Your pet's internal security network -- and what swollen lymph nodes are trying to tell you.
Start at your level — or read all three. Each level links to the others so you can go deeper or share with someone who needs the basics.
Your vet checks your pet's lymph nodes at every exam -- but do you know why? The lymphatic system is your pet's internal security network, and swollen lymph nodes are its alarm bells.
Read Pet Owner LevelLymph node assessment is a core component of every physical examination. Knowing how to palpate, characterize, and document lymphadenopathy -- and when to escalate -- is an essential vet tech skill.
Read Vet Tech LevelThe lymphatic system is the anatomical scaffold of the adaptive immune response. Understanding lymph node architecture, lymphocyte trafficking, and the molecular basis of lymphoma is foundational to veterinary internal medicine and oncology.
Read Pre-Vet LevelUseful for all levels — bookmark this page for quick access.
| Submandibular | Under the jaw |
| Prescapular | Front of shoulder blades |
| Axillary | Armpits |
| Inguinal | Groin |
| Popliteal | Behind the knees |
| Normal | Small, smooth, moveable |
| Normal | Non-painful |
| Abnormal | Larger than usual |
| Abnormal | Hard or fixed in place |
| Most common presentation | Multicentric |
| With chemo (CHOP) | 12-14 months median |
| Without treatment | 4-6 weeks median |
| B cell vs T cell | B cell = better prognosis |
| Most common form | GI lymphoma |
| Low-grade GI | 2-3 years with treatment |
| Risk factor | FeLV infection |
| Diagnosis | Biopsy or cytology |