Shoulder Girdle Flashcards
What are the bones involved in the shoulder girdle?
Sternum: manubrium, body, xyphoid
clavicle
scapula (17 or 19 muscular attachments, 3 angles, 3 borders)
humerus
What are the four joints at which motion happens? What type of movements?
Sternoclavicular, acromioclavicular, glenohumeral, scapulothoracic
interdependent movements
What are the motions at the scapulothoracic joint? How many DOF?
3 DOF
Of scapula: retraction/protraction, elevation/depression, upward/downward rotation of inferior angle
What are the motions at the glenohumeral joint? How many DOF?
3 DOF
abd/add
flex/ext
IR/ER
Describe the sternoclavicular joint.
What two bones are involved?
How many axes?
What kind of joint is it?
What is the CPP? LPP?
Sternum and clavicle
Triaxial
Synovial, saddle
CPP: full elevation
OPP: arm at side
When is clavicle convex? When is it concave?
Convex with superior/inferior
Concave anterior/posterior
Describe SC elevation.
Is clavicle concave or convex?
What plane? Axis?
Rolls? Glides?
Maximum degree of movement?
Clavicle is convex
Rotation in frontal plane around sagittal axis
Convex end of clavicle rolls superior and glides inferior on sternum
45 degrees max.
Describe SC depression.
Movement in what plane? Around which axis?
Rolls? Glides?
Maximum degree of movement?
Rotation in frontal plane around sagittal axis
Convex end of clavicle rolls inferior and glides superior on sternum
10 degrees max.
Describe SC protraction.
Is clavicle concave or convex?
Movement in which plane? Along which axis?
Rolls? Glides?
Maximum degree of movement?
Clavicle is concave
Parallel to horizontal plane around a vertical axis
Rolls and glides anterior on sternum
15-30 degrees of movement
Describe SC retraction.
Movement in which plane? Around which axis?
Rolls and glides?
Maximum degree of movement?
Parallel to horizontal plane around vertical axis
Concave clavicle rolls and glides posterior on sternum
15-30 degrees of movement
Describe SC rotation.
Which axis?
How does the clavicle rotate with arm elevation?
Degrees of movement?
Longitudinal axis
Superior clavicle rotates posteriorly and puts tension on coracoclavicular ligament
20-30 degrees
What are the stabilizing structures of the sc joint?
Articular disc
Capsule
Sternoclav. ligament
Interclav. ligament
Costoclav. ligament
Muscles
What do the anterior/posterior sternoclavicular ligaments do?
Reinforce capsule
Limits A/P movements of clavicle (pro/retract)
Describe the interclavicular ligaments.
Where do they cross?
Where do they attach?
What do they do?
Superior SC joint
Attach to medial end of clavicle
Provide superior joint stability, controls depression
Where do the costoclavicular ligaments attach and what do they do?
Attach to first rib to inferior surface of clavicle
Controls elevation of clavicle on first rib
What is the articular disc? What does it do?
Fibrocartilage that divides joint into M/L cavities
Shock absorber, inc. joint congruency, stability
What are the muscles of SC joint?
Sternocleidomastoid
Sternothyroid
Sternohyoid
Describe the acromioclavicular joint.
What two bones are involved?
What kind of joint? DOF?
CPP? LPP?
Acromion and clavicular
Synovial plane joint with 3 DOF
CPP: 90 degrees ABD
LPP: arm at side
What is moving at the AC joint?
Scapula moving on clavicle
Describe AC upward rotation.
Acromion moves up and out, upward rotation of scapula up to 30 degrees
Describe AC downward rotation.
Which plane and axis?
Where does the arm move?
Frontal plane, sagittal axis
Elevated arm down to rest (180-90), acromion moves down and in
Describe AC IR/ER.
Which plane and axis? Where does scap move?
Transverse plane, vertical axis
Medial border of scap closer or further from thorax
Describe AC sagittal plane movement - a/p tilting
Which axis? Where does scap move?
Frontal axis
Inferior angle of scap moves closer or farther from thorax
What are the typical AC roll and glide?
Same direction
Unpredictable
What do the superior/inferior AC ligaments do and what do they attach?
Reinforce joint capsule
Attach acromion and clavicle
Describe the coracoclavicular ligament.
What two bones are involved?
What are the parts?
What is the role?
When dislocated, where does the clavicle go?
