Learning objectives
The purpose of our educational exhibit is to:
1.
illustrate the normal anatomy and normal US appearance of the tibial nerve;
2.
Describe a systematic technique for US evaluation of such structure;
3.
produce anatomical schemes with didactic purpose and show correlations with sonographic imaging.
Background
The posterior tibial nerve is the larger of the two terminal branches of the sciatic nerve (L4-S3).
It leaves the popliteal fossa between the heads of medial and lateral gastrocnemius muscles and then runs below the characteristic arch of the soleus muscle.
At this level the tibial nerve is lateral to popliteal vessels,
while,
proximally,
it is close to the vessels and crosses to the medial side of the artery.
Then it descends in the median plane of the fibula,
between soleus and deep ankle...
Imaging findings OR Procedure Details
US EXAME
Landmarks at the popliteal fossa:
• Popliteal vessels
Landmarks at the leg:
Soleus muscle
Deep plantar flexor muscles (flexor hallucis longus,
flexor digitorum longus,
and tibialis posterior)
Landmarks at the ankle:
Medial malleolus
Posterior tibial artery
Tibialis posterior and flexor digitorumlongus tendons
Patient position:
supine with the foot externally rotated.
Place the probe in a transverse plane,
cranial and posterior to the medial malleolus.
Identify the posterior tibial artery: the round,
hypoechoic,
pulsatile vessel.
Do not put too much pressure on the probe...
Conclusion
US allows also a quick,
real-time and dynamic imaging and the possibility to compare the US findings against the contralateral side.
To perform US of the tibial nerve,
it is important to know the course of each nerve paying attention to anatomic landmarks and common sites of injury and entrapment such as tarsal tunnel.
References
Bianchi S,
Martinoli C,
editors.
Ultrasound of the musculoskeletal system.
Milan,
Italy: Springer Verlag; 2009.
Chiou HJ,
Chou YH,
Chiou SY,
Liu JB,
Chang CY.
Peripheral nerve lesions: role of high-resolutionUS.
Radiographics.
2003;23:15.8.
Fornage BD.
Peripheral nerves of the extremities: imaging with US.
Radiology.
1988;167:179–82.
Mentzel M,
Fleischmann W,
Bauer G,
Kinzl L.
Ankle joint denervation.
Part 1.
Anatomy: the sensory innervation of the ankle joint.
Foot Ankle Surg.
1999;5:15–20.
Peer S,
Kovacs P,
Harpf C,
Bodner G.
High-resolution sonography of lower extremity peripheral nerves:...