The Muscular System- Extrinsic Muscles Flashcards
Extrinsic Muscles of the thoracic limb and related areas
List the Subcutaneus Muscle
Cutaneous truncii
List the 8 Extrinsic Muscles of the Thoracic Limb
- Superficial pectoral
A. Transverse
B. Descending - Deep pectoral
- Brachiocephalicus
A. Cleidobrachialis
B. Cleidomastoideus
C. Cleidocervicalis - Omotransversarius
- Trapezius
- Rhomboideus(Rh.)
A. Capital/ Rh. capitis
B. Cervical/ Rh. cervicis
C. Thoracic/ Rh. thoracis - Latissimus dorsi
- Serratus ventralis
A. Cervical part
B. Thoracic part
List the 2 muscles of the head and neck
- Sternocephalicus
A. Sternomastoideus
B. Sterno-occipitalis - Platysma
List the 4 muscles of mastication (chewing)
- Temporalis
- Masseter
- Digastricus
- Mylohyoideus
Attachment
The junction of a skeletal muscle to bone.
3 types:
A. Tendon
B. Aponeurosis
C. Fleshy
Tendon
An extension of the epimysium that consists of dense connective cord-like tissue
Aponeurosis
Dense fibrous connective tissue much like the tendon but organized into a thin sheet of tissue
Fleshy
An apparent direct attachment of muscle to the bone. The muscle is in fact attached to the periosteum of the bone by very short tendons
Origin
The attachment at the less movable end of the muscle or usually the more proximal end
Insertion
The attachment at the more movable end of the muscle; in the limbs this is usually the most distal end
Action
The body movement that a contraction of the muscle will produce
Umbilicus
A small flat or slightly raised scar on the ventral midline of the abdomen approx. 1/3 the dist. From the xiphoid cartilage to the penis or vulva; serves as a landmark when abdominal surgery is performed
Teats; Mammary Papillae; Mammae
They are positioned in 2 rows on either side of the abdomen and are usually divided into thoracic, abdominal & inguinal. Tomcat-2
Queen-8
Dogs-8 to12
Costal Arch
Caudal ventral border of the rib cage formed by the costal cartilages of the 10th, 11th & 12th ribs; the 13th rib does not attach to the costal arch.
Origin of Descending Superficial Pectoralis muscle
The smaller portion of the superficial pectoralis arises from the first 2 sternebrae and it’s fibers run in a craniolateral direction.
Origin of Transverse Superficial pectoralis muscle
The larger transverse portion originates on the first 2 or 3 sternebrae; the fibers run more transversely
Origin of Superficial Pectoralis muscle
Cranial sternum
Insertion of Superficial pectoralis muscle
descending and transverse portions both insert on the greater tubercle of the humerus
Action of Superficial pectoralis muscle
Adducts the thoracic limb
Origin-Cranial sternum
Insertion- Greater tubercle of the humerus
Action- adducts the thoracic limb
Superficial Pectoralis muscle
Origin of Omotransversarius muscle
Wing of the atlas
Insertion of Omotransversarius muscle
Spine & Acromion of Scapula
Action of Omotransversarius muscle
Advances the limb and/or pulls the head & neck to the side
Transect the Omotransversarius muscle through its middle to observe what?
Hint-Found in the fascia medial to this muscle & cranial to the scapula.
The superficial cervical lymph node.
What is the Origin of the Trapezius muscle
The dorsal aspect of the neck and thorax
What is the insertion of the Trapezius muscle
Spine of the Scapula
What is the action of the Trapezius muscle
Elevates and abducts the forelimb
Origin- dorsal aspect of the neck & thorax
Insertion- Spine of the scapula
Action- Elevates and abducts forelimb
Trapezius Muscle
What are the 2 portions of the Trapezius muscle called? Where are they located?
Cervical portion- lies Cranial to Scapular Spine
Thoracic Portion- lies Caudal to the Scapular spine
Where is the Rhomboideus Muscle located and what does it hold?
Lies beneath the trapezius muscle.
Holds the dorsal border of the scapula close to the body
What is the insertion of the Rhomboideus muscle?
dorsal border of the scapula and/or it’s cartilage
What are the 3 parts of the Rhomboideus muscle?