Clavicle to coracoid process of scapula
Trapezoid (lateral), conoid (medial)
CONTROL VERTICAL JOINT STABILITY, upward rotation, medial displacement of clavicle, create longitudinal rotation of clavicle
Elevated clavicle
What are the muscles for the AC joints?
Upper trapezius, deltoid
Describe the scapulothoracic joint.
What kind of joint is it?
Where is it?
Not a true joint, not a bone to bone union
Between T2-T7 and is about 6 cm from spine
Describe ST joint elevation.
Where does the scap move?
Prime movers?
Glide superiorly
upper trapezius, levator scapula, rhomboid major, rhomboid minor
Describe ST joint depression.
Where does the scap move?
Prime movers?
Glide inferiorly
Subclavius, pec minor, low pec major, low trap, low serratus anterior, low lat dorsi
Describe ST joint retraction.
Where does the scap move?
Prime movers?
Glide medially on thorax
Rhomboid major, rhomboid minor, mid trap, upper lat dorsi
Describe ST joint protraction.
Where does the scap move?
Prime movers?
Glide laterally on thorax
Pec major, pec minor, serratus anterior
Describe ST joint upward rotation.
Where does the scap move?
Prime movers?
Inferior angle moves away from vertebral column
60 degrees of scap rotation available at ST joint
Upper trap, lower trap, serratus anterior
FORCE COUPLE
Describe ST joint downward rotation.
Where does the scap move?
Prime movers?
Inferior angle closer to veterbral column
Levator scap, rhomboid major, rhomboid minor, pec minor
also lat dorsi, low pec major
What is the function of scapular movement at AC and SC joints?
Orient glenoid fossa for optimal contact with head of GH
Add range to arm elevation
Provide stable base for GH movement
What are the stabilizing structures of ST joint?
ST stability comes from stability of SC and AC joints
All muscles with attachment to scapula or thorax
What is the origin of Upper Trapezius?
occipital bone, cervical spinous processes via nuchal ligament
What is the insertion of Upper Trapezius?
Lateral third of clavicle, acromion, AC joint
What is the action of Upper Trapezius?
Elevation, upward rotation, retraction of scapula
What is the innervation of Upper Trapezius?
Accessory nerve, C3-4
What is the origin of Middle Trapezius?
Spinous processes of T1-T5
What is the insertion of Middle Trapezius?
Acromion and spine of scapula
What is the action of Middle Trapezius?
retraction of scapula
What is the innervation of Middle Trapezius?
Accessory nerve, C3-4
What is the origin of Lower Trapezius?
spinous processes of T6-T12
What is the insertion of Lower Trapezius?
root of spine of scapula
What is the action of Lower Trapezius?
depression, retraction, upward rotation of scapula
What is the innervation of Lower Trapezius?
Accessory nerve, C3-4
What is the origin of Levator Scapula?
Transverse processes of C1-4
What is the insertion of Levator Scapula?
Medial, superior border of scapula
What is the innervation of Levator Scapula?
C3, C4
What is the action of Levator Scapula?
Elevtaion and downward rotation of scapula
What is the origin of Rhomboids?
Spinous processes of C7-T5
What is the insertion of Rhomboids?
medial border of scapula
What is the innervation of Rhomboids?
dorsal scapular nerve C4-5
What is the action of Rhomboids?
retraction, elevation, downward rotation of scapula
What is the origin of serratus anterior?
first 8 ribs
What is the insertion of serratus anterior?
Medial border of scapula between superior border of inferior angle
What is the innervation of serratus anterior?
Long thoracic C5-7
What is the action of serratus anterior?
Protraction, upward rotation, depression of scapular
What is the origin of pec major?
clavicular - medial half of clavicle
sterno - sternocostal cartilage 1-6
What is the insertion of pec major?
lateral lip of intertubercular groove
What is the innervation of pec major?
lateral and medial pectoral nerve, C5-T1
What is the action of pec major?
C - GH flexion rest to 60 degrees
ADD
IR
S - GH extension 180-90
Horizontal ADD
Scapular depression
Scapular protraction
What is the origin of pec minor?
ribs 3-5
What is the insertion of pec minor?
Coracoid process
What is the action of pec minor?
Medial pectoral nerve (C8, T1)
What is the innervation of pec minor?
Scapular depression, protraction, downward rotation