The Shoulder Girdle Flashcards
Define the shoulder girdle -
Bones joints and muscles associated with the attachment of the upper limb to the trunk (sternum)
What makes up the shoulder girdle ?
Joints in the shoulder girdle -
Scapula
Clavicle
Sternum
Joints - acromioclavicular
Sternoclavicular
Scapula-thoracic junction (medial side of scapula to back of ribs)
What are the functions of the shoulder girdle?
Increases ROM in the upper limb by changing the position of the glenoid fossa
Clavicle absorbs tension and compression stresses, allowing transmission of forces from upper limb to trunk
Describe the shape of the clavicle and the medial and lateral end:
S shaped bone
Medial end - convex anteriorly
Rounded, triangular cross section
Articulates with sternum (sternoclavicular joint)
Lateral end - broad and flattened
Concave anteriorly
Articulates with acromion process of scapula (acromioclavicular joint)
Bony points on the clavicle
Deltoid tubercle -
Trapezoid line and conoid tubercle -
Deltoid - attachment of anterior fibres of deltoid
Trapezoid and conoid - attachment of the coracoclavicular ligament
Bony points on clavicle
Subclavian groove -
Costal tuberosity -
Subclavian - subclavian vessels - blood vessels
Costal tuberosity - attachment of the costoclavicular ligament
What muscles attach to the clavicle ?
Sternocleidmastoid
Pectoralis major
Trapezius (upper)
Deltoid (anterior)
Subclavius - sits under clavicle
Describe the scapula:
Sits posteriorly
‘Flat’ bone
Articulates with humerus, forming gleno-humeral joint
Articulates with the clavicle, forming the acromioclavicular joint
Many bony points for the muscle attachment
Describe the borders and angles of the scapula -
(Posterior spect)
3 borders - medial, lateral and superior
2 angles - inferior and superior
2 surfaces - anterior (costal), posterior (dorsal)
Spine of scapula
Acromion process
Supraspinous/infraspinous fossa
Describe aspects of the scapula -
(Anterior)
Subscapular fossa
Coracoid process
Infraglenoid/supraglenoid tubercle
Glenoid cavity/fossa
Articular surface on acromion
Describe the aspects of the sternum:
Sits on body midline anteriorly
Articulates with clavicle (sternoclavicular) and ribs (first seven ribs)
Made up of three parts:
Manubrium - most superior
Sternum - middle section
Xiphoid process - inferior, smallest aspect
What is the shoulder complex made up of?
Clavicle and scapula
Joints of the shoulder girdle
Acromioclavicular joint -
Classify
Synovial plane joint
Between acromion of scapula and lateral end of clavicle
Articular surfaces - small facets on lateral clavicle and acromion process
Covered by fibrocartilage
Intra-Articular disc
Joints of the shoulder girdle
Acromioclavicular joint
Ligaments present and movement:
Ligaments - acromioclavicular and coracoclavicular
Movement - small gliding movements
Joints of the shoulder girdle
Sternoclavicular joint
Classify -
Between manubrium of sternum and medial end of clavicle
Synovial saddle joint
Joints of the shoulder girdle
Sternoclavicular joint
Articular surfaces, ligaments and movement-
Articular surfaces - clavicle, covered in fibrocartilage
Manubrium - concave and covered in hyaline cartilage
Intra-Articular disc
Ligaments - anterior sternoclavicular
Posterior sternoclavicular
Costoclavicular
Movement - small gliding movements
Describe the scapulothroacic junction -
Not a true joint
Articulation o the scapula with the thorax
Depends on the integrity of the sternoclavicular joint and the acromioclavicular joint
Any movement of the scapula on the thorax results in movement at either the ACJ or SCJ or both
Movements at the the shoulder girdle
Elevation -
Depression -
Elevation - 10cm upwards
Produced by - upper trapezius and levator scapulae
Depression - 2cm downwards
Produced by - serrated anterior and pectoralis minor
Movements at the shoulder girdle
Protraction-
Retraction -
Protraction - forwards 5cm anterior movement
Produced by - serrated anterior and pectoralis minor
Retraction - 2cm from normal posture
Produced by - rhomboid major/minor and middle trapezius
Movements at the shoulder girdle
Lateral/upward rotation -
Medial/downward rotation -
Lateral - occurs when arm elevated above head
Produced by upper and lower trapezius and serratus anterior
Medial - occurs when arm moves back to body
Produced by - rhomboid major/minor, pectoralis minor and levator scapulae
These rotations are real important as they are responsible for the huge ROM available at the shoulder joint
Muscles acting on shoulder girdle
Subclavius -
Lies inferiorly to clavicle
Proximal - costochondral junction of 1st rib (more medial to distal attachment)
Distal - inferior surface of middle 1/3 clavicle
Nerve - subclavian nerve C5,6
Actions - stabilises the sternoclavicular joint
Depresses lateral end of the clavicle
Muscles acting on shoulder girdle
Pectoralis minor -
On the anterior chest wall
Proximal - anterior and superior surfaces ribs 3,4,5
Distal - coracoid process of scapula
Nerve - medial and lateral pectoral nerves C5-8 and T1
Actions - shoulder girdle depression/protraction
Accessory muscle of respiration
Muscles acting on shoulder girdle
Serratus anterior -
Proximal - anterior (costal) surface of medial border or scapula
Distal - lateral surfaces of upper 8-9 ribs
Nerve - long thoracic nerve C5-7
Actions - shoulder girdle depression and lateral rotation of scapula
Muscles acting on the shoulder girdle
Trapezius, upper attachments and actions -
Proximal - superior nuchal line and external occipital protuberance (bony projection at base of skull)
Distal - lateral 1/3 clavicle
Nerve- accessory nerve C3,4
Action - elevation of shoulder girdle
Lateral ovation of scapula
Cervical side flexion and extension
