Muscles cours 1 (2).pdf

Muscles cours 1 lol Fasciae of the Neck Superficial fascia of the neck Deep fascia of the neck  Superficial fascia of the neck = Connective tissue Origin: Superficial temporal, paro...

Muscles cours 1 lol Fasciae of the Neck Superficial fascia of the neck Deep fascia of the neck  Superficial fascia of the neck = Connective tissue Origin: Superficial temporal, parotid and masseteric fasciae, and it continues caudally into the superficial scapular fascia and ventrally into the superficial trunk fascia of the sternal region and axillary fascia Contains: m. sphincter colli superficialis and the platysma. It encloses the stern, and cleidocephalicus muscles and trapezius The bilateral portions of the fascia meet dorsally and ventrally.  Deep fascia of the neck Extends deep to the mm. sternocephalicus, cleidocephalicus, and omotransversarius Covers: m. sternohyoideus and sternothyroideus superficially and surrounds the trachea, thyroid gland, larynx, and esophagus.  Deep fascia of the neck Has divisions such as: Pretracheal fascia: Location: This fascia is situated anterior (ventral) to the trachea. Attachments: It attaches to the wing of the atlas, the longus capitis muscle, and the scalene muscles. Enclosure: As it passes ventrally, it encloses the trachea and esophagus. Continuity: Laterally, it continues with an extension of the deep fascia that forms the carotid sheath, which encloses the common carotid artery, internal jugular vein, and vagus nerve. Prevertebral fascia: Location: This fascia lies dorsal to the trachea and is on the ventral surface of the longus colli muscle. Attachments: Cranially, it is attached to the base of the skull. Caudally, it extends along the ventral surface of the first six thoracic vertebrae into the thorax. Continuity: It continues with the endothoracic fascia. scalene m  Superficial external fascia of the trunk covers the thorax and abdomen There are no a1achments with the dorsal ends of the thoracic and lumbar vertebrae. Thus, as on the neck, the fascia can be picked up with folds in the skin. Covers the mm. trapezius and la=ssimus dorsi, as well as parts of the pectoral muscles, omotransversarius, deltoideus, and triceps brachii.  Thoracolumbar fascia (deep external fascia of the trunk) Covers the erector spinae muscle in the thoracic and lumbar region. It attaches to the spinous processes of the thoracic, lumbar and sacral vertebrae, the supraspinous ligament, the sacral tuberosity, the iliac crest and the coxal tuberosity. Cranioventrally, it con?nues as the axillar fascia, caudally as the gluteal fascia and ventrally as the abdominal tunic. Superficial layer: It gives rise to the la?ssimus dorsi cranially and the two oblique abdominal muscles and the serratus caudalis caudally. Deep leaf: It lies medial to the scapula, medial to the rhomboideus and and lateral to the erector spinae muscles.  Cutaneous muscles of the neck Superficial sphincter muscle of the neck (m. sphincter colli superficialis) Platysma muscle Deep sphincter muscle of the neck (m. sphincter colli profundus) Cutaneous muscle of the neck (m. cutaneus colli) Innervation: cervical branch of the facial nerve  Superficial sphincter muscle of the neck (m. sphincter colli superficialis) Direct continuation of the sphincter colli superficialis of the head Best developed in the laryngeal region deep to the skin. Delicate transverse fibers span the ventral borders of the platysma muscles at the junction of the head and neck. Occasionally fibers of the sphincter colli superficialis reach the thorax, radiate over the shoulder joint, or blend with the cervical part of the platysma.  Platysma muscle Well-developed muscular sheet in carnivores and pigs Origin: Radiates into the facial cutaneous muscle Function: It tenses and moves the skin on the dorsal and lateral side of the neck.  Deep sphincter muscle of the neck (m. sphincter colli profundus) Carnivorous and equine: present Pigs and ruminants: absent It extends from one side of the neck to the other and end dorsally and ventrally on the median raphe. More caudally is attached to the sternal manubrium. It also continues on the face and dissociates itself. It lies beneath the platysma and cutaneous muscles of the face on the lateral aspect of head and neck. It tenses the superficial fascia in the laryngeal region.  