Rotator Cuff

Rotator Cuff

The rotator cuff is the primary structure that holds the humeral head against the glenoid fossa. The articulation of the humeral head against the glenoid fossa is very weak

Bones & Bony landmarks

- supraspinous fossa, infraspinous fossa, & subscapular fossa of scapula

- suprascapular notch of scapula

- spinoglenoid notch

- greater & lesser tubercles of humerus

- surgical neck of humerus

- anatomical neck of humerus

The Rotator cuff stabilizes what?

The shoulder

What makes a rotator a rotator?

It inserts into the lesser or greater trochanter. If it doesn’t, then it’s not a rotator

A strong rotator cuff prevents what?

Shoulder dislocation

Rotators

1. supraspinatus m.

2. infraspinatus m.

3. teres minor m.

4. subscapularis m.

supraspinatus m O

O: supraspinous fossa of scapula

supraspinatus m I

I: greater tubercle of humerus

Tendons go under the acromion process

supraspinatus m F

Initiates shoulder abduction

supraspinatus m N

suprascapular n

If troubled with this muscle, what as a provider should you ask the patient to do?

Abduct from 0 to 15

Subacromial Space

- space between acromion process and humeral head

- contains subacromial bursa & supraspinatus m. tendon

- frequent site of supraspinatus m. tendon impingement/tearing

What does the subacromial bursa separate?

- subacromial bursa separates the acromion process from the

supraspinatus muscle tendon

Supraspinatus tendinitis and subacromial bursitis

Injuries are bimodal and postmenopausal

Sometimes the shape of the acromion is hooked into the bursa

Shoulder joint capsule can become should capilitis

Fix:

Rest, surgical repair

infraspinatus m. O

O: infraspinous fossa of scapula

infraspinatus m. I

I: greater tubercle of humerus

infraspinatus m. F

F: lateral/external rotation of shoulder

Pitchers, quarterback

infraspinatus m. N

N: suprascapular n.

Largest rotator

Infraspinatus

Test if the Infraspinatus is working?

Touch the back of the spine. If its weak, you may not have trouble with lateral rotation, but if atrophied, it will allow the humeral head to sublux

Teres minor m O

O: lateral border of scapula

Teres minor m I

I: greater tubercle of humerus

Teres minor m F

F: lateral/external rotation of shoulder

Teres minor m N

N: axillary n.

What two muscles work together?

Infraspinatus and Teres Minor

subscapularis m. O

O: subscapular fossa of scapula

subscapularis m. I

I: lesser tubercle of humerus (only muscle that inserts here)

subscapularis m. F

F: medial/internal shoulder rotation

Never any problesm here

subscapularis m. N

N: upper & lower subscapular nn.

Pain at the less of humerus…

Inflammed subscapularis

all rotator cuff mm. function dynamically to ____

hold humeral head in place

against glenoid fossa and to prevent subluxations of the humeral head

Other muscles – these muscles have nothing to do with the rotator cuff!

- teres major m.

teres major m. I

I: medial lip of intertubercular groove of humerus

teres major m. F

F: medial/internal rotation of shoulder, adducts shoulder

teres major m. N

N: lower subscapular n.

Nerves associated with the rotator cuff

1. axillary n.

2. suprascapular n.

3. upper subscapular n.

4. lower subscapular n.

All are branches of the brachial plexus

1. axillary n.

located in quadrangular space, along with the posterior humeral circumflex artery

Axillary N. Motor

- motor to teres minor and deltoid mm.

Axillary N. Sensory

- sensory to the skin over the deltoid muscle

If the surgical neck is lacerated…

Can lacerate the axillary N.

Axillary Neuropathy

Causes deltoid atrophy

Check to see if deltoid works by abducting and sensory

2. suprascapular n.

- passes deep to/under the transverse scapular ligament, through the “scapular foramen”

- then, the suprascapular nerve passes through the spinoglenoid notch

When a N. goes under…

It’s never good

Damage to Suprascapular N.

No shoulder abduction

No external/lateral rotation

Shoulder sublux/dislocation

Holding shoulder (Humeral Head)

Shoulder appears dropped

Suprascapular N. motor

- motor to supraspinatus & infraspinatus mm.

3. upper subscapular n.

- motor to subscapularis m.

4. lower subscapular n.

- motor to subscapularis and teres major mm.

Quadrangular Space

(lateral to the long head of the triceps brachii m.)

Quadrangular Space Borders:

Borders:

Lateral border: surgical neck of the humerus

Medial border: long head of triceps brachii m.

Superior border: teres minor m.

Inferior border: teres major m.

Quadrangular Space Contents

axillary n. & posterior humeral circumflex artery

Lateral/External Rotation

Arm over head past ears

Medial/Internal Rotation

Arm under to back pocket

Triangular Space

(medial to the long head of the triceps brachii m.)

Triangular Space Borders:

Superior border - Teres minor muscle

Inferior border - Teres major muscle

Lateral border - Long head of the triceps brachii muscle

Triangular Space Contents

scapular circumflex artery

Transverse Cervical artery

branch of the subclavian artery

- travels with CN XI to trapezius muscles and rotator cuff muscles

Thoracodorsal artery

branch of axillary artery

- travels with thoracodorsal nerve to latissimus dorsi muscle and rotator

cuff muscles

Suprascapular artery

branch of subclavian artery

- travels with suprascapular nerve to the rotator cuff muscles

- travels OVER the transverse scapular ligament

Posterior Humeral Circumflex artery

branch of axillary artery

- travels with the axillary nerve, through the quadrangular space, to the deltoid muscle and rotator cuff muscles

Scapular Circumflex artery

Branch of axillary artery

- travels through the triangular space to the rotator cuff muscles

Transverse Scapular Ligament

dense, tight band of connective tissue uniting the margins of the suprascapular notch

What does the Transverse Scapular Ligament Create

- this ligament creates a “scapular foramen”

Transverse Scapular Ligament function

It provides a conduit for the suprascapular neurovascular bundle

- repetitive overhead activities can rupture the ligament or over-stretch it, causing compression to the suprascapular nerve

suprascapular artery & vein

go OVER the ligament

suprascapular nerve

goes UNDER the ligament and and through the scapular

foramen

Most proximal fractures occur where?

Surgical neck

Most subluxations of the humeral head occur…

Anteriorly and inferiorly because there is weak rotator protection

How to distinguish between a deltoid or supraspinatus injury

Test abduction

• Supraspinatus it trouble getting to 15

• Deltoid if trouble getting to 120