(1)
Department of Anatomy, Xuzhou Medical College, Xuzhou, Jiangsu, China
1 Superficial Lymphatics of the Head and Neck
Lymphatic vessels arose in the dermis, the galea aponeurotica and the subcutaneous tissues around the canthi of the eyelids, the side of the nose, the corner of the mouth and the neck. Vessels tracked radially towards their first-tier lymph nodes, branching, diverging and converging along their course. Sometimes, vessels were seen crossing or anastomosing with neighbouring vessels (Figs. 3.1 and 3.2).
Fig. 3.1
A radiograph of the superficial tissue on both sides of the head and neck region of the same cadaver after lead oxide injection showing the distribution of the lymph vessels and lymph nodes. Note the asymmetrical lymphatic pathway patterns
The lymphatic drainage patterns were different from person to person and even asymmetrical on each side of the same body (Fig. 3.1). The majority of the vessels converged to form large collectors, and some of them diverged before entering their first-tier lymph nodes (Figs. 2.20, 2.21 and 2.22).
Fig. 3.2
Distribution of the lymphatics in the superficial tissue of the left head and neck (including the platysma)
Importantly, it was found that collecting lymph vessels in the head and neck did not always enter their first-tier lymph nodes but sometimes bypassed them (Figs. 2.24, 2.25, 3.1, 3.2 and 3.3).
Figures 3.4 and 3.5 show the quantity, origin and course of lymph vessels and relationship between vessels; they also show how lymph vessels travel to the nodes in the superficial tissue of the head and neck.
Three lymphatic territories were represented in the superficial tissues of the head and neck – the scalp, the face and the cervical regions.
Fig. 3.3
Distribution of the lymphatics in the superficial tissue of the right head and neck. Some of the parietal lymphatic vessels (highlighted in green) bypass the retroauricular lymph nodes and enter the deep occipital and internal jugular lymph nodes
Fig. 3.4
Distribution of the lymphatics in the superficial tissue of the left head and neck above the platysma. Vessels are colour coded, highlighting the different vessel groups and lymph nodes. (1) Retroauricular lymph node. (2) Preauricular lymph nodes. (3) Parotid lymph nodes. (4) Submandibular lymph nodes. (5) Buccinator lymph node. (6) Deep occipital lymph nodes
Fig. 3.5
Distribution of the lymphatics in the superficial tissue of the left head and neck deep to the platysma. Vessels are colour coded, highlighting the different vessel groups and lymph nodes. (1) Superficial occipital lymph nodes. (2) Deep occipital lymph nodes. (3) Retroauricular lymph node. (4) Preauricular lymph nodes. (5) Submandibular lymph nodes. (6) Submental lymph nodes. (7) Parotid lymph nodes. (8) Infra-auricular lymph nodes. (9) Internal jugular lymph nodes. (10) Anterior jugular lymph node. (11) Supraclavicular lymph nodes. (12) Anterior jugular lymph node
1.1 Scalp Region
The lymph-collecting vessels were dense in the scalp region and arose from precollectors about 2 cm from the midline, which ran downwards and backwards and travelled in a “wavelike” or “snakelike” fashion to reach their first-tier (sentinel) lymph nodes in the subcutaneous tissue (Figs. 3.4 and 3.5). The lymphatic vessels diverged and converged along their course. Sometimes they crossed over or anastomosed with neighbouring vessels. The scalp lymphatic vessels include the frontal, the parietal and the occipital groups.
1.1.1 Frontal Group
An average of four collecting lymph vessels (ranging from three to six) were identified in the frontal section. Between the superior edge of the eyebrow and the coronal suture, vessels coursed radially in the deep aspect of the subcutaneous tissue towards their first-tier lymph nodes. They then branched, diverged and converged along their course; vessels drained to the preauricular and/or parotid lymph nodes (Figs. 3.4 and 3.5), and the preauricular and retroauricular lymph nodes (Fig. 3.6); the nasolabial, preauricular and retroauricular lymph nodes (Fig. 3.7); and the buccinator, preauricular, retroauricular and deep parotid lymph nodes (Fig. 3.8).