Cutaneous muscle of the neck (m. cutaneus colli) (cervical cutaneous muscle) It is not present in carnivores. Origin: from the manubrium of the sternum and covers the jugular groove Situated at the ventral aspect of the neck  Erector Spinae Muscles we have divisions: 1 le plus loin de la Iliocostallis m colonne spinalis m longissimus m transversospinalis m On the spinalis m: 3 le plus proche de la colonne spinalis cervicic spinalis thoracis 2 le 2e plus lojn de la Dorsal musculature, associated with the vertebral column and On the longissimus m: colonne entre le 1 et ribs. L.capital 3 Various divisions: iliocostalis, longissimus, and spinalis muscles. L.cervical Action: Extensors of the vertebral column; unilateral action L.thoracic produce lateral movements of the trunk L.lumbar On the transversospinallis m: 4 sous le 3 semispinalis (capitis, cervicis, thoracis) multifidus rotators  Ilioostalis m Series of longitudinal fascicles lateral to the other epaxial muscles Arise on the ilium and constitute a lumbar portion, whereas the cranial fascicles extend to the first thoracic vertebra and constitute the thoracic portion. Cervical portion constituted by the last fascicle that inserts on the 7th cervical vertebra Origin: Sacrum/Illiac Crest/Spinous; Processes of lower lumbar/thoracic vertebrae Insertion: Ribs Artery: Lateral sacral artery Action: Fixation of the vertebral column or lateral movement when only one side contracts; aids in expiration by pulling the ribs caudally. Innervation: Dorsal branches of the nn. thoraci and lumbares.  M. Spinalis Most medial of the erector spinal group Spinalis cervicis: cervical part of the spinalis muscle that attaches to cervical vertebral spinous processes. Spinalis thoracis: thoracic part of the spinalis muscle that attaches to thoracic vertebral spinous Origin: extends across the spinous processes of one or more thoracic vertebrae, and sometimes last cervical vertebra Insertion: spinous processes of 2nd to 5th cervical vertebrae Action: To fix the thoracic vertebral column and to extend the neck. Innervation: Medial branch of the dorsal branches of the cervical and thoracic nerves (nn. cervicales et thoracici).  Longissimus M Erector spinae muscle that lies medial to the m. iliocostalis. It composes the major portion of the epaxial muscle mass Extend from the ilium to the head. Divisions: capital, cervical, thoracic and lumbar M. Sacrocaudalis lateralis: Caudal continuation of the m. longissimus on the tail. Longissimus capitis M Lies medial to the mm. longissimus cervicis and splenius Covers the m. semispinalis capi*s along its ventral border and extends from the first 3 thoracic vertebrae to the temporal bone Origin: transverse processes of the first thoracic and last cervical vertebrae Insertion: wing of the atlas. Action: Extension of the atlantooccipital joint. The atlantal por*on in unilateral ac*on rotates the atlantoaxial joint, whereas in bilateral ac*on it fixes the atlantoaxial joint. Innervation: Dorsal branches of the cervical nerves (nn. cervicales). Longissimus cervicis M Origin: Continuation of the longissimus thoracis, transverse processes of the first 5-8 thoracic vertebrae Insertion: last cervical vertebra Action: Extends the neck; in unilateral action to raise the neck obliquely and turn it to one side. Nerve: Dorsal branches of the thoracic nerves.  Longissimus thoracic Origin: Illiac crest to the last cervical vertebra. Insertion: All thoracic ribs. Action: Extension of the vertebral column. Raising of the cranial portion of the body from the pelvis, sacrum, and loin; in conjunction with the other muscles, fixation of the vertebral column; deflection of the back by fixation of the cervicothoracic junction; sudden raising of the caudal portion of the body; which is initiated by means of the rear extremities. Nerve: Dorsal branches of the thoracic nerve.  Longissimus lumborum Origin: Iliac crest and ventral surface of the ilium and spinous processes and supraspinous ligament. Insertion: Ends on accessory processes of the sixth to first lumbar vertebrae. Action: Extension of the vertebral column. Raising of the cranial portion of the body from the pelvis, sacrum, and loin; in conjunction with the other muscles, fixation of the vertebral column; deflection of the back by fixation of the cervicothoracic junction; sudden raising of the caudal portion of the body; which is initiated by means of the rear extremities. Nerve: Dorsal branches of the thoracic and lumbar nerves  Transversospinalis m Medial epaxial muscle mass composed of a number of different systems of fascicles that join one or more vertebrae. Collective term for the epaxial muscles that are primarily medial to the iliocostalis and longissimus muscles and lateral to the spinalis, interspinalis, and intertransversarius groups. 