Cervical & Pectoral Muscles

Cervical & Pectoral Muscles

• Muscles of the dorsal cervical region
• Muscles of the ventral cervical region
• Pectoral muscles

Cervical Muscles

• Muscles of the neck are located on the dorsal and lateral sides of the cervical column
• Some neck muscles are associated with the hyoid apparatus
• The hyoid apparatus supports the tongue, larynx, and pharynx
• Muscles of the dorsal cervical region
• Muscles of the ventral cervical region

Dorsal Cervical Muscles

• Trapezius
• Omotransverse
• Rhomboid
• Serratus ventralis
• Splenius
• Semispinalis capitis
• Longissimus muscles of head and neck

M. Trapezius

• A thin, triangular muscle with cervical and thoracic parts, lying superficially
• Originates from the supraspinous ligament and the spinous processes, extending from the 3rd cervical to the 9th thoracic vertebra
• Insertion point is on the spine of the scapula
• This muscle elevates the limb and draws it forward in protraction
• Innervated by the accessory nerve
• The cervical part originates on the middorsal raphe of the neck and connects with the omotransverse muscle
• The thoracic part connects with the thoracolumbar fascia

M. Omotransversarius

• Found 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
• The ventral border merges with the cervical part of the trapezius muscle; in horses, it unites with the cleidomastoid muscle
• Originates from the distal portion of the scapular spine, as far as the acromion, and the omobrachial fascia that covers the acromial part of the deltoideus
• Inserts on the caudal end of the wing of the atlas and the transverse process of the axis
• Draws the limb forward via the Accessory nerve

M. Rhomboid

• Lies completely under the trapezius muscle
• This muscle is continuous between his different parts
• The capitis part is only present in carnivores
• Originates from the tendinous raphe of the neck
• Capitis part lies deep to trapezius and inserts on the medial aspect of the dorsal scapula part
• Origin: spinous processes of the cervical vertebrae, dorsal median raphe of the neck near C2-C3 or ligamentum nuchae
• Insertion: cranial angle and dorsal border of scapula including scapular cartilage, cranial to rhomboideus thoracis
• Elevates the limb, pulls the limb and shoulder forward/backward, draws the scapula against the trunk
• Innervated by the dorsal branches of the cervical and thoracic nerves

M. Serratus Ventralis (Cervical Part)

• Covers the caudal half of the lateral surface of the neck
• Originates from the facies serrata of the scapula
• Transverse processes of the last five cervical vertebrae for the cervical part
• It is continuous with a thoracic component that inserts on the first 7-8 ribs
• Support trunk
• Carry the trunk cranially and caudally and innervated by the ventral branches of cervical nerves
• Serratus ventralis cervicis and thoracis are continuous together in Carnivours

M. Splenius

• Located on the dorsolateral aspect of the neck, below the superficial neck muscles as well as covers the longissimus muscle of the head, the semispinal muscle of the head, plus parts of the dorsal spinal muscle
• Originates from the spinocostotransversal fascia and the nuchal ligament with ruminants also originating from spinous processes of the 1-4th thoracic vert
• It is divided into 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) and the Cervical portion inserts on the transverse processes of the 3rd-5th cervical vert
• Action: extends and raises neck
• In unilateral action, draws the head and neck laterally
• Fixates the first thoracic vertebra
• Plays an important role in maintain balance during gallop
• Innervated by the cervicales nerve

M. Semispinalis Capitis

• Large muscular continuation towards the head of the spinalis and semispinalis thoracic and cervical muscles.
• Separated on the left and right by the nuchal ligament and the median fibrous raphe
• Situated at the upper and back part of the neck, deep to the Splenius, and medial to the Longissimus cervicis and capitis
• Origin: Transverse processes of T6-C3
• Insertion area between superior and inferior nuchal line
• Innervated by the greater occipital nerve and posterior rami of spinal nerves of C1-C5
• Action: Extend the head
• Divided into two parts
• Biventer cervicis muscle is the dorsomedial division of semispinalis capitis that originates from the thoracolumbar fascia or thoracic vertebral transverse processes
• Courses superficial to multifidus muscles to insert on occipital bone
• Complexus muscle is the ventrolateral division of semispinalis capitis that arises from cervical vertebral articular processes and inserts lateral to the biventer cervicis on occipital bone.

M. Spinalis Cervicis

• The cervical part of the spinalis muscle that attaches to cervical vertebral spinous processes
• Origin: extends across the spinous processes of one or more thoracic vertebrae, and sometimes the last cervical vertebra
• Insertion: spinous processes of 2nd to 5th cervical vertebrae.
• Fixes the thoracic vertebral column and to extend the neck
• Innervated by the dorsal branches of the cervical and thoracic nerves

M. Interspinalis Cervicis

• Interspinous neck muscles in humans and domestic mammals
• Only in carnivores
• Small, short, thin muscles, extending between the adjacent edges of the last four or five cervical spinous processes, as well as between the first thoracic spinous process and the last cervical one.
• Lie against the interspinous ligaments
• Receive vessels and nerves like the spinal muscles of the neck

Long Muscle of the head (m. longissimus capitis)

