**3.7 Anatomy of the parapharyngeal space**

The base of the parapharyngeal pyramid is located at the skull base and its apex at the greater cornu of the hyoid bone. The PPS is bounded by the following structures:

a.The buccopharyngeal fascia which covers the SPCm, the LVPm, and tensor veli palatini muscles medially,


Inferiorly, the direct communication of the PPS with the submandibular space may be seen at the apex [4, 7, 10, 15].

#### *3.7.1 Parapharyngeal space compartments*

Prasad et al. reported that the PPS is composed of three compartments as follows: the upper part of the PPS is located between the skull base and the axial plane passing through the inferior border of the lateral pterygoid muscle, the lower border of the middle part is formed by the axial plane passing through the mandibular insertion of medial pterygoid muscle, and the lower part is limited with the hyoid bone. The middle part of the PPS is situated at the level of the tonsillar fossa. Also, the upper and middle parts are divided into prestyloid and poststyloid compartments in relation to the styloid diaphragm. Thus, the PPS consists of five parapharyngeal subspaces [18].

The styloid diaphragm is a thick gray fascia which is composed of the posterior belly of the digastric muscle, the styloid musculature (StPm, StGm and stylohyoid muscle-StHm), and the stylohyoid and stylomandibular ligaments. It divides the lower PPS into the prestyloid and poststyloid compartments by extending from the styloid process to the parotid fascia (**Figure 3**). The prestyloid space is localized between the medial pterygoid muscle and SPCm [7, 15, 18].

In the prestyloid part of the upper PPS, minor salivary glands, the posterior division of the mandibular nerve, the internal maxillary artery, fat pad, and tensor veli palatini muscle are located. In the poststyloid part of the upper PPS, the carotid sheath which consists of the internal carotid artery (ICA), internal jugular vein (IJV), vagus nerve, and also just in this superior section the ascending pharyngeal artery, cervical sympathetic chain, and the lower cranial nerves, IX, XI, and XII, are situated [7, 18].

In the prestyloid part of the middle PPS, the fat pad, a deep lobe of the parotid gland, from superior to inferior numerous tonsillar branches of the descending palatine, the ascending pharyngeal, and the ascending palatine arteries between the StGm and StPm are located. In the poststyloid part of the middle PPS, the curves of the internal maxillary, facial, and lingual arteries, cervical sympathetic chain, and the carotid sheath which consists of the ICA, IJV, and the lower cranial nerves (CNIX–CNXII) are situated [5, 7, 18].

#### *3.7.2 Surgical landmarks in the parapharyngeal space in relation to the palatine tonsil*

Different surgical procedures can be used in treatment of the upper airway obstruction due to tonsillar or adeno-tonsillar hypertrophy and peritonsillar abscess. Classic tonsillectomy consists of full removal of the tonsil with its capsule by dissecting the peritonsillar space with or without adenoidectomy. In the post-acute

**37**

*Surgical Anatomy of the Tonsils*

lesions [4, 5].

*DOI: http://dx.doi.org/10.5772/intechopen.93038*

tonsillitis, a peritonsillar abscess may spread into the PPS through the buccopharyngeal fascia. Due to the close proximity of the PPS with the surrounding spaces including pharyngeal mucosal, retropharyngeal, masticator, and parotid spaces, the lesions in these spaces commonly spread into the PPS and result in secondary

Sun et al. reported that the localization of the tumors in the PPS can be identified by some anatomical landmarks during surgical approaches. Because of the tumors in the upper PPS are mostly benign and located in the prestyloid space, the endoscopic transnasal transpterygoid approaches to this region require detailed anatomic knowledge of the surgical anatomic landmarks in this space. They demonstrated that the surgical anatomic landmarks in the prestyloid part of the upper PPS are as follows: the pterygoid process with medial and lateral plates, the tensor veli palatini, the SPCm, the lateral and medial pterygoid muscles, and the fat pad. In the prestyloid part of the lower PPS, the PGa, the SPCm, the pterygomandibular raphe, fat tissue, and the styloid diaphragm could be used as surgical anatomical

landmarks during endoscopic transoral approach (**Figure 3**) [19].

base of the tongue; anterior, retromolar trigone) [5].

dividing the lateral oropharyngeal wall into three layers:

not grossly infiltrating the SPCm.

posteroinferior edge of the StGm.

required [5].