3 muscle groups: Semispinalis (capitis, cervicis, thoracis) Multifidus Rotators  Semispinalis capitis: Large continuation to the head of the spinalis and semispinalis thoracic and cervical muscles. Origin: Transverse processes of T6-C3 Insertion: Area between superior and inferior nuchal line Nerve: Greater occipital nerve and posterior rami of spinal nerves of C1-C5 Action: Extend the head It is situated at the upper and back part of the neck, beneath the Splenius, and medial to the Longissimus cervicis and capitis. The left and right muscles are separated only by the nuchal ligament and the median fibrous raphe. Divided into two parts: Biventer cervicis muscle: the dorsomedial division of semispinalis capitis that originates from the thoracolumbar fascia or thoracic vertebral transverse processes, courses superficial to mutifidi muscles to insert on occipital bone. Complexus muscle: the ventrolateral division of semispinalis capitis that arises from cervical vertebral articular processes and inserts lateral to the biventer cervicis on occipital bone.  Semispinalis cervicis It is fused medially with the spinalis cervicis and continuous with the semispinalis thoracis. Origin: Arises from the tendon of the most cranial thoracic segment of the semispinalis thoracis and from the cranial border of the first thoracic spine. Insertion: On the spinous processes of the fifth to second cervical vertebrae. Action: To fix the thoracic vertebral column and to raise the neck. Nerve: Medial branch of the dorsal branches of the cervical and thoracic nerves. 5e to 2nd cervical  Semispinalis thoracis Bundles that detach form mamillary processes and course over the lateral face of semispinalis muscle to the dorsal portion of spinous processes. Origin: Fascia of Longissimus. Insertion: Spinous processes of the sixth thoracic to sixth cervical vertebra. Action: Fixes the vertebral column and raises the neck. Nerve: Medial branch of the dorsal branches of the cervical and thoracic nerves. 6C to 6T  Multifidus m It is composed of numerous individual portions that overlap in segments and extend from the sacrum to the 2nd cervical vert. As a rule, two vertebrae are passed over by each bundle. The m. multifidus, is continuous in the tail with the sacrocaudalis dorsalis medialis muscle. Origin: mamillary, transverse or articular processes Insertion: spinous processes Action: rotate vertebral column Nerve: Medial branches of the rami dorsales in the lumbar, thoracic and cervical regions. Different bundles may be described as: Multifidi laterales: lateral fascicles Multifidi mediales: medial fascicles Multifidi profundi: deep fascicles  Multifidus m Long (n=8) and short (n=9) muscle bundles deep to the multifidi muscles in cranial thoracic region. Rotatores Longi Origin: Medial surface of the multifidus muscle. Insertion: From the transverse processes of the tenth to the first thoracic vertebrae. Action: Rotation of the greater cranial portion of the thoracic vertebral column about the longitudinal axis in unilateral action; otherwise, fixation. Nerve: Medial branches of the rami dorsales of the thoracic nerves. Rotatores Breves Origin: Medial surface of the multifidus muscle. Insertion: Spinous processes of the first through tenth thoracic vertebrae. Action: Rotation of the greater cranial portion of the thoracic vertebral column about the longitudinal axis in unilateral action; otherwise, fixation. Nerve: Medial branches of the rami dorsales of the thoracic nerves  Interspinal m They are short muscular (carnivores) or tendinous (ungulates) bands between adjacent spinous processes of the caudal cervical, thoracic and 1st few lumbar vertebrae, deep to the multifidi muscles. Origin: spinous processes of the caudal cervical, thoracic and 1st lumbar vertebrae Insertion: spinous processes of the caudal cervical, thoracic and first few lumbar vertebrae. Action: support the ventroflexion of the vertebral column Nerve: Medial branches of the dorsal branches of the cervicla, thoracic and lumbar nerves  Intertransverse m Small muscles that pass between transverse processes, between articular and transverse processes or between mamillary and transverse processes. Origin: transverse processes, mamillary processes Insertion: transverse processes, articular processes