Thoracic_Limb_Muscle_Attachments_and_Functions

Question 1

superficial pectoral

Answer 1

Origin:

first three sternebrae

median fibrous raphe at the ventral midline

Insertion:

Humerus - greater tubercle (whole crest)

Action:

not weight bearing- adduct limb

weight bearing - prevent abduction

Question 2

deep pectoral

Answer 2

Origin:

ventral part of sternum

median fibrous raphe at the ventral midline

Insertion:

lesser tubercle of the humerus (major portion of insertion)

greater tubercle and crest via aponeurosis

Action:

pull trunk cranially when limb is advanced and fixed

extend shoulder draw limb caudally when not supporting weight

Question 3

brachiocephalicus

Answer 3

Origin:

clavicular intersection

Insertion:

distal end of cranial aspect of the humerus middorsal fibrous raphe of the neck mastoid part of the temporal bone

Action:

advance the limb extend shoulder draw head and neck to the side-

Question 4

omotransversarius

Answer 4

Origin:

wing or transverse process of the atlas (cervical vertebra 1)

Insertion:

distal end of the spine of the scapula

Action:

advance the limb flex the neck laterally-

Question 5

trapezius

Answer 5

Origin:

median fibrous raphe of the neck supraspinous ligament

Insertion:

spine of the scapula

Action:

elevate and abduct limb at the shoulder-

Question 6

rhomboideus

Answer 6

Origin:

base of skull (nuchal crest of occipital bone) median fibrous raphe of neck spinous process of thoracic vertebrae

Insertion:

dorsal border of scapula

Action:

elevate limb draw scapula against trunk-

Question 7

latissimus dorsi

Answer 7

Origin:

thoracolumbar fascia last 2 - 3 ribs

Insertion:

teres major tuberosity of the humerus via the teres major tendon

Action:

draw limb caudally (eg digging) flex shoulder-

Question 8

serratus ventralis

Answer 8

Origin:

ribs transverse processes of cervical vertebrae

Insertion:

-serrated face of the scapula-

Action:

support trunk depress scapula-

Question 9

deltoideus

Answer 9

Origin:

spine and acromial process of the scapula

Insertion:

deltoid tuberosity of the humerus

Action:

flex shoulder-

Question 10

infraspinatus

Answer 10

Origin:

infraspinous fossa of the scapula

Insertion:

lateral side of the greater tubercule of the humerus (small circumscribed area)

Action:

laterally stabilizes the shoulder (prevents medial rotation while weight-bearing) abduct and laterally rotate shoulder assists other muscles in the extension or flexion of shoulder-

Question 11

teres minor

Answer 11

infraglenoid tubercle of the scapula distal caudal border of the scapula -teres minor tuberosity of the humerus-laterally stabilizes the shoulder (prevents medial rotation while weight-bearing) laterally rotate shoulder flex shoulder (assists other muscles) –

Question 12

supraspinatus

Answer 12

supraspinous fossa of the scapula-greater tubercle of the humerus (thick tendon)-laterally stabilizes the shoulder (prevents medial rotation while weight-bearing) extend shoulder-

Question 13

subscapularis

Answer 13

subscapular fossa of the scapula-lesser tubercle of the humerus-medially stabilizes the shoulder (prevents lateral rotation while weight-bearing) adduct shoulder extend shoulder-

Question 14

teres major

Answer 14

caudal angle and caudal border of the scapula subscapularis muscle-teres major tuberosity of the humerus-flex shoulder rotate arm medially-

Question 15

coracobrachialis

Answer 15

coracoid process of the scapula-crest of the lesser tubercle of the humerus near the teres major tuberosity-mainly a shoulder stabilizer but can assist other muscles in adduction and/or extension of the shoulder-

Question 16

tensor fasciae antebrachii

Answer 16

fascia covering the lateral surface of the latissimus dorsi muscle-olecranon of the ulna in common with the tendon of insertion of the triceps brachii muscle-extend elbow-

Question 17

triceps brachii

Answer 17

caudal border of scapula (long head) tricipital line proximal humerus (neck lesser tubercle and crest of the lesser tubercle)-olecranon of ulna-flex shoulder (long head) extend elbow (all heads)-

Question 18

anconeus

Answer 18

lateral supracondylar crest of the humerus lateral and medial epicondyles of the humerus-proximal and lateral aspect of the ulna-extend elbow-

Question 19

biceps brachii

Answer 19

supraglenoid tubercle of the scapula-radial and ulnar tuberosities-extend shoulder flex elbow-

Question 20

brachialis

Answer 20

proximal and lateral aspect of the humerus-radial and ulnar tuberosities-flex elbow-

Question 21

extensor carpi radialis

Answer 21

lateral supracondylar crest of the humerus-metacarpal tuberosities (dorsal aspect) of MC II and III-extend carpus-

Question 22

common digital extensor

Answer 22

lateral epicondyle of the humerus-extensor processes of the distal phalanx of digits II III IV and V-extend the joints of the four principal digits-

Question 23

lateral digital extensor

Answer 23

lateral epicondyle of the humerus-extensor processes of the distal phalanx of digits III IV and V proximal ends of all phalanges of same digits-extend the joints of digits III IV and V-

Question 24

ulnaris lateralis

Answer 24

lateral epicondyle of the humerus-lateral aspect of the proximal end of MC V accessory carpal bone-abduct carpus flex carpus-

Question 25

supinator

Answer 25

lateral epicondyle of the humerus-cranial aspect of proximal radius-supination (rotate antebrachium laterally so that the palmar surface of the paw faces medially)-

Question 26

pronator teres

Answer 26

medial epicondyle of the humerus-medial border of the radius-pronation (rotate the antebrachium medially so that the palmar surface of the paw faces the ground)-

Question 27

abductor pollicis longus

Answer 27

lateral and cranial border of the ulna interosseus membrane between the radius and ulna-proximal end of metacarpal I-abduct digit I-

Question 28

flexor carpi radialis

Answer 28

medial epicondyle of the humerus medial border of the radius-palmar surface of proximal MC II and III-flex carpus-

Question 29

superficial digital flexor

Answer 29

medial epicondyle of the humerus-palmar surface of the base of the middle phalanges of digits II III IV and V-flex digits II - V –

Question 30

flexor carpi ulnaris

Answer 30

medial epicondyle of the humerus caudal and medial aspect of olecranon-accessory carpal bone-flex carpus-

Question 31

deep digital flexor

Answer 31

medial epicondyle of humerus ulna radius-flexor tubercle (palmar surface of the base) of the distal phalanx of each digit-flex digits-