Approximately 80% of primary oropharyngeal tumors originate from the tonsillar fossa and their incidence in younger patients increases. The tumors in the tonsillar fossa and the PPS can be removed by endoscope-assisted lateral oropharyngectomy approaches, transoral robotic surgery, or laser microsurgery. The lateral pharyngeal wall is composed of three deep fascia layers from inward to outward: the capsule of the tonsil, the pharyngobasilar fascia, and the buccopharyngeal fascia [5, 15, 19]. Depending on these fascia layers, De Virgilio et al. reported their lateral oropharyngectomy classification based on three types of surgical procedures and four possible extensions (superior, soft palate; posterior, pharyngeal wall; inferior,

Type 1 contains the removal of the palatine tonsil deep to the pharyngobasilar fascia with the resection of all or part of the anterior pillar excluding the SPCm. The aim of this procedure is mostly diagnostic, but it can be used in surgical treatment

Type 2 is resection of the palatine tonsil, the PGm, the PPm, and the SPCm deep to the buccopharyngeal fascia. It can be therapeutic for invasive malignant tumors

Type 3 includes the resection of the buccopharyngeal fascia with extension to the pterygoid muscle and PPS adipose corpus in addition to Type 2 contents. According to the extension of the tumor, the resection of the PPS tissue up to the exposure of the ICA could be included, and also a flap coverage for the ICA is

Similarly, Mirapeix et al. identified an applicable dissection method based on the anatomic stratification and evident anatomic landmarks [4]. They performed the dissections layer by layer from within outward and described this technique by

The first layer, medial to styloid muscles, includes important surgical landmarks such as the SPCm, PGm, PPm, and StGm, the pharyngobasilar fascia, and a vascular network, which is composed of the branches of the descending and ascending palatine arteries and the ascending pharyngeal artery. The vascular supply of the tonsillar fossa can be identified by the PGm and PPm, and also the lingual branch of the GPn mostly crosses at the midpoint between PGm and PPm or along the

The second layer is observed after resection of the constrictor muscles and located in the PPS medial to the styloid diaphragm. The surgical landmarks are composed of the styloid musculature, the buccopharyngeal fascia, the stylohyoid ligament, the pharyngeal venous plexus, and the GPn. The insertion point of the

of noninvasive hyperplasia, dysplasia, or carcinoma in situ of the tonsil.

#### *Surgical Anatomy of the Tonsils DOI: http://dx.doi.org/10.5772/intechopen.93038*

*Oral and Maxillofacial Surgery*

the parotid gland anterolaterally,

may be seen at the apex [4, 7, 10, 15].

parapharyngeal subspaces [18].

(CNIX–CNXII) are situated [5, 7, 18].

situated [7, 18].

*tonsil*

*3.7.1 Parapharyngeal space compartments*

b.The fascia overlying the masticator space, the medial pterygoid muscle, the sphenomandibular ligament, the ramus of the mandible, and the deep lobe of

d.The pterygomandibular raphe between the medial pterygoid plate and the mylohyoid line of the mandible and interpterygoid fascia anteriorly,

Inferiorly, the direct communication of the PPS with the submandibular space

Prasad et al. reported that the PPS is composed of three compartments as follows: the upper part of the PPS is located between the skull base and the axial plane passing through the inferior border of the lateral pterygoid muscle, the lower border of the middle part is formed by the axial plane passing through the mandibular insertion of medial pterygoid muscle, and the lower part is limited with the hyoid bone. The middle part of the PPS is situated at the level of the tonsillar fossa. Also, the upper and middle parts are divided into prestyloid and poststyloid compartments in relation to the styloid diaphragm. Thus, the PPS consists of five