Fig. 3.6
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The frontal group of lymph vessels (brown) enters the preauricular and retroauricular lymph nodes (purple)
Fig. 3.7
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The highlighted region shows the frontal group of lymph vessels (brown) and related lymph nodes (purple)
Fig. 3.8
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The frontal group of lymph vessels (highlighted brown) and related lymph nodes (purple)
1.1.2 Parietal Group
An average of 6 collecting lymph vessels (ranging from 4 to 12) were identified in the parietal section. Vessels travelled radially in the deep aspect of the subcutaneous tissue between the coronal and the lambdoid sutures towards their first-tier lymph nodes. They drained to one or multiple groups of the preauricular, retroauricular, deep occipital or internal jugular lymph nodes (Figs. 3.4, 3.5, 3.9, 3.10 and 3.11).
Fig. 3.9
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The parietal group of lymph vessels (highlighted light blue) and related lymph nodes (purple)
Fig. 3.10
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The parietal region of lymph vessels (highlighted light blue) enters retroauricular lymph nodes (purple)
Fig. 3.11
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The parietal group of lymph vessels (highlighted light blue) enters preauricular and retroauricular lymph nodes (purple)
Fig. 3.12
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The parietal group of lymph vessels (highlighted light blue) and related lymph nodes (purple). Note some of them merge with neighbouring vessels before entering the lymph nodes
Fig. 3.13
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The parietal group of lymph vessels (highlighted light blue) enters the retroauricular and internal jugular lymph nodes (purple)
1.1.3 Occipital Group
An average of six collecting lymph vessels (ranging from four to nine) were identified in the occipital section. Vessels travelled radially in the deep aspect of the subcutaneous tissue between the lambdoid suture and the posterior hairline towards their first-tier lymph nodes. They drained to one or multiple groups of the superficial, deep occipital and internal jugular lymph nodes (Figs. 3.4, 3.5, 3.14, 3.15 and 3.16).
Fig. 3.14
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The occipital group of lymph vessels (orange) enters superficial occipital lymph nodes (purple)
Fig. 3.15
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The occipital group of lymph vessels (orange) enters deep occipital lymph nodes (purple)
Fig. 3.16
Lymphangiogram of the integument of the head and neck after a lymphatic contrast injection. The occipital group of lymph vessels (orange) enters superficial occipital and internal jugular lymph nodes (purple)
Clinical Implication
The incidence of skin cancer, especially melanoma, is very high in Western countries (particularly in Australia) (Uren et al. 1999; Thompson et al. 2004). Reports have shown that, after statistical analysis by using lymphoscintigraphy for scalp cancer patients, lymphatic drainage (or metastasis) of up to 43% of patients was not to the closest or regional lymph nodes, but to unpredictable or distant lymph nodes. It can be seen, from Figs. 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 3.10, 3.11, 3.12, 3.13, 3.14, 3.15 and 3.16, there were individual differences in lymphatic pathways within the scalp.
1.2 Facial Region
Lymphatic vessels were sparse in the facial region. An average of four lymph vessels (ranging from three to five) were found. Vessels travelled radially from medial to lateral towards their first-tier lymph nodes in the subcutaneous tissue between the eyebrow and the inferior border of the mandible. Four groups of vessels were identified in the origin.
1.2.1 Eyelid Lymph Vessels
The lymph capillary plexus arose in the dermis of the upper and lower eyelids. They formed an outer canthus lymph vessel at the outer canthus, an inner canthus lymph vessel at the inner canthus and an inferior eyelid lymph vessel at the middle-inferior section of the lower eyelid (Fig. 3.17).
Fig. 3.17
A schematic diagram of eyelid lymph vessels. Note that the inferior eyelid lymph vessel (dotted line) can merge with either the outer or inner canthus lymph vessels
Outer Canthus Lymph Vessel
Inner Canthus Lymph Vessel
Formed by the lymph capillary plexus, a collecting lymph vessel arose in the inner canthus, travelled obliquely in the subcutaneous tissue and drained to the submandibular, parotid or buccinator lymph nodes (Figs. 3.4, 3.5, 3.17, 3.18, 3.19 and 3.20). Occasionally, one upper-inner canthus vessel was found running horizontally and laterally above the superior edge of the eyebrow. It then travelled obliquely backwards and downwards on the lateral side of the eyebrow, passed over the zygomatic process, descended to converge with the outer canthus vessel and drained to the submandibular lymph node (Fig. 3.20).
