Forearm and Hand Flashcards
carpi
wrist
pollicis
thumb
digitorum
digits 2-5
indicis
digit 2
digiti minimi
digit 5
extrinsic hand muscle have muscle bellies located where?
in the forearm
extrinsic muscle provide what to movements?
strength
intrinsic hand muscles have muscle bellies located where?
in the hand
intrinsic muscle provide what to movements?
precision
the median nerve innervates which muscles of layer one of the flexor forearm? what are their actions?
pronator teres (pronates) flexor carpi radialis (abducts wrist) radial deviation palmaris longus (flexes)
the ulnar nerve innervates what muscle of layer one? what movement does it perform?
flexor carpi ulnaris? flexion and adducts the wrist
how many muscles are in layer 2 of the flexor forearm? what are its actions? what digits are covered? what nerve innervates it?
- flexor digitorum superficialis
flex the elbow, wrist, cmc, mcp, pip joints
median nerve
what muscles make up layer 3 of the flexor forearm?
flexor pollicis longus
flexor digitorum profundus
what innervates the flexor pollicis longus?
median nerve
what innervates flexor digitorum profundus?
digits 2&3 median nerve
digits 4&5 ulnar nerve
what muscle is in layer 4 of the flexor forearm? where does pronation occur? what nerve innervates it?
pronator quadratus
pronation occurs at radioulnar joints
innervated by median nerve
what forms the roof of the carpal tunnel
flexor retinaculum
what structures travel through the carpal tunnel?
flexor digitorum tendons (8) (flexor digitorum superficialis and profundus) flexor pollicis longus (1) median nerve (1)
inflammation of synovial sheath cause median nerve entrapment- this is called?
carpal tunnel syndrome
what are the three muscle compartments of the extensor forearm? what nerve are they innervated by? the tendons traveling into the hand are held against bone by what?
lateral, medial , deep
all innervated by radial nerve
tendons traveling into hand are held against bone by extensor retinaculum
what are the three muscles in the lateral group of the extensor forearm? what movements do they do?
brachioradialis (supination and pronation)
extensor carpi radialis longus (abduct wrist)
extensor carpi radialis brevis (abduct wrist)
*all flex the elbow
extensor carpi muscles cross and extend wrist
why do the lateral muscles of the extensor forearm flex the the elbow instead of extend?
they cross anterior to the transverse axis of the elbow
brachioradialis muscle is the handshake muscle, why?
it supinates and pronates
pronates a supinated forearm, supinates a pronated forearm
what are the medial muscles of the extensor forearm? what is their action? what happens when tendons reach the hand?
extensor carpi ulnaris- extends the elbow and the wrist (aDducts wrist)
extensor digitorum
extensor digiti minimi
*tendons from extensor hoods/ expansions
can the extensor digitorum and extensor digiti minimi fully extend pip and dip joints?
No
-they need help from the intrinsic hand muscles
what are the deep muscles of the extensor forearm?
supinator extensor indicis abductor pollicis longus extensor pollicis brevis extensor pollicis longus
what movement do the abductor pollicis longus, extensor pollicis brevis and extensor pollicis longus?
extensor pollicis longus travels posterior to the transverse axis so it extends the wrist
abductor pollicis longus, extensor pollicis brevis cross the wrist anterior to the transverse axis so they flex the wrist
*abduct the wrist
what makes up the anatomical snuffbox?
abductor pollicis longus
extensor pollicis brevis
extensor pollicis longus
what artery travels through the snuffbox?
radial artery
the dorsal hand has no? what does it have instead?
intrinsic muscles in the dorsum of the hand
extensor retinaculum, tendons, hood
what crosses CMC and MCP joints of digit 1 and is innervated by the median nerve?
Thenar eminence
what muscles are in the thenar eminence?
Flexor pollicis brevis
abductor pollicis brevis
opponens pollicis
what crosses the CMC and MCP joints of digit 5 and is innervated by the ulnar nerve
Hypothenar eminence
what muscles are in the Hypothenar eminence?
abductor digiti minimi
flexor digiti minimi
opponens digiti minimi
what is a muscle that is not a part of the Thenar eminence but it also moves the thumb? what is it innervated by?
Adductor pollicis brevis
the ulnar nerve
what do lumbricals originate from? what are they innervated by?
originate from tendons of flexor digitorum profundus
lumbricals 1&2- median nerve
lumbricals 3&4- ulnar nerve
what are the deepest muscles in the palmar hand?
Dorsal and palmar interossei
the dorsal and palmar interossei cross what joints? what is the midline? What nerve innervates it?
Cross MCP joints
digit 3 is midline
and innervated by ulnar nerve
Dorsal interossei perform what action
abduct
the palmar interossei
adduct
lumbricals and interossei have commonalities what are they?
both lumbricals and interossei insert on extensor hood
cross anterior to MCP joints, flex MCP joints
pulls tense extensor hood.
the only way to fully extend PIP and DIPs is
the lumbricals and interossei muscle tense extensor hood. Since the extensor hood is posterior to PIP and DIP joints, they extend pip and dip joints
the ulnar nerve travels through which canal?
Guyon’s canal
damage to the ulnar nerve can result in?
sensory loss to digits 4&5
“claw hand”
Damage to the ulnar nerve can cause claw hand. How?
loss of all interossei and two lumbricals.
digits 4&5- hyperextended MCP, flexed PIP and DIP
what branches off of the ulnar artery?
common interosseous artery
which artery is more superficial? Radial or ulnar?
radial
in the hand the ulnar becomes? what branches from it
the superficial palmar arch
common digital artery which birfucates into the proper digital arteries `
the radial artery wraps around the thumb and travels through the snuffbox? what artery does it become?
deep palmar arch
true or false: there is an anastomoses between arches and arteries in the hand?
true
damage to the hypothenar can cause? What helps prevent full occlusion?
hypothenar hammer injury- (damaged and occluded ulnar artery)
the radial artery and anastomosis prevent full occlusion.
When abducting the arm fully through 180°, how much of the elevation is due to movement of the glenohumeral (shoulder) joint, and how much is due to rotation of the scapula?
Abduction of the arm is actually a fairly complex process. During the first 30° of abduction, only the glenohumeral joint is in motion, caused first by the supraspinatus primarily (0°-15°) and then by the deltoid. From about 30° to 120°, both the glenohumeral joint and the scapula are moving such that for every 3° of abduction, 2° are contributed by glenohumeral movement and 1° by scapular rotation. From 120° to 180°, abduction results exclusively from rotation of the scapula (the greater tubercle of the humerus bumps against the acromion at about 120°).
