Shoulder Joint, Scapular and Pectoral Regions

How to determine scapular movements?

Where is the end point of the glenoid cavity?

What runs through the suprascapular notch?

Suprascapular avn.

Pectoral Girdle Components

Clavicles and scapulae

3 Synovial Joints of the Pectoral Girdle

1. Sternoclavicular

2. Acromiclavicular

3. Glenohumeral

Which joint is the actual shoulder joint?

Glenohumeral

Non-Synovial Joint of the Pectoral Girdle

Scapulothoracic (scapula + ribs)

- Has non membrane around the joint and no synovial fluid

Which joints of the pectoral girdle does movement occur at? (3)

1. Sternoclavicular

2. Acromioclavicular

3. Glenohumeral

Which 2 joints must be noted when assessing the ROM of the pectoral girdle?

1. Glenohumeral

2. Scapulothoracic

Ratio for UL Movement (aka Scapulothoracic Rhythm)

1:2

- For every 3 degrees of movement, 1 degree occurs at the scapulothoracic and 2 degrees at the glenohumeral

Sternoclavicular Joint Type

Synovial, saddle

- Functions like a ball and socket!!

Sternoclavicular Joint

Sternal end of the clavicle + manubrium of the sternum + 1st costal cartilage

Where is the sole articulation between the UL and axial skeleton?

SC joint

SC Joint Fibrocartilage

The SC joint has fibrocartilage within the joint

- Divides the space into two compartments

- Provides shock absorption

4 Ligaments of the SC Joint

1. Anterior sternoclavicular ligaments

2. Posterior sternoclavicular ligaments

3. Interclavicular ligament

4. Costoclavicular ligament (extrinsic)

Anterior + Posterior SC Ligament Attachments

Attach from the manubrium and costal cartilage to the anterior/posterior surface of the clavicle

Anterior + Posterior SC Ligament Support

Reinforces the SC joint anteriorly/posteriorly and prevents displacement of the clavicle in these directions

Interclavicular Ligament Attachments

Attaches the two sternal ends of the clavicle, and the superior border of the manubrium

Interclavicular Ligament Support

Strengthens the joint capsule superiorly

Costoclavicular Ligament Attachments

Attaches the clavicle to the 1st rib/costal cartilage

Costoclavicular Ligament Support

Prevents excessive elevation of the clavicle

Function of all 4 of the SC Joint Ligaments

To keep the sternal end of the clavicle close to the manubrium

Typical Clavicular Fracture

- Most often occurs with a FOOSH

- Most commonly occurs in the middle 1/3 of the bone

Acromioclavicular Joint Type

Synovial, Plane (small joint)

Acromioclavicular Joint

Acromial end of the clavicle + acromion of the scapula

- Loose joint capsule allows for rotation of the clavicle

Fibrocartilage of the AC Joint

Incomplete articular disc (fibrocartilage) is located inside of the joint capsule

Coracoclavicular Ligament

Extrinsic ligament that anchors the clavicle to the coracoid process

Main Stabilizer of the AC Joint

Coracoclavicular Ligaments

- Prevents superior translation of the clavicle

2 Parts of the Coracoclavicular Ligament

1. Conoid ligament (medial and posterior)

- Strong

2. Trapezoid ligament (lateral and anterior)

- Weak

Separated Shoulder

-Typically occurs with a direct force on the acromion process, less commonly with a FOOSH

- Disruption of the AC joint

How to determine the severity of a separated shoulder injury?

Depedant on the damage to the coracoclavicular ligaments (ie. are they still intact?)

Tear of the AC + CC ligament?

Nothing is holding the acromial end of the clavicle down

- Clavicle looks like it will protrude through the skin

Glenohumeral Joint Type

Synovial, ball and socket

Glenohumeral Joint

Head of the humerus + glenoid cavity of the scapula

Glenoid Labrum

Deepens the GH joint (fibrocartilage)

Main role of the rotator cuff mm.?

Hold the humerus to the scapula

What muscle's tendon is inside of the GH joint capsule?

Biceps brachii long head m.

How many rotator cuff mm. are posterior/superior/anterior/inferior to the GH joint?

