GA Leg and Foot

First Three Layers of Foot Muscles AFA- 222- FAF

1.Abductor- Flexor- Abductor 2.2nd layer- 2 long tendon muscles (Flexor hallucis longus and Flexor digitorum longus), 2 intrinsic muscles (Lumbricals and Quadratus plantae) 3.Flexor- Adductor- Flexor

DEEP FIBULAR NERVE

• Branch of Common Fibular Nerve • Motor to Anterior Crural Compartment muscles • Sensory to area between metatarsals 1 and 2 1. The Deep Fibular (peroneal) nerve is the nerve of the anterior compartment. a. Motor to the muscles of anterior compartment b. Sensory to the skin on dorsum of the foot in the web space between first 2 toes.

TIBIAL NERVE LESION

• Cannot plantar flex ankle • Cannot toe walk • Drag foot on ground * Also test for S1. S1 has other tests, eversion and Achilles tendon reflex test. Tibial nerve lesions are tested by plantarflexion. A S1 radiculopathy can also cause weakness in plantarflexion. One way to distinguish is that a S1 lesion would also result in weak eversion.

PLANTARIS

• Origin -Lateral supracondylar line of femur and oblique popliteal ligament • Insertion - Tendo calcaneus onto calcaneus • Action - Plantar flex ankle joint Weak knee flexion. • Nerve - Tibial The Plantaris is a short muscle with a long tendon. This muscle arises from a line above the lateral femoral condyle and is a very weak 2 joint muscle.

FLEXOR DIGITORUM LONGUS

• Origin -Medial part of posterior tibia below the soleal line, tendinous attachments to fibula • Insertion - Distal phalanges of lateral 4 toes • Action - Flexes DIP of toes • Nerve - Tibial Flexor Digitorum longus inserts onto the distal phalanx of the lateral 4 toes and is responsible for flexing the distal interphalangeal (DIP) of the remaining 4 toes.

SOLEUS

• Origin -Posterior head of the fibula, upper ¼ of the posterior fibula, soleal line and medial border of tibia • Insertion - Tendo calcaneus onto calcaneus • Action - Plantar flex ankle joint • Nerve - Tibial The Soleus arises from the posterior aspect of the fibula and soleal line and medial tibia. It is a 1 joint muscle. It does not cross or act on the knee.

Lateral Ligament of Ankle

•3 thin bands binding lateral malleolus to talus and calcaneus bones •Calcaneofibular Lig. •Posterior Talofibular Lig. •Anterior Talofibular Lig. •Resists excessive inversion •Often torn - typical "ankle sprain" - with excessive inversion The Lateral ligament is composed of 3 separate ligaments (anterior talofibular, posterior talofibular and calcaneofibular ligaments) that connect the lateral malleolus to the calcaneus and talus. It supports the lateral aspect of the ankle and guards against excessive supination/inversion of the foot.

PLANTAR FLEXION

•Achilles' Tendon Muscles (Arrow) -Gastrocnemius -Soleus -Plantaris •Innervation: Tibial Nerve •Any muscles that passes posterior to the ankle joint will plantar flex. Examples: -Tibialis posterior -Flexor digitorum longus -Flexor hallucis longus -Fibularis longus (FL) -Fibularis brevis

PLANTAR MUSCLESLAYER 1

•Arise from Calcaneus and Plantar Fascia -Abductor Hallucis (1) inserts into medial side of proximal phalanx of 1st toe. Abducts and flexes MTP joint of big toe. Medial Plantar nerve -Abductor Digiti Minimi (V) (2) inserts into lateral side of proximal phalanx of 5th toe. Abducts and flexes 5th Toe. Lateral Plantar Nerve

DORSAL SURFACE

•Arise from dorsum of Calcaneus •Extensor Digitorum Brevis (1) joins dorsal digital expansion along with Extensor Digitorum Longus. Helps extend MP joint of toes 2-4 •Extensor Hallucis Brevis (2) joins dorsal digital expansion along with Extensor Hallucis Longus. Also goes to proximal phalange of great toe. Helps extend MP joint great toe •Both muscles innervated by Deep Fibular Nerve •Extensor Brevis helps straighten out pull of longus tendons 1. Extensor hallucis brevis is a muscle attaching from the dorsal surface of the calcaneus to the base of proximal phalanx of great toe. This muscle extends the metatarsophalangeal (MTP) joint of the hallux and is innervated by the deep fibular nerve. 2. Extensor digitorum brevis attaches from the dorsal surface of the calcaneus onto the dorsal hood portion of the dorsal expansion of the of each of the toes 2-4. This muscle assists the extensor digitorum longus extending the MTP joints of toes 2-4 and is innervated by the deep fibular nerve.

Saphenous Nerve

•Largest and longest cutaneous branch of Femoral n. •Supplies skin on medial side of leg and foot The Saphenous nerve is unique in that it is the only nerve branch in the leg or foot not from the sciatic nerve. It is a cutaneous sensory nerve from the medial leg and foot. It is a branch of the femoral that continued through the adductor canal. It is also a major contributor of the L4 dermatome of the medial leg.

MUSCLE ACTIONS-Pronation

•Lateral Crural Muscles - Primary action is eversion part of pronation of foot in regard to the tarsal joints. • Innervated by Superficial fibular nerve • Component of the S1 myotome

Blood Supply Posterior Compartment

- Popliteal Branches into Anterior and Posterior Tibial Arteries. - Posterior Compartment-Posterior Tibial and Fibular Artery along fibula. - P- Popliteal. AT- Anterior tibial. PT Posterior tibial. (SF-in radiology terms is the Femoral artery which becomes the popliteal) The Posterior Tibial Artery is the primary artery of the posterior leg. It supplies the muscles in deep and superficial compartments. It then passes posterior to the medial malleolus where its pulse can be easily palpated. The fibular artery is one of the larger branches of the posterior tibial artery. It supplies the muscles in the posterior compartment that are attached to the fibula. It also supplies blood to the muscles in the lateral crural compartment along with some branches from the anterior tibial artery. Thrombophlebitis is inflammation of the veins of the leg with thrombus formation that can occur in the superficial or deep veins of the leg. Risk factors include long plane rides a complications can be the thrombus moving to the lungs and becoming a pulmonary embolism.

Tibiofibular Joints

1.Proximal Tibiofibular Joint- From the head of the fibula to the lateral tibial condyle. Strengthened by anterior and posterior tibiofibular ligaments. Slight movement with the ankle joint. Transmits weight from the foot to the knee. 2.Distal Tibiofibular Joint- Fibrous joint-syndesmosis between the distal end of the fibula and that of the tibia. Interosseous membrane connects the two bones and there are ligaments that strengthen this area. Anterior and Posterior Tibiofibular ligaments. Stabilize the ankle joint by binding the malleoli to the talus. High ankle sprains occur at this area.

INVERSION INJURY

1.Swelling and bruising over the lateral aspect of the ankle indicates an inversion injury. 2.Pain upon palpation of the lateral malleolus or just posterior to it indicates a fracture. 2.Pain upon palpation anterior and inferior to the lateral malleolus usually means a sprain.