Inferior Eyelid Lymph Vessel
A collecting lymph vessel was formed by the lymph capillary plexus in the middle-inferior spot of the lower eyelid; it travelled obliquely in the subcutaneous tissue and converged either with the outer or inner canthus lymph vessels and then drained into related lymph nodes (Figs. 3.4, 3.5, 3.17, 3.18, 3.19 and 3.20).
Fig. 3.18
Lymphangiogram of the face after lymphatic contrast injection. The inferior eyelid vessel merges to a tributary of the outer canthus lymph vessels (dark green) and forms a main vessel in the zygomaticus, which converges with the inner canthus lymph vessel in the cheek and then drains to the submandibular lymph node (purple)
Fig. 3.19
Lymphangiogram of the face after lymphatic contrast injection. The outer canthus lymph vessels (dark green) drain to the submandibular lymph nodes (purple). The inner canthus lymph vessel converges with the inferior eyelid vessel (dark green), crosses over the outer canthus lymph vessel in the cheek and then flows into the parotid lymph node (purple)
Fig. 3.20
Lymphangiogram of the face after lymphatic contrast injection. The outer canthus lymph vessels (dark green) converge with the inferior eyelid lymph vessel in the zygomaticus and the upper tributary of the inner canthus vessel in the cheek draining to the submandibular lymph nodes (purple). The inner canthus lymph vessel flows into the buccinator lymph node (purple)
Clinical Implication
As eyelid lymph vessels are situated superficially in the orbital area, they are easily damaged by injury or due to iatrogenic reasons, thus causing eyelid lymphoedema (Klapper and Patrinely 2007; Chalasani and McNab 2010; Aveta et al. 2011). The avalvular lymph capillary vessels connect the outer, inner canthus and inferior eyelid lymph vessels in the upper and lower eyelids (Fig. 3.17). Lymph flows to either the outer or inner canthus vessels in the upper eyelid and the outer, inner canthus or inferior eyelid lymph vessels in the lower eyelid. Due to this, lymphoedema of the eyelid will occur if multiple vessels are damaged (for details, see pages 198–199).
The lymphatic drainage patterns of the eyelid are differed from person to person. It is suggested to locate the sentinel lymph node by using lymphoscintigraphy for biopsy in the treatment of eyelid cancer patients, which may help to reduce the recurrent rate.
1.2.2 Nasal Lymph Vessels
Arising from the lateral side of the external nose, nasal lymph vessels travelled obliquely downwards from median to lateral sides in the subcutaneous tissue of the cheek. They drained to the nasolabial, buccinator or submandibular lymph nodes or merged with neighbouring vessels before entering the related nodes (Figs. 3.4, 3.5, 3.21, 3.22, 3.23, 3.24 and 3.25).
1.2.3 Oral Lymph Vessels
Arising from the corner of the mouth in each side, one or two collecting lymph vessels travelled in the subcutaneous and drained directly to the buccinator, submandibular or submental lymph nodes or merged with neighbouring lymph vessels before entering the related nodes (Figs. 3.4, 3.5, 3.21 and 3.22).
1.2.4 Mental Lymph Vessels
An average of three collecting lymph vessels (ranging from two to four) were found in the chin. They travelled in the deep aspect of the subcutaneous tissue of the chin and drained to the submental and/or submandibular lymph nodes (Figs. 3.4, 3.5 and 3.26).
Fig. 3.21
Lymphangiogram of the face after lymphatic contrast injection. Nasal lymph vessels (pink) and a short oral lymph vessel (light orange) enter one of the buccinator lymph nodes (purple). Note that a tributary of nasal lymph vessels converges with the frontal lymph vessel (brown) before entering the node
Fig. 3.22
Lymphangiogram of the facial region after lymphatic contrast injection. A nasal lymph vessel (pink) converging with an oral lymph vessel (light orange) drains to one of the submandibular lymph nodes (purple)
Fig. 3.23
Lymphangiogram of the face after lymphatic contrast injection. Nasal lymph vessels (pink) drain to the nasolabial lymph node (purple)
Fig. 3.24
Lymphangiogram of the face after lymphatic contrast injection. Nasal (pink) and oral (light orange) lymph vessels merge to the inner canthus lymph vessel (green) and drain to the submandibular lymph node (purple)
Fig. 3.25
Lymphangiogram of the face after lymphatic contrast injection. An oral lymph vessel (light orange) merges to the internodal lymph vessel (blue) and then drains to the submandibular lymph node (purple)
Fig. 3.26
Lymphangiogram of the face after lymphatic contrast injection. Mental lymph vessels (aqua blue) drain to submental lymph nodes (purple)
1.3 Cervical Region
Three groups of collecting lymph vessels were identified in the cervical region.
