Forelimb Muscles Flashcards
Extrinsic Muscles
Attach the limb to the trunk to move the whole limb
Intrinsic Muscles
Move limb bones relative to one another
Forelimb muscles are classified by 6 types of movement
-flexors
-extensors
-rotators
-elevators
-protractors
-retractors
Protractor and Retractor muscles are
extrinsic
Flexors
reduction in the angle of the joint
Extensors
increasing the angle of the joint
Protractors
Moving the whole limb forwards (off the ground)
Rotators
Supination and Pronation
Elevators
Raise the limb
Retractors
Moving the whole limb backwards (on the ground)
Shoulder Support Muscles (7)
-Serratus ventralis
-Rhomboideus
-Superficial Pectoral
-Deep Pectoral
-Trapezius
-Brachiocephalicus
-Latisimus dorsi
Serratus ventralis (origin/insertion)
O: Cervical vertebrae and ribs
I: Fascies serrara of scapula
Rhomboideus Parts (3)
-Capital (smallest, least substantial)
-Cervical
-Thoracic
Cervical Rhomboideus (origin/insertion)
O: Median raphe of neck
I: Dorsal Scapula
Thoracic Rhomboideus (origin/insertion)
O: Spinous processes of thoracic vertebrae
I; Dorsal Scapula
Superficial Pectoral (origin/insertion)
O: Sternebrae 1-3
I: Greater tubercle of humerus
Deep Pectoral (origin/insertion)
O: Sternum
I: Lesser tubercle of humerus and medical brachial fascia
The Brachium is
the upper forelimb
Trapezius is (3)
-thin
-superficial to Rhomboideus
-has two parts (Cervical and Thoracic )
Cervical Trapezius (origin/insertion)
O: Median raphe of neck
I: Spine of scapula
Thoracic Trapezius (origin/insertion)
O: Supraspinous Ligament
I: Spine of scapula
Accessory (CN XI) Nerve innervates the
-Trapezius
-Cleidocervicalis
-Celidomastoideus
Remnant of the clavicle is
Clavicular Tendon
Brachiocephalicus has 3 parts:
-Cleidobrachialis
-Cleidocervicalis
-Cleidomastoideus
All three parts of the Brachiocephalicus originate at
Clavicular Tendon
Cleidobrachialis (origin/insertion)
O: Clavicular Tendon
I: Cranial humerus
Cleidocervicalis (origin/insertion)
O: Clavicular Tendon
I: Median raphe of neck
Cleidomastoideus (origin/insertion)
O: Clavicular Tendon
I: Mastoid process of skull
The flattest shoulder support muscle is the
Latissimus dorsi
The largest shoulder support muscle is the
Brachiocephalicus
Latissimus dorsi (origin/insertion)
O: Thoracic and Lumbar vertebral fascia
I: Proximal humerus
What are the three muscles highlighted
Green: Brachiocephalicus
Purple: Trapezius
Yellow: Deep Pectoral
What are the four shoulder support muscles highlighted below? What has been removed?
Orange: Rhomboideus
Purple: Serratus ventralis
Green: Latissimus dorsi
Yellow: Deep Pectoral
Removed: Trapezius
Protractors of the forelimb: (4)
-Brachiocephalicus
-Cervical and Capital Rhomboideus
-Superfical Pectoral
-Cervical Trapezius
Adduction
Moving the limb towards the midline of the body
Adductor of the forelimb
Superficial Pectoral
Abduction
Moving the limb away from the midline of the body
Abductors of the forelimb
-Deltoideus
-Cervical and Thoracic Trapezius
What is the MAIN abductor of the forelimb
Deltoideus
2 parts of the Deltoideus
-Acromial
-Spinal
The Deltoideus inserts at
Deltoid tuberosity
Acromial Deltoideus (origin/insertion)
O: Acromion
I: Deltoid tuberosity
Spinal Deltoideus (origin/insertion)
O: Spine of scapula
I: Deltoid tuberosity
5 Retractors of the forelimb:
-Latissimus dorsi
-Rhomboideus (thoracic)
-Superficial Pectoral
-Deep Pectoral
-Trapezius (thoracic)
2 Elevators of the forelimb:
-Trapezius
-Rhomboideus
3 Flexors of the shoulder:
-Teres Major
-Deltoideus (acromial and spinal)
-Infraspinatus
Teres Major (origin/insertion)
O: Caudal scapula
I: Teres tuberosity (major)
Largest Flexor of the shoulder
Infraspinatus
Infraspinatus (origin/insertion)
O: Infraspinous fossa
I: Greater tubercle
Infraspinous fossa is
The large area on the lateral side of the scapula, immediately under the spine of the scapula
What three muscle insert on the Greater Tubercle
-Superficial Pectoral
-Infraspinatus
-Supraspinatus
Teres major is best seen on the
Medial aspect
Two Extensors of the shoulder:
-Brachiocephalicus
-Supraspinatus
The Musculocutaneous nerve innervates the
Biceps brachii
Supraspinatus (origin/insertion)
O: Supraspinous fossa
I: Greater tubercle
Supraspinous fossa is located on
The lateral part of the scapula, above the spine of scapula
Suprascapular nerve innervates
-Infraspinatus
-Supraspinatus
Two flexors of the elbow:
-Biceps brachii
-Brachialis*
Which ventral muscle mass in reptiles became cranial in mammals
Biceps brachii
Which dorsal muscle mass in reptiles became caudal and cranial in mammals
Triceps brachii
Biceps brachii (origin/insertion)
O: Supraglenoid tubercle of scapula
I: Radial and Ulnar tuberosities
Extensor of the elbow is
Triceps brachii
Triceps brachii has ___ heads in the dog
four
All heads of the Triceps brachii insert at the
Olecranon
Which nerve innervates the Triceps brachii
Radial
Four heads of the Triceps brachii and their respective origins
- Long - caudal scapula
- Lateral - tricipital line
- Medial - lesser tubercle
- Accessory - neck of humerus
The accessory head of the triceps brachii is deep to
the lateral head of the triceps brachii
Which two muscles of the forelimb work as antagonists? What do they do?
