muscles of the arm Flashcards
what is the only articulation of the pectoral girdle with the thoracic wall
between clavicle and manubrium
what are the 4 muscles that attach the pectoral girdle to the thoracic wall
pec major
pec minor
subclavius
serratus anterior
what are the 5 muscles that attach the pectoral girdle to the vertebral column
trapezius latissimus dorsi levator scapulae rhomboid major rhomboid minor
origin of pectoralis major
has 2 heads:
- clavicular
- sternocostal
route and insertion of pec major
fibres converge towards insertion onto the proximal humerus
- as they converge the clavicular head fibres overlap the sternocostal fibres)
function of pec major
adductor
medial rotation
accessory muscle of inspiration
route of subclavius muscle
passes laterally from anteromedial part of first rib to inferior surface of clavicle
function subclavius muscle
stabilises the clavicle
route of pec minor
costal cartilages 3-5 and converge up to the corocoid process
function of pec minor
stabilises the scapula
accessory muscle of inspiration
depression of the shoulder
origin of serratus anterior
lateral aspect of ribs 1-8
route and insertion of serratus anterior
travels posteriorly underlapping the scapula to insert onto the medial border of the scapula
function of serratus anterior
protraction of the scapula
what is the nerve supply of serratus anterior
long thoracic nerve
what happens when the long thoracic nerve is damaged
scapula no longer stays close to the chest wall on protraction = birds wing appearance
what are the 6 muscles that attach the humerus to the scapula
deltoid subscapularis supraspinatus infraspinatus teres minor teres major
which muscles make up the rotator cuff muscles
subscapularis
supraspinatus
infraspinatus
teres minor
nerve supply to deltoid muscle
axillary nerve
origin of deltoid
spine of scapula, acromion and clavicle
insertion of deltion
fibres converge and deltoid tubercle of the humerus
functions of the deltoid
- anterior fibres = flexion
- posterior = extension of the shoulder
- whole muscle together = abductor after initiation by supraspinatus
route of supraspinatus
arises from supraspinous fossa and goes into the superior facet
function of supraspinatus
initiates abduction
route of infraspinatus
arises from infraspinous fossa to middle facet
function of infraspinatus
lateral rotator
route of teres minor
lateral border of the scapula and goes into the inferior facet
function of teres minor
lateral rotator
route of subscapularis
subscapula fossa –> inserts into lesser tubercle of the humerus by passing infront of the shoulder joint
function of subscapularis
stabilser
medial rotator
route of teres major
inferior angle of the scapula and heads towards the proximal humerus just below the lesser tubercle in the bicepital groove
function of teres major
adducts
medially rotates
what are the anterior muscles of the upper arm
coracobrachialis
biceps
brachialis
what are the posterior muscles of the upper arm
only triceps
origin of the 2 heads of bicepts
short head - coracoid process
long head - supraglenoid tubercle of the scapula
insertion of bicepts
fibres of short and long head converge to insert at the radial tuberosity
function of biceps
- when elbow extended - flexor
- when elbow flexed - supernator
what is the rule for superficial muscles
have a proximal origin and a distal insertion
what is the rule for deep muscles
arise from the shaft of the long bone in which they overlie
brachialis origin and insertion
origin - distal half of the anterior shaft of the humerus
insertion - coronoid process of the ulnar
(crosses anterior to the elbow joint)
function of brachialis
flexion
origin and insertion of coracobrachialis
coracoid process above to shaft of the humerus halfway down
function of coracobrachialis
assists in flexon and adduction
origins of the 3 heads of triceps
long - infraglenoid tubercle
lateral - linear attachment of the proximal attachment of the posterior aspect of the humerus
medial - whole of the back of the shaft of the humerus
insertion of triceps
all three heads of triceps converge into the triceps tendon and insert into the alecronon of the ulnar
function of triceps
extensor of the elbow joint
what are the 5 anterior superficial muscles of the forearm
pronator teres flexor carpi radialis palmaris longus flexor dig superficialis flexor carpi ulnaris (from thumb to little finger)
what is the common origin of the 5 superficial muscles of the forearm
anterior aspect of the medial epicondyle of ulnar
route of flexor carpi radialis
heads across to radial side and inserts into the base of the 2nd and 3rd metacarpal
insertion of palmaris longus
blends with the flexor reticinaculum
origin of flexor digitorum superficialis
common flexor origin + both bones of the forearm
insertion of flexor digitorum superficialis
