Bones of the Shoulder Girdle

- Mr. Brewer

Bones of the Shoulder

• 4 Major Bones that make up the Shoulder Girdle:– Humerus (Upper Arm

Bone)– Clavical (Aka the “collar

bone”)– Scapula (Aka the

“Shoulder Blade”)– Sternum (Aka the

“Breast Plate”)https://www.youtube.com/watch?v=D3GVKjeY1FM

Humerus

• The Humerus is the upper arm bone.

• Important boney landmarks:– Head of the

Humerus– Greater Tubercle– Lesser Tubercle– Bicipital Groove– Olecranon Fossa– Lateral AND Medial

epicondyles

Clavicle

Clavicle:

- The Clavicle is “S” in shape.- It extends from the Sternum in the

middle of the chest, to the acromion of the Scapula.

- The Clavicle is most vulnerable for fractures right in the middle 1/3 where the bone bends.

- Due to the fact that the clavicle is very “superficial”, there will be a higher chance of fractures due to a direct blow to the region.

Scapula

Scapula:- The role of the scapula is to

provide protection from the dorsal aspect of the body to some internal organs, while allowing a wide range of movement ability at the shoulder joint.

- Important landmarks of the Scapula:

- Glenoid Fossa (Cavity)- Coracoid Process- Acromion Process- Spine of the Scapula- Inferior Angle

Scapula

• The Coracoid Process:– The Coracoid process

protrudes anteriorly from the subscapular surface.

– It is the origination of the Short Head of the Biceps tendon.

• The Acromion:– The Acromion is formed at

the lateral tip of the scapula.– It is the point where the

Clavicle connects to the scapula and forms the shoulder girdle.

Scapula – Glenoid• Glenoid Fossa:

– The Glenoid Fossa is a flat surface of the scapula where the humeral head comes together to form the Glenohumeral, aka the “Shoulder Joint”.

– The Glenoid Labrum:• The Labrum of the shoulder is much like

the labrum of the Hip.• It covers the peripheral edge of the

glenoid, and acts as a cushion for the humeral head, while providing additional stability to the shoulder because of it’s “concave” nature.

• This Cushion reduces bone-to-bone contact, and absorbs shock when the humerus is forced into the shoulder.

• Attached to the Labrum at the most superior aspect is the Long Head of the Biceps.

SternumThe Sternum is broken into 3 major parts:1. Manubrium

- Suprasternal Notch: AKA the Jugular Notch

- Clavicular Notch: Where the clavicle inserts into the sternum.

2. Body- The body of the Sternum has several notches

or Costal Facets that act as insertion points for the cartilage that connects the ribs in the front.

3. Xiphoid Process- The xiphoid process is similar to the “coccyx”

of the tail bone.- It acts as an extension with no major role or

function, but can be injured or fractured with a direct blow to the area.

- Sometimes that can happen during CPR.

Joints• Joints are created when two or more bones articulate with each

other. • There are 4 Major Joints of the Shoudler:

– Sternoclavicular (SC) Joint• Where the Clavicle meets the Sternum at the Manubrium.

– Acromioclavicular (AC) Joint• Where the Clavicle meets the Scapula at the Acromion Process.• This is where a Shoulder sprain or “separated shoulder” injury can occur.

– The Scapulothoracic Joint• This is a “false” joint.• The Scapula and thoracic area (Rib Cage) do not actually articulate, but

because the Scapula glides around the rib cage it is considered to be a joint.

– Glenohumeral (GH) Joint• AKA the “Shoulder Joint”• Where the Head of the Humerus inserts into the Glenoid Fossa of the

Scapula.

Joints of the Shoulder

Ligaments

The Ligaments of the Shoulder Complex:- The ligaments of the shoulder need to be strong for structure support, but flexible enough to allow for a variety of movements through a wide range of motion. - A sprain or tear of the Acromio-Clavicular Ligament can result in a “separated shoulder”. (AKA an AC sprain)

Bursa

• There are 4 Major Bursa of the shoulder joint. (Picture is missing the subscapular bursa)– They all act as friction

reducers for tendons that cross through the shoulder joint.

– Although helpful in that regard, the bursa sacs can be inflamed and cause pain in the shoulder via repeated use and/or over use of the shoulder.