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Flashcards in The Pectoral Girdle Deck (36)
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The Pectoral Girdle consists of?

The clavicle and scapula


What joint links the free limb to the axial skeleton?

The sternocalvicular joint


Why are muscles required to stabilise the shoulder joint?

Because as the shoulder joint is extremely mobile, it has sacrificed stability, which needs to be overcome with muscles


How are movements in the pectoral girdle classified?

By the movement of the scapula


Superior rotation

Glenoid points superiorly


Whats another name for the forearm?



Clavicle functions?

-To act as a strut to stop muscles attached to the scapula pulling it into the thorax.
-acts as an attachment point for muscles


Where is the weak point of the clavicle?

2/3 medially, 1/3 laterally. Here there is no muscles attached, so force of the free limb is transmitted to this area, making in a common place of breaking


The two roughened areas of the clavicle are, and what is their purpose?

1) Coracoclavicular area
2) Costoclavicular area
This allows for attachments of two ligaments that stabilise the clavicle


What is the purpose of having a mobile scapula?

For the hands. These need to be extremely sensitive and mobile with the environment


What are the borders of the scapula?

Medial, lateral and superior


What processes of the scapula are?

spinous, acromion and coracoid


What are the four fossas of the scapula?

Subscapula, supraspinous, infraspinous and glenoid


There is a groove in the middle of the clavicle, what is this called and what is it for?

Subclavian groove, for the subclavian muscle to run through


What does the clavicle articulate with?

The acromion process of the scapula, and the manubrium of the sternum


What are the four important joints of the pectoral girdle?

1) Sternoclavicular (synovial)
2) Acromioclavicular (synovial)
3) Shoulder joint
4) Scapula-thoracic (conceptual)


scapulothoracic joint

scapulothoracic join conceptual joint where scapula moves along the thoracic wall


What are the main stabilisers of the Sternoclavicular joint?

Anterior and posterior sternoclavicular ligaments
costoclavicular ligament
interclavicular ligament


Is posterior or anterior sternoclavicular ligament stronger?

Posterior is significantly stronger as there is a need to protect the posterior arteries that run behind the clavicle


Purpose of interclavicular ligament

Runs along the jugular notch, that supports the superior aspect of the SC joint. This is the only joint between the two sides, and means that the SC joints can't be seperated


O and I of subclavius muscle. Purpose

O= first rib and costicartilage
I= subclavian groove
Acts as a brace to oppose any upwards tension of on the clavicle


What supports the inferior part of the clavicle?

The costoclavicular ligament


Main stabilisers of the acromioclavicular joint?

acromioclavicular ligament
Coracoclavicular ligament (conoid + trapezoid)


What is special about the coracoclavicular ligament of the acromioclavicular joint?

Muscles like trapezoid attach and pull clavicle upwards. The CC ligament apposes this, and allows for the limb to be passively hanging with low energy expenditure


What is the purpose of 'stabilising muscles'?

When stimulated, these muscles do not move but inside contract to stabilise the joint. this is especially important for highly mobile joints


O? I? Nerve? Action?

O= skull -T12
I= anatomical horseshoe
Nerve= accessory nerve
Action= retracts, elevates and depresses scapula


Levator Scapulae
O? I? Nerve? Action?

O= transverse process of upper cervical
I= superior angle of scapula
Nerve= dorsal scapula nerve
Action= elevate and internally rotates scapula


Rhomboid Min & Maj
O? I? Nerve? Action?

O= spinous process
I= medial border of scapula
Nerve= dorsal scapula nerve
Action= retracts, elevates and inferiorly rotates scapula
can act as a stabiliser.


Latissimus Dorsi
O? I? Nerve? Action?

O= T7 - sacrum
I= anterior humerus
Nerve= Thoracodorsal nerve
Action= adducts, internally rotates humerus


Pectoralis Major

O= clavicular and sternocostal
I= anterior humerus
Nerve= lateral and medial pectoral nerve
Action= Adducts and internally rotates humerus