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Anatomy & Histology: INBDE study notes and practice questions

Anatomy questions are applied: a nerve, vessel or muscle is described by its supply or action, and you must connect it to a clinical finding or procedure. Tooth morphology, histology and development of the face and palate also appear.

568 practice questions · 16 patient cases

Practice Anatomy & Histology

Where it fits in the official INBDE blueprint

Foundation Knowledge (FK 1). Nearest foundation knowledge area: FK 1. See the content outline for the official weights. This mapping is approximate: real items combine a clinical area with a foundation area.

What this area tests

High-yield checklist

Common traps

These notes are original study aids, not official exam content. Confirm clinical details against current guidelines.

Sample questions

1. Which muscle's posterior fibers are responsible for retruding (retracting) the mandible?

  1. The posterior fibers of the temporalis muscle
  2. The masseter
  3. The medial pterygoid
  4. The lateral pterygoid
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Correct answer: A. The posterior fibers of the temporalis muscle

The posterior, more horizontally oriented fibers of the temporalis muscle pull the mandible backward, retruding it — while its more vertically oriented anterior fibers primarily contribute to elevation (closing).

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2. Which anatomical structure is most closely associated with wrapping around the parotid gland?

  1. Masseter muscle
  2. Mandibular ramus
  3. Stylohyoid ligament
  4. Medial pterygoid muscle
Show answer and explanation

Correct answer: B. Mandibular ramus

The MANDIBULAR RAMUS wraps around the parotid gland anteriorly. The parotid gland sits in the parotid space bounded by the ramus anteriorly, zygomatic arch superiorly, and mastoid/SCM posteriorly. The facial nerve traverses and divides within it.

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3. In a forensic dental investigation, from which structure is DNA most reliably obtained?

  1. Cementum
  2. Dental pulp
  3. Enamel
  4. Periodontal ligament
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Correct answer: B. Dental pulp

The dental pulp is the richest source of DNA in a tooth for forensic identification. It contains blood vessels, nerves, and connective tissue cells with abundant nuclear DNA. The pulp is also well protected within the hard tooth structure, making it resistant to environmental degradation, fire, and decomposition — crucial advantages in forensic cases.
  • A. ❌ Cementum has limited cellularity compared to pulp.
  • B. ✅ CORRECT – The dental pulp is the preferred source of DNA for forensic identification due to its cellular richness and protection inside the tooth.
  • C. ❌ Enamel contains no cells and therefore no nuclear DNA.
  • D. ❌ The PDL provides some DNA but is subject to degradation and not the primary forensic source.

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4. Which cells are primarily responsible for physiologic root resorption of primary teeth?

  1. Fibroblasts
  2. Odontoblasts
  3. Odontoclasts (a type of osteoclast)
  4. Osteoblasts
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Correct answer: C. Odontoclasts (a type of osteoclast)

Root resorption of primary teeth is carried out by odontoclasts (morphologically similar to osteoclasts) — multinucleated giant cells that resorb root dentin and cementum.
  • A. Fibroblasts synthesize collagen and extracellular matrix components but are not involved in hard tissue resorption.
  • B. Odontoblasts form dentin throughout life but do not resorb it — they are formative, not resorptive.
  • C. CORRECT. Odontoclasts (dentinoclasts) are the cells responsible for resorbing root dentin and cementum during physiologic root resorption of primary teeth. They are functionally and morphologically equivalent to osteoclasts.
  • D. Osteoblasts are bone-forming cells — they deposit new bone matrix and do not resorb hard tissues.

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5. All of the following are of ectomesenchymal origin EXCEPT:

  1. Dental pulp
  2. Dentin
  3. Cementum
  4. Oral mucosa (stratified squamous epithelium)
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Correct answer: D. Oral mucosa (stratified squamous epithelium)

The oral mucosa (stratified squamous epithelium) is derived from ectoderm (not ectomesenchyme). Ectomesenchyme (neural crest-derived mesenchyme) gives rise to: dental pulp, dentin (odontoblasts), cementum (cementoblasts), periodontal ligament, alveolar bone, and connective tissue of the face. The epithelial lining of the oral mucosa is ectodermal, while the underlying lamina propria connective tissue is ectomesenchymal.

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6. Endochondral ossification occurs in the formation of _______________.

  1. All bones
  2. Flat bones
  3. Long bones
  4. Elastic cartilage
  5. Mesenchymal sheets
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Correct answer: C. Long bones

Endochondral ossification ('within cartilage') forms long bones, the cranial base, and part of the mandible from a cartilage model. Intramembranous ossification ('within membrane') forms the cranial vault, maxilla, and the other part of the mandible directly from mesenchyme.

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7. Where is the lingual thyroid gland most commonly located?

  1. Base of tongue (posterior)
  2. Submandibular triangle
  3. Lateral neck
  4. Anterior floor of mouth
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Correct answer: A. Base of tongue (posterior)

A lingual thyroid results from failure of the thyroid gland to descend from its embryologic origin at the foramen cecum. It is therefore located at the base (posterior part) of the tongue, near the foramen cecum. It appears as a midline reddish-brown mass at the tongue base. It may be the only functional thyroid tissue in some patients — always check thyroid function before removal.
  • A. ✅ CORRECT – Lingual thyroid occurs at the base of the tongue, near the foramen cecum, due to failed descent during embryogenesis.
  • B. ❌ The submandibular triangle contains the submandibular gland, not an ectopic thyroid.
  • C. ❌ Lateral neck masses from thyroid tissue are thyroglossal duct remnants or lateral ectopic thyroid, not lingual thyroid.
  • D. ❌ The anterior floor of mouth is not the location of a lingual thyroid.

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8. Which anatomical structure wraps around the parotid gland, forming its capsule?

  1. Masseter muscle
  2. Medial pterygoid muscle
  3. Mandibular ramus
  4. Sternocleidomastoid muscle
Show answer and explanation

Correct answer: C. Mandibular ramus

The mandibular ramus is the bony structure that wraps around (overlies) the parotid gland anteriorly and laterally. The parotid gland is lodged in the parotid space bounded by: the mandibular ramus anteriorly, the external auditory meatus superiorly, the mastoid process and sternocleidomastoid muscle posteriorly. The masseter muscle overlies the parotid superficially in the cheek area, but the ramus is the key wrapping structure in classic anatomy teaching.

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Patient cases

All Anatomy & Histology questions (568)