Anatomy Exam 2 (Third Slides)

What are the muscles of mastication (chewing)?

Temporalis and masseter.

Origin of temporalis muscle

Squamous portion of temporal bone.

Insertion of temporalis muscle

Coronoid process of mandible.

Action of temporalis muscle

Elevates and retracts the mandible.

Origin of masseter muscle

Zygomatic arch.

Insertion of masseter muscle

Ramus and angle of mandible.

Action of masseter muscle

Elevates and protracts the mandible.

What cranial nerve innervates the temporalis and masseter?

Trigeminal nerve (CN V).

What type of joint is the TMJ?

Synovial joint.

Bones forming the TMJ

Mandibular fossa of temporal bone and head of mandible.

What structure divides the TMJ cavity into two parts?

Articular disc.

What type of cartilage is the TMJ articular disc?

Fibrocartilage.

Hinge movements of the TMJ

Elevation and depression.

Planar movements of the TMJ

Protraction and retraction.

What is unique about the hyoid bone?

It does not articulate with any other bone.

Location of the hyoid bone

Anterior neck below the mandible.

Shape of the hyoid bone

U-shaped.

Function of the hyoid bone

Attachment site for muscles involved in swallowing and speaking.

Origin of genioglossus

Mandible.

Insertion of genioglossus

Tongue and hyoid.

Action of genioglossus

Protracts the tongue.

Main action needed to stick out your tongue

Contraction of genioglossus.

Origin of hyoglossus

Hyoid bone.

Insertion of hyoglossus

Lateral tongue.

Action of hyoglossus

Depresses and retracts the tongue.

What nerve innervates the tongue muscles discussed?

Hypoglossal nerve (CN XII).

Location of suprahyoid muscles

Superior to the hyoid bone.

Action of suprahyoid muscles

Elevate the hyoid bone and larynx during swallowing.

Location of infrahyoid muscles

Inferior to the hyoid bone.

Action of infrahyoid muscles

Depress the hyoid bone and larynx during swallowing.

What two bones form the temporomandibular joint?

Mandible and temporal bone.

List the six functions of the vertebral column

Support head and trunk, protect spinal cord, allow passage of spinal nerves, provide muscle attachment, provide pelvic attachment, maintain upright posture.

How many cervical vertebrae are there?

7.

How many thoracic vertebrae are there?

12.

How many lumbar vertebrae are there?

5.

How many sacral vertebrae are there?

5 fused vertebrae.

How many coccygeal vertebrae are there?

Typically 4 fused vertebrae.

What is lordosis?

Exaggerated secondary curvature of the lumbar region.

What is kyphosis?

Exaggerated primary curvature of the thoracic region.

What is scoliosis

Lateral curvature of the vertebral column.

What is the vertebral body?

Large anterior weight-bearing portion of a vertebra.

Function of transverse processes

Sites of muscle attachment.

Function of spinous process

Site of muscle attachment projecting posteriorly.

What is the vertebral foramen?

Large opening that allows passage of the spinal cord.

What is the intervertebral foramen?

Opening between adjacent vertebrae that allows passage of spinal nerves.

What are articular processes?

Superior and inferior projections that form joints with adjacent vertebrae.

What joint is formed by articular processes?

Zygapophyseal joint.

Type of zygapophyseal joint

Planar synovial joint.

Movement allowed by zygapophyseal joints

Gliding movements.

What type of joint is an intervertebral disc joint?

Symphysis (cartilaginous joint).

Movement at intervertebral disc joints

Slight movement.

What is the annulus fibrosus?

Outer fibrocartilage ring of an intervertebral disc.

What is the nucleus pulposus?

Jelly-like inner portion of an intervertebral disc.

Function of nucleus pulposus

Acts as a shock absorber.

What is a herniated disc?

Condition where the nucleus pulposus bulges through a weakened annulus fibrosus.

Why is a herniated disc painful?

It can compress a spinal nerve.

Location of anterior longitudinal ligament

Anterior side of vertebral bodies.

Function of anterior longitudinal ligament

Limits extension of vertebral column.

Location of posterior longitudinal ligament

Posterior side of vertebral bodies.

Function of posterior longitudinal ligament

Limits flexion of vertebral column.

Location of ligamentum flavum

Between vertebral arches.

Function of ligamentum flavum

Helps maintain posture.

What feature is unique to cervical vertebrae?

Transverse foramina.

What passes through transverse foramina?

Vertebral arteries and veins.

Which cervical vertebra is called the atlas?

C1.

Which cervical vertebra is called the axis?

C2.

Which cervical vertebra is vertebra prominens?

C7.

Function of the atlas (C1)

Supports the weight of the head.

What joint is formed by the atlas and occipital bone?

Atlanto-occipital joint.

Type of atlanto-occipital joint

Biaxial.

Movements of the atlanto-occipital joint

Flexion, extension, and lateral flexion.

What motion does the atlanto-occipital joint allow?

Nodding "yes."

What structure projects upward from the axis?

Dens (odontoid process).

What joint is formed by the atlas and axis?

Atlanto-axial joint.

Type of atlanto-axial joint

Pivot synovial joint.

Movement allowed by atlanto-axial joint

Rotation.

What motion does the atlanto-axial joint allow?

Shaking the head "no."

What ligament holds the dens in place?

Transverse ligament.

Characteristics of thoracic vertebrae

Long slender spinous processes and costal facets.