The Shoulder Girdle Flashcards
What is the shoulder girdle?
The bones, joints and muscles associated with the suspension of the upper limb on the trunk
What is the shoulder?
The area of articulation of the upper limb with its girdle
name the bones of the shoulder girdle
Scapula and clavicle
What are the joints of the shoulder girdle (names)?
Acromiclavicular joint
Sternoclavicular joint
Scapula-thoracic junction
What is the clavicle?
A strut to hold the scapula and therefore the numerous out to the side of the body away from the thorax
What Does the medial end of the clavicle articulate with?
Sternum
What does the lateral end of the clavicle articulate with?
The acromion of the scapula
What are the key points on the clavicle?
Deltoid tuberosity
Trapezoid line and conoid tubercle
Subclavian groove
Costal tuberosity
What attaches at the deltoid tubercle?
Anterior fibres of deltoid
What attaches at the trapezoid line and conoid tubercle?
The coracoclavicular ligament
What is the subclavian groove for?
The subclavian vessels
What attaches at the costal tuberosity?
Costocalvicular ligament
Describe the scapula
A classic flat bone, there for protection of the thoracic cavity and multiple anchor points for many muscles
What are the names of the 3 borders of the scapula?
Medial, lateral and superior
What are the names of the two angles of the scapula?
Inferior and superior
What are the names of the 2 surfaces of the scapula?
Costal/anterior
Dorsal/posterior
What are the names of the 3 bones processes of the scapula?
The head, acromion process, coracoid process
What are the names of the fossae of the scapula?
Supraspinopus and infraspinous
Where is the acromioclavicular join found?
It is the junction between the lateral end of the clavicle and the medial facing aspect of the acromion process
What type of joint is the acromiclavicular joint?
Synovial plane joint
What movements occur at the acromioclavicular joint?
Very small glides of acromion on clavicle
What type of joint is the sternoclavicular joint?
Synovial saddle joint
What muscles are involved in elevation of the shoulder girdle?
Upper fibres of Trapezius
Levator Scapulae
What muscles are involved in depression of the shoulder girdle?
Serratus Anterior
Pectoralis Minor
What muscles are involved in protraction of the shoulder girdle?
Serratus Anterior
Pectoralis Minor
What muscles are involved in retraction of the shoulder girdle?
Rhomboid major
Rhomboid Minor
Middle Trapezius
What muscles are involved in lateral rotation of the shoulder girdle?
Upper and lower fibres of Trapezius
Serratus Anterior
What muscles are involved in medial rotation of the shoulder girdle?
The Rhomboids
Pectoralis Minor
Levator Scapulae
Name the muscles acting on the shoulder girdle
Subclavius
Pectoralis Minor
Pectoralis Major
Serratus Anterior
Trapezius
Levator Scapular
Rhomboid Major
Rhomboid Minor
What is the innervation of subclavius?
Subclavian nerve C5,6
What is the main function of subclavius?
Steadies the clavicle
What is Pectoralis Minor deep to?
Pectoralis Major
Where is the origin of Pectoralis Minor?
Ribs 3,4 and 5
Where does Pectoralis minor insert?
Coracoid process of the scapula
What is the innervation of Pectoralis Minor?
Medial Pectoral nerve C8
What are the actions of Pectoralis Minor?
Protracts and medially rotates the scapular against resistance
Where does Serratus Anterior insert ?
Outer surfaces of upper 8-9 ribs
Where does Serratus Anterior originate ?
Costal surface of medial border of scapula
What is the innervation of Serratus Anterior?
Long thoracic nerve C5-7
What are the actions of Serratus Anterior?
Protraction and lateral rotation of scapula
Where does trapezius originate?
Superior unchallenged line and external occipital protuberance of the occipital bone
Spinous processes of C7-T12 and Supraspinous ligament
Where do upper fibres of trapezius insert?
Lateral 1/3 of clavicle
Where do middle fibres of trapezius insert?
Acromion and spine of scapula
Where do the lower fibres of trapezius insert?
Medial end of scapular spine
What are the actions of the upper fibres of trapezius?
Elevation of the shoulder girdle
Lateral (side) flexion of the neck
Both together (extension of neck)
What is the action of the middle fibres of trapezius?
Retraction of shoulder girdle
What is the action of the lower fibres of trapezius?
Depression of the scapula against resistance
What is the action of the upper and lower fibres of trapezius together (with Serratus anterior)?
Lateral rotation of the scapula to increase range of movement of upper limb
What are the functional activities of trapezius?
Steadies scapula
Provides fixation
Produces lateral rotation of scapula
Produces retraction of scapula
Produces depression of scapula against resistance
Where does Levator scapulae originate?
Transverse processes of C1,2,3,4
Where does Levator scapular insert?
Superior portion of the medial border of scapula
What is the nerve supply of levator scapulae?
Dorsal scapulae nerve
What are the actions of levator scapulae?
Elevation and medial rotation
Where does rhomboid minor originate?
C7 and T1 spinous processes and Supraspinous ligament
Where does rhomboid minor insert?
Medial border of scapula spine
Where does rhomboid major originate?
T2-T5 spinous processes and Supraspinous ligament
Where does rhomboid major insert?
Medial border, inferior to the scapula spine
What is the nerve supply of the rhomboids?
Dorsal capsule nerve C4-5
What are the actions of the rhomboids?
Retraction and medial rotation of scapula
How does the shoulder girdle increase range of activity of upper limb?
Changes position of the glenoid fossa, relative to chest wall
Clavicle holds shoulder away from chest wall
Why is the shoulder girdle important?
Increases range of activity of upper limb
Clavicle absorbs tension and compression stresses
Name the 7 muscle acting on the shoulder girdle
Subclavius
Pectoralis minor
Serratus anterior
Trapezius
Levator scapulae
Rhomboid major
Rhomboid minor
What are the functions of trapezius?
Stabilises scapula and clavicle
Facilitates upper limb movement above head
Hat is the nerve supply of trapezius?
Accessory nerve
C3/4 nerve roots
