Development, Joints Flashcards
Germ layers of the arm
NO endoderm
Ectoderm: skin and nerves
Mesoderm: Somites -> muscles
Lateral plate mesoderm: bones, connective tissue
Apical Ectodermal Ridge
signals growth proximal/distally
Zone of Polarizing Activity
Expressed in caudal part of limb
Signals development of the ulna and fingers 4-5
Dorsal/ventral differentiation
From interaction of dorsal and ventral ectoderm
Compartments
Anterior divisions of brachial plexus innervate anterior compartment muscles
Posterior divisions of brachial plexus innervate posterior compartment muscles
Limb rotation
Upper limb rotates 90 degrees laterally
Repositions elbow
(Lower limb rotates medially)
Types of synnovial joints
Hinge, pivot, condyloid, saddle, ball and socket, plane
Sternoclavicular joint
Ball and socket (functions as a saddle)
Really strong, almost never dislocates
Anterior/posterior sternoclavicular ligaments
Disc helps cushion joint (LOTS of force on it)
Acromioclavicular joint
Plane
Acromioclavicular, coracoclavicular, coracoacromial ligaments
Not as strong as sternoclavicular, tends to rupture
Glenohumeral joint
Ball and socket
Superior, middle, inferior glenohumeral ligaments
Joint is very mobile but no very stable
Humeroradial joint
Ball and socket (functions as a hinge because of ulna)
Radial collateral ligament
Humeroulnar joint
hinge
Posterior, anterior, transverse ulna collateral ligaments
Proximal radioulnar joint
Pivot
Pronation/supination
Annular ligament holds radius against ulna
Carpals
Proximal row: scaphoid, lunate, triquetrium, pisiform
Distal row: trapezium, trapezoid, capitate, hamate
Distal radio-ulnar joint
Pivot
Interosseous membrane, dorsal and palmar radioulnar ligaments
