Joints of upperlimb

Question 1

Sternoclavicular joint (type, axis)

Articular surfaces covered with …

Ligaments

Movements

Blood supply

Nerve supply

Answer 1

Ball & socket (spheroidal) by definition but functionally its limited + articular disc
3 axes joint that produces rotation and Circumduction.
Fibrocartilage

: Establishes the strength of the SC joint
 Anterior + Posterior sternoclavicular ligaments.
 Interclavicular ligaments.
 Costoclavicular ligaments- (Limits the elevation of pectoral girdle).

• Movements of the joint:
   Elevation / Depression (along saggital axis) (~60º)
   Forward and backward rotation of clavicle (along transverse axis)
   Protraction / Retraction (along vertical axis) (~30º)
   Circumduction (produced from both movements above)

Blood supply: internal thoracic artery, suprascapular artery.
- Nerve supple: supraclavicular n. branch.

Question 2

Acromioclavicular joint

type, axes, articular disc, ligaments, movements, blood, nerve

Answer 2

Plane type of joint that functions as a very limited Ball & socket (spheroidal).
3 axes of movement, Mobility at the AC joint allows the scapula to move in
three dimensions so that it follows the contours of the ribcage. After all, the
scapula must move on the ribcage, and the ribcage is not flat!
- The joint contains an incomplete articular disk.
- Articular surfaces covered with fibrocartilage, joint capsule is relatively loose,
attached to the margins of articular surfaces. Synovial membrane lines the
fibrous layer.
- Ligaments:  Acromioclavicular ligament: strengthens superiorly.
 Coracoclavicular ligament: strong pair of bands:
- Vertical Conoid ligament (triangle shaped).
- Horizontal Trapezoid ligament.
Also provides passive suspension of scapula and free limb from
clavicle and prevents dislocation.
 Coracoacromial ligament (belongs also to glenohumarl joint).

• Movements of the joint: The scapula moves around each of the three acromioclavicular
  axes:
   The scapula Protracts & Retracts (Wings) around a vertical axis
   The scapula can be Elevated & Depressed in a Frontal plane
   The scapula tips around a transverse axis.
   The scapula rotates upward or downward around saggital axis through the
  joint’s capsule.
• Blood Supply: Suprascapular and thoracoacromial arteries.
• Nerve Supply: Supraclavicular and Axillary nerves

Question 3

Glenohumeral Joint

type, axes, articular disc, ligaments, movements, blood, nerve

Answer 3

• Ball & socket type of joint
• Fibrocartilage glenoid labrum (lip): around the margins of glenoid cavity, deepens and
  enlarges the shallow cavity. Hylaine cartilage covers the articular surfaces.
  Ligaments:  Coracohumeral ligament: strengthens superiorly.
   Glenohumeral ligaments: 3 fibrous bands, strengthens the caspule
  anteriorly.
   Transverse humeral ligament: hold the tendon of long head of biceps
  inside the intertubercular sulcus.
   Coracoacromial ligament: forms the coracoacromial arch together
  with the acromion and coracoid process.
  Extremly strong extrinsic protective arch above the head of humerus,
  preventing superior dislocation (like when standing on a desk with your
  arms pushing it).
• Movements: free moving joint, 3 axes:
   Anteversion / Retroversion (Anteflexion / Retroflextion) along transverse axis.
   Abduction / Adduction along saggital axis.
   Outward (lateral) / Intward (medial) Rotation along vertical axis.
   The combination of these 3 types of movements produces circumduction.
  Blood supply: Anterior and Posterior circumflex humeral arteries.
• Nerve supple: Suprascapular, Axillary and lateral pectoral nerves.

Question 4

So the weakest point in the glenohumeral joint

Answer 4

So the
weakest point in the joint is inferiourly, a location where the dislocation of the head of
humerus occurs the most.