Capital-rhomboideus capitis
Cervical-rhomboideus cervicis
Thoracic-rhomboideus thoracis
Origin of the rhomboideus capitis?
nuchal crest of the occipital bone
Origin of the rhomboideus cervicis?
median fibrous tissue on the dorsal aspect of the neck
Origin of the rhomboideus thoracis?
spinous process of the first 7 thoracic vertebrae
Action of the rhomboideus muscle?
elevates forelimb
In horse and cattle the rhomboideus muscle only has 2 parts:
thoracic & cervical
Origin of the Latissimus Dorsi muscle?
spinous process of the lumbar & the last 7 or 8 thoracic vertebrae
Insertion of the Latissimus Dorsi muscle?
teres major tuberosity of the humerus & the teres major tendon
Action of the Latissimus Dorsi muscle?
draws limb caudally;
flexes the shoulder joint
Latissimus Dorsi muscle?
Large muscle that lies caudal to the scapula & covers much of the thoracic wall
Serratus ventralis muscle?
this large muscle acts as a sling to support the body between the forelegs
How many parts does the serratus ventralis muscle have and what are they called?
2 parts
Cervical part
Thoracic part
Origin of the Cervical part of the Serratus Ventralis muscle?
cervical vertebrae
Origin of the Thoracic part of the Serratus Ventralis muscle?
ribs
Insertion of the Serratus Ventralis muscle?
the serrated face on the dorsomedial aspect of the scapula
Action of the Serratus Ventralis muscle?
supports the trunk & depresses the scapula
Where does the name Serratus come from?
The serrated appearance of the muscle on the ventral aspect of the thoracic portion
Origin-
-Cervical part-cervical vertebrae
-Thoracic part- ribs
Insertion- serrated face on the dorsomedial aspect of the scapula
Action- supports the trunk & depresses the scapula
Serratus Ventralis Muscle
Origin- 1: nuchal crest of the occipital bone
2: median fibrous tissue on the dorsal aspect of the neck
3: spinous process of the first 7 thoracic vertebrae
Insertion-dorsal border of the scapula and/or it’s cartilage
Action- elevates forelimb
Rhomboideus muscle
1: Capital; rhomboideus capitis
2: Cervicle; rhomboideus cervical
3: Thoracic; rhomboideus thoracis
Origin- spinous process of the lumbar & last 7 or 8 thoracic vertebrae
Insertion- teres major tuberosity of the humerus & the teres major tendon
Action- draws limb caudally; flexes the shoulder joint
Latissimus Dorsi Muscle
Origin of the Deep Pectoral muscle?
Sternum
Insertion of the Deep pectoral muscle?
Cats- Crest of the greater tubercle
Dog- primarily the lesser tubercle of the humerus w/ some attachment to the greater tubercle
Action of the Deep Pectoral muscle?
Adducts the limb & pulls the limb caudally
Origin- Sternum
Insertion-
Cats- Crest of the greater tubercle
Dog- primarily the lesser tubercle of the humerus w/ some attachment to the greater tubercle
Action- Adducts the limb & pulls the limb caudally
Deep Pectoral Muscle
foreleg
brachium
The brachiocephalicus forms the upper margin of the _____________ in animals.
Jugular groove
This tendinous region , which is considered the origin of the Brachiocephalicus muscle, is a vestige of the clavicle found in humans.
Clavicular Intersection
Origin of the Brachiocephalicus Muscle?
Clavicular Intersection
The Brachiocephalicus MM. splits into how many parts?
What are they called?
3 parts:
-Cleidobrachialis &
Cleidocephalicus*
Which splits into:
-Cleidomastoideus
-Cleidocervicalis
- horses only have 2 Cleidobrachialis & Cleidocephalicus
Insertion of Cleidobrachialis part of the Brachiocephalicus MM.?
the cranial humerus
cats- ulna
Insertion of Cleidomastoideus part of the Brachiocephalicus MM.?
the mastoid process of the temporal bone
Insertion of Cleidocervicalis part of the Brachiocephalicus MM.?
dorsal neck
For the Brachiocephalicus MM., the region from the clavicle to the foreleg is called?
Cleidobrachialis
For the Brachiocephalicus MM., the region from the clavicle to the head is called?
