Shoulder APTA (1) Flashcards
What kind of joint is the GH joint?
- triaxial synovial joint
What is the angle of inclination of the humerus?
- angle of the head relative to the humeral shaft
- 130*
What is considered “normal” alignment between the head of the humerus and the shaft in the transverse plane? What is the range of what can be normal?
- angled 30* posteriorly (retroversion)
- anywhere from -6.7 to 47.5* per one study
What is the orientation of the glenoid fossa relative to the scapula?
- slight lateral rotation (7*)
- slightly posteriorly oriented
- slight superior angulation (5*)
What type of tissue is the labrum made of?
- fibrocartilage
What two aspects of the labrum help improve stability for the GH joint?
- deepens the fossa
- creates intraarticular vacuum with the capsule which also helps stability
Where are the attachment points of the GH joint capsule?
- the glenoid neck and labrum
- anatomical neck of the humerus, except inferomedially where it extends a slight ways down the humeral neck
What are the two openings to the GH joint capsule?
- between the humeral tubercles, allowing the biceps tendon to exit the joint
- connection between the joint and the subscapularis bursa
Most extracapsular ligaments are where relative to the GH joint?
- superior and anterior
The superior GH ligament resists what motion, when the arm is in which position?
- restrains inferior translation
- when the arm is in an adducted position at the side
Tears or damage to the superior capsule may result in increased translation in which direction(s)?
- anterior and inferior
The middle GH ligament resists what motion, when the arm is in which position?
- anterior humeral translation when the arm is abducted up to ~45*
- external rotation when the arm is at the side
Describe the orientation and makeup of the inferior GH ligament.
- expansive band of tissue in the inferior capsule with thickened anterior and posterior portions
What is the general function of the inferior GH ligament?
- anterior and posterior bands work in conjunction to limit anterior translation when the GH joint is abducted to 90*
- during ER and abduction, the anterior band wraps around the front of the GH joint and limits anterior translation
- during IR, posterior band wraps around and limits posterior translation
How far from the vertebrae is the medial (vertebral) border of the scapula in a neutral position?
- ~5 cm
The scapula spans which levels of the thoracic spine?
- 2nd superiorly
- 7th inferiorly
The plane of the scapula is rotated ~ ___ to ___ from the coronal plane.
- ~30* to 45*
What is the neutral orientation of the scapula relative to vertical?
- 10-20* superiorly
- 10-20* anteriorly
The only skeletal articulation between the axial region and the appendicular upper limb occurs: ____
- at the sternoclavicular joint
The most important ligament at the SC joint is likely the _______. What movements does it limit?
- posterior sternoclavicular ligament
- limits anterior and posterior translations
What is thought to be the function of the interclavicular ligament?
- restrains inferior forces on the medial clavicle
T or F;
The disc in the AC joint becomes degenerated early in life.
- T
Describe the structure of the AC joint.
- synovial planar joint with 3 degrees of freedom
- has a joint capsule, and a disk/meniscus that isn’t well understood
What two ligaments add stability to the AC joint?
- Conoid
- coracoclavicular (trapezoid)