The styloid diaphragm is a thick gray fascia which is composed of the posterior belly of the digastric muscle, the styloid musculature (StPm, StGm and stylohyoid muscle-StHm), and the stylohyoid and stylomandibular ligaments. It divides the lower PPS into the prestyloid and poststyloid compartments by extending from the styloid process to the parotid fascia (**Figure 3**). The prestyloid space is localized

In the prestyloid part of the upper PPS, minor salivary glands, the posterior division of the mandibular nerve, the internal maxillary artery, fat pad, and tensor veli palatini muscle are located. In the poststyloid part of the upper PPS, the carotid sheath which consists of the internal carotid artery (ICA), internal jugular vein (IJV), vagus nerve, and also just in this superior section the ascending pharyngeal artery, cervical sympathetic chain, and the lower cranial nerves, IX, XI, and XII, are

In the prestyloid part of the middle PPS, the fat pad, a deep lobe of the parotid gland, from superior to inferior numerous tonsillar branches of the descending palatine, the ascending pharyngeal, and the ascending palatine arteries between the StGm and StPm are located. In the poststyloid part of the middle PPS, the curves of the internal maxillary, facial, and lingual arteries, cervical sympathetic chain, and the carotid sheath which consists of the ICA, IJV, and the lower cranial nerves

*3.7.2 Surgical landmarks in the parapharyngeal space in relation to the palatine* 

Classic tonsillectomy consists of full removal of the tonsil with its capsule by dissecting the peritonsillar space with or without adenoidectomy. In the post-acute

Different surgical procedures can be used in treatment of the upper airway obstruction due to tonsillar or adeno-tonsillar hypertrophy and peritonsillar abscess.

c.The styloid process, the StGm and StPm posterolaterally,

e.The prevertebral fascia and muscles posteriorly.

between the medial pterygoid muscle and SPCm [7, 15, 18].

**36**

tonsillitis, a peritonsillar abscess may spread into the PPS through the buccopharyngeal fascia. Due to the close proximity of the PPS with the surrounding spaces including pharyngeal mucosal, retropharyngeal, masticator, and parotid spaces, the lesions in these spaces commonly spread into the PPS and result in secondary lesions [4, 5].

Sun et al. reported that the localization of the tumors in the PPS can be identified by some anatomical landmarks during surgical approaches. Because of the tumors in the upper PPS are mostly benign and located in the prestyloid space, the endoscopic transnasal transpterygoid approaches to this region require detailed anatomic knowledge of the surgical anatomic landmarks in this space. They demonstrated that the surgical anatomic landmarks in the prestyloid part of the upper PPS are as follows: the pterygoid process with medial and lateral plates, the tensor veli palatini, the SPCm, the lateral and medial pterygoid muscles, and the fat pad. In the prestyloid part of the lower PPS, the PGa, the SPCm, the pterygomandibular raphe, fat tissue, and the styloid diaphragm could be used as surgical anatomical landmarks during endoscopic transoral approach (**Figure 3**) [19].

Approximately 80% of primary oropharyngeal tumors originate from the tonsillar fossa and their incidence in younger patients increases. The tumors in the tonsillar fossa and the PPS can be removed by endoscope-assisted lateral oropharyngectomy approaches, transoral robotic surgery, or laser microsurgery. The lateral pharyngeal wall is composed of three deep fascia layers from inward to outward: the capsule of the tonsil, the pharyngobasilar fascia, and the buccopharyngeal fascia [5, 15, 19]. Depending on these fascia layers, De Virgilio et al. reported their lateral oropharyngectomy classification based on three types of surgical procedures and four possible extensions (superior, soft palate; posterior, pharyngeal wall; inferior, base of the tongue; anterior, retromolar trigone) [5].

Type 1 contains the removal of the palatine tonsil deep to the pharyngobasilar fascia with the resection of all or part of the anterior pillar excluding the SPCm. The aim of this procedure is mostly diagnostic, but it can be used in surgical treatment of noninvasive hyperplasia, dysplasia, or carcinoma in situ of the tonsil.