Transition Leg to Ankle and Foot

1.The primary action of the ankle joint is dorsiflexion and plantarflexion. These movements are from the actions of the leg muscles. 2.Tendons that pass behind the malleoli are plantar flexors. Tendons that pass anterior are dorsiflexors

Muscles of the Foot

1.There are two Intrinsic muscles of the Dorsum of the Foot: Extensor Hallucis Brevis and Extensor Digitorum Brevis. 2.The are Four Layers of the Intrinsic and Extrinsic Plantar Muscles. *The first 3 layers can be learned by the mnemonic AFA-222- FAF. The fourth layer is the dorsal and plantar interossei muscles. Medial Plantar Nerve Innervates most of the intrinsic muscles related to the great toe, except the adductor hallucis. Medial plantar nerve also innervates the flexor digitorum brevis. Lateral Plantar nerve to the fifth toe muscles, all interossei, adductor hallucis and quadratus plantae.

Important Transition Area of Leg to Ankle. "Tom, Dick, and Harry" in the Tarsal Tunnel

At the medial malleolus: There are three extrinsic muscles to the foot, the Posterior Tibial Artery and Vein, and Tibial nerve. They are in a location called the Tarsal Tunnel. A space between the tibia and calcaneus with the flexor retinaculum as a roof. A mnemonic for these muscles and neurovascular structures is Tom, Dick And Very Nervous Harry. Tibialis Posterior, Flexor Digitorum Longus, Posterior Tibial Artery, Posterior Tibial Vein, Tibial Nerve, Flexor Hallucis Longus.

Lateral longitudinal Arch:

Bones - Calcaneus - Cuboid - Metatarsal bones 4 & 5 Function- Low arch transmits weight directly to ground.

Transverse Arch:

Bones - Cuboid - Cuneiforms - Base of the Metatarsals. Function- Support weight and motion, side to side. Blue - transverse arch. Black- Tarsometatarsal joint.

Medial longitudinal Arch:

Bones - Talus - Navicular - Cuneiforms - Metatarsal bones 1-3 Function- High arch distributes weight to heel and heads of metatarsal

Dorsiflexion and Plantar flexion are the major movements at the ankle joint

Both movements take place in the sagittal plane around a medial to lateral axis of motion. 1. Dorsiflexion involves bringing the dorsum forefoot to the anterior surface of the leg. 2. Plantar Flexion involves moving the plantar surface of the foot towards the ground while raising the heel off of the ground. 3. The terms dorsiflexion and plantar flexion are used rather than flexion and extension because of the length of the foot. When the ankle joint moves in dorsiflexion, the front portion of the foot (fore foot) moves upwards towards the anterior surface of the tibia. However, while the fore foot moves in this direction, the heel or hind foot moves in the opposite direction away from the posterior surface of the leg. To avoid any confusion calling these complex movements flexion or extension, this movement is called dorsiflexion while the opposite movement with the forefoot moving away from the tibia is called plantarflexion. B. Abduction and Adduction involve movements that take place in the axial (transverse plane) around a vertical axis of movement. C. Eversion and Inversion describe rotary type movements that take place in the frontal plane around a horizontal anterior to posterior axis of movement. D. Pronation and supination are terms that incorporate all 3 of the above movements and provide a more accurate description of how the ankle and tarsal joints move because these movements take place around an oblique axis of motion. 1. Pronation combines dorsiflexion, abduction and eversion 2. Supination combines plantar flexion, adduction, and inversion

Clubfoot

Clubfoot- congenital deformity of the foot. Commonly the foot is plantarflexed, adducted and inverted. A common variation is "talipes equinovarus" where the foot is turned medially. This a a common topic in the board review books.

Dorsalis Pedis Artery

Dorsum of the Foot: 1. Sensory Innervation to the dorsum of the foot comes from the common fibular nerve. a. The deep fibular nerve supplies the region between the first 2 metatarsal bones. b. The superficial fibular nerve supplies the rest of the dorsum. c. The dermatome for most of the dorsum of the foot is L5. 2. The main artery supplying the dorsum of the foot is the dorsalis pedis artery. This is a continuation of the anterior tibial artery. a. Pulse is palpable over the navicular bone b. Forms an anastomotic connection with the lateral plantar branch of the tibial artery to form the deep plantar arch. 3. Veins draining the dorsum of the foot form the dorsal venous arch that can be a site for venipuncture. Two veins form from this arch. a. The small saphenous vein drains the lateral side of the leg and foot. It empties into the popliteal vein in the popliteal fossa. b. The great saphenous vein drains the medial side of the leg and foot. It empties into the femoral vein in the femoral triangle.

Sural Nerve

Formed by cutaneous branches of the tibial and common fibular nerves The sural nerve can have branches from the tibial and common fibular nerves. It is a cutaneous sensory nerve and receives sensation from the lateral posterior leg and foot. This nerve can be found in the lab running with a small saphenous vein.

Bones of the foot Dorsum

Hallux or big toe has only two phalanges Tarsal Bones- Calcaneus, Talus, Navicular, Cuboid, Medial, Intermediate, and Lateral Cuneiforms.

Popliteus

Knowing the attachments of the popliteus is essential to remembering it's actions. To unlock the knee, the popliteus laterally rotates the femur when the leg is in weight bearing. When the tibia is free to move in non weight bearing the popliteus can unlock the knee by medially rotating the tibia. The Popliteus arises by a tendon from the lateral femoral condyle to insert onto the posterior surface of the tibia. This muscles acts to unlock the knee as the knee goes from extension to flexion. The femur moves laterally or the tibia moves medially to unlock the knee depending on weight bearing and if the tibia is free to move. Simply put, if the leg is weight bearing such as in standing, the femur moves to unlock the knee. If the leg is not weight bearing on the ground, the tibia can move.

Supination/Pronation is primarily at the tarsal joints.

Movements of the Foot Joints - The Subtalar and Transverse Tarsal joints work together to perform: Inversion/supination. Involves turning the sole of the foot inwards/medially. All of the weight is on the 5th toe/5th metatarsal and the sole of the foot points inward. The muscles responsible for this movement include the tibialis anterior and tibialis posterior. They are innervated by the deep branch of the common fibular nerve (L4) and tibial nerve (L4 part of tibial), respectively. They receive their blood supply from the anterior and posterior tibial arteries, respectively. Eversion/pronation. Involves turning the sole of the foot outwards/laterally. All of the weight is on the big toe/1st metatarsal and the sole of the foot points outward. The muscles responsible for this movement reside in the lateral crural compartment (fibularis longus and brevis). They are innervated by the superficial branch of the common fibular nerve (L5) and receive blood supply from the fibular artery (a branch of the posterior tibial artery).

