Karteikarten
2 The Shoulder
Karten in diesem Stapel (26)
- 11.1 What is the pectoral girdle?A bony ring, incomplete posteriorly, formed by the scapulae and clavicles and completed anteriorly by the manubrium of the sternum
- 21.1 Name a major bone of the pectoral girdle. What two joints are present in the pectoral girdle? What are two functions of the pectoral girdle?Clavicle - connects upper limb to trunk via Sternoclavicular joint
Sternoclavicular joint
Acromioclavicular joint
Keeps arm away from thorax, giving maximum freedom of movement
Keeps arm lateral to rib-cage - 31.1 What comprises the superior appendicular skeleton? Where does this articulate with the axial skeleton and what does this allow? How is the pectoral girdle supported, stabilized and propelled?Pectoral girdle + bones of free part of upper limb
Articulates with the axial skeleton only at the sternoclavicular joint, allowing great mobility
PG supported, stabilized and propelled by axio-appendicular muscles which attach to ribs, sternum and vertebrae of axial skeleton - 41.1 What does a fractured clavicle result from? What happens anatomically? How common is a fractured clavicle?Result of either direct or indirect force
Weight of arm drags lateral fragment inferiorly
Action of sternocleidomastoid pulls medial fragment superiorly
2-5% of adult fractures
Most frequently fractured bone in childhood - 51.1 State three things the clavicle protectsBrachial plexus
Major underlying vessels
Apex of lung - 61.1 Describe the structure of the clavicle in terms of thirds and curvatureMedial two thirds are convex anteriorly
Lateral third is flattened and concave anteriorly
The elongated capital ‘S’ appearance (due to curvature) of the clavicle increases the resilience - 71.1 Describe the structure of the scapula. What is a major structural use? Comment on the two types of surfaces encountered What ends the spine of the scapula?Triangular flat bone on posterolateral aspect of the thorax, overlies 2nd to 7th ribs
Attachment site for many shoulder/pectoral girdle muscles
Convex posterior surface of scapula unevenly divided by spine of scapula into small supraspinous fossa and larger infraspinous fossa
Concave costal surface has large subscapular fossa
Lateral end of spine of scapula – acromion, subcutaneous ‘point of the shoulder’ that articulates with acromial end of clavicle - 81.1 What can be said about the humerus in terms of size and articulationLargest bone in upper limb
Articulates with scapula at glenohumeral joint (head of Humerus articulates with glenoid cavity of scapula) and radius and ulna at elbow joint - 91.1 What is the sternoclavicular joint an articulation of?Synovial articulation between clavicle and manubrium of the sternum and 1st costal cartilage
Strength due to strong ligaments
Only articulation between upper limb and axial skeleton - 101.1 What is the acromioclavicular joint an articulation of? Where is this located?Acromion and clavicle
Located 2-3cm from ‘point of shoulder’
No muscles cross AC joint
Muscles moving scapula apart move AC joint - 111.1 What are six movements of the scapular. What muscles control this movement?Elevation
-Trapezius (descending)
Depression
-Gravity
Protraction
-Serratus anterior
-Pectoralis minor
Retraction
-Trapezius (middle)
Upward rotation
-Trapezius (descending)
-Serratus anterior (inferior)
Downward rotation
-Latissimus dorsi - 121.2 Explain the articulation that results in the glenohumeral jointGlenoid cavity and head of humerus
-Cavity accepts approx. one third of Humerus head, held in cavity by tonus of the musculotendinous rotator cuff
Shallow glenoid cavity deepened by having ring of fibrocartilage – ‘glenoid labrum’
Fibrous joint capsule loose and baggy - 131.2 What restricts large freedom of movement?Laxity of articular capsule
Large humeral head compared to shallow/small glenoid cavity - 141.2 What are the movements at the glenohumeral joint?Flexion-extension
Abduction-adduction
Medial and lateral rotation
Circumduction (combination of all movements) - 151.2 State four ligaments that can be found around the sternoclavicularGlenohumeral ligament
-Evident only on internal aspect of capsule, strengthen anterior aspect
Coracohumeral ligament
-Strong band, passes from base of CP to anterior aspect of greater tubercle, strengthens capsule superiorly
Transverse humeral ligament
Broad fibrous band, runs from greater to lesser tubercle, converts sulcus into canal for tendon of long head of biceps brachii and its synovial sheath
Coraco-acromial ligament
Spans between coraco-acromial arch (extrinsic, protective structure formed by smooth inferior aspect of acromion and CP of scapula) - 161.2 Explain the clinical significance of the dislocation of the glenohumeral jointIndicates Humerus head has descended anterior to infraglenoid tubercle and long head of triceps
Caused by excessive extension and lateral rotation of humerus
Head of Humerus driven infero-anteriorly
Fibrous layer of joint capsule and glenoid labrum may be stripped from anterior aspect of glenoid cavity, making joint weaker
Hard blow to Humerus when glenohumeral joint fully abducted tilts head of humerus inferiorly onto weaker part of
joint capsule
Tears capsule and dislocates joint
Strong flexor and adductor muscles pull humeral head anteriorly
Axillary nerve injury - close relationship to inferior part of glenohumeral joint - 171.3 List the movements of the glenohumeral jointF
- 181.3 Chief flexors and Chief extensors - what muscles produce these movements?Chief flexors
-Pectoralis major (clavicular part)
-Deltoid (anterior part)
-Coracobrachialis assisted by biceps brachii which stabilises the joint
Chief extensors
-Latissimus dorsi
-Deltoid (posterior fibres)
-Teres major
-Long head of triceps brachii helps stabilise the joint - 191.3 Chief abductors and Chief adductors - what muscles produce these movements?Chief abductor
-Deltoid (all parts but especially central fibres)
-1st 10 degrees of abduction initiated by supraspinatus
Chief adductors
-Pectoralis major
-Latissimus dorsi
-Gravity is prime mover - 201.3 Chief medial rotator and Chief lateral rotator - what muscles produce these movements?Chief medial rotator
-subscapularis
Chief lateral rotator
-infraspinatus - 211.3 What are the four rotator cuff muscles?Supraspinatus
Infraspinatus
Teres minor
Subscapularis - 221.3 What do the rotator cuff muscles form?Form musculotendinous cuff around glenohumeral joint blending with articular capsule
-3 attach to greater tuberosity of humerus
-1 attaches to lesser tuberosity of humerus - 231.3 How is the relatively large humeral head held in the shallow glenoid cavity?Tonic contraction
- 241.3 Where is the subacromial bursa located? What does this allow?Located between acromion, coraco-acromial ligament and deltoid superiorly and joint capsule of glenohumeral joint
Allows supraspinatus tendon to move under coraco-acromial arch and deltoid over joint capsule and greater tubercle of humerus - 251.3 Where is the subscapular bursa located? What does this protect?Located between tendon of the subscapularis and neck of scapula
Protects tendon where it passes inferior to root of CP and over neck of scapula - 261.3 What is bursitis also known as? What does it cause?Subacromial bursa inflammation
Causes pain on abduction of arm
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- University Locomotor Karteikarten am 2 The Shoulder, erstellt von Ifeoma Ezepue am 15/01/2016.
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