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Anatomy > Postterior Forearm And Hand > Flashcards

Postterior Forearm And Hand Flashcards

1
Q

Extensor retinaculum

A

Thickening of investing fascia of forearm to hold extensor tendons in place across back of wrist

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2
Q

T/F Fibrous digital sheaths, osseofibrous tunnels, and synovial tendon sheaths are present on the Dorsum of the digits

A

F, they are absent on the dorsum

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3
Q

Posterior muscle group of forearm

A

. Radiodorsal, extensor, or extensor/supination group
. All innervated by radial nerve
. Divided into superficial and deep layers

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4
Q

Superficial layer of posterior forearm muscle group location

A

. Most superficial layer of extensor muscles of forearm and hand
. Originate from lat. epicondyle (common extensor origin) and lat. supracondylar ridge

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5
Q

Deep posterior forearm muscle group location

A

. Deep layer of extensor muscles of forearm and hand

. Originate from post. Aspect of radius, ulna, and interosseous membrane in between

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6
Q

Superficial layers of posterior muscle group from lateral to medial

A 
. Brachioradialis
. Extensor carpi radialis longus
. Extensor carpi radialis brevis
. Extensor digitorum 
. Extensor digiti minimi (quinti)
. Extensor carpi ulnrius 
. Anconeus
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7
Q

Brachialis OIA

A

O: Lateral supracondylar ridge of humerus
I: Distal end of the radius near the styloid process
A: Flexes the forearm, partially supinates from a fully pronated position.

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8
Q

Extensor carpi radialis longus OIA

A

O: Lateral supracondylar ridge
I: Base of second metacarpal
A: Extends and abducts the hand. Weakly flexes the forearm.

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9
Q

extensor carpi radialis brevis OIA

A

O: Lateral epicondyle of the humerus (common extensor origin)
I: Base of third metacarpal
A: Extends and weakly abducts the hand. Like all muscles attaching to the lat. epicondyle, it assists in extending the forearm

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10
Q

Extensor digitorum OIA

A

O: Lateral epicondyle
I: Tendons go to digits II, III, IV, and often V. Each tendon inserts on the base of prox. phalanx, and splits into central band to the base of middle phalanx and two side-bands (collateral bands) to the base of the distal phalanx.
A: Extends the MCP joint, and PIP and DIP joints, assists in extending hand and forearm

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11
Q

Extensor tendon assembly

A

. Tendons of interosseous and lumbrical muscles unite w/ central band and side bands
. Aponeurotic sheet unites these tendons over prox. Phalanx and MCP joint
. Sagittarius band passes on each side of MCP joint and attaches to palmer side of capsule

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12
Q

Sagittal band function

A

. Hold extensor digitorum (ED) tendon in place preventing bowstringing during full extension and hyperextension of MCP joint

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13
Q

Extensor expansion

A

. Triangular in nature and called “the wing”

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14
Q

What occurs when MCP joint extends beyond 180 degrees?

A

. ED can’t overcome passive resistance of long digital flexors (FDS and FDP) so PIP and DIP go into flexion

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15
Q

How to extend IP joints when MCP is extended over 180 degrees?

A

. Requires lumbricals and interossei

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16
Q

MCP

A

Metacarpophalangeal joint

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17
Q

DIP

A

Distal interphalangeal joint

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18
Q

PIP

A

Proximal interphalangeal joints

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19
Q

Extensor digiti minimi OIA

A

O: Lateral epicondyle
I: Joins ED tendon of little finger
A: Same actions as ED but only for digit V

20
Q

Extensor carpi ulnaris

A

O: Lateral epicondyle and posterior
border of the ulna
I: Base of fifth metacarpal
A: Extends and adducts wrist.
Assists in extending the forearm

21
Q

Anconeus OIA

A

O: Posterior side of the lateral epicondyle
I: Lateral side of the proximal part of the ulna, including the olecranon process
A: Assists triceps in extending the forearm. Stabilizes the elbow joint. Abducts
the ulna during pronation.

22
Q

Deep layer of posterior muscle group of forearm

A 
. Supinator
. Abductor pollicis longus 
. Extensor pollicis brevis 
. Extensor pollicis longus 
. Extensor indicis
. Anatomical snuff box
23
Q

supinator OIA

A

O: Lateral epicondyle, radial collateral ligament of the elbow, and lateral side of
the proximal part of the ulna
I: Spirals around the proximal part of the radius to insert on its posterior, lateral,
and anterior sides
A.Supinates forearm by swiveling radius; less powerful supination than biceps
brachii unless forearm is extended.