ANTERIOR COMPARTMENT

Muscles - Tibialis anterior (1) - Extensor digitorum longus (2) - Extensor hallucis longus (3) - Fibularis tertius • Actions -Dorsiflex ankle -Inversion -Extend toes -Weak eversion • Nerve - Deep fibular (Yellow) • Artery - Anterior tibial A.The Muscles in the anterior crural compartment are responsible for dorsiflexing the ankle joint and extending the toes. The Tibialis Anterior is a supinator (inverter) of the foot. Supination occurs when the all of the weight of the body is placed on the outer portion of the foot and the sole of the foot is turned inward. As a group, the anterior compartment muscles arise from the tibia, fibula, and interosseous membrane. These muscles are innervated by the deep fibular (peroneal) nerve and include Tibialis anterior, Extensor hallucis longus, Extensor digitorum longus and the Fibularis (Peroneus) tertius. B. Nerve 1. The Deep Fibular (peroneal) nerve is the nerve of the anterior compartment. a. Motor to the muscles of anterior compartment b. Sensory to the skin on dorsum of the foot in the web space between first 2 toes. C. Artery 1. The Anterior Tibial artery is one of 2 terminal branches of the popliteal artery. This is the main artery to the anterior crural compartment. It supplies the muscles in this compartment before changing its name to the dorsalis pedis artery after it passes distal to the ankle joint. 2. The anterior tibial artery lies deep within the anterior crural compartment and, as such, its pulse cannot be palpated. An indication of the anterior tibial pulse may be found by palpating the dorsalis pedis artery as it cross the navicular bone on the dorsum of the foot.

EXTENSOR HALLICUSLONGUS

Origin - Anterior surface of fibula - Interosseous membrane • Insertion - Distal phalanx of great toe (hallux) • Action - Dorsiflex ankle - Extends great toe at IP joint The Extensor hallucis longus attaches to the distal phalanx of the great or first toe. This muscle acts to extend the interphalangeal (IP) joint of the big toe and dorsiflex the ankle joint.

FIBULARIS TERTIUS

Origin - Anterior surface of fibula - Interosseous membrane • Insertion - Dorsum of 5th metatarsal • Action - Dorsiflex ankle - Evert tarsal joints • Synergist of Tibialis anterior to obtain pure dorsiflexion of ankle The Fibularis (Peroneus) tertius attaches to the dorsum of the 5th metatarsal. The fibularis tertius acts to dorsiflex the ankle and pronate the foot. a. When acting with the tibialis anterior these 2 muscles act to dorsiflex the ankle without any supination or pronation of the tarsal joints.

Extensor digitorum longus

Origin - Lateral tibial condyle - Anterior surface of fibula - Interosseous membrane • Insertion - Dorsal Expansion of lateral 4 toes • Action - Dorsiflex ankle - Extends toes at MTP joints attaches to the extensor expansion of the lateral 4 toes. This muscle extends the metatarsophalangeal (MTP) joints of the remaining 4 toes as well as dorsiflexing the ankle joint.

FIBULARIS BREVIS

Origin - Middle of Lateral surface of fibula • Insertion - Dorsal surface of tuberosity on 5th metatarsal • Action - Eversion and pronation of tarsal joints. Plantarflexion. • Nerve - Superficial Fibular Nerve The Fibularis (peroneus) brevis attaches to the base of the tuberosity of the 5th metatarsal bone. Main action is eversion/pronation of the foot and can plantarflex. Innervation- Superficial fibular nerve. Eversion can also be a test of the myotome S1,

TESTS-Compare both sides left and right.

Physical examination of the ankle joint a. To differentiate between sprain and fracture, palpate the posterior edge of both malleoli and the base of metatarsal 5. Tenderness or pain can indicate a fracture. b. Tests for Ligament damage. (1) The components of the lateral collateral ligament of the ankle are most often damaged (inversion injury). In assessing ligament damage, always compare the left and right ankles for differences. (2) Anterior Draw Test- grasp the calcaneus in one hand and the anterior surface of the leg in the other. Pull the heel forward. If there is more than 3mm of movement, the anterior talofibular ligament is damaged. (3) Talar Tilt Test - Stabilize the distal leg in one hand while grasping the talus between the thumb and first finger. If the affected ankle has excessive movement than the opposite side during inversion, the calcaneofibular ligament is likely damaged. A comparable tilt test can be used to test the deltoid ligament, (4) Squeeze Test - Pain upon compression of the distal tibia and fibula about 2-3 inches above the ankle indicates a tearing of the distal portion of the interosseous membrane and/or the inferior/distal tibiofibular ligaments (High Ankle Sprain).

Blood Supply of leg

Popliteal Artery Branches into Anterior and Posterior Tibial Arteries. Anterior Compartment-Anterior Tibial Artery with Deep Fibular Nerve Posterior Compartment- Posterior Tibial and Fibular Arteries with the Tibial Nerve Innervation. Lateral Compartment- Branches of the Fibular from Posterior Tibial Artery. Also some branches derived from the Anterior Tibial Artery. P- Popliteal. AT- Anterior tibial. PT Posterior tibial. (SF-in radiology terms is the Femoral artery which becomes the popliteal) Within the popliteal fossa, the popliteal artery divides into its 2 terminal branches 1. The anterior tibial artery supplies blood to the anterior compartment of the leg. This artery changes its name to the dorsalis pedis artery after it crosses the ankle joint. The dorsalis pedis artery supplies structures on the dorsum of the foot and continues on as the deep plantar artery to the form the plantar arch with the lateral plantar artery. The posterior tibial artery supplies blood to the posterior compartment of the leg. This artery courses posterior to the medial malleolus where it's pulse can be palpated. The artery terminates by dividing into the medial and lateral plantar arteries that supply the plantar surface (sole) of the foot. The fibular artery is a branch of the posterior tibial artery. It supplies blood to the posterior and lateral compartments of the leg. The fibular artery runs along the fibula in the posterior compartment but is not in the lateral compartment. Branches of the fibular artery help supply the lateral compartment.

Blood Supply Anterior Compartment

Popliteal Branches into Anterior and Posterior Tibial Arteries. Anterior Compartment-Anterior Tibial with Deep Fibular Nerve Please also note the deep location of the anterior tibial artery in the anterior compartment. P- Popliteal. AT- Anterior tibial. PT Posterior tibial. (SF-in radiology terms is the Femoral artery which becomes the popliteal) The Anterior Tibial artery is one of 2 terminal branches of the popliteal artery. This is the main artery to the anterior crural compartment. It supplies the muscles in this compartment before changing its name to the dorsalis pedis artery after it passes distal to the ankle joint over the navicular bone. Dorsalis pedis pulse can be taken over the navicular bone.

Arches and Ligaments of the Foot

The ankle transmits the weight of the body to the calcaneus and the heads of the metatarsals, as well as to the 3 arches of the foot (the medial and lateral longitudinal arches and the transverse arch). The medial longitudinal arch is higher and better defined than the lateral longitudinal arch. The transverse arch runs along the base of the metatarsals. The structural integrity of the foot is maintained by a number of ligaments that interconnect the tarsal bones, keeping them in proper alignment and giving support to the foot. The spring ligament supports the medial longitudinal arch. The long and short plantar ligaments support the lateral longitudinal arch. The tendon of the fibularis longus muscle supports the transverse arch.