- 2 posterior

- 1 superior

- 1 anterior

- 0 inferior

4 Ligaments of the GH Joint

1. Glenohumeral

2. Coracohumeral

3. Transverse humeral

4. Coracoacromial

Glenohumeral Ligaments

- Intrinsic ligaments that reinforce the anterior aspect of the GH joint

- Have a superior, middle, and inferior

Coracohumeral Ligament

Intrinsic ligament connecting the coracoid process to anterior aspect of the greater and lesser tubercles

How does the coracohumeral ligament support the GH joint?

Superiorly

Transverse Humeral Ligament

Connects the two tubercles, forming a tunnel for the long head of biceps brachii tendon to enter the joint capsule

Coracoacromial Ligament

Extrinsic ligament connecting the coracoid and acromion processes

How does the coracoacromial ligament support the GH joint?

Strong superior support to prevent superior dislocation

Shoulder Dislocation

- Clinically classified as anterior (most common) or posterior

- Due to lack of inferior support, the humeral head typically moves inferior and then anterior

- Commonly tears the glenoid labrum

Deltoid Fascia

Over the deltoid m.

Pectoral Fascia

Over the pectoral mm.

Brachial Fascia

On the arm

Antebrachial Fascia

On the forearm

Palmar Aponeurosis

Over the palm

What 2 vv. does the dorsal venous network give rise to?

1. Cephalic v.

2. Basilic v.

Median Cubital v.

Connects the cephalic and basilic vv.

What v. does the cephalic v. drain into?

Axillary v.

Basilic v.

Dives deep into the arm (through the fascia) about 1/2 way up the arm

- Runs with brachial v.

4 Rotator Cuff mm.

1. Supraspinatus m.

2. Infraspinatus m.

3. Teres minor m.

4. Subscapularis m.

Which of the 4 rotator cuff mm. is the only one that doesn't rotate the humerus?

Supraspinatus m.

Most commonly torn rotator cuff mm.?

The tendon of supraspinatus m. bc of the subacromail bursa

Subacromial Bursa

Between the acromion and the supraspinatus tendon

The scapulohumeral and pectoral mm. are all inn. by branches of ___?

Brachial plexus

Suprascapular n. Inn. (2)

1. Supraspinatus m.

2. Infraspinatus m.

What branch of the BP is suprascapular n. off of?

Superior trunk

The suprascapular a. + v. go ___ the superior transverse scapular ligament and the suprascapular n. goes ___?

Over, under

( army goes over the bridge, navy goes under the bridge)

The suprascapular nva. pass lateral to the ___ to enter the infraspinous fossa?

Spinoglenoid notch

If the suprascapular n. was compressed at the spinoglenoid notch, what weaknesses would the pt present with?

ER of humerus

What 2 mm. does the axillary n. inn.?

1. Teres minor m.

2. Deltoid m.

If the axillary n. is damaged, what 2 movements would a pt present with?

Shoulder ER + abduction

The axillary n. is a branch of the BP ___?

Posterior cord

The upper + lower subscapular nn. are branches from the BP ___?

Posterior cord

If the upper + lower subscapular nn. are damaged, what weaknesses will the pt present with?

IR of humerus

What mm. do the upper and lower subscapular mm. inn.?

1. Subscapularis m. = Both

2. Teres major m. = Lower only

What VR is long thoracic n. formed from?

C5-7

What m. does long thoracic n. inn.?

Serratus anterior m.

What m. does subclavian n. inn.?

Subclavius m.

The subclavian n. is a branch of the BP ___?

Superior trunk

Main blood supply to the entire UL?

Subclavian a.

Name change of subclavian a. after passing under the clavicle?

Axillary a.

Name change of axillary a. after passing teres major m.?

Brachial a.

What 2 aa. does the brachial a. divide into?

1. Radial a.

2. Ulnar a.

Scapular Anastomosis

Suprascapular + dorsal scapular aa. anastomose with circumflex scapular + thoracodorsal aa.

Triangular Space Borders (S/I/L)

S = Teres minor m.

I = Teres major m.

L = Long head of triceps brachii m.

Triangular Space Contents

Circumflex scapular vessels

Is the triangular space medial or lateral to the long head of triceps brachii?

Medial

Quadrangular Space Boundaries (S/I/M/L)

S = Teres minor m.

I = Teres major m.

M = Long head of triceps brachii m.

l = Surgical neck of humerus

Quadrangular Space Contents (2)

1. Axillary n.

2. Posterior circumflex humeral vessels

Is the quadrangular space medial or lateral to the long head of triceps brachii?

Lateral