Biceps (flex) and Triceps (extend)
Which two muscles of the elbow work as synergistic muscles? What do they do?
Biceps and Brachialis, both flex the elbow
Antagonistic muscles have
opposing action
Synergistic muscles have
the same action
Supinator (origin/insertion and function)
O: Lateral epicondyle
I: Proximal 1/3 of radius
F: turns radius so palm turns up (ie. supinates)
Pronator teres (origin/insertion and function)
O: Medial epicondyle of humerus
I: Medial radius
F: turns paw ventral (ie. pronates)
Which nerve innervates the Supinator
Radial
Which nerve innervates the Pronator teres
Median
3 Extensors of the Carpus
-Extensor Carpi Radialis
-Common Digital Extensor
-Lateral Digital Extensor*
Which nerve innervates Dorsal Muscle Mass
Radial
Extensor Carpi Radialis (origin/insertion)
O: Lateral epicondylar crest
I: Dorsal metacarpals II and III
Common Digital Extensor (origin/insertion)
O: Lateral epicondyle
I: Dorsal distal phalanges II-V
Both the Extensor Capri Radialis and Common Digital Extensor are innervated by the
Radial Nerve
Extensors of the Digits are all held in place by the
Extensor Retinaculum
3 Extensors of the Digits
-Common Digital Extensor
-Lateral Digital Extensor*
-Abductor Pollicis Longus*
Which muscle extends digit I (dew claw)
Abductor Pollicis Longus*
5 Flexors of the Carpus
-Flexor Capri Radialis*
-Flexor Carpi Ulnaris
-Ulnaris Lateralis*
-Superficial Digital Flexor
-Deep Digital Flexor
Flexor Carpi Ulnaris has ___ heads called ____
Two heads:
-Humeral
-Ulnar
Which muscles are highlighted below? What is there function?
Orange: Extensor Carpi Radialis
Blue: Abductor Pollicis Longus
Yellow: Common Digital Extensor
Purple: Lateral Digital Extensor
Function: Extensors of the Carpus and Digits
Which nerve(s) innervates Ventral Muscel Mass
Ulnar and Median
Both the humeral and ulnar heads of the Flexor Carpi Ulnaris insert at the
Accessory Carpal
The humeral head of the Flexor Carpi Ulnaris originates at the
Medial epicondyle
The ulnar head of the Flexor Carpi Ulnaris originates at the
Medial Olecranon
Which nerve innervates the Flexor Carpi Ulnaris
Ulnar Nerve
Superficial Digital Flexor (origin/insertion)
O: Medial Epicondyle
I: Palmar middle phalanx II-V
Deep Digital Flexor is innervated by
The median and ulnar nerves
Superficial Digital Flexor is innervated by the
Median nerve
The Deep Digital Flexor has ___ heads and they are ___
3 heads:
-Humeral
-Ulnar
-Radial
All three heads of the Deep Digital Flexor insert at the
Palmar distal phalanx II-V
What are the three heads of the Deep Digital Flexor and where are their origins?
Humeral Head: Medial epicondyle humerus
Radial Head: Radius
Ulnar Head: Ulna
The Manica Flexoria occurs at ___ and allows for ____
-each weight-bearing digit
-splits the Superficial Digital Flexor so that a “tunnel” is formed where the Deep Digital Flexor can continue
4 Flexors of the Digits:
-Superficial Digital Flexor
-Deep Digital Flexor
-Interosseous*
-Lumbricales*
Which two muscles are between each digit
-Interosseous*
-Lumbricales*
Two muscles that are both flexors of the carpus and digits
-Superficial Digital Flexor
-Deep Digital Flexor