Action: fixation and lateral flexion of the cervical and lumbar vertebral column Nerve: Dorsal branches of the cervical, thoracic and lumbar nerves. Different groups: Intertransversarii lumborum: Medial and lateral bundles Intertransversarii thoracis Intertransversarii cervicis: Dorsal, middle and ventral bundles Intertransverse cervical m. Dorsal: bundles that run horizontally between cranial articular processes Intermediate: bundles that run cranioventrally from a cranial articular process to the caudal end of the transverse process skipping one vertebra in a cranial direction (C5 to C3 for example) Ventral: bundles that run horizontally between caudal ends of two consecutive transverse processes  Muscles of the dorsum Epaxial muscles that form a continuous column throughout most of the vertebral column: serratus dorsalis, the erector spinae, transverse spinalis, interspinalis and intertransversarii. Extrinsic muscles of the thoracic limb that attach to the thorax: trapezius, latissimus dorsi, and rhomboideus  Superficial layer of the extrinsic musculature of the thoracic limb Extrinsic muscles of the thoracic limb that attach to the thorax: trapezius, latissimus dorsi, and rhomboideus The superficial layer of the girdle musculature joins the forelimb to the trunk. It is responsible for coordinating the movements of the limb, trunk, head and neck. It consists of the following muscles: Latissimus dorsi m. Trapezius m. Sternocleidomastoid m. (sternocephalic m. and brachiocephalic m.) Omotransverse m. Superficial pectoral m.  Latissimus dorsi m Lies caudal to the muscles of the scapula and brachium on the dorsal half of the lateral thoracic wall. Origin: Superficial leaf of the lumbosacral fascia and spinous processes of the lumbar vertebrae and the last 7-8th thoracic vertebrae, and it arises muscularly from the last 2-3 ribs. Insertion: Teres tubercle and the greater tubercle of the humerus. 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. Innervation: Nn. pectorales caudales, and n. thoracodorsalis.  Trapezius m Cervical part: It arises on the mid-dorsal raphe of the neck and the thoracic portion on the supraspinous ligament and the dorsal spinous processes, extending from the third cervical vertebral to the ninth thoracic vertebra. Both portions end on the spine of the scapula Thoracic part: It unites with the thoracolumbar fascia and the cervical part with the omotransverse muscle.  Superficial pectoral m Occupy the space between the ventral part of the thoracic wall and the proximal part of the thoracic limb, forming the ventral aspect of the axilla. Origin: Paramedially on the cranial end of the sternum. Insertion: Entire crest of the greater tubercle of the humerus. Action: Supports the limb, draw back the limb inward, draw the limb forward or backward according to its position, and draw the trunk sideward. Nerve: cranial pectoral nerves and branches form cervical nerves 7 and 8 Divides into: Descending (m. pectoralis descendens): originates from the manubrium of the sternum and terminates on the crest of the greater tubercle of the humerus. Transverse pectoral muscle (m. pectoralis transversus): It arises caudal to the descending pectoral muscle from the ventral aspect of the sternum and blends with the fascia of the forearm.  Superficial pectoral m Carnivores: descending pectoral muscle difficult to distinguish from the thicker transverse pectoral muscle. Both cover the biceps muscle and end together on the crest of the greater tubercle of the humerus. Horse: Descending pectoral m.: forms a distinct prominence cranial to the sternum. It extends between the manubrium of the sternum and the humeral crest. Transverse pectoral m: originates from the 1-6th costal cartilages and the sternum and blends with the fascia of the forearm on the medial aspect of the elbow.  