Compartment Syndromes

The compartments of the leg are surrounded by a thick fascia. This fascia does not allow for much expansion if there is swelling of the compartment. Pressure can then be placed on the structures contained within, such as the deep fibular nerve and anterior tibial artery in the anterior compartment.

Sprains are Tears in the Ligaments.

The lateral or medial -deltoid ligaments can be sprained or one of their components. The fibers can be stretched- grade 1, partially torn- grade 2, or fully torn-grade 3. The lateral ligament is the most commonly sprained of the ankle ligaments.

LOWER LIMB DERMATOMES

The location of dermatomes and myotomes are an important topic for the lower limb. A sensation deficit or symptom in an area of skin will give evidence of a nerve root that may be involved. A myotome test will add to the evidence found with the sensation deficit. Please know these prime examples for this unit: L4- Medial leg and foot- sensation. Weakness of foot inversion tests the L4 myotome. Always compare weakness to the other side. L5. Sensation deficit to the dorsum of the foot. Weakness in dorsiflexion. L5 can also be tested by hip abduction and the Trendelenberg sign/test. Comparison to a nerve lesion: Lack of sensation to most of the dorsum of the foot can also be caused by a common fibular nerve lesion but the motor loss for this lesion would be greater and involve weak dorsiflexion and eversion. S1. Sensation loss to lateral leg and foot. Weakness in eversion and also in plantarflexion (toewalking)

Lower Limb Myotomes

The location of dermatomes and myotomes are an important topic for the lower limb. A sensation deficit or symptom in an area of skin will give evidence of a nerve root that may be involved. A myotome test will add to the evidence found with the sensation deficit. Please know these prime examples for this unit: L4- Medial leg and foot- sensation. Weakness of foot inversion tests the L4 myotome. Always compare weakness to the other side. L5. Sensation deficit to the dorsum of the foot. Weakness in dorsiflexion. L5 can also be tested by hip abduction and the Trendelenberg sign/test. Comparison to a nerve lesion: Lack of sensation to most of the dorsum of the foot can also be caused by a common fibular nerve lesion but the motor loss for this lesion would be greater and involve weak dorsiflexion and eversion. S1. Sensation loss to lateral leg and foot. Weakness in eversion and also in plantarflexion (toewalking)

Anterior Drawer Test

The test shown to the left is called the Anterior Draw test. This test produces a positive result if the anterior talofibular ligament is damaged. Generally an indentation (sulcus sign) is seen anterior to the lateral malleolus.

Talar Tilt Test

The tibia is held and with your hand on the calcaneus you tilt the talus to create inversion. Laxity and a sulcus sign inferior to the lateral malleolus indicates damage to the calcaneofibular part of the lateral ligament. A similar talar tilt can be used to check the deltoid ligament for the medial side.

Tibialis anterior

passes anterior to the medial malleolus to insert onto the inferior surface of the 1st cuneiform bone and the first metatarsal. The tibialis anterior acts to dorsiflex the ankle and supinate the foot.

SUPERFICIAL FIBULAR NERVE

• Branch of Common Fibular Nerve • Motor to Lateral Crural Compartment muscles • Sensory to most of dorsum of foot A lesion to the superficial fibular nerve would result in weak eversion/pronation and a sensation deficit to most of the dorsum of the foot. This nerve lesion would have to be distinguished from a S1 lesion which would have similar symptoms but would be differentiated by doing other tests for S1. For example, S1 radiculopathy could affect the posterior compartment muscles and plantarflexion. The sensory innervation for S1 would not be the dorsum of the foot. Sensation to the dorsum of the foot is L5.

DROP FOOT

• Common and/or deep fibular nerve lesion - Inability of anterior crural muscles to dorsiflex ankle joint • L5 Radiculopathy could also cause weakness in the anterior compartment and drop foot. • Difficulty heel walking Drop foot is a description of the inability to dorsiflex the ankle due to a nerve lesion of the Deep fibular or common fibular nerves. It also could occur with weakness of these muscles from a L5 radiculopathy..

PLANTAR ARTERIES-Deep Plantar Arch

• Deep Plantar Arch • Anastomosis between: - Deep branch of Dorsalis pedis - Lateral Plantar artery Blood supply to the plantar surface of the foot comes from the medial and lateral plantar branches of the posterior tibial artery. The latter joins the dorsalis pedis artery, a branch of the anterior tibial artery, to form the deep plantar arch that brings the anterior tibial artery (dorsalis pedis branch) into anastomotic connection with the posterior tibial artery (lateral plantar branch).

LATERAL COMPARTMENT

• Muscles - Fibularis longus - Fibularis brevis • Action - Everters/Pronate tarsal joints. Can assist plantarflexion. • Nerve - Superficial Fibular (Yellow) • Artery - None; Muscles are supplied by Fibular branch of the Posterior Tibial Artery and branches of the Anterior Tibial artery Pronation has a component movement of eversion=plantar surface turns outward. The 2 muscles in the lateral crural compartment act to primarily pronate or evert the foot. This occurs when the plantar surface of the foot turns outward and all of the weight is placed on the medial 2 metatarsals of the foot. The muscles are attached to the shaft of the fibula. 1. The Fibularis (peroneus) longus crosses the bony plane on the plantar surface of the foot to insert onto the 1st metatarsal and medial cuneiform bone. 2. The Fibularis (peroneus) brevis attaches to the base of the tuberosity of the 5th metatarsal bone. 3.Muscular innervation of these muscles is by the Superficial fibular nerve. This nerve has sensory innervation to most of the dorsum of the foot except between the first two toes. 4.Blood Supply. No main artery in this compartment. Branches of the fibular and anterior tibial supply this compartment.

POSTERIOR COMPARTMENT DEEP

• Muscles - Tom, Dick, Harry Muscles a. Tibialis posterior (3) b. Flexor Digitorum longus (4) c. Flexor Hallucis longus (5) • Action - Flex toes - Supinate tarsal joints • Nerve - Tibial (Yellow) • Artery - Posterior Tibial; Fibular Deep Compartment contains muscles that arise from the posterior aspect of the shaft of the tibia, fibula, and interosseous membrane. Tibialis posterior is the stongest supinator. The main function of most of the other muscles is to flex the toes. Popliteus is an exception to toe flexion and "unlocks" the knee. The muscles include: Popliteus, Flexor Hallucis longus, Flexor Digitorum longus, and Tibialis posterior. Actions:inversion/supination of tarsal joints, plantarflexion, flexion of toes, unlocking of knee. Innervation-Tibial nerve Arteries: Posterior tibial and Fibular.

POSTERIOR COMPARTMENT SUPERFICIAL LAYER

• Muscles ( Triceps Surae) - Gastrocnemius (1L ; 1M) - Soleus (2) - Plantaris ( Orange) • Action - Plantar flex ankle joint • Nerve - Tibial (Yellow) • Artery Posterior Tibial; Fibular Superficial Compartment contains the triceps surae muscles. These muscles form a common tendon, the Achilles Tendon or Tendo Calcaneus. Through this tendon, these muscles attach to the back of the heel bone (calcaneus). These muscles, acting concentrically, are powerful plantar flexors of the ankle joint. In so doing, they help provide the propulsive force to enable to foot to leave the ground during the transition from weight-bearing to non-weight bearing. Once the limb is in non-weight bearing, it is free to move forward as we take a step. The muscles in the superficial group are the:Gastrocnemius, Soleus and Plantaris.

