Joints of shoulder girdle Flashcards
Classify the sternoclavicular (SC) joint
Synovial saddle joint, with fibrocartilaginous intra-articular disc
Capable of 3 degrees of freedom:
1- protraction/retraction
2- elevation/depression
3- MR/LR
State the structures that are involved in the SC joint articulations
consists of sternal end of the clavicle, the clavicular notch of the manubrium of sternum and the superior surface of the first costal cartilage.
The joint is separated into two compartments by a fibrocartilaginous articular disc; increasing congruence of articulations
Briefly describe the articular surface of the clavicle with the manubrium
clavicular and sternal joint surfaces are convex and concave, respectively in the vertical plane; Clavicular surface is slightly concave while that of the sternum is convex in the horizontal plane, thus forming a saddle joint.
Congruence improved by fibrocartilaginous intra-articular disc
inferior aspect of both the clavicle and sternum, as well as the intervening joint space, rest on the first costal cartilage.
larger clavicular articular surface than that of the sternum, projecting above the upper margin of the manubrium
All articular surfaces covered in fibrocartilage
List the ligaments of the SC joint
Intercapsule - Anterior and posterior sternoclavicular, interclavicular ligament
Extracapsule- Costoclavicular ligament.
Classify the acromioclavicular (AC) joint
Synovial Plane
3 degrees of freedom- passive movements
State the structures that are involved in the AC joint articulations
Small oval facets on lateral end of clavicle and medial acromial process of scapula
joint cavity is partially divided by an fibrocartilaginous intra-articular disc - suspended from the upper part of the capsule.
Briefly describe the articular surface of the clavicle with the acromion
between the acromial (lateral) end of clavicle and the clavicular facet of the acromion of scapula. The clavicular articular surface is oval and slightly convex while the acromial surface is accordingly concave. Both articular surfaces are covered with fibrocartilage.
List the ligaments of the AC joint
Intercapsule - superior & inferior acromioclavicular ligaments - runs horizontally from the acromion to the lateral clavicle. Superior AC ligt covers the joint capsule, reinforcing its superior aspect.
Extracapsular - Coracoclavicular ligament - trapezoid, conoid lgts
State attachments of AC joint capsule
Loose fibrous capsule attached to articular margins reinforced by superior & inferior acromioclavicular ligaments
Synovial membrane lines all non articular surfaces
Partial fibrocartilaginous disc attached to superior capsule
State attachments and role of coracoclavicular ligament
Origin: root of coracoid process
Extends superiorly
Inserts:
(Trapezoid lig) trapezoid line of clavicle
(Conoid lig) conoid tubercle of clavicle
Function to support AC joint capsule, limit anteroposterior movement of clavicle and medial displacement of acromion under clavicle in laterally directed forces to shoulder
State attachments of SC joint capsule
Strong Fibrous capsule attached to articular margins of clavicle and sternum extending inferiorly onto upper surface of first costal cartilage
thickened on its anterior and posterior aspects (anterior/posterior SC ligs) but loose superiorly (interclavicular lig) and inferiorly (costoclavicular lig)
Complete intra articular fibrocartilaginous disk attached to capsule dividing joint into two separate compartments; also attaches to posterosuperior border of sternal end of clavicle and sternal end of first costal cartilage
Synovial membrane lines each compartment
State attachments and role of interclavicular ligament
spans medial ends of clavicle and jugular notch
strengthens the superior aspect of the SC joint capsule
State attachments and role for costoclavicular ligament
attaches from costal cartilage of rib I to inferomedial end of clavicle
reinforces the inferior aspect of the SC joint, acting to limit clavicle elevation and anteroposterior movement
Classify the scapulothoracic junction
Articulation between scapular and thorax but not a joint
