Olfactory nerve
Updates to Article Attributes
The olfactory nerve is the first (CN I) cranial nerve (TA: nervus olfactorius or nervus cranialis I) and is responsible for conveying the sense of smell from the nasal cavity to the brain. Along with the optic nerve, it is actually a peripheral extension of the central nervous system.nerve'nerve' refers only refers to the short first order neurones (olfactory filaments) located on the olfactory mucosa. The olfactory bulb, tract and striae are often incorrectlyerroneously referred together as CN Ithe olfactory nerve, whichbut they are actually partan extension of the central nervous system (see olfactory system).
Summary
location: olfactory groove; anterior cranial fossa near the midline
branches and supply: 20 or so olfactory filaments in the roof of the nasal cavity
Gross anatomy
Course
Olfactory filaments
The bipolar cell is the first-order sensory neurone located at the olfactory mucosa on the roof of the nasal cavity, immediately inferior to the cribriform plate of the ethmoid bone. This cell is analogous to the sensory cells of spinal nerves, whose cell bodies reside in the dorsal root ganglion. There are approximately 20 bipolar olfactory cells on each side in humans. Their central processes form filaments which pass through the cribriform plate, pierce the dura mater and relay in the olfactory bulb.
Olfactory bulb
The olfactory bulb is the paired expanded anterior portion of the nerve that sits in the olfactory fossa. It houses the cell bodies of mitral cells, the second-order neurones of the olfactory system.
Olfactory tract
The central process of these second-order neurones forms the olfactory tract which courses posteriorly, superior to the olfactory groove of the anterior cranial fossa, and inferior to the olfactory sulcus (lateral to gyrus rectus, and medial to the orbital gyri).
Olfactory striae
Anterior to the anterior perforated substance, the olfactory tract divides to form the medial and lateral olfactory striae. This triangular area of division is referred to as the olfactory trigone. The lateral olfactory striae project to the uncus. The medial olfactory striae ultimately project to the hypothalamus and brainstem nuclei.
Radiographic features
MRI
Coronal images are the best to depict the olfactory nerve as it is situated deep in the olfactory groove.
Related pathology
-<p>The <strong>olfactory nerve</strong> is the <strong>first</strong> <strong>(CN I)</strong> <a href="/articles/cranial-nerves">cranial nerve</a> (<a href="/articles/terminologia-anatomica-1">TA</a>: nervus olfactorius or nervus cranialis I) and is responsible for conveying the sense of smell from the nasal cavity to the brain. Along with the <a href="/articles/optic-nerve">optic nerve</a>, it is actually a peripheral extension of the <a href="/articles/central-nervous-system-1">central nervous system</a>. Strictly speaking, the olfactory nerve only refers to the short first order neurones (olfactory filaments) located on the olfactory mucosa. The olfactory bulb, tract and striae are often incorrectly referred together as CN I, which are actually part of the central nervous system (see <a href="/articles/olfactory-system" title="Olfactory system">olfactory system</a>).</p><h4>Summary</h4><ul>- +<p>The <strong>olfactory nerve</strong> is the <strong>first</strong> <strong>(CN I)</strong> <a href="/articles/cranial-nerves">cranial nerve</a> (<a href="/articles/terminologia-anatomica-1">TA</a>: nervus olfactorius or nervus cranialis I) and is responsible for conveying the sense of smell from the nasal cavity to the brain. Strictly speaking, the term olfactory 'nerve' refers only to the short first order neurones (olfactory filaments) located on the olfactory mucosa. The olfactory bulb, tract and striae are often erroneously referred together as the olfactory nerve, but they are actually an extension of the <a href="/articles/central-nervous-system-1" title="Central nervous system">central nervous system</a> (see <a href="/articles/olfactory-system" title="Olfactory system">olfactory system</a>).</p><h4>Summary</h4><ul>