FIBULARIS LONGUS

• Origin - Head and Superior Lateral surface of fibula • Insertion - Medial Cuneiform and base of first metatarsal on plantar surface • Action - Eversion and pronation of tarsal joints; helps ankle plantar flexion • Superficial Fibular Nerve The Fibularis (peroneus) longus crosses the bony plane on the plantar surface of the foot to insert onto the 1st metatarsal and medial cuneiform bone. Eversion/Pronation of the foot at the tarsal joints. Passes behind the lateral malleolus and can act as a plantarflexor. Innervation Superficial fibular nerve. Also can be involved with testing the S1 myotome with eversion. ( Pronation involves three movements, dorsiflexion, abduction and the main action of eversion)

GASTROCNEMIUS

• Origin - Lateral head- Lateral surface of the lateral condyle of femur. - Medial head-popliteal surface of the femur, superior to the medial condyle • Insertion - Tendo calcaneus onto calcaneus • Action - Plantar flex ankle joint - Flexes knee joint • Nerve - Tibial The Gastrocnemius has medial and lateral heads of origin from the medial and lateral femoral condyles. Since these muscles arise superior to the knee joint, it can act to flex the knee and plantar flex the ankle joint. Thus, the gastrocnemius is a 2 joint muscle.

SUPINATION

• Prime movers: - Tibialis posterior (Green arrow) • Supinates foot • Plantar flexes ankle - Tibialis anterior (Black arrowhead) • Supinates foot • Dorsiflexes ankle • Innervation - Tibialis Posterior • Tibial nerve • L4 myotome - Tibialis anterior • Deep fibular nerve • L4 myotome

STABILITY-Muscle Action Needed

• Stability maintained by eccentric contractions of superficial calf muscles • Must expend muscle energy to maintain stable configuration • Also helped by inferior tibiofibular ligaments

Anterior Compartment Syndrome

• Swelling and/or Enlargement of muscles in anterior compartment • Necrosis - Compress anterior tibial artery - Loss of blood to anterior compartment muscles ** Can be acute or chronic. The most common type of compartment syndrome is Anterior Compartment Syndrome. The anterior crural fascia compresses the muscles in this compartment between the tibia and fibula, offering little "give" when the muscles hypertrophy and expand. It is usually an increase in the size of tibialis anterior muscle that is often responsible for this syndrome. The tibialis anterior rests on the interosseous membrane. Hypertrophy can compress the anterior tibial artery, diminishing the blood supply to the structures in the anterior compartment including the deep fibular nerve and other muscles. Muscle and/or nerve ischemia can result, increasing pain in the area of the anterior portion of the leg. The pain increases with activity and decreases with rest. If the situation is prolonged, muscle weakness and /or wasting can occur.

TIBIAL NERVE

• Terminal Branch of Sciatic • Supplies muscles in Posterior Crural Compartment and Plantar Foot. • Sensory to sole of foot and calcaneus The Tibial Nerve is one of the 2 terminal branches of the sciatic nerve. It supplies all of the muscles in all posterior compartments of the leg. This nerve also supplies all of the muscles on the plantar surface of the foot and is sensory to the skin on the sole of the foot.

POSTERIOR COMPARTMENT

• The posterior compartment of the leg is divided into a superficial and deep group. • Actions: - Plantar flex ankle joint - Flex toes - Inversion - Flex knee - Unlock the knee • Nerve - Tibial • Artery Posterior Tibial and Fibular The Posterior Crural Compartment can be subdivided into 2 separate compartments A. Superficial Compartment contains the triceps surae muscles. B. Deep Compartment contains muscles that arise from the posterior aspect of the shaft of the tibia, fibula, and interosseous membrane. The main function of most of these muscles is to flex the toes. Popliteus is an exception to toe flexion and "unlocks" the knee. C. The Tibial Nerve is one of the 2 terminal branches of the sciatic nerve. It supplies all of the muscles in all posterior compartments of the leg. This nerve also supplies all of the muscles on the plantar surface of the foot and is sensory to the skin on the sole of the foot. D. The Posterior Tibial Artery is the primary artery of the posterior leg. It supplies the muscles in all compartments. It then passes posterior to the medial malleolus where its pulse can be easily palpated. The fibular artery is one of the larger branches of the posterior tibial artery. It supplies the muscles in the posterior compartment that are attached to the fibula. It also supplies blood to the muscles in the lateral crural compartment along with some branches from the anterior tibial artery.

Anterior compartment syndrome-Acute

•Acute- Trauma, Fractures, Bruising, Crush injuries of this compartment are possible causes of acute compartment syndrome. Steroid use can also be a cause. Can be a medical emergency. •The increased pressure in the confined space can negatively affect the blood flow and nerve health. A fasciotomy may be performed.

PLANTAR MUSCLES LAYER 3 - continued

•Adductor Hallucis (3) -Origin: Oblique head from base of metatarsals 2-4; Transverse head MTP joints of toes 2-5. -Insert: Onto lateral side of proximal phalanx of great toe. Adducts MTP joint of big toe -Lateral Plantar Nerve

Summary of Nerves to the Leg

•All of the Leg is supplied by branches of the Sciatic Nerve •** Except the Saphenous nerve to the skin of the medial leg and part of foot. This nerve is a branch of the Femoral nerve. 1.The sciatic nerve from the lumbosacral plexus divides into the Tibial nerve and the Common Fibular nerve. These nerves and their branches supply the muscles and skin of the leg and foot. 2.The saphenous nerve branch of the femoral supplies the medial leg and possibly medial foot with sensory to the skin. No motor.

DORSIFLEXION

•Anterior Crural Muscles - Tibialis anterior (TA) Also Inversion of tarsal joints - Extensor Digitorum Longus (EDL) - Extensor Hallucis Longus - Fibularis Tertius (**) Helps evert tarsal joints • Innervation - Deep fibular nerve

Leg compartments

•Anterior compartment: Anterior crural muscles that dorsiflex the ankle, extend the toes, help invert the foot, small amount of eversion. •Lateral compartment: Evert the foot and plantarflex the ankle. •Posterior Compartment: -Superficial: Plantar flex the ankle and flex the knee. -Deep: Flex toes, invert foot, plantarflex, and unlock the knee. A. The ankle and foot play a pivotal role in the weight bearing and locomotion function of the lower limb. The muscles in the leg act to move and/or stabilize the ankle joint and the joints of the foot. The crural fascia divides the leg into 3 functional compartments: the anterior, posterior and lateral crural compartments. 1. The muscles in the anterior compartment primarily act to dorsiflex the ankle and extend the toes. There are also movements of inversion-tibialis anterior and weak eversion with the fibularis tertius. 2. Those in the lateral compartment act to pronate/evert the tarsal joints of the foot. These muscles also act as plantarflexors. 3. The muscles in the posterior compartment are subdivided into 2 functional groups. The deeper muscles act on the toes of the foot and inversion. Those in the superficial compartment, collectively termed the triceps surae muscles, are very important muscles. Eccentric contraction of these muscles is responsible for stabilizing the ankle joint by restraining excessive ankle dorsiflexion. Concentric contraction by these muscles is responsible for powerfully plantar flexing the ankle as occurs when one "pushes off" during walking, running or jumping. The plantaris and gastrocnemius cross the knee joint for attachment and therefore can act to flex the knee. A deep muscle, the popliteus, can act to laterally rotate femur or medially rotate tibia to unlock the knee.

