This article provides a comprehensive list of anatomical variations, which are naturally occurring differences in human morphology. These variations are not considered defects or abnormalities but rather normal deviations that do not inherently indicate pathology.

Head and neck

Skeletal variations

Muscular variations

  • Levator glandulae thyroidea (levator muscle of thyroid gland)
  • Accessory digastric muscle
  • Atlantomastoid muscle[1]
  • Styloauricularis muscle[2]
  • Transversus nuchae muscle
  • Pterygoideus proprius muscle
  • Levator claviculae muscle
  • Levator glandulae thyroidea muscle
  • Cleidoatlanticus muscle
  • Cleidocervical muscle
  • Cleidofascialis muscle
  • Cleidohyoideus muscle
  • Cleidomastoideus muscle
  • Cleido-occipitalis cervicalis muscle
  • Cricocorniculate muscle
  • Cricohyoid muscle (variation of thyrohyoid)
  • Sternoclavicularis anticus muscle
  • Styloauricularis muscle

Vascular variations

  • Persistent left superior vena cava

Nervous variations

  • Trigeminal nerve duplication
  • Aberrant facial nerve course
  • Accessory hypoglossal nerve

Other variations

Vertebral column and ribs

Skeletal variations

Thorax

Skeletal variations

Muscular variations

Other variations

  • Azygos lobe of the lung
  • Tracheal bronchus
  • Cardiac bronchus
  • Supernumerary lung fissures
  • Horseshoe lung

Upper limb

Skeletal variations

  • Bifurcated clavicle
  • Coracoclavicular joint
  • Os acromiale (see Acromion)
  • Capitohamate coalition
  • Carpal boss
  • Bipartite capitate
  • Supracondylar process of the humerus
  • Scapular foramina and tunnels

Muscular variations

Vascular variations

  • Alar thoracic artery
  • Median artery
  • Superficial ulnar artery
  • Variation of the basilic vein

Nervous variations

  • Bifid median nerve
  • Nerve of McKenzie
  • Martin-Gruber anastomosis
  • Riché-Cannieu anastomosis
  • Berrettini anastomosis
  • Froment-Rauber nerve

Other variations

Lower limb

Skeletal variations

  • Femoral anteversion/retroversion
  • Os tibiale externum
  • Fabella (popliteal sesamoid)
  • Calcaneonavicular coalition
  • Accessory navicula
  • Talocalcaneal coalition
  • Cyamella (popliteal fabella)
  • Sesamoid bone of the second, third, fourth, and fifth finger
  • Talus accessorius

Muscular variations

  • Accessory soleus muscle
  • Accessory popliteus muscle
  • Adductor minimus muscle
  • Tensor fasciae suralis muscle
  • Gluteoperinealis muscle
  • Gluteus quartus muscle
  • Popliteus biceps muscle
  • Fibularis (peroneus) quartus muscle
  • Peroneocalcaneus internus muscle

Vascular variations

Nervous variations

Abdomen

Muscular variations

  • Interfoveolar muscle
  • Saphenous muscle
  • Pubotransversalis muscle

Vascular variations

Other variations

  • Accessory spleen
  • Annular pancreas
  • Bifid pancreas tail
  • Double common bile duct
  • Agenesis of vermiform appendix
  • Colon duplication
  • Accessory pancreatic duct
  • Pancreas divisum
  • Gastropancreatic ligament

Pelvis

Vascular variations

  • Uterine artery anastomoses variations

Other variations

References

  1. ^ Lee, Rebecca; Pang, Stephen C.; Borman, William H.; Herrin, Sean O.; Bale, Logan S. W. (2022-10-01). "A prevalence study of the atlantomastoid muscle". Surgical and Radiologic Anatomy. 44 (10): 1349–1353. doi:10.1007/s00276-022-03022-6. ISSN 1279-8517. PMID 36155834.
  2. ^ Touré, Gaoussou; Anzouan-Kacou, Evelyne (2016-10-01). "The styloauricular muscle: clinical relevance and literature review of this rare muscle". Surgical and Radiologic Anatomy. 38 (8): 983–986. doi:10.1007/s00276-016-1633-x. ISSN 1279-8517. PMID 26846137.
  3. ^ Zielinska, Nicol; Karauda, Piotr; Węgiel, Andrzej; Szewczyk, Bartłomiej; Olewnik, Łukasz (2023-11-01). "A very rare case of a thoracobrachialis muscle". Surgical and Radiologic Anatomy. 45 (11): 1493–1496. doi:10.1007/s00276-023-03240-6. ISSN 1279-8517. PMC 10587252. PMID 37733018.
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