Deep layer of the extrinsic musculature of the thoracic limb The deep layer of the girdle musculature of the thoracic limb provides the muscular suspension of the thorax between the limbs and plays a major role in the movement of the neck and limbs. It comprises: Deep pectoral muscle (m. pectoralis profundus) Subclavian muscle (m. subclavius) Rhomboid muscle (m. rhomboideus) Ventral serrate muscle (m. serratus ventralis)  Deep pectoral m Strong muscle which originates from the sternum, the xiphoid cartilage and the costal cartilages and inserts on the medial or lateral aspect of the proximal humerus in the different species. Origin: First to last sternebra and with a superficial marginal portion as the pars abdominalis, from the deep fascia of the trunk to the region of the xiphoid cartilage. Insertion: Lesser tubercle of the humerus. Action: During locomotion, to move the trunk cranially over the advanced limb, extend the shoulder joint; draw the limb backward. Nerve: Pectorales caudales Carnivores: Divided into a major deep portion and a minor superficial, lateral portion. Both portions arise from the sternum and the deep fascia of the trunk. Insertion: minor tubercle of the humerus deep to the superficial (transverse) pectoral muscle. Horse: Deep part is the largest pectoral muscle and arises from the abdominal tunic, the lateral aspect of the sternum, the costal cartilages and the ribs. Insertion: two branches to the lesser and greater tubercles of the humerus and the supraglenoid tubercle of the scapula.  Subclavian m Ruminants: narrow band which takes origin form the 1st costal cartilage and blends with the tendon of insertion of the brachiocephalic muscle. Pig and horse: it arises form the 2nd to 4th costal cartilage, passes over the shoulder joint and unites with the aponeurosis of the supraspinous muscle. Carnivores: not present.  Cervical rhomboid m Lies deel to trapezius muscle and inserts on the medial aspect of the dorsal part of the scapula. Origin: Spinous processes of the the cervical vertebrae. Dorsal median raphe of the neck near C2- C3 (Car, Su) or ligamentum nuchae (Ru, Eq) Insertion: cranial angle and dorsal border of scapula including scapular cartilage, cranial to rhomboideus thoracis Action: To elevate the limb, pull the limb and shoulder forward or backward, to draw the scapula against the trunk. Nerve: Rami dorsales of the cervicales et thoracicales nerve.  Serratus ventralis m In carnivorous: serratus ventralis cervicis and thoracis are continuous together: Origin: Facies serrata of the scapula. Insertion: Transverse processes of the last five cervical vertebrae and on the first seven or eight ribs. Action: Support of the trunk, to carry the trunk forward and backward; inspiration; to carry the shoulder forward and backward with respect to the limb. Nerve: Cervicales and thoracicales nerves.  Serratus dorsalis m Divided into cranial and caudal parts with different innervation and function: M. serratus dorsalis cranialis: Inspiratory part, lies on the dorsal surface of the cranial thorax. Origin: The thoracolumbar fascia and spines of the first 6-8 thoracic vertebra. Insertion: Cranial border and lateral surfaces of ribs 2-10 Action: Lift the ribs for inspiration. Nerve: Intercostales M. serratus dorsalis caudalis: Expiratory part; consists of 3 rather distinctly isolated portions Origin: Thoracolumbar fascia. Insertion: Caudal border of the 11-13th ribs. Action: Draws the last three or four ribs caudally for expiration Nerve: Intercostalis.  Straight thoracic m (rectus thoracic) Origin: First rib, opposite the most ventral portion of the scalenus muscle. Runs caudoventrally from its origin Insertion: Ventral ends of the second through fourth ribs. Its aponeurosis of insertion obliquely crosses the lateral surface of the cranial portion of the aponeurosis of the m. rectus abdominis and blends with the deep fascia of the trunk. Action: Inspiration. Nerve: Lateral branch of the intercostales.  Muscles of the neck (musculi colli) Primarily located in the neck with attachments to the head or thoracic limb Sub m such as: cleidocephalicus and Brachiocephalicus cleidobrachialis Omotransversarius Sternocephalicus Splenius Longuscapitis Longuscolli Scalenus Serratus ventralis cervicis  Longus capitis (long muscle of the head) Long, flat muscle that lies on the lateral and ventral sides of the cervical vertebrae lateral to the m. longus colli. It may be considered as the cranial continuation of the long muscle of the neck. Origin: Arises from caudal branches of the transverse processes of the C2-C6 vertebrae. Insertion: On the muscular tubercles of the basioccipital between the tympanic bullae. Action: Flexes the atlanto-occipital joint and draws the head side ways and the neck downward. Nerve: Rami ventrales of the cervicales nerve.  Longus colli m It lies adjacent to its contralateral fellow on the ventral surface of the bodies of the first six thoracic and all of the cervical vertebrae. Origin: On the convex ventral surfaces of the first six thoracic vertebrae. Insertion: Ventral border on the wing of the sixth cervical vertebra, as well as on the transverse process of the seventh cervical vertebra. Action: Draws the neck downward. Nerve: Rami ventrales of the cervicales nerve. Divided: Cervical and Thoracic (3 incompletely separated parts that arise 1st 6 thoracic vert.) portions.  