Upper Limb Flashcards
The clavicle develops via both intramembranous & endochondral ossification. The medial growth plate is the last in the body to close – approx 23-25 yrs. Why is that useful to know?
- Help identify the age of the skeleton
- To tell if skeletal growth is complete
Describe the plane of the scapula relative to the frontal (coronal) plane of the body:
30-45 degrees
Describe the position of the scapula relative to the thorax:
a) Root of the spine of scapula
b) Inferior angle
a) 3rd rib
b) 7th rib/ intercostal space
State the attachments of the intra-articular disc.
Inferior attachment =
superior attachment =
inferior = cartilage of 1st costal superior = articular surface of clavicle
What is the function of the intra-articular disc?
To enhance joint curvature and contact and to absorb joint forces
Why is rotation of the clavicle termed conjunct rotation?
conjunct rotation occurs as a results of the tightening of a passive structure. During UL abduction the conoid ligament is tightened and causes clavicular rotation
Explain how the conoid ligament produces upward rotation of the clavicle.
What is the advantage of this?
The conoid ligament attaches to the posterior medial part of the clavicle (conoid tubercle), when tightened, the tubercle is pulled towards the coracoid process of the scapular creating upwards rotation. This is advantageous as upwards rotation of the clavicle allows increased rotation of the scapular and this increased GHJ range of motion, through conjunct rotation
the glenoid labrum
• where does it attach?
• what is it made of?
• what are its functions?
attachment: margin of the glenoid cavity
made of: fibrocartilage
functions: to increase articular surface and absorb joint forces
Which tendon attaches to the supraglenoid tubercle and the superior aspect of the labrum and what is a possible consequence of this?
The tendon of the long head of biceps brachii, as a result is can become impinged during GHJ movement
The inferior glenohumeral ligament complex (IGHLC) – has anterior & posterior bands with a loose axillary pouch between them. Why?
The pouch allows extra range of movement when stretched
The transverse humeral ligament is extra-capsular. What is its function?
To hold the tendon of the long head of biceps brachii in place
Which 2 ligaments provide the main resistance to Inferior translation of the humerus when the upper limb is adducted (relaxed standing)?
coracohumeral ligament and superior glenohumeral ligament
The GHJ is the most mobile and most commonly dislocated joint in the body. Anterior-inferior (subcoracoid) dislocation is by far the most common. Which ligament resists anterior / inferior translation of the humeral head on the glenoid when the upper limb is in a position of 90 degrees abduction + external rotation:
anterior band of the inferior glenohumeral ligament complex
Which structures form the coracoacromial arch?
coracoid process of clavicle, acromion process of scapular and coracoacromial ligament
What is the subacromial space?
The space below the coracoacromial arch, which contains the sub-acromial bursa, supraspinatus and long head of biceps brachii tendon
Name the 3 anatomical joints of the shoulder region involved in achieving full (~180 degrees) UL abduction AND state their relative contribution to that movement (in degrees or fractions).
- GHJ > 120 degrees - 2 thirds
- ACJ > 20 degrees
- SCJ > 40 degrees
ACJ & SCJ make up 1 third
What is meant by medial winging of the scapular?
lifting of the medial boarder of the scapular during dynamic movement due to instability
What could cause medial winging of the scapular?
- Muscle weakness:
- Nerve dysfunction:
- Muscle weakness: serratus anterior
2. Nerve dysfunction: long thoracic n. or C5 to C7 trunk
What muscle does the suprascapular nerve innervate?
supraspinatus
infraspinatus
Define varus alignment
distal end is medial compared to the proximal end
Define valgus alignment
distal end is lateral compared to the proximal end
The normal alignment of the humerus and ulna in the frontal plane is
10-15 degrees valgus
The olecranon process of the ulna is an attachment for?
triceps brachii
The ulnar tuberosity of the ulna is an attachment for?
brachialis