Cleidocephalicus
What does Cleidocephalicus split into?
Cleidomastoideus &
Cleidocervicalis
Action of Brachiocephalicus MM?
pulls the limb forward,
extends the shoulder,
depresses & pulls the head and neck laterally
What is the name of the MM. that is a compound Y-shaped MM. w/ 3 parts?
Brachiocephalicus MM.
What is the jugular groove and what muscles make it?
It is a landmark groove, for the jugular vein, running the length of the ventral side of the neck.
Brachiocephalicus MM.(Upper margin) & Sternocephalicus MM. (lower margin)
Origin of the Sternocephalicus MM.
Sternum
Insertion of the Sernomastoideus part of the Sternocephalicus MM.?
Mastoid part of the Occipital bone
Insertion of the Sterno-occipitalis part of the Sternocephalicus MM.?
nuchal crest of the occipital bone
Insertion of the Sternocephalicus MM. in horses?
Occipital bone*
- In horses this MM. does not split
Action of the Sternocephalicus MM.?
depresses the head & neck
and/or
draws the head & neck to the side
Origin of Platysma MM.?
dorsal tendinous raphe at the dorsal midline
Insertion of the Platysma MM.?
fibers of this muscle attach to the muscles surrounding the lips
Action of the Platysma MM.?
Draws the commissures of the lips caudally
Origin- Sternum
Insertion-
1- mastoid part of the occipital bone
2- nuchal crest of the occipital bone
3- Occipital bone
Action- depresses the head & neck
and/or
- draws the head & neck to the side
*In horses this MM. does not split
Sternocephalicus MM.
1-Sternomastoideus part
2- Sterno-occipitalis part
3- Sternocephalicus MM.
Origin- dorsal tendinous raphe at the dorsal midline
Insertion- fibers of this muscle attach to the muscles surrounding the lips
Action- draws the commissures of the lips caudally
Platysma MM.
Platysma MM.
-well-developed sheetlike muscle
-one of the major cutaneus muscles of the neck & head
-usually tightly adherent to the skin
Temporalis MM.
-largest MM. on head
-found on the lateral & dorsal aspects of the skull
-prominent between ears & extends down into the temporal fossa of the skull
Origin of Temporalis MM.?
Parietal bone of the skull
Insertion of temporalis MM.?
Coronoid process of mandible
Action of the Temporalis MM.?
closes the mouth when chewing
-elevates mandible
-moves mandible laterally
Origin- Parietal bone of the skull
Insertion- Coronoid process of mandible
Action- closes mouth when chewing
Temporalis MM.
Origin of Masseter MM.?
zygomatic arch
Insertion of Masseter MM.?
lateral side of the mandible
Action of Masseter MM.?
elevates the mandible to close the mouth when chewing
Masseter MM.?
-lg. MM. found ventral to the zygomatic arch
-makes up cheek region of cat
-lies on the lateral surface of the ramus of the mandible
-covered in aponeurosis
-consists of 3 layers whose fibers run in 3 diff. directions
Digastricus MM.?
- thin superficial straplike MM.
- found along the ventral caudal edge of the mandible
Origin of Digastricus MM.?
occipital and temporal bones
Insertion of Digastricus MM.?
ventral mandible
Action of Digastricus MM.?
opens mouth
Mylohyoideus MM.?
-forms a sling for the tongue
-thin muscular sheet
-fibers run in a transverse direction
Origin of Mylohyoideus MM.?
medial surface of the mandible
Insertion of Mylohyoideus MM.?
ventral median raphe between the bones of the mandible
Action of Mylohyoideus MM.?
raises the floor of the mouth
Origin- medial surface of the mandible
Insertion- ventral median raphe between the bones of the mandible
Action- raises the floor of the mouth
Mylohyoideus MM.
Origin- occipital & temporal bones
Insertion- ventral mandible
Action- opens mouth
Digastricus MM.
Origin- zygomatic arch
Insertion- lateral side of the mandible
Action- elevates the mandible to close the mouth when chewing
Masseter MM.
Masticatory Myositis
-an inflammatory disease in dogs that affects the muscles of mastication
-treatment usually involves steroids
Raphae
-a ridged union of continous biological tissue
Head
Cephalo-
Sternum
Sterno-