Muscles by muscles Sternocleidomastoid m: sternocephalic m (btw sternum and head) brachiocephalic m (btw humerus and head Brachiocephalic m: Origin: Clavicular tendon and the distal end of the cranial surface of the cleidobrachial m (btw vestigial clavicle and humerus) humerus. cleidocephalic m (btw clavicular intersection and head) Insertion: Dorsal surface of the neck. Action: Bilateral fixation of the neck. Nerve: Brachiocephalic. Cleidocephalic m: cleidomastoid (all animals) cleidocervical (carnivors) cleido-occipital (ruminants and pig)  Brachiocephalicus m Origin: Clavicular tendon and the distal end of the cranial surface of the humerus. Insertion: Dorsal surface of the neck. Action: Bilateral fixation of the neck. Nerve: Brachiocephalic. Carnivores – 3 portions, named by their relations hip to the clavicular intersection: Cleidobrachialis, Cleidocephalicus also divided into cervical part and mastoid part (there is an occipital part in Pig and Ruminant)  Cleidobrachial m Distal part of the brachiocephalic m from the clavicular intersection to the cranial humeral crest. Considered as the "clavicular part of the deltoid muscle", but included into the brachiocephalic m Origin: humeral crest on distal end of the cranial surface of the humerus. Insertion: clavicular tendon/clavicular intersection/vestigial clavicle Action: draw the limb cranially and, acting bilaterally, to fix the neck Nerve: rami ventrales of nervi cervicales VII and VII Cleidomastoid m Ventral part extending from clavicular intersection to the mastoid process. Bovines: it inserts also on the muscular tubercle of the occipital bone. Origin: clavicular tendon/clavicular intersection/vestigial clavicle Insertion: mastoid/occipital bone Action: draw the limb cranially and, acting bilaterally, to fix the neck Nerve: accessory nerve, ventral branches of cervical nerves Cleidocervical m Dorsal/proximal part of the cleidocephalic muscle, from clavicular intersection to raphe of cranial portion of the neck. Origin: clavicular tendon/clavicular intersection/vestigial clavicle Insertion: neck Action: draw the limb cranially and, acting bilaterally, to fix the neck Nerve: accessory nerve, ventral branches of cervical nerves Cleido-occipital m Dorsal part of the cleidocephalic m, from clavicular intersection to nuchal crest in pigs and to nuchal line and nuchal ligament in ruminants Origin: clavicular tendon/clavicular intersection/vestigial clavicle Insertion: nuchal ligament, nuchal line, nuchal crest on occipital bone Action: draw the limb cranially and, acting bilaterally, to fix the neck Nerve: accessory nerve, ventral branches of cervical nerves  Steernocephalicus m Origin: It arises as a unit on the manubrium stern Insertion: Mastoid part of the temporal bone and to the dorsal nuchal line of the occipital bone. Action: To draw the head and neck to one side, lateral flexion Nerve: Ventral branches of the cervical nerves and branches of the accessory nerve. Divided in: Mastoid part: Ventral portion that separates as a large bundle that unites with the mastoid part of the cleidocephalicus in a tendon that inserts on the mastoid part of the temporal bone. Occipital part: Attaches to the nuchal crest as far as the midline of the neck by means of a thin aponeurosis.  Sternocephalic m. In carnivores 2 portions: Sternomastoid m. Sterno-occipital m. Both arise from the manubrium of the sternum together with the like-named muscles of the contralateral limb and insert on the mastoid process of the temporal bone and the nuchal crest of the occipital bone Bovine and goat – 2 part: Sternomastoid m: attachment as in carnivores Sternomandibular m.: Arises from the manubrium of the sternum and the 1st rib, extends cranially ventral to the jugular groove and attaches to the mandible by means of an aponeurosis. Horse: sternomandibular m. originates from the manubrium of the sternum, borders the trachea and the jugular groove ventrally and laterally and inserts to the mandible  M. Trapezius Thin triangular muscle. It lies superficially and consists of cervical and thoracic parts Origin: supraspinous ligament and the dorsal spinous processes, extending from the 3rd cervical vertebral to the 9th thoracic vertebra Insertion: Spine of the scapula. Action: Elevation of the limb and draws it forward. (protraction) Nerve: Accessory n. It is divided into a cervical and a thoracic por*on by a tendinous band extending dorsally from the spine of the scapula. Cervical part: It arises on the mid-dorsal raphe of the neck and the thoracic portion on the supraspinous ligament and the dorsal spinous processes, extending from the third cervical vertebral to the ninth thoracic vertebra. Both portions end on the spine of the scapula Thoracic part: It unites with the thoracolumbar fascia and the cervical part with the omotransverse muscle.  