PLANTAR MUSCLES LAYER 1-continued.

•Arise from Calcaneus and Plantar Fascia -Flexor Digitorum Brevis (3) inserts into middle phalanx of toes 2-5. •Flexes PIP joints of toes 2-5. •Medial Plantar nerve The muscles of the foot can be divided into those on the dorsal surface and those on the plantar surface. Those on the plantar surface are further divided into 4 different layers. All of the muscles of the foot describe here are intrinsic muscles because they have their proximal and distal attachments in the foot and act on the joints of the foot. 1. First Muscle Layer: a. Abductor Hallucis-1 attaches from the medial process on the calcaneal tuberosity and plantar aponeurosis to the medial side of the base of the proximal phalanx of the great toe. This muscle is innervated by the medial plantar nerve and acts to abduct and flex the hallux. b. Flexor Digitorum Brevis-3 attaches from the medial process on the calcaneal tuberosity and plantar aponeurosis. It divides into 4 tendons that joint with that of the flexor digitorum longus to form a common flexor tendon sheath. The tendons of the brevis split to insert on either side of the base of the middle phalanx of each of the lateral 4 toes. This muscle is innervated by the medial plantar nerve and acts to flex the proximal interphalangeal (PIP) joints of the 4 lateral toes. c. Abductor Digiti Minimi-2 attaches from the medial and lateral processes of the calcaneal tubercle and the plantar aponeurosis to the lateral side of the base of the proximal phalanx of the 5th toe. It is innervated by the lateral plantar nerve and acts to abduct and flex the 5th toe.

Common Fibular Nerve

•Branch of Sciatic n. •Winds around neck of fibula •Superficial Fibular br. (L5, S1) •Motor to lateral compartment muscles •Sensory to most of dorsum of foot •Deep Fibular br. (L5) •Motor to anterior compartment muscles •Sensory to area between first 2 metatarsals •Common fibular nerve lesion •Drop Foot •Cannot heel walk Common Fibular Nerve- Divides into the Superficial and Deep Fibular Nerves. This nerve can be located near the bone at the head of the fibula and can be damaged their with symptoms in both the anterior (deep fibular) and lateral ( superficial fibular) compartments. 1. The Deep Fibular (peroneal) nerve is the nerve of the anterior compartment. a. Motor to the muscles of anterior compartment b. Sensory to the skin on dorsum of the foot in the web space between first 2 toes. 2. . The Superficial Fibular (peroneal) Nerve is one of 2 branches of the common fibular (peroneal) nerve and is the nerve to the lateral compartment. a.This nerve supplies the fibularis longus and brevis muscles. b.This nerve is sensory to most of the dorsum of the foot, except the area between the first 2 toes.

Tibial Nerve

•Branch of Sciatic n. (S1) •Innervates posterior compartment muscles •Cutaneous sensation to plantar surface of foot •Motor to plantar muscles of foot •Lesion •Cannot plantar flex ankle •Cannot toe walk •Weakness of intrinsic plantar foot muscles The Tibial Nerve is one of the 2 terminal branches of the sciatic nerve. It supplies all of the muscles in the posterior compartment of the leg. This nerve also supplies all of the muscles on the plantar surface of the foot and is sensory to the skin on the sole of the foot. It divides at the medial malleolus into medial and lateral plantar nerves to the plantar region of the foot.

Anterior compartment syndrome-Chronic

•Chronic- "Exertional compartment syndrome". Commonly caused by an overuse injury of the muscles. Usually not a medical emergency, though long term it could cause some damage to the muscles and structures. Rest, changing of exercise routine, anti-inflammatories. •Pain in this condition usually stops after exercise is stopped. •Shin splits- commonly used to describe chronic compartment syndrome. The muscles expand causing the fascia to stretch and the formation of tiny bone fractures occur along the tibia. A stricter definition of "shin splints" is ongoing in the literature. Shin Splints are another form of overuse injury involving the anterior compartment muscles. In this case, the muscles expand causing the fascia to "stretch" and result in tiny bone fractures to occur along the tibia. Pain is noticed more during activities and is localized over the region of the tibia.

Medial Ligament of Ankle

•Deltoid Lig. •4 strong bands binding medial malleolus to talus, calcaneus and navicular bones •Posterior Tibiotalar Lig. •Tibiocalcaneal Lig. •Tibionavicular Lig. •Anterior Tibiotalar Lig. •Resists eversion •Very strong The Medial (Deltoid) ligament is composed of 4 separate ligaments (calcaneotibial, anterior tibiotalar, posterior tibiotalar, and tibionavicular ligaments) that connect the medial malleolus with 3 tarsal bones: the calcaneus, talus and navicular. It supports the medial aspect of the ankle joint and guards against excessive pronation/ eversion of the foot. A Pott fracture occurs with excessive eversion and is described as a fracture of the distal fibula accompanied by rupture of the deltoid ligament or fracture of the medial malleolus.

PLANTAR MUSCLES LAYER 3

•Flexor Hallucis Brevis (1)- from cuboid and lateral cuneiform. 2 heads insert on either side of proximal phalanx of great toe. Sesamoid bones at insertion. -Flexes MTP joint of great toe -Medial Plantar Nerve •Flexor Digiti Minimi (V) (2)- base of 5th metatarsal to proximal phalanx of 5th toe. -Flex MTP joint of 5th toe. -Lateral Plantar Nerve a. Flexor Hallucis Brevis attaches from the cuboid and lateral cuneiform bones to the base of the proximal phalanx of the great toe. One head attaches to the medial side of the base while the other attaches to the lateral side of the base. This muscle is innervated by the medial plantar nerve and acts to flex the metatarsophalangeal joint. b. Adductor Hallucis has an oblique head that attaches to the base, 2,3, & 4 metatarsal bones and sheath of Fibularis (peroneus) longus. The transverse head attaches the plantar ligaments of lateral 4 metatarsophalangeal joints. Both heads form a single tendon that inserts onto the medial side of the base of the hallux. This muscle adducts the metatarsophalangeal (MTP) joint of the big toe. It can also help to flex the MTP joint of the big toe. Through the action of the transverse head, this muscle helps maintain the transverse arch of the foot. The lateral plantar nerve innervates this muscle. c. Flexor Digiti Minimi attaches from the base of the 5th metatarsal bone and the sheath of the fibularis longus tendon to the base of the proximal phalanx of the 5th toe. This muscle flexes the MTP joint of the 5th toe and is innervated by the lateral plantar nerve.

