OTR 704 2.1 Head, Neck, Trunk & Spine

What structure is shown?

Cranium

What structure is shown?

Frontal bone

What structure is shown?

Parietal bone

What structure is shown?

Temporal bone

What structure is shown?

Occipital bone

What structure is shown?

External occipital protuberance

What structure is shown?

Mastoid process

What structure is shown?

Mandible

What structure is shown?

Zygomatic arch

What structure is shown?

Maxilla

What structure is shown?

Orbit

What structure is shown?

Foramen magnum

What structure is shown?

Hyoid bone

What structure is shown?

Larynx

What structure is shown?

True ribs (1-7)

What structure is shown?

False ribs (8-10)

What structure is shown?

Floating ribs (11-12)

What structure is shown?

Intercostal spaces

Hyoid bone

Suspended, U-shaped bone; point of attachment for many muscles involved in speech and swallowing

• “Floating” — not directly attached to any other bones

• Elevates to close off the larynx and airway during swallowing

Larynx

“Voice box” formed by several cartilages

Temporomandibular joints (TMJ)

Synovial (modified hinge) joints

• Work in tandem for symmetrical functional motions of the mandible — elevation, depression, protraction, retraction

• Important for chewing, speaking

Integumentary muscles

Muscles of facial expression

What structure is shown?

Clavicle

What structure is shown?

Sternoclavicular joint

What structure is shown?

Sternum

What structure is shown?

Manubrium

What structure is shown?

Sternal body

What structure is shown?

Xiphoid process

What structure is shown?

Intervertebral disc

What structure is shown?

Coccyx (4 fused/semi-fused vertebrae)

What structure is shown?

Sacrum (5 fused vertebrae)

What structure is shown?

Lumbar vertebrae (5)

What structure is shown?

Thoracic vertebrae (12)

What structure is shown (blue highlight)?

Costal facets

What structure is shown?

Axis (C2)

What structure is shown?

Dens (odontoid process)

What structure is shown?

Atlas (C1)

What structure is shown?

Cervical vertebrae (7)

What structure is shown?

Vertebral body

What structure is shown?

Spinous process(es)

What structure is shown?

Transverse process(es)

What structure is shown?

Transverse foramen

What structure is shown?

Lamina

What structure is shown?

Pedicle

What structure is shown?

Superior articular facet

What structure is shown?

Superior articular processes

What structure is shown?

Inferior articular processes

What structure is shown?

Vertebral foramen

Buccinator action

Contracts cheeks to narrow mouth; directs bolus inside mouth; engages when blowing air out of narrowed mouth (e.g., balloon)

Orbicularis oris action

Seals mouth for swallowing; drinking from a straw; eating from a spoon

Masseter action

Elevates and protrudes mandible (e.g., chewing, speech)

Masseter origin

Zygomatic arch

Masseter insertion

Angle and ramus of mandible

Masseter innervation

CN V (Trigeminal n.)

Temporalis action

Elevates and retracts mandible (e.g., chewing, speech)

Temporalis innervation

CN V (Trigeminal n.)

Pharynx

“Fork in the road” between respiratory and digestive systems; the throat (nasopharynx + oropharynx + laryngopharynx)

Suprahyoids action

Elevate hyoid, tongue, and larynx during swallowing; depress mandible; retracts the mandible (digastric only); engages during verbal communication, swallowing

Infrahyoids action

Depresses hyoid and thyroid cartilage during speech and swallowing

Pre-oral phase of swallowing/feeding

Anything that works to bring food/drink to the mouth

Oral preparatory phase of swallowing/feeding

1st phase — mastication and salivation create a bolus

• VOLUNTARY

Oral transit phase of swallowing/feeding

2nd phase — tongue propels bolus toward pharynx

• VOLUNTARY

Pharyngeal phase of swallowing/feeding

3rd phase — hyoid/larynx elevates, nasopharynx are oropharynx are sealed, epiglottis covers larynx, and bolus descends

