Class 9 - THE MUSCLES OF THE NECK AND THE BACK Flashcards
Landmark of the neck (cervical) region
Sternocleidomastoid (SCM)
Anterior region of the neck is divided into two triangles by the SCM
Anterior triangle
Posterior triangle
Muscles of the anterior of the neck assist in…
Deglutition and speech
Two groups of muscles in relation to the hyoid bone
Suprahyoid muscles
Infrahyoid muscles
Suprahyoid muscles form…
The floor of the mouth
Suprahyoid muscles action
Elevate the hyoid bone, the floor of the mouth and the tongue when swallowing
Four suprahyoid muscles
- Digastric
- Stylohyoid
- Mylohyoid
- Geniohyoid
Suprahyoid muscles actively…the mandible when…
Depress the mandible when we need to open the mouth wider
Digastric origin
Anterior belly from inner side of inferior border of mandible
Posterior belly from temporal bone
Digastric insertion
Body of hyoid via an intermediate tendon
Digastric action
Elevates hyoid bone
RMA: Depresses mandible (opening mouth)
Digastric innervation
Anterior belly: mandibular division of trigeminal (V) nerve
Posterior belly: facial (VII) nerve
Stylohyoid origin
Styloid process of temporal bone
Stylohyoid insertion
Body of hyoid bone
Stylohyoid action
Elevates hyoid bone and draws it posteriorly
Stylohyoid innervation
Facial (VII) nerve
Mylohyoid origin
Inner surface of mandible
Mylohyoid insertion
Body of hyoid bone
Mylohyoid action
Elevates hyoid bone and floor of mouth and depresses mandible
Mylohyoid innervation
Mandibular division of trigeminal (V) nerve
Geniohyoid origin
Inner surface of mandible
Geniohyoid insertion
Body of hyoid bone
Geniohyoid action
Elevates hyoid bone, draws hyoid bone and tongue anteriorly. Depresses mandible
Geniohyoid innervation
First cervical spinal nerve (C1)
Infrahyoid muscles look like
Ribbons or straps inferior to the hyoid bone
Infrahyoid muscles action
Depress the hyoid bone and move the larynx when swallowing and talking
Four infrahyoid muscles
- Omohyoid
- Sternohyoid
- Sternothyroid
- Thyrohyoid
Omohyoid origin
Superior border of scapula and superior transverse ligament
Omohyoid insertion
Body of hyoid
Omohyoid action
Depresses hyoid bone
Omohyoid innervation
Branches of spinal nerves C1-C3
Sternohyoid origin
Medial end of clavicle and manubrium of sternum
Sternohyoid insertion
Body of hyoid bone
Sternohyoid action
Depresses hyoid bone
Sternohyoid innervation
Branches of spinal nerves C1-C3
Sternothyroid origin
Manubrium of sternum
Sternothyroid insertion
Thyroid cartilage of larynx
Sternothyroid action
Depresses thyroid cartilage of larynx
Sternothyroid innervation
Branches of spinal nerves C1-C3
Thyrohyoid origin
Thyroid cartilage of larynx
Thyrohyoid insertion
Greater horn of hyoid bone
Thyrohyoid action
Depresses hyoid bone
RMA: elevates thyroid cartilage
Thyrohyoid innervation
Branches of spinal nerves C1-C2 and descending hypoglossal (XII) nerve
The head is attached to the vertebral column at the…
Atlanta-occipital joint
Suboccipital muscles
Deep muscles in the back of the head attached between the occipital bone and C1-C2
Bilateral contraction of the neck muscles allows for…
Balance
Unilateral contraction of the neck muscles allow for…
- Rotation
- Flexion
- Extension
- Lateral flexion
Sternocleidomastoid (SCM) origin
Sternal head: manubrium of sternum
Clavicular head: medial third of clavicle
Sternocleidomastoid (SCM) insertion
Mastoid process of temporal bone and lateral end of superior nuchal line of occipital bone
Sternocleidomastoid (SCM) bilateral action
Flex cervical portion of vertebral column, extend head at AOJ
Sternocleidomastoid (SCM) unilateral action
Lateral flexion of neck and head to same side
Rotate head opposite to contracting muscle
Lateral flexion to opposite side of contracting muscle
Sternocleidomastoid (SCM) posterior fibre action
Assist in extension of head
Sternocleidomastoid (SCM) RMA
Elevates sternum during forced inhalation
Sternocleidomastoid (SCM) innervation
Accessor (XI) nerve, C2 and C3
Superior attachments of the posterior neck and back
- Splenius capitis
2. Splenius cervicis
Erector spinae muscle group is most…
Medial and superficially located group of muscles in the back
Erector spinae muscle group consist of…
Iliocostalis muscles (lateral)
Longissimus muscles (intermediate)
Spinalis muscles (medial)
Erector spinae muscle group actions
Principal extensor of the spine, maintain erect posture.
Acting unilaterally they laterally flex the spine
Iliocostalis group consist of…
Iliocostalis cervicis
Iliocostalis thoracis
Iliocostalis lumborum
Iliocostalis action
Acting together: extend and maintain erect posture of vertebral column and their respective region
Acting singly: laterally flex vertebral column of their respective regions to same side as contracting muscle
Longissimus group (intermediate) consists of…
Longissimus capitis
Longissimus cervicis
Longissimus thoracis
Spinalis group (medial) consists of…
- Spinalis capitis
- Spinalis cervicis
- Spinalis thoracis
Spinalis group muscles run…
Closest to the spinous processes
Transversus spinalis group run from…
Transverse processes to spinal processes above
Transversus spinalis group muscle fibres are..
Oblique in direction
Transversus spinalis group are…than the…
Deeper than the erector spinae group
Transversus spinalis group are…and…of the spine
Extensors and rotators
Transversus spinalis group contains…
- Semispinalis capitis
- Semispinalis cervicis
- Semispinalis thoracis
- Multifidus
- Rotatores
Rotatores muscles are arranged…
Along the whole extension of the vertebral column
Rotatores muscles extend from the…to the…
The transverse process of one vertebra to the laminae of superior vertebrae two to three segments above
Segmental muscles (deepest)
Main postural muscles
Stabilizing the vertebral column by “locking” the vertebrae to each other
Segmental muscles unite the…and…of…
Spinous and transverse processes of consecutive adjacent vertebrae
Segmental muscles include
- Intertransversarii
2. Interspinalea
Scalene muscle actions
Acting bilaterally: flex the head and elevate ribs during forced inspiration
Acting unilaterally: laterally flex and rotate the head
Scalene muscles include:
- Anterior scalene
- Middle scalene
- Posterior scalene