Hello everybody,hope you all are doing well and i am too.we are in the process of learning of lower limb and we finished one major nerve common peroneal nerve.now we are going to learn about Tibial nerve.there is so much to learn about it.so lets learn tibial nerve and it course.
It is originated from anterior division of L4,L5,S1,S2,S3
It is a part of sciatic nerve
It supplies Posterior compartment of thigh and leg
First we have to know what muscles are present in posterior compartment in thigh and leg
POSTERIOR COMPARTMENT OF THIGH
1)Semitendinosus
2)Semi membranous
3)Biceps femoris(it has long head and short head)
Longhead of biceps femoris is supplies by Tibial nerve
Short head of biceps femoris is supplies by Common peroneal nerve
This is the only exception we can see
The above three muscles are called as True hamstrings
4)Adductor magnus - it is "hybrid muscle"(muscle which is supplied by two nerves)
Adductor part of adductor magnus is supplied by Obturator nerve
Hamstring part is supplied by Tibial nerve
Short head of biceps femoris and adductor magnus are called as modified or false hamstring muscles
POSTERIOR COMPARTMENT OF LEG
1)Lateral head and medial head of gastrocnemius muscle
2)Soleus muscle - it is called peripheral heart
3)plantatis muscle- it has longest tendon in the whole body
4)Tibialis posterior
5)Flexor hallucis longus
6)Flexor digitorum longus
1,2,3 muscles are considered as muscles present in superficial layer
4,5,6 muscles are considered as muscles present in deep layer
The reason is when we are running or walking the soleus muscle contracts and relaxes as a result the venous blood pumped back into the circulation
It prevents varicose veins
This is the reason we have walk/run daily put some work to soleus muscle so that we won't get varicose veins.we should not encourge our daily life to sedentary lifestyle
Triceps surae
It is the combination of lateral&medial heads of gastrcnemius and soleus muscle
Neurovascular bundle is absent in the superficial layer of the posterior compartment of leg
Loss of flexion of knee joint and loss of plantar flexion
The tibial nerve then divides into Medial plantar nerveand Lateral plantar nerve and supplies to 4 layers of foot.
The foot of muscles are arranged in 4 layers.these muscles are supplies by Medial plantar nerve and Lateral plantar nerve
In upper limb we learnt that ulnar nerve is considered as dominant nerve of hand as it supplies 15 muscles of hand out 20.
Like that in foot also,the Lateral plantar nerve is considered as dominant nerve in the foot because it supplies most of muscles of foot except 4 muscles which are supplies by Medial plantar nerve
[Image source](Flexes the lateral four digits at the proximal interphalangeal joints)
| Muscle | Nerve supply | Action |
|---|---|---|
| Abductor hallucis | Medial plantar nerve | Abducts and flexes the great toe |
| Abductor digiti minimi | Lateral plantar nerve | Abducts and flexes the 5th digit |
| Flexor digitorum brevis | Medial plantar nerve | Flexes the lateral four digits at the proximal interphalangeal joints |
| Muscle | Nerve supply | Action |
|---|---|---|
| Quadratus plantae/Flexor digitorum accessories | Lateral plantar nerve | Assists flexor digitorum longus in flexing the lateral four digits |
| Lumbricals L1(Unipennate) | Medial plantar nerve | Flexes at the metatarsophalangeal joints, while extending the interphalangeal joints |
| Lumbricals L2,L3,L4(Bipennate) | Lateral plantar nerve | Flexes at the metatarsophalangeal joints, while extending the interphalangeal joints |
Two tendons are present in this layer
Flexor hallucis longus tendon and Flexor digitorum longus tendon
| Muscle | Nerve supply | Action |
|---|---|---|
| Flexor hallucis brevis | Medial plantar nerve | Flexes the proximal phalanx of the great toe at the metatarsophalangeal joint |
| Flexor digiti minimi | Lateral plantar nerve | Flexes the proximal phalanx of the fifth digit |
| Adductor hallucis | Lateral plantar nerve | Adduct the great toe. Assists in forming the transverse arch of the foot |
| Muscle | Nerve supply | Action |
|---|---|---|
| Plantar interossei-3(Unipennate) | Lateral plantar nerve | Adduct digits three to five and flex the metatarsophalangeal joints |
| Dorsal interossei-4(Bipennate) | Lateral plantar nerve | Abduct digits two to four and flex the metatarsophalangeal joints |
Medial plantar nerve supplies only 4 muscles of sole of foot and remaining muscles all are supplied by Lateral plantar nerve.
The 4 muscles which are suppled by Medial plantar nerve are -
1)Abductor hallucis
2)Flexor digitorum brevis
3)First lumbrical
4)Flexor hallucis brevis*
It is sensory supply to skin
It supplies to plantar surface too.
| Nerve | Cutaneous area supplied by nerve |
|---|---|
| Lateral plantar nerve | Lateral 1½ digits of foot |
| Medial plantar nerve | Medial 3½ digits of foot |
Tibial nerve gives a cutaneous branch called sural nerve
Sural nerve supplies to the skin on lateral side of leg and the foot
Thanks for reading,
With regards