Type 2 is resection of the palatine tonsil, the PGm, the PPm, and the SPCm deep to the buccopharyngeal fascia. It can be therapeutic for invasive malignant tumors not grossly infiltrating the SPCm.

Type 3 includes the resection of the buccopharyngeal fascia with extension to the pterygoid muscle and PPS adipose corpus in addition to Type 2 contents. According to the extension of the tumor, the resection of the PPS tissue up to the exposure of the ICA could be included, and also a flap coverage for the ICA is required [5].

Similarly, Mirapeix et al. identified an applicable dissection method based on the anatomic stratification and evident anatomic landmarks [4]. They performed the dissections layer by layer from within outward and described this technique by dividing the lateral oropharyngeal wall into three layers:

The first layer, medial to styloid muscles, includes important surgical landmarks such as the SPCm, PGm, PPm, and StGm, the pharyngobasilar fascia, and a vascular network, which is composed of the branches of the descending and ascending palatine arteries and the ascending pharyngeal artery. The vascular supply of the tonsillar fossa can be identified by the PGm and PPm, and also the lingual branch of the GPn mostly crosses at the midpoint between PGm and PPm or along the posteroinferior edge of the StGm.

The second layer is observed after resection of the constrictor muscles and located in the PPS medial to the styloid diaphragm. The surgical landmarks are composed of the styloid musculature, the buccopharyngeal fascia, the stylohyoid ligament, the pharyngeal venous plexus, and the GPn. The insertion point of the

StGm refers to junction of the tongue with anterior pillar, and the lingual branch of the GPn can be identified along the posteroinferior border of the StGm. The pharyngeal venous plexus is located in a space between the StGm and SPCm. The facial artery and the hypoglossal nerve cross the StHm which extends parallel to the stylohyoid ligament. The GPn travels downward along the posterolateral aspect of the StPm.

The third layer lateral to styloid diaphragm refers to the poststyloid part of the PPS. Surgical landmarks in this layer consist of the styloid musculature, the posterior belly of the digastric muscle, the ICA, the hypoglossal nerve, and lingual and facial arteries. Especially, the StGm is an essential landmark to identify the localization of the ICA posterolaterally, the lingual nerve anteriorly, and the submandibular gland inferolaterally. The hypoglossal nerve crosses laterally to medially over the ascending pharyngeal originating from the superolateral border of the external carotid artery (ECA) in the poststyloid part of the lower PPS [4].

During transoral robotic surgery (TORS), the dissection of the SPCm from the pterygomandibular raphe refers to a window into the prestyloid compartment of the PPS. The tendon of the medial pterygoid muscle leads to identification of the buccopharyngeal fascia and indicates a safe plane in the prestyloid compartment of the PPS [7, 19]. Also, the plane that is constituted by the styloid musculature and the stylohyoid ligament is an essential surgical landmark for ICA identification. Wang et al. demonstrated that the styloid process, styloid diaphragm, pharyngeal venous plexus, GPn, and pharyngeal branch of the vagus are located between the ECA and the ICA and subdivide the PPS into prestyloid and poststyloid spaces (**Figure 3**). The curves of the branches of the ECA (lingual, facial, ascending pharyngeal, internal maxillary arteries) are located in the prestyloid space, and also the ascending pharyngeal artery crosses the StGm at the distal third near the tonsillar fossa surgical field [20]. In addition, the lingual artery and hypoglossal nerve are located lateral to the StGm, and the lingual artery passes between greater cornu of hyoid and the StGm where it has high risk of hemorrhage during the resection of the base of the tongue [21]. The fact that in the PPS the facial artery is located inferolateral to the StGm is of great importance, because a dissection lateral to the StGm or resection of tonsillar malignancy may result in significant hemorrhage. In PPS after branching from the facial artery, the tonsillar and ascending palatine arteries course between the StGm and the StPm and then pierce the SPCm to supply the tonsil [22]. So, the fact that the StGm is in close relationship with the branches of the ECA should be kept in mind when the transoral dissection space at the level of the tonsillar fossa is dissected in the superolateral direction, and the dissection deep into the plane of this muscle must be performed rigorously and accurately [16, 20].

