Anatomy and muscular innervation of Posterior Tibial Nerve in detail

1. Anatomy of Posterior Tibial
Nerve
BY: Syed Irshad Murtaza
Clinical Neurophysiology
Dept.
AKUH Karachi.
Date: 15-05-2013

2. Anatomy of Tibial Nerve
• The Tibial Nerve also known as posterior tibial
nerve is the largest nerve of sciatic division.
• It is formed by the fibers of L4 and L5 of
lumber and the S1, S2 and S3 of sacral ventral
(anterior) rami.

4. Sciatic nerve and hamstring muscles
• The sciatic nerve is the broadest nerve of the human
body (2.5cm at its origin). It descends along the back
of the thigh and just above the popliteal fossa it
separates into its two terminal divisions (Posterior
tibial and common fibular(peroneal) nerve).
• Before the bifurcate it supplies 3muscles (hamstring)
as semitendinosus, semimembranosus and biceps
femoris (long and short head). All hamistring muscles are
believed to have tibial nerve components except the
short head of biceps femoris which has peroneal
component.

5. Cont’d
• The tibial nerve then
descends along the
back of the thigh and
the popliteal fossa to
the distal border of the
popliteus muscle,
passing with the
popliteal artery and
vein to enter the leg.

6. • In the popliteal fossa
the nerve gives off
branches to gastroc-
nemius (S1,S2) ,
popliteus (L4,L5,S1)
and soleus (S1,S2)
mucsles.

7. • Gastrocnemius (S1,S2) is involved in standing,
walking, running and jumping. The medial head
originates at the medial epicondyle of the femur
while the lateral head originates at the lateral
epicondyle of femur.

8. Popliteus Muscle
• The popliteus (L4,L5,S1)
muscle in the leg is used to
unlock the knee by laterally
rotating the femur on the
tibia during a closed chain
movement (such as one
with the foot in contact
with the ground).
Popletius muscles

9. • The Soleus (S1,S2) is
a powerful muscle in
the back part of the
lower leg (the calf). It
runs from just below
the knee to the heel,
and is involved in
standing and walking.

10. Cutaneous innervation
• The sural nerve
(S1,S2) is formed by
the joined fibres of
tibial and common
peroneal nerve and
runs down the calf to
supply the lateral
aspect of the ankle
and foot. It ends on
the lateral side of the
5th
digit.

12. Muscular supply Below soleus
• Below the soleus
muscle the tibial
nerve lies close to the
tibia bone and
supplies the tibialis
posterior (L4, L5,S1)
first.
• The muscle is mainly
responsible for the
inversion of the foot.

13. • The Flexor Digitorum Longus
(L5,S1,S2) is the next muscle
supplied by tibial nerve after
TP, which is situated on the
medial side of the leg. At its
origin it is thin & pointed, but
it gradually increases in size as
it descends. This muscle
serves to flex (curl) the lesser
toes (2nd
, 3rd,
, 4th
& 5th
toes) or
(flexion of phalanges II-V)
without plantar flexion or foot
inversion.

14. Flexor Hallucis LongusFlexor Hallucis Longus..
The Flexor Hallucis Longuslexor Hallucis Longus
(L5,S1,S2)(L5,S1,S2) is situated on the
fibular side of the leg. It
arises from the inferior two-
thirds of the posterior
surface of the body of the
fibula, with the exception of
2.5 cm.
Flexion of the great toe
without co’activation of
other muscles, activates the
flexor hallucis longus.

15. Passing through tarsal tunnel
• The nerve passes into the foot below the
medial malleolus.
• Here it is bound down by the flexor
retinaculum in company with the posterior
tibial artery. Before entering the tarsal tunnel
the nerve splits into 3 different paths. One
nerve (calcaneal) continues to the heel, the
other two nerve (medial and lateral plantar)
continue on the bottom of the foot.

16. Division of tibial nerve at ankle

17. Division of tibial nerve at ankle

18. Medial Plantar Nerve
• The medial platar nerve gives off cutaneous
and muscular branches.
• Cutaneous branches supply to skin of the sole,
foot, including the the digital branches of the
hallux, the 2nd
,3rd
and half of the 4th
toe.
• The Muscular branches in foot are mainly as,
• Abductor hallucis (S1, S2)
• Flexor digitorum brevis (S1, S2)
• Flexor hallucis brevis (S1, S2) and
• First lumbrical (S1, S2)

19. Origination & Functions
– Abductor hallucis (S1, S2)
Originates at the medial process of
the calcaneus & serves in
abduction of great (big) toe.
Flexor digitorum brevis (S1, S2)
Originates at the medial process
of calcaneus & serves in flexion
of four lesser toes.
Flexor hallucis brevis (S1, S2)
Originates at the plantar surface and
the tendon of the tibialis posterior.
It serves in flexion of the great toe.

20. Lateral Plantar Nerve
• The lateral plantar nerve
supplies the skin of the 5th
toe
and lateral half of the 4th
digit.
• The muscular branches supply
most deep muscles of the foot
including,
• Flexor Digitorum accessorius (S1,S2)
• Abductor Digiti minimi (Quinti) (S1, S2)
• Flexor Digiti Minimi Brevis (S1, S2)
• 2nd
and 4th
lumbricals (S1, S2) &
• Adductor hallucis (S1, S2)

21. ENTRAPMENT OF TIBIAL NERVE
• Entrapment involves pressure on the nerve where
it passes through a narrow structure (tarsal tunnel),
the compression is known as tarsal tunnel
syndrome (TTS).
• Clinically the following symptoms may be seen
• Sensation changes on the bottom of the foot (sole)
• Numbness, tingling, or other abnormal sensations.
• Burning sensation
• Pain
• Weakness of the knee or foot, difficulty in walking.

23. Recording techniques for Motor NCS
• Tibial Nerve is recorded from the abductor
hallucis muscle.
• It is stimulated from the ankle and knee.
• The normative values are
• Distal Latency: ≤ 5.8msec
• Conduction velocity: ≥ 41msec
• CMAP amplitudes: ≥ 4mV
• F-wave latency: ≤ 5msec.

24. RECORDING TECHNIQUES FOR MEDIAL AND LATERAL
PLANTAR (Mixed Nerves)
Recording site. Medial ankle
G1 is placed on tibial nerve above & posterior to the medial
malleolus.
G2 is placed 3-4 cm proximally.
G3 is placed between active recording & stimulating electrodes
Stimulation sites.
Medial sole (medial planter nerve)
Lateral sole (lateral plantar nerve).
Distance14cm from the recording electrode.
Measure 10cm from the recording site in to the sole of the foot.
Then additional 4cm on a line drawn parallel to the web space
between the 1st
& 2nd
toes for medial plantar, while additional
4cm on a line drawn parallel to the web space between the 4th
&
5th
toes for lateral plantar nerve.

25. NCS technique for Plantar nerves
Medial plantar mixed
nerve study
Lateral planter mixed
nerve study.

26. Recording technique for sural sensory NCS
• Recording Site: Posterior Ankle
• G1 placed posterior to the lateral malleolus.
• G2 placed 3-4 cm distally
• G3 place between G1 & stimulating electrodes
• Stimulation Site: Posterior-lateral calf
• Distance: 14Cm
• Normative Data: Peak latency: ≤4.4msec
• SNAP amplitude: ≥ 6uv
• Conduction velocity: ≥35-40uV

27. Thanks for the patience.
• Never underestimate others, nor allow others
underestimating you, because one might do it better than
you, and at the same time you may do it better than others.
BY. IM