M. Omotransversarius Between the wing of the atlas, the transverse process of the axis and the fascia covering the lateral aspect of the shoulder joint and the spine of the scapula. Ventral border is fused to the cervical part of the trapezius muscle and in the horse, it unites with the cleidomastoid muscle. Origin: Distal portion of the scapular spine, as far as the acromion, and from that part of the omobrachial fascia that covers the acromial part of the deltoideus. Insertion: Caudal end of the wing of the atlas and the transverse process of the axis Action: To draw the limb forward. Nerve: Accessory n.  Rhomboid m. The rhomboid muscle is continuous between his different parts: Rhomboideus capitis: Capital part of the rhomboid muscle, only present in carnivores, arising form the tendinous raphe of the neck. Cervical rhomboid m. Thoracic rhomboid muscle: originates form the spinous processes of the the cranial thoracic vertebrae.  Cervical rhomboid m. Lies deep to trapezius muscle and inserts on the medial aspect of the dorsal part of the scapula. Origin: Spinous processes of the the cervical vertebrae. Dorsal median raphe of the neck near C2- C3 (Car, Su) or ligamentum nuchae (Ru, Eq) Insertion: cranial angle and dorsal border of scapula including scapular cartilage, cranial to rhomboideus thoracis Action: To elevate the limb, pull the limb and shoulder forward or backward, to draw the scapula against the trunk. Nerve: Dorsal branch of the cervical and thorcic nerves.  M. Splenius Dorsolateral aspect of the neck Below the superficial muscles of the neck and covers the longissimus muscle of the head, the semispinal muscle of the head and parts of the dorsal spinal muscle Origin: from the spinocostotransversal fascia and the nuchal ligament; Ruminants (also from spinous processes of the 1-4th thoracic vert). Divided: capital and a cervical portion (m. splenius capitis et cervicis); carnivores only capital portion. Insertion: Capital portion continues to the nuchal crest of the occiput (horse: the mastoid process of the temporal bone). Cervical portion inserts on the transverse processes of the 3rd-5th cervical vert. Action: Extends and raises the neck. In unilateral action to draw the head and neck laterally. Fixation of the first thoracic vertebra. It plays an important role in maintaing balance during gallop. Nerve: Cervicales.  M. Scalenus 2 or 3 separate muscles: Pig and ruminants: 3 muscles (dorsal, ventral and middle scalene muscles Horse: dorsal muscle is absent Carnivores: ventral muscle is absent All three portions extend from the transverse processes of the 3rd to 7th cervical vert. to the lateral surface of the 1st and the 3rd to the 8th ribs (depending on the species) Origin: Transverse processes of cervical vertebrae An obvious division between its muscular and tendinous portions is visible at the 5th rib, making it a useful landmark Action: Long muscle of the neck and the scalene muscles belong to a group of muscles, which depress and flex the neck downward. In unilateral action, to bend the neck laterally, lateral flexion. When the neck is fixed, the dorsal part can act in inspiration. Ventral scalenus m. Origin: middle portion of first rib Insertion: transverse processes of C3-C6 (Pig also C1 and C2) Action: Draws the neck downward. In unilateral action, to bend the neck sideward. When the neck is fixed, the supracostal part can act in inspiration. Nerve: ventral branches of the cervical and thoracic nerves. Middle scalenus m. Origin: transverseprocessesofC3-7(dogC6-7, pig also C1-2) Insertion: dorsal portion of the lateral surface of ribs 1 (3 and 4) Action: Draws the neck downward. In unilateral action, to bend the neck sideward. When the neck is fixed, the supracostal part can act in inspiration. Nerve: ventral branches of the cervical and thoracic nerves. It is located dorsally from the ventral