Shoulder Anatomy

This is an axial T1 MRI image at the top of the shoulder. All structures look dark because of fat suppression. We use fat suppression with T1 images because for this study we injected contrast into the joint. Fat suppression is commonly used after contrast is given on MRI to increase the conspicuity of the contrast material as you will see on later images.

This is a lower sequential axial image just above the shoulder joint.

What muscle (arrows) and tendon (arrowheads) are these?

The supraspinatus muscle and tendon.

We are starting to get down to the joint space do you see the white contrast.

Note the anterior, lateral and posterior heads of the deltoid.

AnteriorLateral

Posterior

This image is further inferior, do you see the coracoid process? Remember this is an anterior structure.

Do you remember the attachments onto the coracoid process?

The coracobrachialis and the short head of the biceps muscle. Also the pectoralis minor attached to the coracoid process.

Can you find the subscapularis tendon on this image?

What articular part of the scapula articulares with the humerus?

This is the glenoid

Can you find the fibrocartilagenous glenoid labrum?

Anterior labrum

Posterior labrum

What is the function of the glenoid labrum?

To add surface area and provide stability to the glenohumeral joint.

Where does the labrum tear with an anterior shoulder dislocation?

Hard question

Anteriorly and inferiorly

Do you see this patients’ anterior inferior labral tear?

There is high signal between the anterior and inferior labrum and the bony glenoid characteristic of a labral tear. This case was kind of subtle, so we put the patient in an abducted externally rotated arm position to displace the torn labrum.

Here you can better see contrast between the labrum and glenoid.

This is the final image in this axial set. What is this black structure between the greater and lesser tuberosities surrounded by contrast?

This is the long head of the biceps tendon in the bicipital groove. It is common to have contrast surround this structure as it passes through the shoulder joint before it inserts onto the suoperior labrum.

This is a coronal proton density image starting in the posterior aspect of the shoulder. What bone is marked by the arrows?

This is the acromion

What posterior rotator cuff muscle are marked by the upcoming arrows?

Teres minor

Infraspinatus

What posterior rotator cuff tendon is marked by the arrows?

Infraspinatus tendon

What is this ligament attaching onto the acromion?

Hard question

Coracoacromial ligament

What lateral muscle is this?

Deltoid

Take a look at this mid coronal image though the shoulder joint. You see the glenoid and humerus as if you are looking at a frontal x-ray

Can you find the supraspinatus muscle?

How about the trapezius muscle?

As we are more anterior here, can you trace the intraarticular portion of the long head of the biceps tendon as it inserts onto the superior labrum?

On this anterior image can you find the short head of the biceps tendon as it attaches to the coracoid and the subscapularis tendon?

Short head of biceps tendon

Tendon of subscapularis

Can you see the neurovascular structures in the anterior aspect of the axilla?