In the PPS lateral to the styloid diaphragm, the ICA lies about 10–20 mm behind the palatine tonsil at the level of the epiglottis apex, whereas its distance to the ET is approximately 23.5 mm. So, it is closer to the lateral pharyngeal wall in the poststyloid part of the lower PPS than in the upper PPS, and the risk of arterial trauma during tonsillectomy increases with a decrease in the distance to the pharyngeal wall. Also, the level of the common carotid artery bifurcation higher than the epiglottis apex is more susceptible to common carotid artery trauma during surgery [23]. During radical tonsillectomy, because the lingual nerve lies lateral to the SPCm, it may be injured at the anterior border of the medial pterygoid muscle [15].

The GPn extends from the jugular foramen to the base of the tongue in the lateral wall of the pharynx. Because of the close relationship of the GPn with the StPm, it is divided into three parts: upper (jugular foramen, upper border of the StPm), middle

**39**

*Surgical Anatomy of the Tonsils*

GPn deep to the SPCm [17].

bleeding during surgical dissection.

*3.8.1 Arterial supply*

arteries (**Figure 4**).

*3.8.2 Venous drainage*

into the IJV (**Figure 4**) [6, 7].

the mandible posteriorly [6, 7].

*3.8.3 Lymphatic drainage*

geal artery.

**3.8 Vascular network and innervation of the tonsils**

of the tongue) [17].

upper PPS.

*DOI: http://dx.doi.org/10.5772/intechopen.93038*

of the ICA and may result in vascular injury.

(upper-lower borders of the StPm), and lower (lower borders of the StPm, the base

The upper part travels between the ICA and IJV behind the styloid process and gives the carotid body and carotid sinus branches in the poststyloid part of the

The middle part extends downward along the inferolateral border of the StPm and gives off branches to the StPm and pharyngeal wall in the poststyloid part of the lower PPS. Particularly, this part passes obliquely anterior to the distal segment

The lower part passes through a space or slit between the SPCm and MPCm to enter the pharynx. Between the StGm and StPm, it lies along the inferior border of the palatine tonsil or beneath the capsule and gives the tonsillar branch. Generally, it gives terminal branches at the junction of the PPa with the base of tongue, known as glossotonsillar sulcus, which is anatomic landmark for the terminal part of the

During surgical interventions including transoral tonsillectomy, tumor resection, and the SPCm block, the integrity of this nerve may be damaged and result in dysphagia and taste disturbance. In recurrent tonsillitis, the adherence of the capsule with surrounding structures makes it difficult to remove the hypertrophic tonsillar capsule from the tonsillar bed, or the dissection of the capsule which is firmly adherent with the lingual branch of this nerve causes disturbance of the nerve functions [3, 7, 17]. During transoral surgery, early description of the StPm allows to specify the GPn which crosses over the ICA and serves as a surgical landmark to protect it in the PPS. Also, the surgeon should keep in mind the association of the GPn with a venous plexus in the glossotonsillar sulcus to prevent iatrogenic

The tonsil and tonsillar fossa with boundaries are supplied by the branches of the ECA including lingual, facial, ascending pharyngeal, and internal maxillary

The upper part is supplied by descending palatine artery branch of the internal maxillary artery and the middle and inferior branches of the ascending pharyn-

The lower part is supplied by an ascending palatine artery branch of the facial

The veins of the tonsil and tonsillar fossa drain into the paratonsillar vein and then into the pharyngeal venous plexus. This plexus drains through the facial vein

The lymphatics pierce the SPCm and drain into the upper deep cervical lymph nodes principally jugulodigastric lymph nodes which are located below the angle of

The middle part is supplied by tonsillar branch of the facial artery.

artery and dorsal lingual branch of the lingual artery [20, 23].

*Oral and Maxillofacial Surgery*

of the StPm.

