Head, TMJ & Mandibular Movements

Head and Temporomandibular Joint

• The head consists of two bony parts which include the cranium and the face
• There is one synovial joint: the temporomandibular joint (TMJ)
• TMJ is the only skeletal movement of note in the head
• The articulation occurs between the mandible (jaw) and the temporal bone
• The movement is simultaneous

Synovial Joints

• Capusles surround them filled w/Synovial fluid, for motion, therefore friction is reduced and motion is enhanced

Cranial Bones

• These include the frontal, parietal, temporal, sphenoid, and occipital bones

Facial Bones

• These include the nasal, maxillae, mandible, and zygomatic bones
• The nasal bones form the bridge of the nose

Mandibular Movements

• Depression: Lowering the mandible to open the mouth within the sagittal plane about a frontal axis
• Elevation: Raising the mandible to close the mouth within the sagittal plane about a frontal axis
• Protraction (Protrusion): Moving the mandible anteriorly within the horizontal plane about a vertical axis
• Retraction (Retrusion): Moving the mandible posteriorly within the horizontal plane about a vertical axis
• Bilateral TMJ movement occurs simultaneously and identically for all motions except lateral deviation
• During lateral deviation, one TMJ moves laterally while the other moves medially
• The normal resting position of the TMJ is with the teeth slightly apart and lips closed

Arthrokinematics of Mouth Opening

• For the mouth to open (osteokinematic movement of depression), arthrokinematic movements must occur within the joint
• First, the mandibular condyle rolls forward (anteriorly along the disc), followed by a downward and forward glide
• Intracapsular disc found in the upper and lower joint spaces facilitate these movements
• As a fibrous cartilage, the disc improves the fit, reduces friction, and distributes the load within the joint

Mandibular Depression

• Mandibular condyle rolls on the disk, causing anterior glide of the condyle as the ramus moves posteriorly

Protraction and Retraction

• Anterior and posterior glide, respectively, occur in the upper joint space

Lateral Deviation

• One mandibular condyle spins in the mandibular fossa to the same side as the deviation
• The other mandibular condyle glides anteriorly

Bones and Landmarks and Cranial Bones

• The listed cranial bones are flat bones, whereas the listed facial bones are irregular bones
• Landmarks of note for the cranial bones include the sutures, fossae, and the occipital condyles (knuckle-like structures that articulate with the atlas of the spinal column)
• Be aware of the cranial bones which comprise the various fossa

Zygomatic Arch

• is made up of structure/bones
• Include points of articulation which form the TMJ with the surrounding landmarks

Mandible Landmarks

• Include the convex point of articulation for the TMJ, the mandibular condyle, as well as the ramus, notch, and coronoid process
• Do not confuse with the coracoid process of the scapula

Ligaments and Cartilage

• Ligaments articulate with the hyoid & styloid process
• The thyroid cartilage forms the front (anterior) portion of the larynx (voice box), the outward projection is the Adam's apple
• Both males and females have the Adam’s apple
• A cut zygomatic arch can demonstrate the articular disc and joint spaces

Hyoid Bone

• The Hyoid's primary functions are to facilitate swallowing, support the tongue and larynx, and assist with breathing

Joints

• Cranium and face joints are synarthrosis-fibrous structures
• TMJ: Is synovial, ball and socket and has three degrees of freedom

Temporalis Muscle

• It is a broad, fan-shaped, superficial muscle found within the temporal fossa (deep to the zygomatic arch)
• Contributes to elevation, retraction, and lateral deviation of the mandible
• Can be felt when you bite down hard, placing fingers on the side of your head between your eyes and ears
• Knowing the cranial nerve innervations
• CN 5 (trigeminal) is both a sensory and motor nerve, provides sensation feedback for the face, forehead, and cheek, and controls muscle movement for chewing

Masseter Muscle

• Is a thick, superficial, nearly quadrilateral-shaped muscle
• Can be felt by biting forcefully with fingers placed on your cheek
• Its primary functions are elevation, protrusion, and lateral deviation (can act unilaterally)
• Also innervated by CN 5 (chewing)

