumeral joint like rotator cuff muscles?

no

What are all the scapular muscles involved?

SITS, Teres major, and serratus anterior

Trapezius Muscle Action: 

1. Upper fiber: ______ scapula _______

2. Middle fiber: retract scapula (pulling shoulders back)

3. Lower fiber: depress scapula

elevate; shrugging

Trapezius Muscle Action: 

1. Upper fiber: elevate scapula shrugging

2. Middle fiber: _____ scapula

3. Lower fiber: depress scapula

retracting (pulling shoulders back)

Trapezius Muscle Action: 

1. Upper fiber: elevate scapula shrugging

2. Middle fiber: retracting scapula

3. Lower fiber: _____ scapula

depress

What fibers of the trapezius mucles helps with upward rotation of the scapula? (required for raising your arm above 90°)

upper and lower fibers

Trapezius muscle is innervated by what nerve?

spinal accessory nerve (CN XI) 

Whats the origin for the trapezius muscles?

base of the occiput spinous process (think midline of the skull -> spine)

What’s the insertion for the trapezius muscles?

spine of scapula acromion process clavicle (think shoulder girdle = clavicle + scapula)

Which muscles are required for abduction of the arm above 90°?

Trapezius + Serratus anterior

What’s the 1st origin of the latissimus Dorsi?

Inferior angle of scapula

What’s the 2nd origin of the latissimus Dorsi?

thoracolumbar aponeurosis

What’s the 3rd origin of the latissimus Dorsi?

iliac crest

What’s the 4th origin of the latissimus Dorsi?

T7-L5

What’s the insertion of the latissimus Dorsi?

bicipetal groove

What nerve innervates the Latissimus Dorsi muscle? What are their roots?

Thoracodorsal nerve; C6–C8

What the primary action for the Latissimus Dorsi muscle?

Medial rotation (internal

Latissimus Dorsi Actions: 

1. _______

2. ________

3. _____ ______ (internal)

Adduction, Extension, Medial rotation (All asisting arm (humerus) mvmt)

What’s the origin for the elevator scapulae muscle?

transverse process C1-C4

What’s the insertion for the Levator Scapulae muscle?

Superior angle

Levator Scapulae: Action

1. ______ _____ 

2. _____ _____ scapula - assisting glenoid cavity inferiorly

Elevating scapula, inferior rotation

What nerve innervates the Levator Scapulae?

Dorsal scapular nerve (C5)

Patient presents with shoulder elevation difficulty and pain along the superior medial scapular border—what muscle may be tight or injured?

Levator scapulae

In the one box what is the origin of the Rhomboid major?

spinous process T2-T5

In the 4th box what is the insertion of the Rhomboid major?

vertebral border

In the 3rd box what is the insertion of the Rhomboid minor?

root of the spine of the scapula

In the 2nd box what is the origin of the Rhomboid minor?

spinous process C7 and T1

Rhomboids muslcles - Action: 

1. _____ scapula 

2. Aid in scapula ______

Key: They are essential for stabilizing the scapula against the thoracic wall.

retracting; elevation

What nerve innervates the Rhomboid muscles? 

Dorsal scapular nerve (C5)

The ________ elevates the scapula and can assist in downward rotation.
The ________ retract the scapula and assist in downward rotation

Levator scapulae; Rhomboids

The Levator scapulae _______ the scapula and can assist in downward rotation.
The Rhomboids _____ the scapula and assist in downward rotation

elevate; retract

In the 1st box what’s the origin for the pectoralis major muscles?

clavicular head: medial clavicle

In the 2nd box what’s the origin for the pectoralis major muscles?

sternal head: sternum and upper 6 ribs

what’s the insertion for the pectoralis major muscles?

bicipital groove

Pectoralis major - Action

1. ________

2. ______ _____ rotation (shoulder and humerus)

3. ________ (clavicular head)

4. _______ from a flexed position

Adduction, medial rotation, flexion, extension

What is the nerve that innervates the pectoralis major?

Medial and lateral pectoral nerves

What is the origin of the pectoralis minor?

3rd, 4th, 5th rib

What’s the insertion for the pectoralis minor?

coracoid process

Pectoralis Minor - Action

1. _______ scapula by pulling in :anteriorly and inferiorly

2. _______ of the scapula

stabilize, protraction

What nerve innervates the pectoralis minor?

medial pectoral nerve

Tight pectoralis minor contributes to what primary roots are affecte?