StGm refers to junction of the tongue with anterior pillar, and the lingual branch of the GPn can be identified along the posteroinferior border of the StGm. The pharyngeal venous plexus is located in a space between the StGm and SPCm. The facial artery and the hypoglossal nerve cross the StHm which extends parallel to the stylohyoid ligament. The GPn travels downward along the posterolateral aspect

The third layer lateral to styloid diaphragm refers to the poststyloid part of the PPS. Surgical landmarks in this layer consist of the styloid musculature, the posterior belly of the digastric muscle, the ICA, the hypoglossal nerve, and lingual and facial arteries. Especially, the StGm is an essential landmark to identify the localization of the ICA posterolaterally, the lingual nerve anteriorly, and the submandibular gland inferolaterally. The hypoglossal nerve crosses laterally to medially over the ascending pharyngeal originating from the superolateral border of the external

During transoral robotic surgery (TORS), the dissection of the SPCm from the pterygomandibular raphe refers to a window into the prestyloid compartment of the PPS. The tendon of the medial pterygoid muscle leads to identification of the buccopharyngeal fascia and indicates a safe plane in the prestyloid compartment of the PPS [7, 19]. Also, the plane that is constituted by the styloid musculature and the stylohyoid ligament is an essential surgical landmark for ICA identification. Wang et al. demonstrated that the styloid process, styloid diaphragm, pharyngeal venous plexus, GPn, and pharyngeal branch of the vagus are located between the ECA and the ICA and subdivide the PPS into prestyloid and poststyloid spaces (**Figure 3**). The curves of the branches of the ECA (lingual, facial, ascending pharyngeal, internal maxillary arteries) are located in the prestyloid space, and also the ascending pharyngeal artery crosses the StGm at the distal third near the tonsillar fossa surgical field [20]. In addition, the lingual artery and hypoglossal nerve are located lateral to the StGm, and the lingual artery passes between greater cornu of hyoid and the StGm where it has high risk of hemorrhage during the resection of the base of the tongue [21]. The fact that in the PPS the facial artery is located inferolateral to the StGm is of great importance, because a dissection lateral to the StGm or resection of tonsillar malignancy may result in significant hemorrhage. In PPS after branching from the facial artery, the tonsillar and ascending palatine arteries course between the StGm and the StPm and then pierce the SPCm to supply the tonsil [22]. So, the fact that the StGm is in close relationship with the branches of the ECA should be kept in mind when the transoral dissection space at the level of the tonsillar fossa is dissected in the superolateral direction, and the dissection deep into the plane of this muscle must be performed rigorously and

In the PPS lateral to the styloid diaphragm, the ICA lies about 10–20 mm behind the palatine tonsil at the level of the epiglottis apex, whereas its distance to the ET is approximately 23.5 mm. So, it is closer to the lateral pharyngeal wall in the poststyloid part of the lower PPS than in the upper PPS, and the risk of arterial trauma during tonsillectomy increases with a decrease in the distance to the pharyngeal wall. Also, the level of the common carotid artery bifurcation higher than the epiglottis apex is more susceptible to common carotid artery trauma during surgery [23]. During radical tonsillectomy, because the lingual nerve lies lateral to the SPCm, it may be injured at the anterior border of the medial pterygoid

The GPn extends from the jugular foramen to the base of the tongue in the lateral wall of the pharynx. Because of the close relationship of the GPn with the StPm, it is divided into three parts: upper (jugular foramen, upper border of the StPm), middle

carotid artery (ECA) in the poststyloid part of the lower PPS [4].

**38**

muscle [15].

accurately [16, 20].

(upper-lower borders of the StPm), and lower (lower borders of the StPm, the base of the tongue) [17].

The upper part travels between the ICA and IJV behind the styloid process and gives the carotid body and carotid sinus branches in the poststyloid part of the upper PPS.

The middle part extends downward along the inferolateral border of the StPm and gives off branches to the StPm and pharyngeal wall in the poststyloid part of the lower PPS. Particularly, this part passes obliquely anterior to the distal segment of the ICA and may result in vascular injury.