1.3.1 Anterior Cervical Group
Two layers of lymphatic vessels were identified in the anterior superficial neck.
Superficial Anterior Cervical Lymph Vessels
Above the platysma, each lymphatic vessel travelled in a different direction, running upwards, horizontally or obliquely. Medially, between the inferior border of the mandible and the laryngeal prominence vessels, they pierced the platysma near the midline and drained to the submental lymph node; between the laryngeal prominence and jugular notch, they pierced the platysma and drained to the supraclavicular lymph node. Laterally, vessels turned over the lateral edge of the platysma and then drained to the submandibular lymph node (Figs. 3.4, 3.5, 3.27, 3.28 and 3.29).
Occasionally, medial vessels between the laryngeal prominence and jugular notch drained into the anterior superficial jugular lymph nodes (Fig. 3.28).
Anterior Cervical Lymph Vessels
Below the platysma, vessels travelled above the deep fascia and drained to the anterior jugular lymph node (Fig. 3.5) or supraclavicular lymph node (Fig. 3.29).
Fig. 3.27
Composite drawing and X-ray of the jaw and the skin of the anterior neck. Above the platysma, the superficial anterior cervical lymph vessels (red) travel in different ways and drain into the related lymph nodes (purple). Green arrows indicate the direction of the lymph flow
Fig. 3.28
Composite drawing and X-ray of the jaw and the skin of the anterior neck. Above the platysma, the superficial anterior cervical lymph vessels (red) travel in different ways and drain into the related lymph nodes (purple). Green arrows indicate the direction of the lymph flow
Fig. 3.29
(a) Lymphangiogram of the right face and neck after lymphatic contrast injection shows the distribution of the anterior cervical lymph vessels below the platysma. Aqua highlights the mental lymph vessels; blue indicates the intermodal lymph vessels. The red-coloured vessel is a continuing lymph vessel arising above the platysma; its position is indicated by a doted red line and arrow. They drain into the related lymph nodes (purple). (b) The distribution of the superficial anterior cervical lymph vessels (red) above the platysma and their related lymph nodes (purple). Green arrows indicate the direction of the lymph flow
1.3.2 Lateral Cervical Group
In the lateral side of the neck, lymph vessels were abundant and complex. They are situated between the inferior border of the earlobe and the root of the neck and travel in different directions and multiple layers – the subcutaneous (superficial), the inter- and/or intramuscular (middle) and the perivascular (deep) layers. Most of them were sited between lymph nodes and named the internodal collecting lymph vessels (Figs. 3.5 and 3.29).
1.3.3 Posterior Cervical Group
Collecting lymph vessels were sparse in the posterior area of the neck. Two sets of the vessels were found. The diameter of the collecting lymph vessel was about 1 mm after lymphatic injection.
Supratrapezoid Lymph Vessels
Supraclavicular Lymph Vessels
Vessels travelled anteromedially in the deep aspect of the subcutaneous in the root of the neck draining to lateral internal jugular and/or supraclavicular lymph nodes (Figs. 3.5 and 3.30).
Fig. 3.30
Lymphangiogram of the head and neck after lymphatic contrast injection, showing the internodal lymph vessels (blue), supratrapezoid vessels (light green), supraclavicular vessels (yellow) and related lymph nodes (purple)
1.4 Auricular Region
Four groups of lymph vessels were identified in the auricle (Figs. 3.31, 3.32, 3.33, 3.34 and 3.35).
1.4.1 Preauricular Lymph Vessels
The lymph capillary plexus was distributed over most of the anterior aspects of the auricle. Medially, they converged to form a collecting lymph vessel running in the subcutaneous of the crus of helix. The vessel drained directly or indirectly (merged with a frontal lymph vessel) to the preauricular lymph nodes (Figs. 3.31, 3.32, 3.33 and 3.34 green vessels).