scalene muscle. In many species, it is separated with ventral scalene by the brachial plexus, but this boundary is not present in carnivores like dogs, causing a lot of problem of definition Dorsal scalenus m. Origin: From the 3rd to 8th rib (varying between species) to insert to the 3rd to 6th cervical vertebrae in all domes*c mammals (except in the horse, and small rum in which this muscle is absent). Insertion: transverse processes of C3-C6 vertebrae AcCon: Draws the neck downward. In unilateral ac*on, to bend the neck sideward. When the neck is fixed, the supracostal part can act in inspira*on. Nerve: Nerve: ventral branches of the cervical and thoracic nerves. This muscle is situated laterally from the ventral and middle scalene (so the official denomina*on "dorsal scalene" may be very confusing).  M. Serratus ventralis (cervical part) Covers the caudal half of the lateral surface of the neck. Origin: Facies serrata of the scapula Insertion: Transverse processes of the last five cervical vertebrae (cervical part). This is continuous with a thoracic component that inserts on the first 7-8 ribs. 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. Innervation: Ventral branches of cervical nerves.  Cutaneous muscles of the trunk Cutaneus trunci m = 7 Cutaneous omobrachial m. (not labelled) Preputial m = num 8 Supramammary m. (not labelled)  Cutaneous trunci Covers a great portion of the thorax and abdomen. It extends from the gluteal region to the thoracic region and dips medial to arm with the deep pectoral muscle. Origin: Superficial gluteal fascia. Insertion: Axilla and on caudal border of deep pectoral muscle. Action: Shakes the skin to remove foreign bodies and increase heat production. It also tenses the skin when required. The prepu?al muscle draws the prepuce over the glans after erection. The supramammary muscle aids in support of the mammary glands and perhaps in milk ejec?on. Nerve: Efferent supply, lateral thoracic nerve, afferent supply, lateral thoracic and lateral branches of the intercostal nerves and the costoabdominalis, iliohypogastricus, ilioinguinlalis and genitofemorilis.  Cutaneous omobrachial m It covers the lateral aspect of the shoulder and arm Its fibres begin about the upper part of the scapular region and extent vertically downwards to the upper part of the forearm They are continuous behind with the abdominal part It covers the lateral aspect of the shoulder and forearm in ruminants and the horse and tenses the skin in that region.  Preputial m Present in carnivores, pigs and ruminants and are strongest in the bull. Can be divided: cranial portion (protracts the prepuce), and a caudal portion (retracts the prepuce).  Supramammary m Paired muscle in female carnivores (homologous with the m. preputialis of the male) Origin: Extending between the xiphoid to the pubic region, covering the mammary glands. Function: support of the mammary glands and perhaps in milk ejection Innervation: Efferent supply, lateral thoracic nerve; afferent supply, lateral thoracic and lateral branches of the intercostal nerves and the nn. costoabdomi- nalis, iliohypogastricus, ilioinguinalis, and genitofemoralis.  Sternohyoideus m Originates from the manubrium of sternum and the firs rib and inserts on the basihyoid bone. It meets its contralateral partner on the midline of the neck and they extend cranially, covering the ventral surface of the trachea. Origin: Deep surface of the manubrium of the sternum and the cranial edge of the first costal cartilage. Insertion: Basihyoid bone. Action: Pulls the basihyoid bone and tongue caudally. Nerve: ventral branches of cervical nerves, and sometimes hypoglossal nerve  Sternothyroideus m Separates from the sternohyoid in the middle of the neck and inserts on the thyroid cartilage of the larynx. It is covered in the neck by the sternocephalic, and covers more of the lateral surface of the trachea. Origin: first costal cartilage Insertion: thyroid cartilage Action: draw the hyoid apparatus, larynx and tongue caudally Nerve: ventral branches of cervical nerves  Specific muscles of the head Lateral straight muscle of the head (m. rectus capitis lateralis) Origin: Ventral surface of the wing of the atlas Inserts: Base of the paracondylar process of the occipital bone Ventral straight muscle of the head (m. rectus capitis ventralis) Origin: Ventral arch of the atlas. Insertion: Basioccipital bone. Both muscles Action: flexes the atlanto-occipital joint and tilts the head.