• INVOLUNTARY

Esophageal phase of swallowing/feeding

4th phase — esophageal peristalsis advances bolus toward the stomach

• INVOLUNTARY

Aspiration

Food or liquid descending beneath vocal folds and entering trachea

Cranial nerves

Twelve pairs of nerves that arise from the brainstem and innervate the head and neck; identified by Roman numeral and name

• CNs do not have contralateral control → ipsilateral deficits with cortical injury (exception: CN II & CN III)

CN I

• Name: Olfactory

• Sensory or motor: Sensory

• Function: Olfaction (smell)

CN II

• Name: Optic

• Sensory or motor: Sensory

• Function: Vision

CN III

• Name: Oculomotor

• Sensory or motor: Motor

• Function: Moving eye up, down, medially (superior/inferior/medial rectus muscles); raising eyelid (levator palpebrae muscle); constricting pupil (sphincter pupillae muscle)

CN IV

• Name: Trochlear

• Sensory or motor: Motor

• Function: Moving eye down and medially (superior oblique muscle)

CN V

• Name: Trigeminal

• Sensory or motor: Both

• Function: Mastication (masseter, temporalis, pterygoid muscles); sensation to face and TMJ

CN VI

• Name: Abducens

• Sensory or motor: Motor

• Function: Abducting the eye (lateral rectus muscle)

CN VII

• Name: Facial

• Sensory or motor: Both

• Function: Facial expression; taste (sensory innervation to anterior 2/3 of tongue)

CN VIII

• Name: Vestibulocochlear

• Sensory or motor: Sensory

• Function: Hearing, vestibular sense (head position relative to gravity)

CN IX

• Name: Glossopharyngeal

• Sensory or motor: Both

• Function: Swallowing; taste; salivation

CN X

• Name: Vagus

• Sensory or motor: Both

• Function: Visceral regulation (parasympathetic); speech

CN XI

• Name: Spinal accessory

• Sensory or motor: Motor

• Function: Scapular elevation (trapezius muscle); rotation of head (sternocleidomastoid muscle)

CN XII

• Name: Hypoglossal

• Sensory or motor: Motor

• Function: Movements of tongue

Orbicularis oculi action

Specialized fibers contribute to involuntary closure during blinking or sleeping

• Semi-voluntary closure to squint or when in pain

Levator palpebrae action

Elevates eyelid

Levator palpebrae innervation

CN III (Oculomotor n.)

Superior rectus action

Elevates (upward movement of) eye

Superior rectus innervation

CN III (Oculomotor n.)

Inferior rectus action

Depresses (downward movement of) eye

Inferior rectus innervation

CN III (Oculomotor n.)

Medial rectus action

Turns eye medially (inward)

Medial rectus innervation

CN III (Oculomotor n.)

Lateral rectus action

Turns eye laterally (outward/abduction)

Lateral rectus innervation

CN VI (Abducens n.)

Superior oblique action

Downward & medial rotation of the eye

Superior oblique innervation

CN IV (Trochlear n.)

Inferior oblique action

Upward rotation of the eye

Inferior oblique innervation

CN III (Oculomotor n.)

What cranial nerve that controls eye movement is most commonly impacted by traumatic head injury?

CN VI (Abducens n.); located laterally on the side of the head and is more vulnerable to trauma

Core (trunk) components

The back, abdomen, thorax (chest), and pelvis

• Bones, connective tissues, muscles, neuromuscular innervation

• Osteo components: vertebral column, ribs, sternum

Regions of the vertebral column

• Cervical (7)

• Thoracic (12)

• Lumbar (5)

• Sacral (5 fused)

• Coccygeal (4 semi-fused vertebrae)

Spinal curves

• Lordosis (cervical & lumbar) — anterior

• Kyphosis (thoracic & sacral) — posterior

Spinal curve development

• Born with a C-spine (single kyphotic curve)

• Lordotic curvatures develop through experience

  • Tummy time → cervical curvature

  • Creeping (quadruped) → lumbar curvature

  • Further development of spinal curvature through weight-bearing in sitting & walking

Atlantooccipital joint

Articulation of atlas (C1) and the occiput (skull); allows for capital flexion and extension

Atlantoaxial joint

Articulation of the atlas (C1) and axis (C2); allows for rotation of the head