• It lies medial to the mm. longissimus cervicis and splenius. Covers the m. semispinalis capitis along its ventral border
• Origin: transverse processes of the first thoracic and last cervical vertebrae
• Insertion: wing of the atlas
• Action: Extension of the atlantooccipital joint.
• The atlantal portion rotates the atlantoaxial joint in unilateral action while in in bilateral action it fixes the atlantoaxial joint
• Dorsal branches of the cervical nerves (nn. cervicales)

Long Muscle of the neck (m. longissimus cervicis)

• Action Extends the neck; in unilateral action to raise the neck obliquely and turn it to one side
• The Origin is a continuation of the longissimus thoracis, transverse processes of the first 5-8 thoracic vertebrae
• The Insertion is the last cervical vertebra
• Innervated by the dorsal branches of the thoracic nerves
• Long muscle of the neck, thoracic and lombar(m. longissimus)

Ventral Cervical Muscles

• Cervical fascia
• Sternocephalic
• Brachiocephalic
• Sternohyoid
• Sternothyroid
• Scalene

Cervical Fascia

• Direct continuation of the fasciae of the head termed "fascia of the neck (fascia cervicalis)" is a collective term for connective tissue layers of the neck
• Contains m. sphincter colli superficialis and the platysma
• Encloses stern, and cleidocephalicus muscles and trapezius
• Bilateral portions of the fascia meet dorsally and ventrally
• Origin: Superficial temporal, parotid and masseteric fasciae, continuing caudally into the superficial scapular fascia and ventrally into the superficial trunk fascia of the sternal region and axillary fascia

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
• 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 -Fibers of the sphincter colli superficialis may reach the thorax, radiate over the shoulder joint, or blend with the cervical part of the platysma

Platysma

• In carnivores and pigs, the Platysma is a well-developed muscular sheet
• Originates from the facial cutaneous muscle
• Tenses, moves the skin on the dorsal and lateral side of the neck

Deep Sphincter Muscle

• In carnivores and equine it is present, while in pigs and ruminants, it is absent
• Extends from one side of the neck to the other, ending dorsally/ventrally on the median raphe
• More caudally is attached to the sternal manubrium
• Beneath the platysma and cutaneous muscles of the face on the lateral aspect of head and neck, tenses the superficial fascia in the laryngeal region

Cervical Cutaneous Muscles

• Not in carnivores
• Originates from the manubrium of the sternum and covers the jugular groove
• Situated at the ventral aspect of the neck

M. Sternocleidomastoid

• Divided into 2 parts
• Sternocephalic between the sternum and the head
• Brachiocephalic between the humerus and the head and further subdivided
• Cleidobrachial muscle: between the vestigial clavicle and the humerus
• Cleidocephalic muscle: between the clavicular intersection and the head

M. Sternocephalic

• In carnivores there are 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
• In Bovine and Goat has – 2 parts
• Sternomastoid m.: Shows the same 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 attachés to the mandible via aponeurosis
• In Horses
• Sternomandibular muscle originates from the manubrium of the sternum
• Borders the trachea and the jugular groove ventrally and laterally and inserts to the mandible
• Action: Bilateral fixation of the neck
• Accessory nerve

M. Brachiocephalic

• Origin: clavicular tendon and the distal end of the cranial surface of the humerus and insertion: dorsal surface of the neck.
• Action: Bilateral fixation of the neck. Move the limb forward,
• Nerve: accessory and axillary n
• Consist of the Cleidobrachial muscle, Clavicular intersection, and Cleidocephalic muscle
• Mastoid part (Ceidomastoid muscle) is within All animals
• Cervical part (Cleidocervical muscle) is within Carnivorous
• Occipital part (Cleido-occipital muscle) is within ruminants and the pig

M. Cleidobrachial

• Distal part of the brachiocephalic muscle from is the clavicular intersection to the cranial humeral crests
• A humeral crest on the distal end of the cranial surface of the humerus is where it Originates from
• A clavicular tendon, clavicular intersection or vestigial clavicle is where it inserts
• Action: draws the limb cranially ad acting bilaterally, to fix the neck
• Innervated via the axillary nerve

M. Cleidomastoid

• Extends ventrally extending from clavicular intersection to the mastoid process
• Originating in the Clavicular tendon/clavicular intersection/vestigial clavicle
• Insertion: mastoid/occipital bone
• In Bovines: it inserts also on the muscular tubercle of the occipital bone
• Action: draws the limb cranially, acting bilaterally, to fix the neck
• Accessory nerve

M. Cleidocervical

• Present in carnivores
• Dorsal part of the cleidocephalic muscle, from clavicular intersection to raphe of cranial portion of the neck
• Originates at clavicular tendon/clavicular intersection/vestigial clavicle is the
• Insertion: neck
• Action: draws the limb cranially, acting bilaterally, to fix the neck
• Accessory nerve

M. Cleido-occipital

• Present in pigs and ruminants
• Dorsal part of the cleidocephalic muscle, from clavicular intersection to nuchal crest in pigs and to nuchal line and nuchal ligament in ruminants
• Originates at the clavicular tendon/clavicular intersection/vestigial clavicle
• Action: draws the limb cranially, acting bilaterally, to fix the neck
• Innervated by the accessory nerve

