ANATOMY:CH3 (Pharynx-Tail)

M. platinus

(m. uvulae) is a small, straight muscle that runs

longitudinally through the soft palate.

M. platinus

Action: To shorten the palate and curl the caudal border

ventrally

M. platinus

(m. uvulae) is a small, straight muscle that runs

longitudinally through the soft palate.

M. platinus

Action: To shorten the palate and curl the caudal border

ventrally

M. cricothryroideus

is a thick muscle on the lateral surface of

the larynx between the thyroid lamina and the cricoid cartilage

M. cricothyroideus

Action: To pivot the cricoid cartilage on its thyroid

articulation, thus tensing the vocal cords.

M. cricoarytenoideus dorsalis

arises from the entire length of

the dorsolateral surface of the cricoid cartilage.

M. cricoarytenoideus dorsalis

• Action: To open the glottis by abducting the vocal folds.

M. cricoarytenoideus lateralis

arises from the lateral and

cranial surface of the cricoid cartilage

M. cricoarytenoideus lateralis

• Action: To pivot the arytenoid cartilage medially and close

the rima glottis.

M. thyroarytenoideus

is the parent muscle mass, which has

given rise to the m. ventricularis and the m. vocalis.

M. thyroarytenoideus

• Action: To relax the vocal cord and constrict the glottis.

M. vocalis

is a medial division of the original thyroarytenoid

muscle mass.

M. vocalis

• Action: To draw the arytenoid cartilage ventrally, thus

relaxing the vocal cord

M. ventricularis

is a cranial division of the thyroarytenoid

muscle mass, which has shifted its origin in the dog from the

thyroid cartilage to the cuneiform process of the arytenoid

cartilage

M. ventricularis

• Action: To constrict the glottis and dilate the laryngeal

ventricle.

M. arytenoideus transversus

originates broadly on the

muscular process of the arytenoid cartilage at the line of

insertion of the thyroarytenoideus.

M. arytenoideus transversus

• Action: To constrict the glottis and adduct the vocal folds

M. hyoepiglotticus

a small, spindle-shaped muscle, arises from

the medial surface of the ceratohyoid bone

M. hyoepiglotticus

• Action: To draw the epiglottis ventrally.

M. sternohyoideus

Action: To pull the basihyoid bone and

tongue caudally.

M. sternothyroideus

Action: To draw the hyoid apparatus,

larynx, and tongue caudally

M. thyrohyoideus

Action: To draw the hyoid apparatus

caudally and dorsally.

M. mylohyoideus

Action: To raise the floor of the mouth and

draw the hyoid apparatus rostrally.

M. ceratohyoideus

Action: To decrease the angle formed by

the thyrohyoid and ceratohyoid bones

M. geniohyoideus

Action: To raise the basihyoid bone.

M. occipitohyoideus

Action: To move the stylohyoid bone

caudally

M. rectus capitis ventralis

Action: Flexion of the

atlantooccipital joint.

M. rectus capitis dorsalis major and minor

Action: Both

rectus dorsalis muscles extend the atlantooccipital joint.

M. rectus capitis lateralis

Action: Flexion of the

atlantooccipital joint.

M. obliquus capitis cranialis-

Action: Extension of the

atlantooccipital joint.

m. obliquus capitis caudalis

Action: Unilateral: rotation of the

atlas and thus the head on the axis; bilateral: fixation of the

atlantoaxial joint

M. brachiocephalicus

lying on the neck deep to the m.

sphincter colli superficialis and platysma as a long, flat muscle,

extends between the brachium and the head and neck.

M. splenius capitis

Action: In unilateral action to draw the

head and neck laterally, lateral flexion. It also functions in

fixation of the first thoracic vertebra

M. longus capitis

Action: To flex the atlantooccipital joint and

to draw the neck ventrally.

M. longus colli

Action: To flex the neck.

M. scalenus

Action: To flex the neck. In unilateral action, to

bend the neck laterally, lateral flexion. When the neck is fixed,

the dorsal part can act in inspiration.

M. serratus ventralis cervicis -

Action: Support of the trunk, to

carry the trunk cranially and caudally; inspiration; to carry the

shoulder cranial and caudal with respect to the limb.

M. trapezius

is a broad, thin, triangular muscle.

M. latissimus dorsi

is a flat, almost triangular muscle that lies

caudal to the muscles of the scapula and brachium on the

dorsal half of the lateral thoracic wall

M. latissimus dorsi

• Action: To draw the trunk cranially and possibly laterally;

extend the vertebral column; and support the limb, draw the

limb against the trunk, and draw the free limb caudally

during flexion of the shoulder joint.

M. rhomboideus

covered by the trapezius, fans out on the neck

and cranial thorax between the median line of the neck and

thorax and the dorsal border of the scapula. It is in part flat and

in part thick, and is divided into three parts.