-</ul><h4>Gross anatomy</h4><h5>Course</h5><h6>Olfactory filaments</h6><p>The bipolar cell is the first-order sensory neurone located at the olfactory mucosa on the roof of the <a href="/articles/nasal-cavity">nasal cavity</a>, immediately inferior to the <a href="/articles/cribriform-plate">cribriform plate</a> of the <a href="/articles/ethmoid-bone-1">ethmoid bone</a>. This cell is analogous to the sensory cells of spinal nerves, whose cell bodies reside in the <a href="/articles/dorsal-root-ganglion">dorsal root ganglion</a>. There are approximately 20 bipolar olfactory cells on each side in humans. Their central processes form filaments which pass through the cribriform plate, pierce the <a href="/articles/dura-mater">dura mater</a> and relay in the olfactory bulb.</p><h6>Olfactory bulb</h6><p>The olfactory bulb is the paired expanded anterior portion of the nerve that sits in the <a href="/articles/olfactory-fossa">olfactory fossa</a>.</p><h6>Olfactory tract</h6><p>The central process of these second-order neurones forms the <a href="/articles/olfactory-tract">olfactory tract</a> which courses posteriorly, superior to the <a href="/articles/olfactory-fossa">olfactory groove</a> of the <a href="/articles/anterior-cranial-fossa">anterior cranial fossa</a>, and inferior to the <a href="/articles/olfactory-sulcus-1">olfactory sulcus</a> (lateral to <a href="/articles/gyrus-rectus">gyrus rectus</a>, and medial to the <a href="/articles/orbital-gyri">orbital gyri</a>).</p><h6>Olfactory striae</h6><p>Anterior to the <a href="/articles/anterior-perforated-substance">anterior perforated substance</a>, the olfactory tract divides to form the medial and lateral olfactory striae. This triangular area of division is referred to as the <a href="/articles/olfactory-trigone" title="olfactory trigone">olfactory trigone</a>. The lateral olfactory striae project to the <a href="/articles/uncus">uncus</a>. The medial olfactory striae ultimately project to the <a href="/articles/hypothalamus">hypothalamus</a> and <a href="/articles/brainstem-nuclei">brainstem nuclei</a>. </p><h4>Radiographic features</h4><h5>MRI</h5><p>Coronal images are the best to depict the olfactory nerve as it is situated deep in the <a href="/articles/olfactory-fossa">olfactory groove</a>.</p><h4>Related pathology</h4><ul>- +</ul><h4>Gross anatomy</h4><h5>Course</h5><h6>Olfactory filaments</h6><p>The bipolar cell is the first-order sensory neurone located at the olfactory mucosa on the roof of the <a href="/articles/nasal-cavity">nasal cavity</a>, immediately inferior to the <a href="/articles/cribriform-plate">cribriform plate</a> of the <a href="/articles/ethmoid-bone-1">ethmoid bone</a>. This cell is analogous to the sensory cells of spinal nerves, whose cell bodies reside in the <a href="/articles/dorsal-root-ganglion">dorsal root ganglion</a>. There are approximately 20 bipolar olfactory cells on each side in humans. Their central processes form filaments which pass through the cribriform plate, pierce the <a href="/articles/dura-mater">dura mater</a> and relay in the olfactory bulb.</p><h6>Olfactory bulb</h6><p>The olfactory bulb is the paired expanded anterior portion of the nerve that sits in the <a href="/articles/olfactory-fossa">olfactory fossa</a>. It houses the cell bodies of mitral cells, the second-order neurones of the olfactory system. </p><h6>Olfactory tract</h6><p>The central process of these second-order neurones forms the <a href="/articles/olfactory-tract">olfactory tract</a> which courses posteriorly, superior to the <a href="/articles/olfactory-fossa">olfactory groove</a> of the <a href="/articles/anterior-cranial-fossa">anterior cranial fossa</a>, and inferior to the <a href="/articles/olfactory-sulcus-1">olfactory sulcus</a> (lateral to <a href="/articles/gyrus-rectus">gyrus rectus</a>, and medial to the <a href="/articles/orbital-gyri">orbital gyri</a>).</p><h6>Olfactory striae</h6><p>Anterior to the <a href="/articles/anterior-perforated-substance">anterior perforated substance</a>, the olfactory tract divides to form the medial and lateral olfactory striae. This triangular area of division is referred to as the <a href="/articles/olfactory-trigone" title="olfactory trigone">olfactory trigone</a>. The lateral olfactory striae project to the <a href="/articles/uncus">uncus</a>. The medial olfactory striae ultimately project to the <a href="/articles/hypothalamus">hypothalamus</a> and <a href="/articles/brainstem-nuclei">brainstem nuclei</a>. </p><h4>Radiographic features</h4><h5>MRI</h5><p>Coronal images are the best to depict the olfactory nerve as it is situated deep in the <a href="/articles/olfactory-fossa">olfactory groove</a>.</p><h4>Related pathology</h4><ul>
References changed:
- https://www.britannica.com/science/human-nervous-system/Cranial-nerves#ref605846
Unable to process the form. Check for errors and try again.