Lecture 7 - Pectoral Girdle Flashcards
Pectoral Girdle/Pelvic Girdle Stability vs Mobility
- Shoulder (Pectoral) Girdle: Structurally very MOBLIE, Relatively less stable
- Pelvic Girdle: Structurally very STABLE, Relatively less mobile
What is the clavicle?
- The only long bone that lies in a horizontal position in the body
- Most common to fracture, because of force exerted when falling on an outstretched arm
What are the 3 sections of the clavicle?
- shaft
- sternal end
- acromial end
What is the sternal & acromial end of the clavicle?
- Sternal End: Medial end of the clavicle that articulates with the manubrium of the sternum
- Acromial End: Lateral end of the clavicle that articulates with the acromion of the clavicle
What is the sternoclavicular (SC) joint?
- The only bony articulation between the pectoral girdle of the upper limb & the axial skeleton
- The SC joint allows considerable mobility, enabling the clavicle & scapula to move in upward/downward & anterior/posterior directions
- supported by the costoclavicular ligament which spans the sternal end of the clavicle & the underlying first rib
What are the functions of the clavicle?
- moveable rigid support
- bony passageway
- transmits forces from the upper limb
What are the movements of the scapula?
- Upward/downward rotation
- Protraction/retraction
- Elevation/depression
What are the 6 general landmarks of the scapula?
- medial border
- lateral border
- superior border
- suprascapular notch
- inferior angle/apex
- superior angle
What is the medial/lateral/superior border of the scapula?
- medial Border: Elongated, medial margin of the scapula
- lateral Border: Diagonally oriented lateral margin of the scapula
- Superior Border: Superior margin of the scapula
What is the suprascapular notch?
- Small notch located along the superior border of the scapula, medial to the coracoid process
What is the inferior (apex)/superior angle of the scapula?
- Inferior Angle/Apex: Inferior corner of the scapula located where the medial & lateral borders meet
- Superior Angle: Corner of the scapula between the superior & medial borders of the scapula
What are the 4 landmarks of the posterior surface of the scapula?
- spine of the scapula
- supraspinous fossa
- infraspinous fossa
- acromion process
What is the spine of the scapula?
- Prominent ridge passing mediolaterally across the upper portion of the posterior scapula surface
What is the supraspinous/infraspinous fossa of the scapula?
- Suprapinous Fossa: Narrow depression located on the posterior scapula, superior to the spine
- Infraspinous Fossa: Broad depression located on the posterior scapula, inferior to the spine
What is the acromion process of the scapula?
- The acromion of the scapula?
What are the 2 landmarks of the anterior surface of the scapula?
- subscapular fossa
- coracoid process
What is the subscapular fossa of the scapula?
- Broad depression located on the anterior (deep) surface of the scapula
What is the coracoid process of the scapula?
- Short, hook-like process that projects anteriorly & laterally from the superior margin of the scapula
What are the 4 landmarks of the lateral surface of the scapula?
- glenoid fossa
- supraglenoid tubercle
- infraglenoid tubercle
- acromion process
What is the glenoid fossa of the scapula?
- Also known as the glenoid cavity
- Shallow depression located on the lateral scapula, between the superior & lateral borders
What is the supraglenoid/infraglenoid tubercle of the scapula?
- Supraglenoid Tubercle: Small bump located at the superior margin of the glenoid cavity
- Infraglenoid Tubercle: Small bump located on the lateral border of the scapula, near the inferior margin of the glenoid fossa (cavity)
What is the acromioclavicular joint?
- The articulation between the acromion of the scapula & the acromial end of the clavicle
- Provides attachment of the neck & back muscles that act on the shoulder, as well as muscles that pass across the shoulder joint to act on the arm
What is the coracoclavicular ligament?
- A strong band of connective tissue that anchors the coracoid process of the scapula to the lateral clavicle
- Provides important indirect support for the acromioclavicular joint
What is the coracoacromial ligament?
- A strong triangular ligament of the glenohumeral joint complex
- attaches between the lateral border of the coracoid process 7 the apex of the acromion of the scapula
- Forms the coracoacromial arch; prevents superior displacement of humeral head
What is scapulohumeral rhythm?
- movement of the scapula relative to the movement of the humerus
- the scapula can move on the thorax so it can get to the final ranges of motion; scapula compensates the humerus
- normal ROM for shoulder abduction & flexion is 120 degrees
- OVERALL — approximately 2 degrees of shoulder movement for every 1 degree of scapular movement