24
Q

Outcropping muscles

A

. All originate on post. Side of interosseous membrane and adjacent parts of the radius and/or ulna
. Tendons emerge (outcrop) btw tendons of superficial muscles
. Abductor pollicis longus
. Extensor pollicis brevis
. Extensor pollicis longus
. Extensor indicis

25
Q

Abductor pollicis longus IA

A

I: Base of the first metacarpal, laterally
A: Abducts and extends the first carpometacarpal (CM) joint and abducts the
hand

26
Q

Extensor pollicis brevis IA

A

I: Base of the first metacarpal, laterally
A: Abducts and extends the first carpometacarpal (CM) joint and abducts the hand

27
Q

Extensor pollicis longus

A

I: Base of the distal phalanx of the thumb
A: Extends all joints of the thumb (CM, MCP, and IP). Also extends the hand.

28
Q

Tendon location of extensor pollicis longus

A

. Bends around dorsal tubercle of radius

29
Q

Extensor indicis IA

A

I: Joins ED tendon to index finger.
A: Same actions as ED but only on digit II

30
Q

Anatomical snuff box

A

. Depression btw tendons of extensor pollicis brevis and longus
. Fractured scaphoid is tender here
. Radial artery passes through but pulse difficult to detect bc of tough overlying fascia

31
Q

T/F When other MCP joint are kept from extending, you can still easily extend the index and pinkie finger, but not digits III or IV

A

T

32
Q

Intertendinous connections btw ED tendons

A

. On back of hand, restrain adjacent tendons

. Exist on both sides of digits III, IV, but on 1 side of digits II and V

33
Q

T/F Index and little fingers have their own private extensor muscles

A

T, EI and EDM

34
Q

Besides ED intertendinous connections, what other connections are there to restrain separate extension of digits

A

Intertendinous connections btw tendons of flexor digitorum profundus to digits III, IV, and V
. Connections proximal to wrist

35
Q

Deep transverse metacarpal ligaments

A

. Restrain adjacent digits

. On both sides of digits III and IV but only one side of II and V

36
Q

Radial Nerve

A

. Gives off post. Cutaneous nerve of forearm
. Passes ant. To lat. epicondyle of humerus hidden by brachioradialis
. Innervates anconeus, brachioradialis, and extensor radialis longus
. THen splits into 2 terminal branches

37
Q

Terminal branches of radial nerve and what they supply

A

. Superficial radial nerve: supply skin on dorsum of hand laterally
. Deep radial nerve: penetrates supinator and supplies all other dorsal forearm muscles, called post. Interosseous n. Once emerges from supinator

38
Q

What happens if posterior muscle group of forearm is denervated?

A

. Reduced strength for any movements they take part in and graduallay atrophy
. other muscles can perform these actions and will hypertrophy to compensate
. Contracture deformity

39
Q

What occurs if cutaneous nerve supply around post. Muscle group is affected?

A

. Reduced skin sensation in area supplied
. No total anesthesia bc of overlapping distributions
. If major nerve is cut there could be total anesthesia

40
Q

What occurs when radial nerve is severed in distal brachium?

A

. Inability to extend hand and MP joints
. Weakened supination, ad/abduction of wrist
. Eventual flexion deformity wrist and MP joints and adduction deformity of wrist
. Atrophy of post. Forearm
. Reduced skin sensation down post. Side of forearm, some areas total anesthesia
. No loss of extension

41
Q

Posterior interosseous artery

A

. Major source of blood to dorsal forearm muscles

. Courses w/ post. Interosseous n. Distal to supinator muscle on post. Aspect of forearm

42
Q

Blood pathway to forearm

A

. Ulnar artery -> common interosseous artery -> ant. And post. Interosseous a.

43
Q

Dorsal carpal arch

A

. Formed by branches of radial and ulnar aa. On dorsum of hand
. Gives off branches to dorsum of hand and digits

44
Q

Radial artery

A

. Passes through anatomical snuffbox on hand and ends as deep palmer branch (to deep palmer arterial arch) and branch to dorsal side of index finger

45
Q

Lat. epicondylitis

A

. Tennis elbow
. Repetitive use injury from excessive use of superficial extensor muscles of forearm
. Causes inflammation of periosteum of lat. epicondyle at origin of sup. Extensor muscles
. Pain conveyed by radial n.
. Radiates inf. From lat. epicondyle down post. Aspect of forearm

46
Q

Mallet/baseball finger

A

. Avulsion of insertion of extensor tendon on distal phalanx
. Caused by forceful flexion of DIP while finger is being extended
. Person can extend all joints except for DIP which remains flexed

47
Q

Synovial cyst of wrist

A

Cysts of mutinous fluid (ganglion)
. Nontender swellings that appeal on hand (usually dorsal aspect of wrist)
. Synovial sheaths can communicate w/ synovial cysts

Anatomy (49 decks)

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