Lecture 3: Leg and Foot

Tibialis Posterior Muscle: Origin and Insertion Point

- originates along the tibia, interosseous membrane, and fibula - inserts on the tarsal bones

Tibialis Anterior: Origin and Insertion Point

- originates along the upper lateral surface of the tibia - inserts on navicular bone (medial side of the foot)

Soleus Muscle: Origin and Insertion Point

- originates along the upper posterior edge of the tibia - inserts with the gastrocnemius via the common achilles tendon

Peroneus Longus: Origin and Insertion Point

- originates by the head of the fibula - inserts under the foot at the junction between the cuneiform and 1st (big toe) metatarsal

Plantaris Muscle: Origin and Insertion Point

- originates on the lateral condyle just above the lateral gastrocs head - sends a very very long tendon that stretches all the way down and attaches separately to the calcaneus

4 Compartments of the Leg

1) Lateral Compartment 2) Anterior Compartment 3) Deep Posterior Compartment 4) Superficial Posterior Compartment

2 Muscles in the Lateral Compartment

1) Peroneus Longus 2) Peroneus Brevis

Bones of the Foot (List Toes to Heel)

1) Phalanges 2) Metatarsals 3) Cuneiforms 4) Navicular (Medial) + Cuboid (Lateral) 5) Talus (Medial) + Calcaneus (Lateral)

Bone Structures of the Leg

1) Tibia: Medial and Lateral Condyles, Medial Malleolus 2) Fibula: Head and Neck, Lateral Malleolus

3 Muscles of the Anterior Compartment

1) Tibialis Anterior 2) Extensor Digitorum Longus 3) Extensor Hallucis Longus

"Knot of Henry"

flexor muscle cross point

Compartment Syndrome

injury causes inflammation and edema => increases pressure on compartment blood vessels => ischemic damage

Talus

"ankle bone" that articulates with the distal end of the tibia

"High" Ankle Sprains Effect Which Ligaments?

"tibiofibular ligaments" which connect the tibia and fibula and the base of the ankle

Flexor Hallucis Longus: Origin and Insertion Point

- originates along the posterior/lateral side edge of the fibula - inserts on the end of the big toe

What Bones Constitute the Tarsals?

- Cuneiforms (3) - Navicular - Cuboid - Talus - Calcaneus - Total = 7

Movements of the Foot

- Dorsiflexion (aka Extension) - Plantarflexion - Inversion - Eversion

Action Produced By Lateral Compartment Muscles

- EVERSION of the foot - elevate the lateral side of the foot

3 Muscles of the Superficial Posterior Compartment

- Gastrocnemeus - Soleus (Deep to Gastrocnemeus) - Plantaris Muscle

Inversion Ankle Sprains Effect Which Ligaments?

- Lateral Ligaments - Ligaments attach the FIBULA to the hindfoot

Eversion Ankle Sprains Effect Which Ligaments?

- Medial (Deltoid) Ligaments - Ligaments attach the TIBIA to the hindfoot

Branches of the Anterior Tibial Artery in the Foot

- NO BRANCHES - crosses over the ankle and becomes the dorsal pedis artery - travels just laterally to the extensor hallicus longus

Name the 4 Septa Dividing the 4 Compartments of the Leg

- Posterior Intermuscular Septum => Divides Lateral and Superficial Posterior Compartments - Anterior Intermuscular Septum => Divides Lateral and Anterior Compartments - Interosseous Membrane => Divides Anterior and Deep Posterior Compartments - Transverse Intermuscular Septum => Divides Deep and Superficial Posterior Compartments

Gastrocnemeus Muscle: Origin and Insertion Point

- TWO HEADS! origination on the medial and lateral condyles of the femur - forms a common tendon (achilles tendon) with the soleus muscle and attaches to the calcaneus (heel)

Tibial Tuberosity

- bony prominence on the upper tibia below the knee - serves as the attachment point of the patellar ligament, which is continuous with distal tendon of the quadricep muscles

Branching Sequence of the Popliteal Artery

- branches after crossing the popliteus muscle - branches into 3 arteries: posterior tibial artery, anterior tibial artery, and the peroneal (fibular) artery

Branches of the Posterior Tibial Artery in the Foot

- enters foot medially (tom dick an harry) - becomes medial and lateral plantar arteries

Tarso-Metatarsal Joint

- joint between the cuneiform/cuboids and the metatarsals - divides the midfoot and the forefoot

Peroneus Brevis: Origin and Insertion Point

- located deep to the peroneus longus - originates on the upper shaft of the fibula - inserts on the lateral side of the foot at a point called the "tuberosity of the 5th metatarsal"

