Fascia. A term that just a few years ago had little meaning in the performance and fitness industry. The days of foam rollers collecting dust in the corner have been replaced with courses specializing in fascial dissection, trigger point release and rehab programming related to fascial lines.

Deep Front Arm Line Deep Front Arm Line Deep Front Arm Line zClavipectoral fascia zPectoralis minor zCoracobrachialis zBrachialis zBiceps brachii zRadial periosteum zAbductor pollicis brevis zThenar muscles Deep Front Arm Line zBony Interface: z3rd, 4th, 5th Ribs zObserved muscle Bundle: zPectoralis Minor, clavipectoral fascia Deep Front Arm. The deep front arm line is one that is overused, tight, and of course weak on basically everyone from one degree or another. The front fascial line ends up constricted and the back fascial line lengthened. As we develop, the back line may need more attention to reverse this initial position as our body requires the balance for being upright. For new moms, this is why “tummy time” for babies is so helpful in development.

Deep Front Line A core line that begins deep on the sole of the foot and runs up the inside of the leg to the front of the hip joint and across the pelvis to the front of the spine and on up through the thoracic cavity to the jaw and the bottom of the skull.

As we enter this paradigm shift in the way we look at human movement, corrective exercise and performance I have seen an increase in the appreciation for the foot & the ankle. With almost every fascial line passing through the bottom of the foot, professionals worldwide can appreciate how integrated the foot and the ankle really is with the rest of the body.

In this article series we are going to take the concept of foot function and fascia further than any course or textbook on the market. This first article is dedicated to taking a closer look at how the fascial lines influence great toe range of motion.

Let’s take the importance of fascia and foot function one step further and look at propulsion!

Propulsive Phase of Gait

Whether we are walking, running or jumping – push-off or propulsion is characterized by dorsiflexion of our digits at the metatarsophalangeal joint (MPJ). The joint that takes a majority of the forces during push-off and is responsible for the release of elastic energy is the 1^st MPJ.

As much as dorsiflexion of the 1^st MPJ may seem like a simple biomechanical movement, it is actually quite complex – requiring timed control and activation of our fascial slings.

Let’s take a closer look at the 1^st MPJ.

The First Metatarsophalangeal Joint

The 1^st MPJ is formed by the base of the proximal phalynx and the head of the 1^st metatarsal. Sitting directly under the head of the 1^st metatarsal and lying within the tendons of the flexor hallucis brevis are the sesamoids. Inserting on the medial aspect of the proximal phalynx is the abductor hallucis which is opposed laterally by the adductor hallucis.

As we begin to transition onto the forefoot and into propulsion, what dictates the range of motion of the 1^st MPJ is first metatarsal position in the sagittal plane. The image below illustrates how an elevation of the first metatarsal in the sagittal plane can block the dorsiflexion or gliding the proximal phalynx over the head of the first metatarsal.

So what dictates the position of the first metatarsal in the sagittal plane thereby playing a role in 1^st MPJ dorsiflexion at propulsion?

If you guess the Spiral Line you are correct!

The Spiral Line – Expanded Version

In Thomas Myers’ Anatomy Trains he describes the lower part of the Spiral Line as the tibialis anterior as it joins the peroneus longus at the level of the base of the 1^st metatarsal.

Often referred by Myers at the “stirrup” of the foot, I want to expand upon this concept a little further and demonstrate how the Spiral Line plays a bigger role in propulsion than you may think!

The tibialis anterior muscle runs down the anterior aspect of the lower leg to insert on the medial aspect of the foot on the medial cuneiform (90%) and the base of the 1^st metatarsal (10%). Joining plantarly is the peroneus longus tendon which runs along the lateral aspect of the lower leg, behind the lateral malleolus and under the cuboid to insert on the base of the 1^st metatarsal (90%) and medial cuneiform (10%).

With 90% of it’s insertion on the base of the 1^st metatarsal, the peroneus longus plays an important role in plantarflexion of the 1^st metatarsal allowing dorsiflexion of the 1^st MPJ during propulsion.

So does this mean that for optimal propulsion and dorsiflexion of the 1st MPJ all we need to do is ensure proper activation of the peroneus longus muscle or the Spiral Line?

Unfortunately it isn’t that easy! Proper activation of the Spiral Line is actually integrated with another fascial line – the Deep Frontal Line.