1.4.2 Supraauricular Lymph Vessels
An average of three collecting lymph vessels (ranged from two to four), arising in the superior aspect of the helix, travelled in the subcutaneous of the back of the auricle and converged together and then ran in the subcutaneous of the upper lateral neck to reach the infra-auricular and/or substernocleidomastoid lymph nodes. Occasionally, they were divided into two branches to reach the related lymph nodes (Figs. 3.31, 3.32, 3.33 and 3.34 orange vessels).
1.4.3 Midauricular Lymph Vessels
Arising from the scaphoid fossa near the auricular tubercle, collecting lymph vessels ran downwards, passed over the cartilage at the middle of the rim and then travelled obliquely in the subcutaneous of the back of the auricle, continuing their course in the subcutaneous of the upper lateral neck vessels until the infra-auricular lymph node is reached (Figs. 3.31, 3.32, 3.33, 3.34 yellow and 3.35 orange vessels). Occasionally, the vessel was divided into two branches. One entered the infra-auricular lymph node (Fig. 3.32 yellow vessels), while the other bypassed the node continuing its course (Fig. 3.32, indicated by a large white arrow).
1.4.4 Infra-auricular (Lobule) Lymph Vessels
Arising in the lobule of the auricle, collecting lymph vessels converged and travelled obliquely down to reach the infra-auricular node directly (Figs. 3.31, 3.32 and 3.33 blue vessels) or converged with neighbouring vessels before entering the node (Fig. 3.34 blue vessels). Occasionally, the vessel bifurcated into two branches before reaching the infra-auricular lymph node. One of them entered the node, while the other one bypassed the node and continued its course (Fig. 3.33, indicated by a large white arrow).
Fig. 3.31
A diagram of the lymphatic drainage zones in the anterior and posterior aspects of the auricle. Dashed grey lines divide the auricle into four zones draining, respectively, by the anterior (green), superior (orange), meddle (yellow) and inferior (blue) groups of auricular lymph vessels
Fig. 3.32
(a) Lymphangiogram of the auricle after lymphatic contrast injection. (b) Lymphatic pathways from different origins are highlighted in different colours
Fig. 3.33
(a) Lymphangiogram of the auricle after lymphatic contrast injection. (b) Lymphatic pathways from different origins are highlighted in different colours
Fig. 3.34
(a) Lymphangiogram of the auricle after lymphatic contrast injection. (b) Lymphatic pathways from different origins are highlighted in different colours
Fig. 3.35
The midauricular lymph vessel filled with lead oxide mixture is shown turning over the cartilage of the rim travelling from the anterior to the posterior aspects of the auricle
Clinical Implication
Primary malignant melanoma of the auricle is rare, but the prognosis is poor. Lymphoscintigraphy for mapping sentinel lymph nodes of the auricle has shown varied patterns (Wey et al. 1998; Cole et al. 2003; Thompson et al. 2004). The early anatomical knowledge of the lymphatic drainage in the auricle made it hard to explain the complete lymph drainage patterns. This section has shown that lymph vessels arising from different zones in the auricle could drain to the same or different groups of lymph nodes. Sometimes vessels could bypass the nearest lymph node to reach the node in the distal site. This information may help clinical management of malignancies in this region.
2 Deep Lymphatics of the Head and Neck
2.1 Nasal Cavity and Nasopharynx
The lymph capillary plexus originated from the mucosa of the atrium, three turbinates and the floor of the nasal cavity. They formed a network of precollecting lymph vessels in the submucosa of the lateral wall of the choana (Fig. 3.36). Then, vessels travelled intricately to form two groups of the collecting lymph vessels running in the lateral and retropharyngeal spaces (Figs. 3.36, 3.37, 3.38, 3.39, 3.40 and 3.41).
2.1.1 Lateral Pharyngeal Group
The lateral part of the precollecting lymph vessels in the submucosa of the lateral wall of the choana descended and passed through the lateral wall of the nasopharynx and formed two collecting lymph vessels that descended laterally into the lateral pharyngeal space (Figs. 3.36, 3.37, 3.38, 3.39, 3.40 and 3.41).
