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Muscles of the Lower Leg Cheat Sheet (DRAFT) by

- Lower Leg muscles with trigger point referral

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Anterior compar­tment of Leg

Consists of:
- Tibialis anterior
- Extensor digitorum longus
- Extensor hallucis longus
- Fibularis Tertius

Tibialis anterior

Origin: Upper 1/2 or 2/3 of the lateral surface of the tibia and adjacent intero­sseous membrane
Insertion: Medial cuneiform and base of 1st metatarsal bone of the foot
NS: Deep fibular nerve (L5)
Action: Dorsif­lexion and inversion of the foot

Tibialis anterior TrPs

- Weakness of dorsif­lexion when walking common with Trps
- Active during upright stance - controls excessive sway
-Can be associated with fibularis longus and calf trps/t­ension
- Anterior compar­tment syndrome

Fibularis Tertius - TrPs

- Can overlap with soleus TrPs (Soleus TrPs include the entire achilles tendon and bottom of the heel)

Fibularis Tertius

Origin: Distal anterior surface of fibula , intero­sseous membrane
Insertion: Dorsal surface of metatarsal 5
NS: Deep fibular nerve L5-S1
Action: Dorsif­lexion and eversion of the foot

Extensor Hallucis Longus - TrPs

Extensor Hallucis Longus - palpation

- Ask to extend first toe
- Feel tendon­/muscle belly between extensor digitorum and tibialis anterior tendons

Extensor Hallucis Longus

Origin: Middle portion of the fibula on anterior surface and the intero­sseous membrane
Insertion: Dorsal side of the base of the distal phalanx of the big toe
NS: Deep fibular nerve, deep peroneal nerve (L5 - can be L4-S1)
Action: Extends big toe and assists in dorsif­lexion of the foot -weak everto­r/i­nvertor

Extensor Digitorum Longus TrPs

- Can press on the deep fibular nerve

Extensor Digitorum Longus - Palpation

- Ask to extend toes
- Follow tendons into the muscle belly, between the tibialis anterior and peroneals

Extensor Digitorum Longus

Origin: Anterior lateral condyle of tibia, anterior shaft of fibula and superior 3/4 of intero­sseus membrane
Insertion: Dorsal surface, middle and distal phalanges of lateral four digits
NS: Deep fibular nerve L5-S1
Action: Extends first 4 toes, dorsif­lexion of ankle (works with tibialis anterior, extensor hallucis longus and fibularis tertius)

Tibialis anterior - Palpation

- Lateral to the shaft of the tibia
- Get patient to dorsiflex and follow to the medial cuneform (at medial side of foot)

Plantaris TrPs

- Rupture of this muscle can mimic DVT on MRI and baker's cyst

Plantaris Palpation

- Prone with knee flexed
- Place finger medially, inbetween heads of gastroc
- Feel for oblique angle of the fibres and belly
- Strum thumb acrosss


Origin: Lateral suprac­ondylar ridge of femur
Insertion: Tendo calcaneus (medial side, deep to gastro­cnemius tendon)
NS: Tibial Nerve anterior rami S1-S2
Action: Plantar flexes foot and flexes knee

Soleus - TrPs

- Can refer pain to ipsila­teral SI joint
- Can be linked to LBP due to limiting dorsif­lexion - improper lifting
- Can be linked to growing pains in children
- Satellite TrPs from posterior fibres of gluteus minis
- Check quads if patient complains of knee pain

Soleus - Palpation


Origin: Fibula, medial border of tibia
Insertion: Tendo calcaneus
NS: Tibial nerve, L5-S2
Action: Planta­rfl­exion

Gastro­cnemius - TrPs

- Can be associated with nocturnal cramps - manipu­lative lesions at tibiof­ibular joint
- TrPs activated when climbing steep slope, jogging uphill, riding a bike
- Tight high socks, high heels can cause TrPs

Gastro­cnemius - Palpation

- Standing
- Get patient to tip toe position
- Locate tibial shaft and move laterally off
- Get patient to lie supine and feel laterally
- On prone , flex patient's leg to 90 degrees with foot flexed at 90 degrees, feel the muscle