Fourth Layer contains the interossei muscles

•Interossei layer -Center of Foot = Line through 2nd toe. 2nd toe always Abducts away from this line in either direction. -Dorsal Interossei arise from adjacent metatarsal bones -Insert onto base of proximal phalanx and expansion of both sides of toes 2-4 -Abduct and flex MTP joints of toes 2-4. Extend IP Joints similar to the actions of the hand interossei. -Lateral Plantar Nerve These muscles have their proximal attachments to the metacarpal bones. These muscles act on the metatarsophalangeal (MTP) joints of the foot by performing the following motions: a. Flexion b. Abduction c. Adduction To understand the action of these muscles requires knowing that the center of the foot is the 2nd toe. Moving the toes towards the 2nd toe is called adduction of the MTP joint. Spreading the other toes away from the 2nd toe is called abduction of the MTP joints. In addition, because the interossei also attach to the extensor expansion, they can act to extend the IP joints of the toes d. Dorsal Interossei are 4 in number. They attach from the adjacent sides of all metatarsal bones to insert as follows (1) Medial side 2nd proximal phalanx & extensor expansion (2) Lateral side 2nd proximal phalanx & extensor expansion (3) Lateral side 3rd proximal phalanx & extensor expansion (4) Lateral side 4th proximal phalanx & extensor expansion These muscles abduct and flex the MTP joints of the 2nd - 5th toes and extend the IP joints of these same toes. The lateral plantar nerve innervates these muscles.

Second layer of Muscle is attached to the tendon of the flexor digitorum longus.

•MUSCLES ASSOCIATED WITH FLEXOR DIGITORUM LONGUS (1) •Flexor Digitorum Longus - Posterior Crural Compartment muscle. Inserts onto distal phalanx of toes 2-5. Flexes DIP of toes 2-5. - Innervated by tibial nerve •Quadratus Plantae (2) - attaches from calcaneus to tendon of FDL. Straightens out pull of FDL. - Lateral plantar nerve •Lumbricals (label 3) arise from FDL tendon to join dorsal digital expansion of toes 2-5. Flex MP & Extend IP joints of toes 2-5. -Lumbrical 1 = Medial Plantar nerve. L 2,3,4 = Lateral plantar nerve Mnemonic- 222. 2nd layer, 2 extrinsic muscle tendons- flexor digitorum longus and flexor hallucis longus, and the 2 intrinsic muscles listed here. a. Quadratus Plantae attaches by 2 heads to the body of the calcaneus and plantar fascia and the plantar surface of the calcaneus to the tendon of the flexor digitorum longus. This muscle is innervated by the lateral plantar nerve and is responsible for straightening out the pull of the flexor digitorum longus. b. Lumbricals are 4 worm-like muscles that attach from the 4 tendons that separate from the flexor digitorum longus to the medial side of the extensor expansion of lateral 4 toes. The medial plantar nerve innervates the medial 1 muscles; the lateral plantar nerve innervates the lateral 3 muscles. The lumbricals are ventral to the MP joints of the toes so they act to flex these joints. In addition, because of their insertion onto the extensor expansion, they also extend the IP joints of the lateral 4 toes.

PLANTAR ARTERIES

•Medial and Lateral Plantar arteries supply skin and muscles on plantar Surface of foot. Terminal branches of Posterior Tibial Artery •Medial Plantar Artery (M) supplies structures on medial side of foot •Lateral Plantar Artery (L) supplies most of foot. Terminates by joining with deep plantar branch of Dorsalis Pedis to form Deep Plantar Arch

The Ankle Joint

•Modified hinge joint between Talus (3), Medial Malleolus of Tibia (1) and Lateral Malleolus of Fibula (2) •Most stable position = Dorsiflexion •7 = Calcaneus The ankle is a modified hinge joint between the trochlea of the talus and the lateral and medial malleoli of the fibula and tibia, respectively. It is often called the talocrural joint. Its most stable configuration is in the dorsiflexed position. Since the center of gravity falls anterior to the ankle, the joint is forced into dorsiflexion, a position in which the trochlea fits snugly between the malleoli. Contraction of the triceps surae is responsible for maintaining ankle joint stability.

TIBIALIS POSTERIOR

•Origin - Interosseous membrane - Posterior borders of tibia and fibula •Insertion -Navicular bone -Fibrous extensions to cuneiform and cuboid bones and metatarsal 2-4 -Supinate foot -Aid in ankle plantar flexion This muscle passes posterior to the medial malleolus to insert onto the 2-4 metatarsal bones, the 3 cuneiform bones, cuboid, and the navicular bone. It is the main muscle to supinate the foot. This happens when the sole of the foot faces medially and all of the weight is on the fifth metatarsal. Tibialis posterior is the strongest inverter/supinator of the foot.

FLEXOR HALLICUS LONGUS

•Origin -Inferior 2/3rds of posterior fibula, interosseous membrane • Insertion - Distal phalanx of great toe • Action - Flexes IP joint. • Nerve - Tibial Flexor Hallucis longus inserts onto the distal phalanx of the big toe (hallux). This muscle acts to flex the interphalangeal (IP) joint of the big toe.

PLANTAR FASCIA

•Plantar Aponeurosis (A) tough central Portion of plantar fascia •Compartments: - Lateral (L) contains lateral plantar vessels and nerve , intrinsic muscles attached to 5th Metatarsal -Medial (M) contains medial plantar vessels and nerve and intrinsic muscles attached to 1st metatarsal Plantar Surface muscles are divided into 4 different layers. In addition, consideration must be given to the plantar fascia. 1. Plantar fascia is continuous with the deep fascia of the foot. The thick central portion of this fascia is the plantar aponeurosis. The lateral and medial components of the plantar fascia are less thick. The plantar fascia helps protect the soft tissues of the plantar surface of the foot and provides support for the longitudinal arches. 2. Plantar Aponeurosis is the very tough and thick central portion of the plantar fascia. This aponeurosis arises from the plantar surface of the calcaneus posteriorly. Anteriorly, it divides into 5 slips that attach to the digital flexor tendon sheaths for each toe. The aponeurosis divides the foot into 3 compartments: a. Medial Compartment contains the medial plantar nerves and vessels, the abductor hallucis and the flexor hallucis brevis muscles. b. Lateral Compartment contains the lateral plantar artery and nerve (some sources say the lateral plantar nerve is in the central compartment), the abductor digiti V, and flexor digiti V. c. Central Compartment is the largest and contains the remaining structures on the plantar surface of the foot. Inflammation of the plantar fascia, especially the plantar aponeurosis is a common overuse injury called plantar fasciitis.