Anterolateral Lymph Vessels
The collecting lymph vessels descended anteriorly and then turned posteriorly. It travelled obliquely on the medial side of the external carotid artery to reach its first-tier lymph node – the lateral pharyngeal node. It entered the posterior portion of the node that is situated on the lateral side of the external carotid artery, which is at the level of the origin of the facial artery (Figs. 3.37, 3.38, 3.39, 3.40 and 3.41).
Posterolateral Lymph Vessels
The collecting vessel descended on the medial aspect of the external carotid artery, and one vessel branched off above the origin of the facial artery and then divided into two vessels above the lateral pharyngeal node. One of them entered the lateral pharyngeal lymph node anteriorly. One bypassed the node and crossed the lateral side of the internal carotid artery entering the third-tier lymph node of the retropharyngeal lymph node chain in the retropharyngeal space. The vessel, branching above the origin of the facial artery, travelled medially along the external carotid artery and then divided into two vessels again. One entered the middle portion of the lateral pharyngeal lymph node. The other one bypassed the node and descended to divide again into two vessels on the lateral side just above the bifurcation of the internal and external carotid arteries. One ran anteriorly to enter the subdigastric lymph node, while the other one ran posteriorly to enter the fifth-tier lymph node of the retropharyngeal lymph node chain in the retropharyngeal space (Figs. 3.37, 3.38, 3.39, 3.40 and 3.41).
2.1.2 Retropharyngeal Group
The posterior part of the precollecting lymph vessels in the submucosa of the lateral wall of the choana descended and connected to the lymph capillary plexus in the mucosa around the eustachian tube orifice. On the proximal side of the lymph capillary plexus, one or two precollecting lymph vessels were formed (Figs. 2.76 and 3.36). They travelled horizontally and penetrated the pharyngobasilar fascia near the lateral pterygoid plate of the sphenoid bone and passed through the posterior wall of the pharynx. The vessels then converged to a lymph collector descending in the retropharyngeal space. It entered the first-tier lymph node of the retropharyngeal chain at the level of the styloid process and then the second to seventh tiers lymph nodes of the retropharyngeal chain that lined up in two columns in the lower part of the retropharyngeal space. Three of them were situated more medially and the other three more laterally. The size of lymph nodes varied from 2 mm to 9 mm (Figs. 3.38, 3.39, 3.40 and 3.41).
Fig. 3.36
Photograph (a) and radiograph (b) showing the lymphatic vessels in the nasal fossae and nasopharynx area filled with lead oxide mixture
Fig. 3.37
Photograph (internal view) showing the lymphatic vessels in the lateral pharyngeal space filled with lead oxide mixture. Red and green arrows indicate the flow direction of the anterolateral and posterolateral lymph vessels
Fig. 3.38
Photograph of the interior view of the right half of the head and neck showing the lymph capillary plexus originating in the mucosa of the atrium, three turbinates, the floor of the nasal cavity, the nasopharynx and their pathways. They drain to the related lymph nodes in the parapharyngeal space
Fig. 3.39
Inverted radiograph (medial view) of the right half of the head and neck showing lymphatic pathways in the nasal fossae and nasopharynx
Fig. 3.40
Inverted radiograph of the nasal fossae and pharyngeal and laryngeal tissue, showing the distribution of the lymph vessels and lymph nodes
Note
The group of the retropharyngeal lymph node was found by Rouvière (1938) and was named as Rouvière nodes (Watanabe et al. 1985). According to the description in early studies, retropharyngeal lymph nodes could be subdivided into the lateral and medial groups. The lymph from the mucosa of the nasal cavity drained to the lateral group of node and subdigastric node, while the lymph from the mucosa of the nasopharynx drained to the medial group, the lateral pharyngeal and/or internal jugular lymph nodes. While it can be seen there are two groups of lymphatic pathways in Figs. 3.36, 3.37, 3.38, 3.39, 3.40 and 3.41, the lateral and retropharyngeal lymph vessels, they link the lymph capillary plexus of the nasal cavity and nasopharynx and drain to multiple first-tier lymph nodes. Two groups of lymph vessels connect to each other by precollecting lymph vessels in the choana and collecting lymph vessels around the bifurcation of the carotid arteries, although they travel, respectively, in the lateral and retropharyngeal spaces. This anatomical feature may direct clinical management of cancer treatment.
