7. Upper Extemitry Skeleton Flashcards
Why are upper and lower limbs serial homologues?
Because early in tetrapod evolution, forelimbs and hind limbs developed from similar processes
Hence they have similar bone structure but different function
How does limb development occur?
Limbs initially develop in neutral position
Upper limbs rotate 90 degrees laterally
Lower limbs rotate 90 degrees medially
Upper extremity consists of
Pectoral girdle and upper limb
Pectoral girdle consists of
Scapula and clavicle
Upper limb consists of
Humerus, radius & ulna, carpals, metacarpals, and phalanges
Description of clavicle
“Strut” between sternum and scapula that is the only bony attachment for the upper extremity
Parts of the clavicle
Sternal end and acromial end
Movements of the scapula
Biaxial: elevation/depression and abduction/adduction
Where does the glenohumeral joint connect
Between head of the humerus and glenoid fossa of the scapula
Characteristics of glenohumeral joint
Ball and socket joint that has multiaxial movement and is considered the most mobile joint in the body
Surrounded by ligaments and rotator cuff muscles
Shoulder movements
Flexion-extension, abduction-adduction, medial rotation-lateral rotation, and circumduction
Characteristics of the elbow joint
Found between trochlea of humerus and trochlear notch of ulna
Hinge joint that is uniaxial and stabilized by muscles and ligaments
Elbow movements
Flexion-extension
Characteristics of the radio-ulnar joint
Proximal and distal articulations
Angular ligament holds head of radius to radial notch of ulna
Allows for pronation-supination
Carpal tunnel
Tunnel created by transverse carpal ligament has muscle tendons travel through with median nerve
Carpal tunnel syndrome
Overuse of muscles in capable tunnel that causes tendons to swell and pinch median nerve, resulting in paresthesia or numbness of lateral hand and weakness in thumb movements
Wrist movements
Radial deviation/ulnar deviation and flexion/extension
Bones in palm
Metacarpals
Bones in fingers
Phalanges
Number of phalanges in thumb and digits
2 in thumb and 3 in digits 2-5
Metocarpo-phalangeal movements
Condylar joint with biaxial movement via abduction/adduction and flexion/extension
Interphalangeal movements
Hinge joint with uniaxial movement via flexion/extension
Some Lovers Try Positions That They Can’t Handle
Scaphoid, lunate, triquetral, pisiform, trapezium, trapezoid, capitate, hamate