Fibularis Brevis - TrPs

Fibularis Brevis - Palpation

- Same as Fibularis Longus, feel tendon down to 5th metatarsal

Fibularis Brevis

Origin: Lower 2/3 of lateral fibula
Insertion: 5th metatarsal
NS: Superf­icial fibular nerve (L5-S1)
Action: Planta­rfl­exion, eversion

Fibularis Longus - TrPs

- Can entrap common fibular nerve
- inversion sprains can cause Trps in this muscle
- Feeling of weak ankles
- TrPs in glut minimus can cause satellite TrPs in this muscle
- 2ndary TrPs in EDL can cause TrPs in this muscle
- Can be caused by immobi­lis­ation, morton's foot, LL leg length ineuqlity, sleeping with the foot planta­rflexed and wearing high heeled shoes

Fibularis Longus - palpation

- Place finger at head of fibula and lateral malleous , peroneals are in a straight line down from those two points
- Evert patient's foot and feel muscle tendon and belly

Fibularis Longus

Origin: Proximal part of lateral surface of the shaft of tibia
Insertion: 1st metata­rsal, medial cuneiform
NS: Superf­icial fibular nerve L5-S1
Action: Planta­rfl­exion, eversion, supports the arches

Lateral and Superf­icial posterior compar­tment

Consists of:
- Fibularis longus
- Fibularis brevis
- Gastro­soleus
- Plantaris


Origin: Proximal to articular surfaces of lateral condyle of femur and medial condyle of femur
Insertion: Tendo calcaneus into mid-po­sterior calcaneus
NS: Tibial nerve from sciatic (S1-S2)
Action: Plantar flexes foot (tip toes), flexes knee

tibialis posterior dysfun­ction

1. Tendon length normal with minimal pain and dysfun­ction
2. Tendon elongated, hindfoot mobile with medial foot pain during and after weight­bea­ring, dysfun­ction of the tendon and manipu­lable lesions within the foot bones
3. Tendon elongated, hindfoot deform­ation and stiffness, lateral foot pain and marked eversion of the foot when weight bearing

Tibialis Posterior - TrPs

- Aggravated by running on uneven ground
- Too many toes sign
- TrPs with morton's foot, TrPs in FHL and FDL

Tibialis Posterior

Origin: Tibia and fibula
Insertion: Navicular and medial cuneiform
NS: Tibial Nerve L4-L5
Action: Inversion of foot and plantar flexion of the foot

Flexor Hallicis Longus - TrPs

All flexors- Palpation

- Tom Dick and Harry - tarsal tunnel

Flexor Hallucis Longus

Origin: Fibula, posterior aspect of middle 1/3
Insertion: Plantar surface , base of distal phalanx of hallux
NS: Tibial Nerve (S2 and S3)
Action: Flexes all joints of big toe, plantar flexion of the ankle joint

Flexor Digitorum Longus - TrPs

- FDL stabilises foot - pt complains of pain when walking
- Can be misdia­gnosed as tarsal tunnel syndrome

Flexor Digitorum Longus

Origin: Posterior surface of the body of the tibia
Insertion: Plantar surface , base of distal phalanges of the four lesser toes
NS: Tibial nerve L5-S2
Action: Flexion of the four smaller digits

Popliteus - TrPs

- Exacer­bating by crouching, walking and running, extending the knee
- Knee has a slight loss of ext

Popliteus - Palpation

- Pt prone with knee flexed
- Locate tibial tuberosity and slide medial to the posterior surface of the shaft
- Push gastro­soleus to the sid
- Not always palpable


Origin: Lateral femoral condyle
Insertion: Posterior surface of tibia
NS: Tibial nerve L4-S1
Action: Medially rotates tibia on the femur if the femur is fixed (sitting down), rotates femur on tibia if tibia is fixed (standing up), unlocks the knee to allow flexion, helps to prevent forward displa­cement of the femur during crouching

Deep posterior compar­tment of leg

Consists of:
- Popliteus
- Tibialis Posterior
- Flexor Digitorum longus
- Flexor Hallicus longus