Shoulder Joint (Glenohumeral Joint)

By: Nathan, Melissa, Shanik

Surface Anatomy

Anterior axillary fold

Posterior axillary fold

Anterior axillary line

Manubrium

Surface Anatomy

Clavicular Deltoid origin

Clavicle

Clavicular PectoralisMajor origin

Sternocostal head ofPectoralis Major

Clavipectoral triangle

Surface Anatomy

Descending Trapezius

Ascending Trapezius

Middle Trapezius

Acromial Deltoid origin

Scapular Spine Deltoid originTriangle of Auscultation

Anterior Deltoid

Middle Deltoid

Posterior Deltoid

Classes of Joints

There are three classes of joints in the body which are called:

Fibrous Cartilaginous Synovial

The shoulder is a Synovial Joint

Types of Synovial Joints

There are six types of synovial joints that occur in the body:

Plane or griddle Joints Saddle Joints Hinge Joints Pivot Joints Ball-and-socket Joints Ellipsoid joints The shoulder is a ball-and-socket joint

which allow for ROM in most directions

Types of Synovial Joints

Plane Joint Saddle Joint

Ball-and-Socket Joint

Movements of the Shoulder

The shoulder joint can do most ROM:

Flexion Extension Abduction Adduction Rotation Circumduction

Synovial Membrane

Synovial joints are lined with a membranes called synovial membrane that secretes synovial fluid into the joint for :

Lubrication Nourishes Smooth movements Filling all empty spaces

Articular Cartilage

Bone ends in the synovial joint are covered by hyaline cartilage called Articular Cartilage for smooth gliding movements

The humeral head articulates with the glenoid cavity of the scapula

Articular Capsule

The articular cartilage is surrounded by a joint capsule made of:

Synovial Membrane Fibrous Layer

Helps hold the bones together and allows for movement to happen

Layers of Capsule

Fibrous layer aids in covering periosteum of the bone and helps with strength and stability of the joint

Synovial membrane covers the internal portion of the joint and secretes synovial fluid

Capsule

Membrane

Fluid

Articular Cartilage

Cartilage of Shoulder

Because glenoid cavity is shallow, the head of humerus needs help to articulate with the cavity (Articular Cartilage on surface)

Glenoid Labruim –ring of fibrocartilaginous

material that attaches to the margin of the glenoid cavity

GC

GL

FL

SM

FL- Fibrous Layer, GC- Glenoid Cavity,SM- Synovial Membrane, GL- Glenoid Labruim

Bursae

In some synovial joints, bursae are found

Extension of a synovial membrane that form into a sac

Filled with synovial fluid Help cushion or protect tendons from

rubbing against bones

Bursae of the Shoulder

Subacromial bursa or Subdeltoid bursa Located between

acromion, deltoid, and coracoacromial ligament

Helps with movement of supraspinatus tendon

Subscapular Bursa

Subscapular bursa or subcoracoid bursa Located between the

tendon of the subscapularis muscle and the neck and corocoid proccess of scapula

Protects and reduces friction between the tendon where it passes inferior to the coracoid process and over the neck of the scapula

Ligaments of the Shoulder

Ligaments are fibrous tissue that connects bones to other bones. They are sometimes called articular ligaments

Coracohumeral Transverse humeral Coniod Acromioclavicular Glenohumeral Coracoclavicular Superior transverse scapular

Location of Ligaments

Acromiolclavicular ligament: Extends from the acromion to the clavicle

Coracoclavicular ligament: Anchors the clavicle to the coracoid process of scapula - Conoid: Attaches to the root of the coracoid process, base attaches to the inferior surface of the conoid tubercle of the clavicle

Glenohumeral ligaments: Part of the fibrous layer of the capsule. Consists of superior, middle, and inferior ligaments. All originate from the humerus to margin of glenoid cavity