Medial Pterygoid Muscle

• Deep to the lateral pterygoid
• Contributes to mandibular elevation and protrusion, as well as unilateral contributions to lateral deviation
• Contributes to mandibular depression, protrusion, and lateral deviation

Actions of the Medial and Lateral Pterygoid Muscles

• These directly correlate due to different origins and insertion to their line of pull

Mylohyoid and Geniohyoid Muscles

• Consist of 4 muscles that connect the hyoid to the skull and mandible
• Contributes to elevation of the hyoid and tongue

Muscles of the Head: Mylohyoid and Geniohyoid

• Mylohyoid muscle has the most involvement related to Chewing and is innervated by CNS
• Geniohyoid is innervated by CNia due to its contributions to Swallowing

Stylohoid, Sternohyoid, Omohyoid, Sternothyroid Muscles,& Thyrohyoid

• Know the location/anatomical positions of these Structures

Muscles of the Face

• These are numerous muscles including those that cause expression
• Control of eyes, mouth, & tongue

Muscles of note

• Levator anguli oris: Pulls lip Corner up
• Corrugator Supercilii: Pulls eyebrows together, the mad look
• Frontalis: Lifts eyebrows, the surprised look
• Buccinator: Compresses cheeks, directs food while in mouth
• Orbicularis oris: kissy Movement face expression

Mechanical Advantage of TMJ

• TMJ is a third class lever (A-F-R) when the point of resistance is farther away, creating a longer resistance arm so more forces are needed as opposed to a shorter resistance arm to need less force.

Postural Influences

• Posture affects anatomical alignment, also affects Chewing, Swallowing, etc.

Common Pathologies

• Bruxim is clenching or grinding of teeth, and the locking is a disc movement

Head and Trunk Regions of the Spine

• Bony protection of Spinal Cord
• 5 Spinal regions include cervical: 7 vertebrae, Thoracic: 12 vertebrae, Lumbar: 5 Vertebrae, Sacral: 5 vertebrae and Coccyx: 3 fused Vertebrae

Spinal/Verterbral Curves

• Cervical & lumbar regions: Convex anteriorly where Lordosis Curve Convexly, or in /anteriorly, allows you to look up excessive Curvature
• Thoracic & Sacral regions: Concave anteriorly Kypnotic where curves of the thoracic, & Sacral regions, Curve outwardly / posteriorly (look down) and kyphosis where excessive curvature
• It’s like bow down to the king

Motions of the Vertebral Column

• Vertebral column is triaxial and motions of the neck & trunk
• Flex & extension occur within the sagittal plan about a frontal axis
• Lateral bending (lateral flexion) occurs within the frontal plan about a sagittal axis
• Rotation occurs within the horizontal plan bout a vertical axis
• The atlantooccipital (AO) joint is located at C1 & occiput where flexion & extension is nods when saying "yes" and there’s slight lateral bending
• The atlantoaxial (AA) joint is located at C1-C2 where there’s Rotation as a shake of the dead when saying "no"

Spinal Orientation

• The Cervical Spine is orientation of facets is within the frontal plane W/lateral portion anterior to medial portion of facet Motion in all three planes & axes
• Thoracic Spine Orientation of facets is within the frontal plane Motion limited by ribs in lateral bending
• Lumbar Spine is an orientation of facets is within the sagittal plane for Flexion & extension W/minimal lateral bending
• The Lumbar Spine promotes flexion/extension, minimal lateral bending, & restricted rotation. These faucet joins face more the anteriorly / posteriorly direction, Cousing movement to occur in the Sagittal plane.

Ribs

• Articulate w/ body & transverse processes of vertebral and articulate w/ sternum via Chondrosternal joints
• With elevation & depression as Slight flaring of individual ribs

Sternum

• Minimal movement between manubrium & body & Xiphoid process
• (The parts manubrium (top), the body (middle), & the xiphoid process (bottom))

Bones of the Skull

• Location of the Occipital Condyles, which articulate w/ the atlas of the Spine

Vertebrae

• The body of a vertebrae is anterior to the spinous process

Comparison of Vertebrae

• Cervical vertebrae as smaller lighter which allows for more mobility
• The thoracic vertebrae as larger than the cervical, heart-shaped in nature, & the vertebral foramen is more Circular Lopposed to triangle shape of the others) The spinous process of the thoracic Vertebrae are Sloped downward at a Steeper angle as well, providing greater Stability / protection of the area.
• Lumbar Vertebrae as larger & thicker, w/a snort/blunt Spinous process. Primary function is Support

