The hand Flashcards
What are the 3 types of grip?
Power grip
Precision grip
Hook grip
What is a power grip?
The fingers are flexed around an object with counter pressure from the thumb, e.g. grasping a rod.
What muscle groups must be activated to form a power grip?
Long flexors of the fingers and thumb
Intrinsic muscles of the palm
Extensors of the wrist joint (to give more power to the long flexors)
What is a precision grip?
The object is gripped between the tips of the fingers and the thumb, with the intrinsic muscles of the hand carrying out the fine movements needed. Typically, the wrist and fingers are held rigidly by the long flexors and extensors.
e.g. unbuttoning a shirt.
What is the palmar aponeurosis?
A well-defined region of palmar fascia in the hand that overlies the long flexor tendons of the hand.
Proximal end is continuous with flexor retinaculum and palmaris longus tendon.
Distal end forms 4 bands continuous with fibrous digital sheaths of each finger.
What are the fibrous digital sheaths?
Tubes which contain flexor tendons and their sheaths.
What are septa?
Extensions of fascia that separate the space between the palmar aponeurosis and the bones of the hand into compartments.
What are the muscles in the extensor compartment of the forearm that move the digits?
Extensor digitorum (ED) Extensor indicis (EI) Extensor digiti minimi (EDM)
What are the muscles in the extensor compartment of the forearm that move the thumb?
Abductor pollicis longus (APL)
Extensor pollicis brevis (EPB)
Extensor pollicis longus (EPL)
What are the thenar muscles?
Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis
What are the adductor (intrinsic) muscles of the hand?
Adductor pollicis
What are the hypothenar muscles?
Abductor digiti minimi
Flexor digiti minimi
Opponens digiti minimi
What are the actions of the lumbricals?
Flex at the MCPs
Extend at the IPJs
What are the actions of the palmar interossei?
Adduct the digits (PAD)
There are 3.
What are the actions of the dorsal interossei?
Abduct the digits (DAB)
There are 4.
What type of joint is the carpometacarpal joint of the thumb?
Synovial saddle joint. Articulation between the trapezium and the thumb metacarpal- clinically important as it often becomes osteoarthritic.
What type of joints are the carpometacarpal joints of the digits (excluding thumb)?
Synovial elipsoid joints between the trapezoid, capitate and hamate with the metacarpals of the digits.
CMCs of the index and middle fingers are very rigid, that of the ring finger is less rigid and that of the little finger is very mobile.
What type of joints are the intermetacarpal joints?
Plane synovial joints between the metacarpals and their bases.
What movements occur at the carpometacarpal and intermetacarpal joints?
Flexion and extension
Radial deviation and ulnar deviation
Circumduction