32 Dissection of the Pharynx, Oral Cavity and Larynx

Dissection Structures List pdf

Anatomy Lab Information

Ebling Library’s Anatomy Resources Guide

Link to Review Image Sets (with Hover-Over Labels)

Learning Objectives

Quick links to each step:

Step 1: Bluntly Dissect the Retropharyngeal Space

Step 2: Separate the Atlantooccipital Joint

Step 3: Review Structures of the Carotid Sheath and Clean the Pharyngeal Muscles

Step 4: Open the Pharynx and Identify its Features

Step 5:

Step 6:

Step 7:

Step 8:

Step 9:

Step 10: Clean Up

Instructions

Tools Needed?

What to Do in Lab When You’re Not Dissecting

Step 1: Bluntly Dissect the Retropharyngeal Space

Dissection Directions

**The goal is to remove the head at the atlanto-occipital joint, while preserving as many structures as possible.

• Starting with your donor in the supine position, bluntly dissect the retropharyngeal space superiorly to the base of the skull.
• IDENTIFY and PULL the larynx, trachea, pharynx, esophagus, carotid arteries, vagus nerves and sympathetic trunks away from the spine as far anteriorly as possible.
  • Place a chisel between these structures and the vertebral column/postural muscles
• When you are finished, FLIP the body to the prone position keeping that chisel in place marking those important structures.

Dissection Video

Atlas Images – Click to Enlarge

Donor Images – Click to Enlarge

Knowledge Checks

Step 2: Separate the Atlantooccipital Joint

Dissection Directions

• On your now prone donor, CLEAN the area around the foramen magnum and atlantooccipital joint in order to palpate the transverse processes of the atlas.
  • Look for the vertebral artery as they pass horizontally toward the foramen magnum.
• Insert your scalpel just superior to the vertebral artery and the transverse process of the atlas and inferior to the occipital bone and CUT the muscles and ligaments that cross the atlantooccipital joints.
  • AVOID cutting into the pharynx and other viscera on the other side of your chisel. Keep checking the position of these structures relative to where you are (sometimes) blindly cutting with your scalpel.
  • It will help to have another person position the head in such a way that you can visualize and access the joint spaces.
• When all of those intrinsic neck muscles and ligaments have been cut, the skull, with attached pharynx, nerves, and other structures, should come free from the cervical spine.
• When you are finished, flip the body back to the supine position.

Dissection Video

Atlas Images – Click to Enlarge

Donor Images – Click to Enlarge

Knowledge Checks

Step 3: Review Structures of the Carotid Sheath and Clean the Pharyngeal Muscles

Dissection Directions

• Now that your donor is back in the supine position, reflect the head anteriorly away from the cervical spine to visualize carotid sheath and pharyngeal structures.
• FIND the contents of the carotid sheath from the posterior perspective: the common carotid artery, internal jugular vein and vagus nerve (CN X) on both sides.
• FIND the large superior cervical ganglion and sympathetic chain/trunk on both sides.
• REMOVE the buccopharyngeal fascia along the posterior wall of the pharynx.
  • As you clean off this fascia, you are also removing the pharyngeal plexus (composed of sympathetic, CN X, and CN IX fibers).
• EXPOSE the fibers of the three pharyngeal constrictor muscles: superior, middle, and inferior.
  • Superior pharyngeal constrictor originates from connective tissue pterygomandibular raphe just posterior to buccinator.
  • Middle pharyngeal constrictor originates from the hyoid bone.
  • Inferior pharyngeal constrictor originates from the thyroid cartilage.
  • All constrictor muscles are innervated by CN X (branchiomotor innervation).
• CONFIRM the border between the superior and middle constrictors by following the stylopharyngeus muscle from the styloid process into the wall of the pharynx.
  • LOCATE the glossopharyngeal nerve (CN IX), as it travels along and innervates the stylopharyngeus.

Dissection Video

Atlas Images – Click to Enlarge

Donor Images – Click to Enlarge

Knowledge Checks

Step 4: Open the Pharynx and Identify its Features

Dissection Directions

• CUT along the posterior midline of the pharynx to open the organ. IDENTIFY the boundaries of the naso-, oro- and laryngopharynges and other structures in these spaces.
• In the nasopharynx, IDENTIFY:
  • the nasal septum,
  • soft palate,
  • uvula and
  • opening of the auditory tube.
• In the oropharynx, IDENTIFY:
  • the dorsum of the tongue and area of lingual tonsils,
  • the palatopharyngeal folds,
  • the vallecula epiglottica bounded by the median and lateral glossoepiglottic folds.
• In the laryngopharynx, IDENTIFY:
  • the epiglottis,
  • laryngeal aditus
  • and the piriform recesses.

Dissection Videos

Atlas Images – Click to Enlarge

Donor Images – Click to Enlarge

Knowledge Checks

Step 5

Dissection Directions

Dissection Videos

Atlas Images – Click to Enlarge

Donor Images – Click to Enlarge

Knowledge Checks

Step 6

Dissection Directions

Dissection Videos

Atlas Images – Click to Enlarge

Donor Images – Click to Enlarge

Knowledge Checks

Step 7

Dissection Directions

Dissection Videos

Atlas Images – Click to Enlarge

Donor Images – Click to Enlarge

Knowledge Checks

Step 8

Dissection Directions

Dissection Videos

Atlas Images – Click to Enlarge

Donor Images – Click to Enlarge

Knowledge Checks

Step 9

Dissection Directions

Dissection Videos

Atlas Images – Click to Enlarge

Donor Images – Click to Enlarge

Knowledge Checks

Step 10: Clean Up

Work as a team to make sure the tank and surrounding area is cleaned up.

Clean-Up Checklist:

• Log out and close down all tabs on ipad and return ipad to bucket.
• Clean tools and return to tool table.
• Return prosections to the appropriate tank and cover with cloth.
• Place blue towels in hamper.
• Cover the donor completely with the sheet. (Make sure the block is not underneath the donor.)
• Unlatch and lower the platform one side at a time.
• Close the tank.
• Make sure the tissue waste container is securely closed.
• Turn off overhead lamp.
• Dispose of gloves in trashcans by sink.
• Wash hands.

Dissection Structures Identification List

Image Sources