M. Sternohyoid

• Originates from the manubrium of sternum and the firs rib and inserts on the basihyoid bone
• Meets its contralateral partner on the midline of the neck, and they extend cranially, covering the ventral surface of the trachea.
• Originates from the deep surface of the manubrium of the sternum and the cranial edge of the first costal cartilage
• Inserts on the Basihyoid bone
• Action: Pulls the basihyoid bone and tongue caudally
• Innervated by the ventral branches of cervical nerves, and sometimes hypoglossal nerve

M. Sternothyroid

• Separated from the sternohyoid in the middle of the neck and inserts on the thyroid cartilage of the larynx
• The sternocephalic covers it in the neck and covers more of the lateral surface of the trachea
• Origin: first costal cartilage
• Insertion: thyroid cartilage
• Action: draws the hyoid apparatus, larynx and tongue caudally
• Innervated by the ventral branches of cervical nerves

M. Scalene

• 2 or 3 separate muscles
• Pig and ruminants consist of 3 muscles (dorsal, ventral and middle scalene muscles
• Horse the dorsal muscle is absent
• Carnivores the ventral muscle is absent
• Originates from the Obvious division between its muscular and tendinous portions is visible at the 5th rib, marking it a useful landmark
• Action: Long muscle of the neck and the scalene muscles depress and flex the neck downward
• In unilateral action, bends the neck laterally, in lateral flexion.
• When the neck is fixed, the dorsal part can act in inspiration. Long muscle of the neck
• Ventral component: Transverse processes 3rd to 6th cervical vert to cranial surface of the middle of the first rib;
• Middle component: Transverse processes 6th to 7th cervical vert and insert on the dorsal portion of the lateral surface of ribs 3-4
• Dorsal component: Transverse processes 4th to 6th cervical vert and insert on the lateral surface of ribs 2 and 8

M. Ventral Scalenus

• The Origin consists of the middle portion of the 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 aid inspiration
• Innervated by the ventral branches of the cervical and thoracic nerves

M. Middle Scalenus

• Origin is the transverse processes of C3-7 (dog C6-7, pig also C1-2)
• Insertion the dorsal portion of the lateral surface of ribs 1 (3 and 4)
• Situated dorsally from the ventral scalene muscle
• Action: Draws the neck downward
• In unilateral action it would bend the neck sideward
• When the neck is fixed the supracostal part can aid inspiration
• Innervated by the ventral branches of the cervical and thoracic nerves

M. Dorsal Scalenus

• Origin: a varies by species from the 3rd to 8th rib to insert to the 3rd to 6th cervical vertebrae
• It is however in all domestic mammals except in horses and small ruminants in which this muscle is absent
• Inserts at the transverse processes of C3-C6 vertebrae (pig also C1 and C2)
• Muscle draws the neck downward or will and bends side ways during the fixation of in unidirectional
• Fixed neck leads to the function: supracostal respiration and nerve that acts in its ventral branches also are to action of drawing the neck dorsal

Pectoral Muscles

• Superficial Pectoral Muscles are those are Descending pectoral muscles and Transverse pectoral muscles
• Ascending pectoral muscle
• Subclavian muscle

M. Superficial Pectoral

• Occupies the space between the ventral thoracic wall and the thoracic limb proximal portion and forms ventral axilla
• The Descending division (m. pectoralis descendens), originates from of the sternum and terminates at the crest of the greater tubercle of the humerus
• The Transverse Pectoral It (m. pectoralis transversus)arises caudal to the descending pectoral from the aspect of the sternum and blends with the fascia of the forearm
• Origin: Paramedially on the cranial end of the sternum
• Inserts: Entire crest of the greater tubercle of the humerus
• Carnivores find descending pectoral muscle difficult to distinguish in from the thicker transversus
• Both cover biceps muscle an on the crest of the greater tubercle the humerus

M. Deep Pectoral

• Action supports the limb, draws back of the limb backward it draws limb forward
• Pectoral support the limb,
• Cranial and cervical nerve support limb
• Strong muscle from the sternum, xiphoid cartilage/costal cartilages, inserts on the medial portion of the proximal humerus species.

M. Deep Pectoral

• Action: During locomotion, muscles to move the trunk cranially the advance extends over shoulder draw the limb backward it the

###M.Deep Pectoral (Horse)

• Largest pectoral the muscle of the abdominal and the lateral rib, tunic, aspect arises from the the sternum, tunic costal arises from the the
• Inserts to branches to the tubercle or the capula the humerus: over tubercle
• Action: during trunk, forward the trunk, move trunk muscle the extend a during locomotion move joint the trunk extends joint advanced

M. Subclavian Muscle

• In Ruminants it is band thatoriginates from the first blend and insertion tendon which is forms and costal
• Absent in and carnivores the inserts to which is and muscle the is to which In it absent,
• In swine and shoulder; extends, in at origin (from of or muscle; the sternum muscle The In band from which origin that. to that