M. rhomboideus

• Action: To elevate the limb, pull the limb and shoulder

cranially or caudally; to draw the scapula against the trunk.

M. serratus dorsalis

is an epaxial muscle that is completely

divided into cranial and caudal parts with different innervation

and function

M. serratus dorsalis cranialis

Action: To lift the ribs for

inspiration.

M. serratus dorsalis caudalis

or expiratory part, consists of

three rather distinctly isolated portions.

M. serratus dorsalis caudalis

• Action: To draw the last three or four ribs caudally for

expiration.

Erector spinae muscles

(m. erector spinae) are the dorsal

muscles that include the epaxial muscles located on the dorsal

surface of the vertebral column and ribs.

• These are represented by the various divisions of the

iliocostalis, longissimus, and spinalis muscles.

Iliocostalis muscles

Action: Fixation of the

vertebral column or lateral movement when only one side

contracts; aids in expiration by pulling the ribs caudally.

Longissimus muscle

Action: For the

thoracolumbar portion of the longissimus muscles, extension of

the vertebral column.

Transversospinalis muscle

is a medial epaxial muscle mass

composed of a number of different systems of fascicles that join

one or more vertebra

• The three muscle groups that compose the

transversospinalis muscle are the semispinalis, multifidus,

and rotators.

Interspinal Muscles

Action: Fixation of the

vertebral column.

Intertransverse Muscles

are deep

segments split off from the longissimus system.

mm. intercostales

The spaces between the ribs are filled by the ____?_____, which appear in a double layer, internal and external, and cross each other.

m. levator costarum

Each m. intercostalis externus is adjacent to ___?____dorsally.

m. rectus thoracis

Cranially, on the thorax, the ___?___ covers the

superficial ventral ends of the first ribs;

m. transversus thoracis

the ____?___ crosses the internal surface of the cartilages of the

sternal ribs and the sternum.

mm. retractor costae and subcostalis

The ___?____are special muscles

of the last rib.

mm. intercostales externi

Action: Inspiration; draws the ribs

together so as to enlarge the thoracic cavity.

mm. levatores costarum

Action: Inspiration; the fixed point

is the transverse process of the vertebra.

mm. intercostales interni

- Action: Expiration, to draw the ribs

together so as to narrow the thoracic cavity

mm. subcostales

located medial to the internal intercostal

muscles at the vertebral ends of the caudal ribs, especially ribs

9 to 11.

m. rectus thoracis

- Action: Inspiration.

m. retractor costae

-It bridges the space between the

transverse processes of the first three or four lumbar

vertebrae and the last rib

m. transversus thoracis

sometimes referred to as the

triangularis sterni or the sternocostalis internus.

m. transversus thoracis

Action: The

m. transversus thoracis contributes to expiration

Diaphragm

- is a musculotendinous plate between the

thoracic and the abdominal cavities. It projects cranially into

the thoracic cavity like a dome.

M. obliquus externus abdominis

is an expansive sheet

covering the ventral half of the lateral thoracic wall and the

lateral and ventral parts of the abdominal wall.

M. obliquus externus abdominis

Action: Along with other abdominal muscles, compression

of the abdominal viscera. This action, known as abdominal

press, aids in such vital functions as expiration, urination,

defecation, and parturition. Flexion of the vertebral column

when fellow muscles contract. Lateral bending (lateral

flexion) of the vertebral column.

M. obliquus internus abdominis

Action: Compression and

support of the abdominal viscera.

M. transversus abdominis

is the deepest abdominal muscle

and, like the oblique muscles, it is developed into an extensive

leaf that reaches a thickness of 2 to 4 mm in large dogs

Transversalis fascia

covers the inner surfaces of the mm.

transversi abdominis

M. rectus abdominis

is a long, flat, relatively narrow

(compared with the other abdominal muscles) muscle that

extends from the first costal cartilage to the pecten ossis pubis

M. rectus abdominis

• Action: All functions that depend on abdominal press, such as

expiration, urination, defecation, and parturition; support of the

abdominal viscera; to bring the pelvis cranial; flexion of the trunk

Linea alba

is amidventral strip of collagenous tissue that

extends from the xiphoid process to the symphysis pelvis.

M. cutaneus trunci

Action: shakes the skin to remove foreign bodies

and increase heat production. It also tenses the skin when required.

M. preputialis

Action: draws the prepuce over the glans after erection.

M. supramammaricus

aids in support of the mammary glands and

perhaps in milk ejection.

Pelvic diaphragm

in quadrupedal

mammals is the vertical closure of the pelvic cavity through

which the rectum passes. The two muscles of the pelvic

diaphragm are the m. coccygeus and the m. levator ani.