Intervertebral Foramen & Facet joint

• Pay attention the Superior articular process (Superior in its anatomical position) fastened fastet joint) to the inferior articular process on the next vertebrae is inferior in its anatomical position
• Intervertebral disc is the spongy cushion between the vertebrate and It provide stability is a shock absorber, maintains alignment, & allows. for mobility

Cervical Vertebra

• Show superior view of he atlas & axis and notice the location of the articular processes of the occipital Condyles, as well as the dens of the axis.
• The pink area in the picture of the atlas is where the dens is positioned when in the anatomical position.
• Know the placement of the transverse ligament which prevents displacement of the Dens andSupports the dens from moving and
• The dens (just above the body of Ca) is anterior

Thoracic Vertebrae: Coastal Facets

• There are two locations of articulation: the primary on the transverse processes (Costotransverse joint) , the other on the body of the vertebrae (Costovertebral joint / a.k.a, demifacets)

Thoracic Cage

• The true ribs are 7, false ribs are 3, the floating ribs are a
• Notice the true ribs have a Continuous flow of the rib into the Coastal Cartilage, whereas the false ribs do not directly attach to the sternum.
• They attach to the Coastal Cartilage of the rib and The floating rib have no attachment

Costovertebral & Costotransverse joints

• The ribs attach in this region to coastal Cartilage which joins them to the Sternum.

Bones of the Pelvis

• The Sacrum articulates w/ the hips at the Sacroiliac joint w/a visual of the Connection between the Sacrum & the innominate aka the individual hip bones

Function of the Vertebral Disc

• The innermost portion is the and The outermost portion is the for force distribution, & primarily there The function of the annulus fibrosus is for force distribution, & primarily there for Structural Support Joints of Vertebral Column
• Intervertebral joints between bodies that are Cartilaginous
• Intervertebral facet joints are Superior facet of vertebrae below & inferior facet or vertebra above
• Head of rib is Costovertebral with Vertebral body
• Costotransverse joint: Tubercle of rib & Costal facet on anterior tip of transverse process

Cervical, Thoracic, & lumbar Spine

• There are adjacent Vertebral bodies that have cartilaginous joints which create slight movements where weight-bearing through bodies
• Facet joints are Superior articular process of vertebra below & inferior articular process of vertebra above that have Synovial joints
• Vertebral body joints are cartilaginous (limited movement / more for shock absorption), & facet joints are Synovial (more freely moveable)

Atlantooccipital & Atlantoaxial

• Atlanto Occipital (AO) joints located Between occipital Condyles & Superior articular facets of the atlas, Synovial joints
• Atlantoaxial (AA) point Between (C1) atlas & axis (Ca) in Synovial joints

Vertebral Ligaments

• Anterior Longitudinal Ligament (ALL): runs anterior (front) of the vertebral bodies, from occipital bone to the Sacrum, limits Spinal extension & provides Stability
• Posterior Longitudinal Ligament (PLL): runs posterior of the vertebral bodies, inside the vertebral canal, from occipital bone to sacrum; limits Spinal flexion & provides Support/Stability to the vertebrae & the interverbral discs
• The interspinal Ligament runs in between the Spinous processes, C7 to sacrum; limits excessive flexion
• Supraspinal ligament runs along the tip of the Spinous processes from Cervical to sacrum; limits flexion
• The Ligamentum Flavum which extends from ca to the Sacrum; limits flexion & helps preserve natural Curvature of the Spine

Nuchal Ligament

• It's the key ligament in the Cervical spins (nuchae = neck)
• Supports the head, limits excessive flexion, helps maintain Spinal alignment, & assists in other head movements

Muscles of the Neck and Trunk

• Anterior are sternocleidomastoid, Scalenes (3), Prevertebral group (4) as vertebal muscles
• Lateral Erector spinae group (3) Splenius capitis & Splenius cervicis in the vertebral muscles
• Posterior Rectus abdominis, External oblique, Internal oblique, Transverse abdominis, Quadratus lumborum are vertebral muscles