The lower part passes through a space or slit between the SPCm and MPCm to enter the pharynx. Between the StGm and StPm, it lies along the inferior border of the palatine tonsil or beneath the capsule and gives the tonsillar branch. Generally, it gives terminal branches at the junction of the PPa with the base of tongue, known as glossotonsillar sulcus, which is anatomic landmark for the terminal part of the GPn deep to the SPCm [17].

During surgical interventions including transoral tonsillectomy, tumor resection, and the SPCm block, the integrity of this nerve may be damaged and result in dysphagia and taste disturbance. In recurrent tonsillitis, the adherence of the capsule with surrounding structures makes it difficult to remove the hypertrophic tonsillar capsule from the tonsillar bed, or the dissection of the capsule which is firmly adherent with the lingual branch of this nerve causes disturbance of the nerve functions [3, 7, 17]. During transoral surgery, early description of the StPm allows to specify the GPn which crosses over the ICA and serves as a surgical landmark to protect it in the PPS. Also, the surgeon should keep in mind the association of the GPn with a venous plexus in the glossotonsillar sulcus to prevent iatrogenic bleeding during surgical dissection.

#### **3.8 Vascular network and innervation of the tonsils**

#### *3.8.1 Arterial supply*

The tonsil and tonsillar fossa with boundaries are supplied by the branches of the ECA including lingual, facial, ascending pharyngeal, and internal maxillary arteries (**Figure 4**).

The upper part is supplied by descending palatine artery branch of the internal maxillary artery and the middle and inferior branches of the ascending pharyngeal artery.

The middle part is supplied by tonsillar branch of the facial artery.

The lower part is supplied by an ascending palatine artery branch of the facial artery and dorsal lingual branch of the lingual artery [20, 23].

### *3.8.2 Venous drainage*

The veins of the tonsil and tonsillar fossa drain into the paratonsillar vein and then into the pharyngeal venous plexus. This plexus drains through the facial vein into the IJV (**Figure 4**) [6, 7].

#### *3.8.3 Lymphatic drainage*

The lymphatics pierce the SPCm and drain into the upper deep cervical lymph nodes principally jugulodigastric lymph nodes which are located below the angle of the mandible posteriorly [6, 7].

#### **Figure 4.**

*The vascular supply of the tonsil: PPm, palatopharyngeus muscle; PGm, palatoglossal muscle; SPCm, superior pharyngeal constrictor muscle.*

#### *3.8.4 Nerve supply*

General sensation of the tonsil and tonsillar fossa is supplied by the tonsillar branches of the GPn and the lesser palatine branch of the pterygopalatine ganglion (the maxillary division of the trigeminal nerve) [6, 7].

### **4. Conclusions**

Benign or malign lesions in the tonsil and tonsillar fossa may penetrate the lateral wall of the pharynx, or the PPS may be distorted evidently by the tumors. Due to the anatomical complexity with vital neurovascular structures in the PPS, transoral robotic approach to this region makes it necessary to identify the surgical anatomic landmarks which are required to perform effective surgical intervention quickly and accurately. The detailed and precise anatomic knowledge of the tonsillar region and the PPS allows surgeon to carry out wide resections in a confined

**41**

**Author details**

Anatomy, Konya, Turkey

Necmettin Erbakan University, Meram Faculty of Medicine, Department of

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: gulayzeynep73@gmail.com

provided the original work is properly cited.

Gülay Açar

*Surgical Anatomy of the Tonsils*

complications.

article.

**Conflict of interest**

*DOI: http://dx.doi.org/10.5772/intechopen.93038*

space. In transoral approaches, the classification of the dissection method based on the anatomic stratification or the surgical procedures which is oriented to cardinal points is essential for preoperative planning and to prevent the iatrogenic

The author reports no conflict of interest concerning the materials used in this paper. And the author has no personal financial or institutional interest in this

#### *Surgical Anatomy of the Tonsils DOI: http://dx.doi.org/10.5772/intechopen.93038*

space. In transoral approaches, the classification of the dissection method based on the anatomic stratification or the surgical procedures which is oriented to cardinal points is essential for preoperative planning and to prevent the iatrogenic complications.
