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