W6 L5
Lecture 5 – Neuromusculoskeletal movement
of the axial skeleton
Learning objectives
1. Determine the correct terminology to describe a skeletal muscles action.
2. Determine the movement of the identified muscles of facial expression and mastication.
3. Identify the actions associated with each muscle highlighted during this lecture. 4. Identify and
correlate the joints (structural or functional) or regions with the skeletal muscles that cross them
and the muscles actions produced.
__________________________________________________________________________________
Describing a muscle action - movement terminology
• You must describe two components in your response (the order is not important):
○ The joint(s) appropriate name
○ The specific action that has or will occur at the joint indicated.
• Contralateral: relating to or denoting the side of the body opposite to that on which the muscle
contracts
• Ipsilateral: occurring on the same side of the body
• Bilateral: (B/L) having or relating to two sides; affecting both sides of the body
• Unilateral: (U/L) relating to or affecting only one side of the body
• Osteokinematics: describes the mechanics concerned with the motion of objects without
reference to the forces which cause the motion
• Motion segment: is the smallest physiological motion unit of the spine to exhibit biomechanical
characteristics similar to those of the entire spine
• Line of action: the line along which a force or the resultant of any number of forces may be
considered to act Temporomandibular joint motion
• Synergistic: various muscles are working together to produce a specific action
Muscles of facial expression
• Epicranius: frontal belly of the Occipitofrontalis
○ Action: the frontalis section controls movement of the forehead and eyebrows, enabling
forehead wrinkling.
• Orbicularis Oculi
○ Action: its function is to close the eyelid, and to assist in the passing and draining of tears,
winking, blinking and squinting Synovial joints of the axial skeleton
• Levator palpebrae superioris
○ Action: is the muscle in the orbit that elevates the superior (upper) eyelid
• Orbicularis oris
○ Action: The muscle inserts directly into the lips and controls movements of the mouth and
lips; controls and purses lips
• Buccinator
○ Action: its purpose is to pull back the angle of the mouth, flatten the cheek area, aids in
holding the cheek to the teeth during chewing, keeping the food in the correct position
while chewing
• Platysma
○ Action: it can slightly part the mouth and draw out the corners of the lips to the side and
down; tenses skin of neck
Temporomandibular joint motion
• Actions produced at the TMJ by the muscles of mastication
○ Depression and elevation of the mandible.
○ Protrusion (protraction) and retrusion (retraction) of the mandible.
• Lateral excursion of the mandible
Regional facet joint orientation
• The red line indicates the plane of the superior articular facet whereas the white line represents Regional facet joint orientation
either a vertical or horizontal reference line
• Every set of facet joints at every motion segment within the vertebral column from proximal to
distal will vary, slightly
• The angles indicated for each region are generated from within the mid-region of each region
• Cervical spine facet joints
○ C1 & C2 facets are parallel to the transverse plane
○ At C3-C7 facets progressively increase their orientation to the transverse plane and are
parallel to the frontal plane
○ Motion
▪ Flexion-extension
▪ Lateral flexion Vertebral column - segmental motion and sagittal
Reduced rotation plane curvatures
• Thoracic spine facet joints
○ In the thoracic spine the facets continue to increase their orientation to the transverse
plane and also increase their orientation to the frontal plane
○ Motion
▪ Rotation
▪ Reduced - flexion-extension
▪ Reduced - lateral flexion
CHI108 Page 1
Lecture 5 – Neuromusculoskeletal movement
of the axial skeleton
Learning objectives
1. Determine the correct terminology to describe a skeletal muscles action.
2. Determine the movement of the identified muscles of facial expression and mastication.
3. Identify the actions associated with each muscle highlighted during this lecture. 4. Identify and
correlate the joints (structural or functional) or regions with the skeletal muscles that cross them
and the muscles actions produced.
__________________________________________________________________________________
Describing a muscle action - movement terminology
• You must describe two components in your response (the order is not important):
○ The joint(s) appropriate name
○ The specific action that has or will occur at the joint indicated.
• Contralateral: relating to or denoting the side of the body opposite to that on which the muscle
contracts
• Ipsilateral: occurring on the same side of the body
• Bilateral: (B/L) having or relating to two sides; affecting both sides of the body
• Unilateral: (U/L) relating to or affecting only one side of the body
• Osteokinematics: describes the mechanics concerned with the motion of objects without
reference to the forces which cause the motion
• Motion segment: is the smallest physiological motion unit of the spine to exhibit biomechanical
characteristics similar to those of the entire spine
• Line of action: the line along which a force or the resultant of any number of forces may be
considered to act Temporomandibular joint motion
• Synergistic: various muscles are working together to produce a specific action
Muscles of facial expression
• Epicranius: frontal belly of the Occipitofrontalis
○ Action: the frontalis section controls movement of the forehead and eyebrows, enabling
forehead wrinkling.
• Orbicularis Oculi
○ Action: its function is to close the eyelid, and to assist in the passing and draining of tears,
winking, blinking and squinting Synovial joints of the axial skeleton
• Levator palpebrae superioris
○ Action: is the muscle in the orbit that elevates the superior (upper) eyelid
• Orbicularis oris
○ Action: The muscle inserts directly into the lips and controls movements of the mouth and
lips; controls and purses lips
• Buccinator
○ Action: its purpose is to pull back the angle of the mouth, flatten the cheek area, aids in
holding the cheek to the teeth during chewing, keeping the food in the correct position
while chewing
• Platysma
○ Action: it can slightly part the mouth and draw out the corners of the lips to the side and
down; tenses skin of neck
Temporomandibular joint motion
• Actions produced at the TMJ by the muscles of mastication
○ Depression and elevation of the mandible.
○ Protrusion (protraction) and retrusion (retraction) of the mandible.
• Lateral excursion of the mandible
Regional facet joint orientation
• The red line indicates the plane of the superior articular facet whereas the white line represents Regional facet joint orientation
either a vertical or horizontal reference line
• Every set of facet joints at every motion segment within the vertebral column from proximal to
distal will vary, slightly
• The angles indicated for each region are generated from within the mid-region of each region
• Cervical spine facet joints
○ C1 & C2 facets are parallel to the transverse plane
○ At C3-C7 facets progressively increase their orientation to the transverse plane and are
parallel to the frontal plane
○ Motion
▪ Flexion-extension
▪ Lateral flexion Vertebral column - segmental motion and sagittal
Reduced rotation plane curvatures
• Thoracic spine facet joints
○ In the thoracic spine the facets continue to increase their orientation to the transverse
plane and also increase their orientation to the frontal plane
○ Motion
▪ Rotation
▪ Reduced - flexion-extension
▪ Reduced - lateral flexion
CHI108 Page 1