Fig. 3.41
A composite image of the lymphatic distribution of the nasal cavity, nasopharynx and parapharyngeal area. Yellow, lymph vessels in mucosae of the nasal cavity and nasopharynx. Green, lateral pharyngeal lymph vessels. Light blue, retropharyngeal lymph vessels. Blue, lymphatic vessels from soft palate. Purple, lymph nodes (retropharyngeal nodes are numbered). Red, carotid artery. Dark brown, longus muscles. Light brown, remaining wall of the nasal cavity and pharynx
Clinical Implication
Primary malignant melanoma in the mucosa of the nasal cavity is rare, but the prognosis is poor despite the advances in radical neck surgery, postoperative radiotherapy and chemotherapy (Bhattacharyya 2002; Martin et al. 2004). The recurrence may have an anatomical base. Firstly, the abundant lymph capillary plexus that is distributed on the wall of the nasal cavity and the nasopharynx and the avalvular capillary vessels allow the lymph to drain in various directions. Secondly, two separate pathways travelling in the parapharyngeal spaces have rich connections between them. Thirdly, those vessels can reach multiple first-tier lymph nodes.
Therefore it is suggested that treatment should include both groups of lymph nodes for patients with cancer in the nasal cavity or nasopharynx.
2.2 Soft Palate and Oropharynx
On each side, one or two precollecting lymph vessels arose from the lymph capillary plexus in the mucosa of the inferior aspect of the soft palate (Fig. 2.75). They travelled horizontally towards the lateral oropharyngeal wall and penetrated the wall to form one or two collecting lymph vessels. Then vessels descended to reach the lateral pharyngeal lymph node and/or the subdigastric lymph node (Figs. 3.40, 3.41, 3.42, 3.43, 3.44 and 3.45).
Fig. 3.42
Inverted radiograph of the tongue, soft palate, trachea and oesophagus shows the lymphatic pathway of the soft palate (blue) draining to both the subdigastric and lateral pharyngeal lymph nodes
The lymph capillary plexus originating in the mucosa of the oropharynx formed one to three precollecting lymph vessels (Fig. 3.46) in the submucosal layer. They penetrated the para-oropharyngeal wall and merged with collecting lymph vessels in the parapharyngeal spaces to reach the retropharyngeal and/or lateral pharyngeal lymph nodes (Figs. 3.37, 3.38, 3.39, 3.40 and 3.41).
Fig. 3.43
Radiograph (medial view) of the left half of the head and neck after lead oxide injection shows the lymphatic pathway of the soft palate (blue) draining to the lateral pharyngeal lymph node (purple)
Fig. 3.44
Inverted radiograph of the tongue, soft palate, hard palate and surrounding soft tissue shows the lymphatic pathway of the soft palate (blue) draining to the subdigastric lymph node (purple)
Fig. 3.45
Inverted radiograph of the tongue, soft palate, hard palate and surrounding soft tissue (lateral view) shows the lymphatic pathway of the soft palate (blue) draining to the subdigastric lymph node (purple)
Fig. 3.46
Photograph of the pharyngeal wall after lead oxide mixture injection. The lymph capillary plexus originates in the mucosa of the pharyngeal wall and forms three precollecting lymph vessels draining towards the retropharyngeal space. Red arrows indicate the direction of the lymph flow
2.3 Tongue and Oropharynx
An average of four collecting lymph vessels (ranging from three to five vessels) were found in each side of the tongue. They were described as the apical, anterolateral, posterolateral and posterior lingual lymph vessels (Figs. 3.47, 3.48, 3.49, 3.50, 3.51 and 3.52). The average diameter of the vessels was 0.2 mm (ranging from 0.1 to 0.3 mm).
2.3.1 Apical Lingual Lymph Vessels
The lymph vessel arising from the inferior side on the apical of the tongue travelled backwards 2 mm away from and parallel to the lingual frenulum in the submucosal layer. Above the floor of the mouth, it crossed the midline and ran posterolaterally on the superior side of the contralateral digastric muscle (anterior belly) and then drained into the submandibular node and/or submental node (Figs. 3.47, 3.48, 3.49 and 3.50).
Fig. 3.47
Inverted radiograph of the tongue, hard and soft palates after lead oxide injection showing the lymphatic distribution. Red arrows indicate the direction of the lymph flow
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