Part 2: Veins, Salivary Glands, and Superficial Nerves

Abby Brown

Related Learning Objectives

  • D7.2 Identify the listed salivary glands and describe their point(s) of drainage.
  • D7.7 Identify the venous drainage of the head.
  1. Begin on the lateral aspect of the head, and move caudally toward what remains of the neck. Re-identify the cut stump of the external jugular v. (previously identified in Chapters 3 & 4). Using blunt dissection, trace the external jugular v. into the head and find where it is formed by the confluence of the linguofacial and maxillary veins. (See DG Figs. 5-41, 5-42, and 5-43)

    Related Learning Objective

    • D7.7

     

    • Using blunt dissection, uncover and identify the maxillary v. (See DG Figs. 5-41 and 5-42)

        • Dissection Note: Try not to cut the nerves found in this same dissection field as you dissect the veins!

        • Comment: The maxillary vein is responsible for draining the ear, orbit, palate, nasal cavity, cheek, mandible, and cranial cavity.

    • Using blunt dissection, uncover and identify the linguofacial v., which is created by the confluence of the lingual and facial veins. (See DG Figs. 5-41 and 5-42)

        • Dissection Note: Try not to cut the nerves found in this same dissection field as you dissect the veins!

        • Using blunt dissection, identify the lingual v. which enters the linguofacial vein ventrally, draining blood from the tongue (and larynx). (See DG Fig. 5-42)

        • Using blunt dissection, identify the facial v. which enters the linguofacial vein more dorsally, draining blood from the face. (See DG Fig. 5-42)

  2. Follow the linguofacial vein  and look for the ovoid lymph nodes lying on either side of the vein. These are the mandibular lymph nodes which you should identify in your specimen. (See DG Figs. 2-12 and 3-2)

    Related Learning Objective

    • D7.2

     

  3. In (or near) the crux of the linguofacial and maxillary veins (where they join together to form the external jugular vein), identify the mandibular salivary gland. (See DG Figs. 5-21B & D, 5-24 and 5-48)

    • Dissection Note: The mandibular salivary gland is very round and firm and is covered in a thick capsule. This capsule also covers the sublingual salivary gland which you will identify next.

  4. Incise the capsule surrounding the mandibular salivary gland. Dissect rostral and medial to the mandibular salivary gland to identify the sublingual salivary gland (monostomatic gland). (See DG Figs. 5-24 and 5-48) The sublingual salivary gland has two parts, but we will only identify the monostomatic part.

    • Dissection Note: The sublingual salivary gland is roughly triangular in shape and is found deep to the mandibular salivary gland.

  5. Moving dorsal to the mandibular and sublingual salivary glands, identify the parotid salivary gland surrounding the base of the ear. (See DG Figs. 5-21B and 5-24)

    • Carefully dissect and identify the parotid duct leaving the rostral border of the gland and crossing the cheek/masseter muscle. The parotid duct carries saliva from the parotid salivary gland to the oral cavity.

        • Comment: The parotid duct then empties into the vestibule of the mouth, at the level of the fourth upper premolar tooth, which will be discussed later in this lab.

        • Dissection Note: The parotid duct is a thickened tube-like structure that looks a lot like a nerve when you are dissecting it out. However, unlike a nerve, it runs straight across the cheek to the oral cavity.

  6. There is an additional salivary gland located medial to the zygomatic bone, just ventral to the eye, that you will not dissect on your specimen. This gland is the zygomatic salivary gland and should be observed on the demonstration specimens that have had their zygomatic arch removed.

  7. Using blunt dissection, begin looking for the nerve branches that cross the masseter muscle along its dorsal and ventral aspects. If necessary, reflect the most rostral part of the parotid salivary gland caudally as you perform this dissection. Identify the dorsal and ventral buccal nerves, which are branches of the facial nerve (cranial nerve VII). (See DG Fig. 5-43)

    • The dorsal buccal n. crosses the masseter muscle just dorsal to the parotid duct.

    • The ventral buccal n. crosses the masseter muscle just ventral to the parotid duct.

    • Comment: These buccal branches of the facial nerve innervate muscles of the cheek, lips, and lateral surface of the nose.

  8. Trace the buccal nerves caudally to view their origin from the facial n. as it emerges into view near/just caudal to the base of the ear.

  9. Still using blunt dissection, look for nerve branches extending dorsally from the region of the masseter, toward the ear and eye. Identify the auriculopalpebral n., which is another branch of the facial nerve. (See DG Fig. 5-43)

    • Dissection Note: The auriculopalpebral nerve will send rostral auricular branches toward the ear and palpebral branches toward the eye.

    • Comments:

        • The auriculopalpebral innervates auricular muscles, muscles surrounding the orbit, and also the nose and upper lip.

        • Note that in the dissection field of the facial nerve branches you may see branches of the auriculotemporal n., which is a branch of the mandibular nerve. The auriculotemporal n. is found deep to the origin of the auriculopalpebral n. and need not be dissected.

Dissection Videos for this Section of Material

Veins, Salivary Glands, and Superficial Nerves:

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Dissection Lab Guide for Dog and Cat Anatomy Copyright © by Abby Brown. All Rights Reserved.

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