Coracohumeral ligament: Root of the coracoid process to humeral neck

Transverse Humeral ligament: Broad fibrous band from greater to lesser tubercle. Holds the tendon from the long head of the biceps brachii muscle

Superior transverse scapular ligament: Attached by end of the coracoid process and inserts into the medial end of the scapular notch

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Posterior Musculature

Levator scapulae

Rhomboid Minor

Rhomboid Major

Serratus anterior

Middle Trapezius

Teres Minor

Teres Major

Posterior Deltoid

Infraspinatus

Posterior Musculature

Levator scapulae

Rhomboid Minor

Rhomboid Major

Serratus anterior

Middle Trapezius

Teres Minor

Teres Major

Posterior Deltoid

Infraspinatus

Upper trapezius

Lower trapezius

Posterior MusculatureTrapezius

Innervation: Spinal accessory nerve

Vascularization: Transverse cervical artery

UpperAction: Scapular elevation and upward rotation

MiddleA: Scapular retraction

LowerA: Scapular depression and upward rotation

Levator ScapulaeI: 3rd and 4th Cervical nervesV: Dorsal Scapular ArteryA: Scapular elevation and

downward rotation

Serratus anterior I: Long Thoracic Nerve V: Lateral Thoracic Artery A: Scapular protraction and upward rotation

Rhomboideus Major and Minor I: Dorsal scapular nerve V: Dorsal scapular artery A: Scapular retraction and downward rotation

Posterior Musculature

Deltoid

Latissimus Dorsi

Supraspinatus

Supraspinatus

Infraspinatus

Teres Minor

Teres Major

T1

Musculature

DeltoidsI: Axillary NerveV: Posterior circumflex artery

AnteriorA: Shoulder flexion, medial rotation, horizontal adduction

MiddleA: Shoulder abduction

PosteriorA: Shoulder extension, hyperextension, lateral rotation, horizontal abduction

Latissimus dorsi I: Thoracodorsal nerve V: Deep scapular artery A: Shoulder extension, adduction, medial rotation, hyperextension

Teres Major I: Subscapular Nerve V: Circumflex scapular artery A: Shoulder extension, adduction, medial rotation

Anterior view of Musculature

Clavicle Manubrium

Pectoralis Major

Anterior Deltoid

Subscapularis

Coracobrachialis

MusculaturePectoralis Major

I: Lateral and Medial pectoral nerveV: Lateral Thoracic arteryA: Shoulder adduction, medial rotation, horizontal adduction

Pectoralis MinorI: Medial pectoral nerveV: Axillary arteryA: Scapular depression, protraction, and downward rotation

Coracobrachialis I: Musculocutaneous nerves C6, C7 V: Brachial artery A: Weakly adducts the shoulder joint Origin: Coracoid process Insertion: Medial aspect of humerus

Internal Anatomy

Rotator Cuff

The Rotator Cuff is made up of four muscles, Supraspinatus, Infraspinatus, Teres Minor and Subscapularis. The “SITS” muscles

The tendons of these four muscles merge with the joint capsule of the shoulder as they pass it to insert on the tubercles of the humerus. This insertion forms a partial sleeve around the proximal end of the humerus.

The Rotator Cuff reinforces the joint capsule and holds the head of the humerus in the glenoid cavity.

Rotator Cuff

Muscles of the Rotator CuffSupraspinatus

I: Subscapular nerveV: Subscapular arteryA: Shoulder abduction

Infraspinatus I: Subscapular nerveV: Subscapular arteryA: Lateral rotation, horizontal abduction

Subscapularis I: Subscapular nerve V: Subscapular artery A: Medial rotation

Teres Minor I: Axillary nerve V: Circumflex scapular artery A: Lateral rotation, horizontal abduction

Rotator Cuff TearRotator Cuff Tear

•Common in sports and recreation.

•Joint is not protected ventrally

•Supraspinatus is easily torn with: pitching (baseball) falls (skiing) hard blows from the side (hockey)

Questions?