The Deep Front Line

For the Deep Front Line again we return to Myers Anatomy Trains.

In the plantar foot the Deep Front Line consists of the deep posterior leg compartment including the posterior tibialis, flexor hallucis longus and flexor digitorum longus. For the purpose of this article we are going to focus soley on the posterior tibialis.

Running posterior to the medial malleolus and along the medial aspect of the foot, the Posterior Tibialis inserts onto the navicular. After attaching to the navicular the Posterior Tibialis fans out and has 9 osseous and fascial attachments which includes:

– every tarsal bone (except the talus)

– every metatarsal (except the 1^st)

– peroneus longus tendon

– flexor hallucis brevis muscle

This fascial attachment between the posterior tibialis and the peroneus longus joins the Deep Front Line to the Spiral Line allowing for more integrated foot biomechanics.

EMG studies have shown that the posterior tibiailis activates prior to the peroneus longs during the gait cycle which means this fascial integration between the PT and PL prepares the foot for propulsion.

With the posterior tibialis as a driver of subtalar joint supination or inversion just prior to heel lift, a reflexive activation of the Spiral Line leads to stabilization of the 1^st metatarsal by the peroneus longs – allowing for dorsiflexion of the 1^st MPJ and propulsion.

Client & Athlete Application

When assessing optimal propulsion in our clients and athletes remember the function of the Spiral Line and Deep Front Line on 1^st MPJ dorsiflexion. A limitation in 1st MPJ dorsiflexion or power at propulsion may be related to an impairment in posterior tibialis strength.

To optimize posterior tibialis strength in clients and athletes integrate barefoot exercises such as short foot which picks up the navicular bone and stimulates the Deep Front Line. In addition single leg exercises can used the strength the posterior tibialis and it’s co-activation patterns with the gluteus medius and maximus.

Take a look at our webinar for related information: Optimizing Power at Push Off | High Gear vs Low Gear Position with Dr Emily Splichal

To learn more about about foot function and barefoot strengthening please visit:

Are you barefoot strong?

The Deep Front Line is the body's myofascial core, as it defines the deep three-dimensional space deep within the body. It's main postural function is providing support and lift in the inner arch of the foot, stabilizing both segments of each leg, as well as the hips, supporting the lumbar spine from the front, giving shape to the abdominopelvic balloon, stabilizing the chest while allowing the expansion and relaxation of breathing, and balancing the neck and head.
If this line is lacking definition, strength, and/or proper balance, there is an overall shortening throughout the body, which encourages collapse of the pelvic and spinal core, laying the groundwork for postural deviations in all the other meridians.
The Deep Front Line can be broken down into six parts:
Lowest Common

Deep Front Line Fascia And Tongue

Lower Posterior
Lower Anterior
Upper Posterior
Upper Middle
Upper Anterior
So, I've broken down each list below accordingly.

Connective tissues of the DFL:

Lowest Common:
Fasciae of popliteus
Knee capsule
Lower Posterior:
Posterior intermuscular septum
Pelvis floor fascia
Levator ani
Obturator internus fascia
Anterior sacral fasciae
Anterior longitudinal ligament
Lower Anterior:
Medial intermuscular septum
Upper Posterior:
Anterior longitudal ligament
Upper Middle:
Crura of the diaphragm
Central tendon
Parietal pleura
Fascia prevertebralis

What Is Deep Fascia

Pharyngeal raphe
Medial scalene fascia
Upper Anterior:
Fascia endothoracica
Fascia pretrachialis

Bony landmarks of the DFL:

Lowest Common:
Plantar tarsal bones
Plantar surface of toes
Superior/posterior tibia/fibula
Medial femoral epicondyle
Lower Posterior:
Medial femoral epicondyle

Deep Front Arm Line Fascia

Ischial ramus
Coccyx
Lumbar vertebral bodies
Lower Anterior:
Medial femoral epicondyle
Linea aspera of femur
Lesser trochanter of femur
Lumbar vertebral bodies and transverse processes
Upper Posterior:
Lumbar vertebral bodies
Basilar portion of occiput
Upper Middle:
Lumbar vertebral bodies
Basilar portion of occiput
Cervical transverse processes
Upper Anterior:
Lumbar vertebral bodies
Posterior surface of subtotal
Cartilage
Xiphoid process
Posterior manubrium
Hyoid bone
Mandible

Deep Front Line Fascia

Youtube Deep Front Line Fascia