4th Layer - Plantar Interossei are 3 in number

•Plantar Interossei arise from 3rd -5th metatarsal bones. -Insert onto medial side of base of Proximal phalanx of toes 3-5 -Adduct and flex MTP joints of toes 3-5 -Lateral Plantar Nerve They attach from the medial side of 3, 4, &, 5 metatarsals to the medial side base proximal phalanges of 3, 4, & 5 toes and extensor expansion. These muscles adduct and flex the MTP joints of the 3rd, 4th, and 5th toes and extend the IP joints of these same toes. The lateral plantar nerve innervates the plantar interossei.

Distal Tibiofibular Joint

•Posterior Inferior Tibiofibular Ligament (5) •Together with Anterior Inf. Tibiofibular Lig., keep talus applied to malleoli during dorsiflexion •Can be torn in a "High Ankle Sprain" •Interosseous Ligament (6) •Binds Tibia and Fibula together •Usually torn in "High Ankle Sprain" The Anterior and Posterior Inferior Tibiofibular Ligaments are technically not part of the ankle joint. However they play an important role in stabilizing the joint since they form a very strong connection between the tibia and the fibula.

Pronation at the TARSAL JOINTS

•Pronation - Eversion - Dorsiflexion - Abduction • Primary muscles - Fibularis longus - Fibularis brevis Pronation and Supination take place at ankle/talocrural, subtalar, transverse tarsal joints. 1.The subtalar joint can do all three movements of pronation and supination. 2.Most of dorsiflexion/plantarflexion occurs at the ankle/talocrural joint. 3.The subtalar does not have much dorsiflexion/plantarflexion, these movements are limited at the subtalar joint. space. But does have eversion/inversion and abduction/adduction.

PES PLANUS-Mostly involves the medial arch

•Spring ligament is stretched when full body weight is directly over foot. Arch flattens. •Arch reforms as Spring ligament resumes normal shape and tension when foot is "unweighted". •Damage to Spring ligament means a flattening of medial longitudinal arch placing more emphasis on activity of triceps surae to overcompensate to maintain the arch. Pes Planus (Flat foot) occurs when there is a pronounced flattening of the medial longitudinal arch. When the spring ligament becomes over stretched and weak, it can no longer support the bony configuration of the medial arch. The head of the talus is displaced and flattens the arch. Pes Cavus is an exaggerated high arch of the foot. There are many reasons for the development of pes cavus. Some of the more common ones are: a. Excessive tightness of the intrinsic muscles of the foot. In such a condition, the forefoot is brought closer to the hind foot increasing the height of the longitudinal arches. b. A similar height increase can occur if the plantar fascia is excessively tight. c. An overactive fibularis longus muscle coupled with weak anterior crural compartment muscles, especially the tibialis anterior. The fibularis longus muscle acts to plantar flex and abduct the forefoot on the hind foot during pronation as well as it's main action of eversion. Excessive action of this muscle can result in an exaggerated high longitudinal arch.

Supination at the TARSAL JOINTS

•Supination - Inversion - Plantar flexion. (transverse tarsal not so much subtalar) - Adduction • Primary muscles - Tibialis anterior - Tibialis posterior

Leg Bones

•The Tibia participates in the formation of knee and ankle joints, providing continuity in weight-bearing and weight-transfer. •The Fibula is not part of the bony anatomy of the knee joint, but it serves as a point of attachment for ligaments and tendons that stabilize it. It is part of the ankle joint. •Muscles acting on ankle joint originate from shafts of tibia and fibula. Tibia -This is the larger and stronger of the 2 bones in the leg (the other being the fibula). It articulates superiorly with the femur, laterally with the fibula (interosseous membrane) and inferiorly with the talus via the medial malleolus. It forms the medial aspect of the ankle joint. Gerdy's tubercle is located lateral to the tibial plateau; it is the attachment site for the iliotibial band, and often a site of injury in individuals involved in running. The Tibial tuberosity is the site of attachment for the patella (quadriceps) tendon. In teenagers, pain at this site may be an indication of avulsion of the tibial tubercle, which occurs during a growth spurt (Osgood-Schlatter disease). The Medial (Tibial) Collateral Ligament runs from the medial femoral epicondyle to the shaft of the tibia. Fibula -It articulates with the tibia both superiorly and inferiorly. The superior articulation takes place with the head of the tibia, below the knee joint, while the inferior one happens via the interosseous membrane. The fibula is not a part of the knee joint. It does, however, participate in the formation of the ankle joint. The Lateral (Fibular) Collateral Ligament runs from the lateral femoral epicondyle to the head of the fibula. The Common Fibular nerve winds around the neck of the fibula.

Major joints of the ankle and foot

•There are 4 joints involved with the ankle and foot. The muscles acting on these joints are primarily in the compartments of the leg: •Joints: - Talocrural - ankle joint - Distal Tibiofibular Joint - Sub talar joint between the superior surface of the calcaneus and the inferior surface of the body of the talus - Transverse tarsal joints • Movements at the talocrural, subtalar, and transverse tarsal joints occur around 3 different axes: - Medial-Lateral axis • Dorsiflexion • Plantar flexion - Anterior-Posterior • Inversion • Eversion - Vertical • Adduction • Abduction

PLANTAR NERVES

•Tibial nerve terminates as Medial and Lateral Plantar nerves -Supply skin and muscles on plantar surface •Medial Plantar Nerve (M) - cutaneous to 3.5 toes. Motor to muscles Abductor hallucis, Flexor hallucis brevis, Flexor digitorum brevis, and 1st lumbrical. •Lateral Plantar Nerve (L) Lateral cutaneous to 1.5 toes. Motor to Abductor digiti minimi, Quadratus plantae, 2nd ,3rd and 4rth lumbricals, Adductor hallucis, Flexor digiti minimi, and all the interossei. Tibial Nerve divides into 2 branches that supply sensation to the plantar surface of the foot a. Medial Plantar nerve supplies sensation to the medial portion of the foot. b. Lateral Plantar nerve supplies the lateral portion of the foot. (1) These nerves convey axons from the L5 spinal segment making the plantar surface of the foot a portion of the L5 dermatome. c. The saphenous nerve, a branch of the femoral nerve, supplies the skin along the medial side of the ankle and big toe. This region is part of the L4 dermatome. d. The sural nerve is a usually a branch of the sciatic nerve conveys sensation from the skin over the lateral side of the ankle, 5th toe and some heel, making this region a portion of the S1 dermatome. e. The calcaneal branch of the tibial nerve conveys sensation from the heel region making this region part of the S1 dermatome.

Tarsal Joints

•Transverse tarsal (Chopart) joint- talus/navicular. calcaneus/cuboid. ***- All of the movements of supination/pronation can occur to some extent at this joint. Site of amputations • Subtalar Joint-talus to calcaneus. *Primarily involved with eversion/inversion and abduction/adduction Subtalar Joint - between the calcaneus and the body of the talus. Transverse Tarsal Joint - formed by the articulation of the talus and navicular bones (talonavicular joint), and the calcaneus and cuboid bones (calcaneocuboid joint). They are separate joints that, together, constitute the transverse tarsal joint. Tarsometatarsal Joints - capable of very little movement, they help adapt foot to uneven ground.