Muscles of the Neck

• The Sternocleidomastoid Muscle in the neck contributes to head rotation, lateral flexion, flex lext, can act as an accessory muscle tot he lifting the rib cage for breathing purposes where accessory Nerve innervates it, CN XI
• The SCM is most easily palpated by rotation of the head, palpating the opposite side of whatever direction the head is facing

Scalene Muscles

• The Scalene Muscles are a group of three muscles located in the lateral part of the neck
• These play an important role in neck movement, respiration, and the overall Stability of the Cervical spine

Scalene Muscle Origin

• Anterior Scalene: Originates from the transverse processes of the third to Sixth Cervical vertebrae (03-06)
• Middle Scalene: Originates from the transverse processes of the Second to seventh Cervical Vertebrae (Ca-C7)
• Posterior Scalene: Originates from the transverse processes of the fourth to Sixth Cervical Vertebrae (C4-C6)

Scalene Muscles Insertion

• Anterior Scalene: Inserts into the first rib
• Middle Scalene Inserts into the first rib
• Posterior Scalene: Inserts into the Second rib

Prevertebral Muscles

• Longus Colli has three parts
• Otheres are Longus Capitis, Anterior Rrectus Capitis and lateralis

Suboccipital Muscles

• Muscles include Obliquus capitis, Rectus capitis posterior

Muscles of the Posterior Neck

• Obliquus capitis superior, eRectus capitis posterior minor-Obliquus capitis inferior & Rectus capitis posterior major

Ext Intercostal Muscles

• Origin Lower border of rib above, the insertion is into the upper border of rib below in a way that elevates ribs during inspiration and is innervated by intercostal nerves (T2 through T6)

Internal Intercostal Muscle

• Origin Upper surfaces of costal cartilage and rib below to the insertion Costal cartilage intercostal nerves(T2 through T6)
• The Fibers on pull up lower and internal down

Rectus Abdominus Muscle

• Action is trunk flexion with core stability posture and runs down the Center of the abdominal from the abdominal from the hip to the tendons and sheet of connective tissue

Abdominal Muscles

• Relationship of muscles of the abdominal where the darker muscles in the graphic are more Superficial, Whereas those light in Colors are deeper
• The external oblique Contributes to rotation to the Opposite Side while internal Contributes to rotation to the same side for combined Action
• Rectus with the trunk side

Quadratus Lumborum Muscle

• Deeply assists the pelvic elevating musclen and comes in handy when an individual’s hiking, climbing, or running
• The term "Quadratus" in this Context refers to "Square" Shape by allowing the necessary shift to maximize the ROM needed during said activities

Posterior Trunk Muscles

• The anatomical positions need the anatomical positions (superior, deep, etc.) of the Erector Spinae group (Iliocostalis, Longissimus, +Spinalis) in a Like Standing posture
• Action: Transverse process determines muscle action for posterior trunk muscles for lateral flexion
• Interspinales muscles: O Spin, I spin A neck trunk extends n Spinal

Muscle Movement

• The transvers aspect is a key action to remember with Lateral flexion rotation and extensions with associated lines origin and pull
• It plays an essential role in breathing,intra abdominal structures like compression and contraction while is important for the lungs
• Action blue is origin, green line is the insertion and contraction is muscle contributes to inhalation while relaxation equal expiration

Clinical Mnemonics

• Know the location /positions with the Spinal ligaments especially the external

Diaphragm Innervation

• Remember the diaphragm is innervated by the phrenic nerve, origination gfrom C6 segments on spinal cord.

Common Pathologies and Treatment Recommendations

• Scoliosis is congenital or when one part of the leg is damaged
• Thoracic outlet
• Sciatica is pain descending posterior thigh & leg along path of e the sciatic nerve from a disrupted disk

Pelvis Nutation

• Sacroiliac flexion and rotation on hip
• Pouring water out the back helps rotation

Pelvic Tilt

• To tilt the level of the pelvic and increase the spinal bend or curve on the back
• Know the location/anatomical positions of the Structures ,as Welware is in turn will determine the clinical indications

Anterio View

• Shows the lateral View of the graphic on where the pelvic moves