What is the Soft Palate?
The soft palate is a muscular fold suspended from the posterior border of the hard palate that extends downwards and backwards into the oropharynx, serving as a dynamic valve that regulates airflow between the nose and mouth while playing critical roles in swallowing, speech, and respiration. 1
Anatomical Structure
The soft palate is composed of several intermingled muscles embedded within a fibro-fatty layer, creating a complex three-dimensional structure 2:
- Fibro-fatty layer: Located on the oral side of the soft palate, becoming thick and dense along the midline 2
- Levator veli palatini: Distributed on the nasal side of the soft palate, located approximately 12.3 ± 5.2 mm from the top of the palatopharyngeal arch 2
- Palatopharyngeus: Spreads widely and fills the palatopharyngeal arch 2
- Tensor veli palatini aponeurosis: Merges with the fascia of the soft palate in the midline, continuous with the periosteum of the hard palate 2
- Palatoglossus: Very thin muscle embedded in the palatoglossal arch 2
Functional Roles
Respiratory Function
The soft palate acts as a critical regulator of airflow through the upper airway 1:
- Airflow regulation: The soft palate can rise to touch the posterior pharyngeal wall (closing the nasopharynx) or remain in apposition with the tongue (closing the oropharyngeal isthmus), thereby controlling whether air flows through the nose, mouth, or both 1
- Oronasal breathing: During exercise, speech, or smoking, the position of the soft palate determines the impedance and partitioning of airflow between nasal and oral routes 1
- Sleep-related breathing: The soft palate is involved in the genesis of snoring and obstructive sleep apnea syndrome 1, 3
Speech and Swallowing
The soft palate is essential for normal speech articulation and safe swallowing 3:
- Velopharyngeal closure: The soft palate elevates to separate the nasopharynx from the oropharynx during speech and swallowing 3
- Speech resonance: Proper soft palate function prevents hypernasality and maintains normal speech intelligibility 3
- Prevention of nasopharyngeal reflux: During swallowing, soft palate elevation prevents food and liquid from entering the nasal cavity 4
Sensory Innervation
The soft palate has dense sensory innervation that mediates critical reflexes 5:
- Oral side innervation: The oral (inferior) surface has significantly higher density of sensory nerve fibers compared to the nasal side 5
- Nasal side innervation: Contains approximately 78% of the nerve fiber number and 72% of the percent area found on the oral side 5
- Nerve plexus: Sensory nerve fibers form a dense plexus in the lamina propria of the soft palatal mucosa 5
Clinical Significance
Anatomic Location in Head and Neck Cancer
The soft palate is recognized as a distinct anatomic subsite within the oropharynx 3:
- Oropharyngeal subsite: The soft palate (anterior two-thirds) is classified as part of the oropharynx, distinct from the oral cavity 3
- Tumor involvement: Tumors can arise from or extend to the soft palate, affecting adjacent structures including the tonsillar pillar and nasal cavity 3
Surgical Considerations
Surgical treatment involving the soft palate carries significant functional implications 3:
- Functional deficits: Excision of the soft palate results in speech and swallowing deficits, including severe rhinolalia and velopharyngeal insufficiency in approximately 5% of cases even with limited soft palate involvement 3
- Reconstruction challenges: The dynamic fibromuscular structure of the soft palate cannot be fully duplicated, making reconstruction complex 4
- Treatment decisions: For T1-T2 squamous cell carcinoma involving the soft palate, careful counseling is required regarding the severity of functional deficits when comparing surgery (with or without adjuvant therapy) versus primary radiotherapy 3
Congenital Abnormalities
Soft palate abnormalities are common in certain genetic conditions 3:
- 22q11.2 deletion syndrome: Approximately two-thirds of children have palatal abnormalities, including velopharyngeal dysfunction with or without submucous cleft palate 3
- Velopharyngeal dysfunction: Results from the inability of the soft palate and pharyngeal walls to close properly during speech, complicated by anatomical factors such as palatal clefting, altered velopharyngeal dimensions, and muscle hypoplasia 3