splits into 4 tendons - one for each finger
inserts into either side of the middle phalanges
which forearm muscle makes up the medial side of the forearm
flexor carpi ulnaris
origin of flexor carpi ulnaris
common flexor origin + aponeurotic attachment to the subcutaneous border of the ulnar
insertion of flexor carpi ulnaris
heads for the base of the 5th metacarpal (has pisiform in it)
which 3 muscles of the forearm have their origin from the common flexor tendon + another place
pronator teres
flexor digitorum superficialis
flexor carpi ulnaris
route of pronator teres
diagonally orientated across the front of the forearm and inserts into the midpoint of the shaft of the radius
origin of pronator teres
common flexor origin + medial aspect of coranoid process
what are the 3 deep muscles of the anterior deep forearm
pronator quadratus
flexor digitorum profundus
flexor pollicus longus
route of pronator quadratus
extends across the front of the distal portions of the anterior of the ulnar and radius
origin of flexor digitorum profundus
from the anterior shaft of the ulnar and the adjacent part of the intraosseous membrane
insertion of flexor digitorum profundus
splits into 4 tendons - extends all the way to the distal phalanx (goes between the split of FDS)
function of flexor digitorum profundus
flexor of the wrist
flexor of the distal phalangeal joints
origin of flexor pollicus longus
arises from the shaft of the radius and adjacent part of the intraosseous membrane
insertion of flexor pollicus longus
base of the thumb phalanx
how do the tendons go under the flexor retinaculum
- bottom layer - 4 tendons of flexor digitorum profundus
- middle layer - tendons 2 and 5 of flexor digitorum superficialis
- superficial layer - tendons 3 and 4 of flexor digitorum superficialis
- lateral - flexor polisus longus
attachments of the flexor retinaculum
scaphoid trapezium hook of hamate pisiform (STOP)
which tendon has its own tunnel through the retinaculum
flexor carpi radialis
insertion of flexor carpi ulnaris
base of the 5th metacarpal - pisometacarpal ligament
group of 3 muscles that make up the posterior side of the radial side of the forearm
brachioradialis
extensor carpi radialis longus
extensor carpi radialis brevis
group of 3 muscles that make up the posterior aspect of the forearm
extensor digitorum
extensor digiti minimi
extensor carpi ulnaris
group of 3 muscles of the posterior aspect of the forearm that are deep
abductor pollicis longus
extensor pollicis brevis
extensor pollicis longus
which muscles of the posterior aspect of the forearm have origin from the common extensor origin
extensor carpi radialis brevis
extensor digitorum
extensor digiti minimi
extensor carpi ulnaris
origin of brachioradialis and extensor carpi radialis longus
lateral epicondylar ridge just above the common extensor origin
insertion of brachioradialis
styloid process of the radius
function of brachioradialis
flexor at the elbow
function of extensor carpi radialis longus
extensor
radial deviator
insertion of extensor carpi radialis longus
into the base of the 2nd metacarpal posteriorly
insertion of extensor carpi radialis breviw
into the base of the 3rd metacarpal posteriorly
contraction of which 3 muscles cause radial deviation
flexor carpi radialis
extensor carpi radialis longus
extensor carpi radialis brevis
insertion of extensor digitorum
splits into 4 tendons - then divides into 3
- middle - inserts into the base of the middle phalanx
- lateral and medial - inserts into the base of the distal phalanx
insertion of extensor digiti minimi
5th finger
insertion of extensor carpi ulnaris
base of the 5th metacarpal
function of the extensor carpi ulnaris
extension of the wrist
ulnar deviation
what happens when extensor carpi ulnaris and flexor carpi ulnaris act together
only ulnar deviation
insertion of abductor pollicus longus
base of the 1st metacarpal
insertion of extensor pollicis brevis
inserts into base of proximal phalanx of the thumb
insertion of extensor pollicis longus
goes beneath carpal tunnel and then diverts back to thumb and inserts into the base of the distal phalanx
which two tendons make up the anatomical snuff box
extensor pollicus brevis and extensor pollicis longus
what forms the floor of the anatomical snuff box?
scaphoid
which artery runs through the anatomical snuff box
radial artery
what are the 3 other random muscles on the posterior forearm
aconeus
extensor indicis
supinator
explain the route of apconeus
tends from posterior aspect of lateral epicondyle to posterior aspect of ulnar
what is the route of extensor indicis
runs to the index finger
route of supinator
encircles the proximal shaft of the radius
explain the anatomy of the extensor retinaculum
series of vertical septa that divide the passage for the tendons of the forearm muscles towards the dorsum of the hand into 6 compartments