Plantar Aponeurosis

- most superficial (besides the dermis) structure of the plantar surface of the foot - serves to protect the arteries and nerves underneath

Extensor Hallucis Longus: Origin and Insertion Point

- originates along the anterior surface of the fibula (half way down) - inserts on the top side of the first toe (big toe)

Extensor Digitorum Longus: Origin and Insertion Point

- originates along the anterior surface of the fibula from the head down to the middle - inserts on 2nd to 5th toes (top side)

Flexor Digitorum Longus: Origin and Insertion Point

- originates along the posterior edge of the tibia - inserts on the four smaller toes

How Does the Posterior Tibial Artery and Tibial Nerve Reach the Foot?

- same way the deep posterior compartment muscles do - go down and wrap under at a point posterior to the medial malleolus

What Nerves Provide Sensory Innervation to the Anterior Portions of the Leg and Foot? (4 Nerves)

- saphenous nerve = anterior medial region - common peroneal nerve = proximal anterior lateral region - superficial personal nerve = distal anterior lateral region - deep peroneal nerve = big toe web

Where Do the Nerves of the Leg Come From?

- sciatic nerve branches into the tibial nerve and the common peroneal (aka fibular) nerve - common peroneal nerve then branches into the deep and superficial peroneal nerves

Sustentaculum Tali

- shelf-like projection protruding off the medial surface of the calcaneous under the talus supporting it - also helps guid the medial "tom dick 'an harry" structures as they pass to the plantar surface of the foot

Innervation of the Dorsal Surface of the Foot

- superficial peroneal nerve mostly - saphenous nerve covers the medial side of the leg all the way down to the ankle - sural nerve covers a sliver on the lateral side of the foot

Sural Nerve

- sural = calf - provides cutaneous sensory innervation to the posterior lateral portion of the calf and foot (shown in pink) - sural nerve has two branches (lateral and medial) that fuse, one comes from the tibial nerve, and the other comes from the common peroneal nerve

How Many Phalanges in the Foot?

14 = 4 Toes Have 3 Segments + Big Toe Has 2 Segments

How Many Metatarsals Are There?

5

Do the Deep Posterior Muscles Attach to the Top or Bottom of the Foot?

Bottom!

Interosseous Membrane

CT membrane connecting the tibia and fibula

Which Bone is the Heel Bone

Calcaneus

Name of the Fascia Layer in the Leg

Crural Fascia

Action Produced by the Anterior Compartment Muscles

DORSIFLEXION (extension) of the foot and toes + inversion of the foot (tibialis anterior)

What Nerve Innervates the Anterior Compartment of the Leg?

Deep Peroneal Nerve

What Nerve Innervates the Anterior Compartment Muscles?

Deep Peroneal Nerve, Passes Through the EHL and EDL

Extensor Retinaculum

Holds anterior compartment muscle tendons down at the ankle joint

What Vein Drains the Posterior Portion of the Leg and Foot?

Lesser Saphenous Vein

Arteries of the Leg Branch from Which Artery?

Popliteal Artery

Which Arteries Supply the Foot?

Posterior and Anterior Tibial Arteries

Tibial Nerve vs. Tibial Division of the Sciatic Nerve

Same Thing

What Nerve Innervates the Lateral Compartment Muscles?

Superficial Peroneal Nerve

What Nerve Innervates the Lateral Compartment of the Leg?

Superficial Peroneal Nerve

T or F: Deep Posterior Muscles Cross Paths Before Inserting

TRUE! the flexor digitorum longus tendon and the flexor hallucis longus have to cross paths since they insert on opposite sides of the foot

What Nerve Innervates the Deep Posterior Compartment of the Leg? Superficial Posterior?

Tibial Nerve Supplies Both Compartments

Foot Drop

can occur from damage to the *deep peroneal nerve* or the common peroneal nerve (because deep branches from that)

Innervation of the Plantar Surface

comes from the tibial nerve, which has medial plantar and lateral plantar branches

Transverse Tarsal Joint

contains the talonavicular and calcaneocuboid joints. Divides the hindfoot and midfoot

Tom, Dick, 'AN Harry

order of structures going down the medial side of the lower leg to the foot (from lateral to medial)

Tarsal Tunnel

thickening of fascia that holds together the "tom, dick, 'an harry" structures as they pass to the bottom of the foot behind the medial malleolus

Extensor Retinacula

thickening of the crural fascia around the ankle

Peroneal Retinaculum

two components of dense fascia that hold the peroneus longus and brevis tendons in place as they travel along the lateral side of the ankle