Elbow And Forearm

Question 1

3 joints at elbow

Answer 1

humeroulnar
humeroradial
proximal radioulnar joint - not involved in flex. or ext. but passively moves

Question 2

where does humerus articulate

Answer 2

with the forearm bones - laterally with radius at the rounded capitulum and medially with ulna bone at the trochlea

Question 3

epicondyles on distal end of the humerus

Answer 3

theres a medial and a lateral epidcondyle
located proximal to the capitulum and trochlea
sites muscle attachment

Question 4

components of the proximal end of the ulna

Answer 4

trochlear notch
2 processes:
larger process is called olecranon and is posterior - elbow prominence
smaller process is the coronoid process which is anterior

Question 5

describe the distal end of the ulna

Answer 5

head is anterior and articulates with the radius
styloid process is posterior and medial - wrist ligaments
does not articulate with carpal bones - fibrocartilaginous ligament prevents this
ulnar articulates with radius instead

Question 6

describe the proximal end of the radius

Answer 6

head of radius articulates with capitulum of humerus and radial notch of ulna
radial tuberosity is where biceps attach - medial

Question 7

describe the distal end of the radius

Answer 7

articulates with ulna and proximal carpal bones
styloid process laterally - wrist ligaments attach
ulnar notch medially

Question 8

humeroulnar joint function and structure

Answer 8

trochlea of humerus with trochlear notch of ulna
flexion and extension - ulnar processes limit range of motion
no pronation or supination
reinforced by ulnar collateral ligament

Question 9

humeroradial joint function and structure

Answer 9

capitulum of humerus with radius head
lateral
reinforced radial collateral ligament
supination/pronation

Question 10

flexors of the arm

Answer 10

biceps brachii
coracobrachialis
brachialis

Question 11

structure of biceps brachii

Answer 11

2 heads attach to scapula:
long head - tubercle superior to glenoid cavity
short head - coracoid process of scapula
both heads converge to make a tendon which inserts onto the radial tuberosity on radius - gives off bicipital apneurosis which attaches biceps indirectly to posterior border of ulna
muscle bellies lie over coracobrachialis
innervated by musculocutaneous nerve

Question 12

actions of biceps brachii

Answer 12

powerful flexor at shoulder and elbow
supinator at radioulnar joints when elbow is fixed
short head flexes shoulder
long head holds humerus against glenoid cavity especially if arm abducted

Question 13

structure and function of coracobrachialis

Answer 13

attachments - coracoid process of scapula - inserts on medial humerus
actions - flexes shoulder and weak adductor
innervated by musculocutaneous nerve

Question 14

structure and function of brachialis

Answer 14

attachments - anterior surface of distal humerus - across elbow to coronoid process ulna
actions - flexes elbow
innervated by musculocutaneous nerve

Question 15

extensors of arm

Answer 15

triceps

anconeus

Question 16

triceps attachments and innervation

Answer 16

long head - infraglenoid tubercle of scapula
lateral head - superior, posterior humerus
medial head - posterior humerus distal to groove for radial nerve
long and lateral fuse and join on deep surface by medial - form common tendon which inserts into superior olecranon of ulna and deep fascia
innervation - radial nerve

Question 17

anconeus attachments and innervation

Answer 17

attachments - lateral epicondyle of humerus and posterior olecranon of ulna
innervation - radial nerve

Question 18

anconeus function

Answer 18

extends elbow and has a role in pronation

Question 19

describe forearm rotation

Answer 19

at radioulnar joints
radius rotates, proximal ulna stays in place - around axis from radius head to ulna styloid process
independent and below shoulder and elbow

Question 20

describe the wrist during pronation

Answer 20

palm turned posteriorly
proximal radius lateral to ulna
distal radius medial to ulna

Question 21

describe the wrist during supination

Answer 21

palm turned anteriorly

radius lateral and parallel with ulna

Question 22

describe the superior radioulnar joint

Answer 22

associated with elbow - joint capsule and synovial membrane are continuous with that of elbow joint
pivot joint between head of radius and the osseofibrous ring (radial notch of ulna and annular ligament)
radius rotates in pronation/supination
radial annular ligament = strong fibres, encircles head of radius

Question 23

describe the inferior radioulnar joint

Answer 23

pivot synovial joint - head of ulna and ulnar notch of radius
held together by an articular disc and the interosseous membrane

Question 24

describe the membrane between the radius and ulna

Answer 24

interosseous membrane = broad thin fibrous tissue separating bones
pronation to supination = fibres change from relaxed to tense in the neutral position - relax once forearm supinates
forms the radio-ulnar syndemosis = fibrous joint between r and u
divides forearm into anterior and posterior
site of attachment for muscles of forearm

Question 25

what happens during dislocation or subluxation of the radial head

Answer 25

dislocation or subluxation if jerked by UL when forearm pronated tears distal attachment of annular ligament radial head moves distally out

Question 26

supinator muscles

Answer 26

biceps brachii and supinator

Question 27

supinator attachments

Answer 27

origin - 2 heads: deep head - supinator crest of ulna superficial head - lateral epicondyle of humerus insertion - lateral proximal radius

Question 28

pronation muscles

Answer 28

pronator teres and pronator quadratus

Question 29

pronator teres attachments

Answer 29

origin - 2 heads: superficial - medial epicondyle of humerus deep - medial of coronoid process ulna insertion - crosses the forearm and attaches to middle of shaft of radius

Question 30

structure of the cubital fossa

Answer 30

an important transition between arm and forearm concavity - anterior to elbow joint triangular depression that is bound by the brachioradialis laterally and the pronator teres medially brachial artery enters base of fossa and leaves as radial and ulnar arteries median nerve runs through radial nerve laterally if brachioradialis retracted

Question 31

2 layers of forearm muscle

Answer 31

superficial: long muscles - humerus to hand (act on elbow and wrist) and humerus to digits (act on elbow, wrist and digits) deep: arise from forearm bones and pass to digits - crossing and acting on wrist and digit joints

Question 32

anterior superficial muscles of the forearm

Answer 32

``` pronator teres flexor carpi radialis palmaris longus flexor capi ulnaris flexor digitorum superficialis ```

Question 33

posterior superficial muscles of the forearm

Answer 33

``` extensor carpi brevis extensor digitorum extensor digiti minimi extensor carpi ulnaris brachioradialis extensor carpi radialis longus anconeus ```

Question 34

anterior deep muscles of the forearm

Answer 34

flexor pollicis longus flexor digitorum profundus pronator quadratus

Question 35

posterior deep muscles of the forearm

Answer 35

extensor indicis extensor pollici longus extensor pollicis brevis abductor pollicis longus