C8 n CT1

Tight pectoralis minor contributes to what vascular/nerve syndrome?

neurogenic thoracic outlet syndromen (nTOS: compression of the brachial plexus)

The _____ ______ nerve DOES NOT innervates the pectoralis minor because it goes around the muscle. 

lateral pectoral

In box one what’s the origin for the deltoid muscle ?

posterior fiber: spine of the scapula

In box 2nd what’s the origin for the deltoid muscle ?

anterior fibers: lateral clavicle

In box 3rd what’s the origin for the deltoid muscle ?

lateral fibers: acromion process

what’s the insertion for the deltoid muscle ?

deltoid tuberosity

Deltoid - Action
1. Anterior: ______ + _____ rotation
2. Middle: abduction
3. Posterior: {{c3::extension}} + {{c3::lateral}} rotation

What’s the anterior fiber actions?

flexion, medial 

Deltoid - Action
1. Anterior: flexion + medial rotation
2. Middle: ________
3. Posterior: extension + lateral rotation

What’s the medial fiber actions?

Abduction

Deltoid - Action
1. Anterior: flexion + medial rotation
2. Middle: abduction
3. Posterior: ______ + _____ rotation

What’s the posterior fiber actions?

extension; lateral

What nerve innervates the deltoid muscle?

Axillary nerve

Patient cannot abduct arm after shoulder fracture—what muscle and nerve are likely affected?

Deltoid; axillary nerve

What’s the origin of the supraspinatus muscle?

supraspinous fossa

What’s the insertion of the supraspinatus muscle?

head of humerus

Supraspinatus muscle - Action
1. Initiates______ of arm for the first ___.

abduction; 15 degrees

What nerve innervates the supraspinatus muscle?

Suprascapular nerve (C5–C6)

What’s the origin of the infraspinatus muscle?

infraspinous fossa

What’s the insertion of the infraspinatus muscle?

head of the humerus

Infraspinatus muscle - Action
1. _____ rotation of _______

External; humerus

What nerve innervate the infraspinous muscle?

Suprascapular nerve (C5–C6)

Patient has weakness resisting lateral rotation at 90° abduction—muscle?

Infraspinatus

What’s the origin of the teres minor muscle?

lateral edge of the scapula

What’s the insertion of the teres minor muscle?

head of the humerus

Teres minor - Action: 
1. _____ rotation of humerus
Notes: holds the head of the humerus + glenoid cavity

External

What nerve innervates the Teres minor muscle?

Axillary nerve (C5-C6)

________ rotates externally and innervated by the suprascapular nerve.
_________ rotates externally and innervated by the axillary nerve.

Infraspinatus ; Teres minor

Infraspinatus rotates externally and innervated by the _________ nerve.
Teres minor rotates externally and innervated by the _______ nerve.

suprascapular; axillary

Weakness in posterior shoulder dislocation—muscle? 

Teres minor

What’s the origin for the subscapularis muscle?

subscapular foss

What’s the insertion for the subscapularis muscle?

lesser tuberosity of humerus

Subscapularis muscle - Action: 
1. ______ rotation of humerus

internal

What nerve innervates the Subscapularis muscle?

upper and lower subscapular nerve (C5-C6)

Which muscle internally rotates the humerus and stabilizes the shoulder?

Subscapularis

What’s the origin of the teres major muscle?

upper surface of the inferior angle of scapula

What’s the insertion of the teres major muscle?

medial lip of the bicipital groove

What’s teres major primary action?

Internal (medial) rotation

Teres major - Action: 
1. ______ rotation (primary) 
2. ________
3. ________ of arm 

internal, adduction, extension

What nerve innervates the teres major muscle?

Lower subscapular nerve (C5–C6)

What’s the origin of the serratus anterior muscle?

upper 8th and 9th ribs

what’s the insertion of the serratus anterior muscle?

medial border of scapula

Serratus Anterior - Action: 
1. ________
2. _______ rotation of scapula
Notes: Holds the scapula against the thoracic wall to prevent winged scapula

Protraction, superior (upward)

What nerve innervates the Serratus Anterior muscle?

long thoracic nerve