TIS
Chapter 1
Functional Anatomy Review of the Ankle and Foot
TALOCRURAL JOINT
OSSEOUS COMPONENTS
The talocrural joint is formed by the articulation between the trochlea (body) of the talus and the mortice of the ankle, which is formed from the distal tibia and its malleollus, and the malleollus of the fibula. The trochlea athough round is not shaped liked a cylinder, but rather cone shaped (specifically a frustrum of a cone). Thus, during dorsiflexion and plantarflexion of the talocrural joint the amount of trochlear rotation occurring laterally is greater than medially. The amount of distal tibiofibular joint separation during maximum dorsiflexion has been estimated at 3 to 5 mm.
LIGAMENTOUS COMPONENTS
The Lateral Collateral Ligaments consists of three specific structures, including the:
- Anterior talofibular ligament (1)
- Calcaneofibular ligament (2)
- Posterior talofibular ligament (3)
Anterior talofibular ligament and the posterior talofibular ligament provide support to the talocrural joint. The calcaneofibular ligament plays an important role in providing stability to both the talocrural and the subtalar joints.
Medial Collateral Ligament or Deltoid Ligament (6) is a strong, triangular shaped band and consists of superficial (4) and deep (5) fibers. The deltoid ligament has attachments to the navicular, and in a continuous line, along the median margin of the planter calcaneonavicular lIgament to the sustentaculum tale of the calcaneus. It attaches to the apex as well as to the anterior and posterior borders of the medial malleolus.
SUBTALAR JOINT
OSSEOUS COMPONENTS
The posterior or "true" subtalar joint involves the articulation between the concave posterior facet on the inferior surface of the talus and the convex posterior facet on the superior surface of the calcaneus. These two bones are connected by a fibrous capsule, and by lateral, posterior, medial, interosseous talocalcaneal, and cervical ligaments.
LIGAMENTOUS COMPONENTS:
The two major ligaments of the posterior suotalar joint are: the interosseous talocalcaneal ligament and the cervical ligament.
The Interosseous Talocalcaneal Ligament which is a thick, quadrilateral ligament that originates from the sulcus calcanei, near the capsule of the posterior subtalar joint. The fibers travel in a upward and medially, and insert on the sulcus tali medially. The inner fibers are shorter than the outer fibers, thus the medial fibers become taut in eversion.
The Cervical Ligament is the strongest of the ligaments connecting the two bones. It originates in the anteromedial segment of the sinus tarsi near the origin of the Ext. Digit. Brevis. The fibers travel upward and medially to attach on the inferior, medial aspect of the neck of the talus. Its fibers become taut during supination of the subtalar joint.
STRUCTURES ON THE SUPERIOR SURFACE ON CALCANEUS
MID-TARSAL JOINT
OSSEOUS COMPONENTS
The midtarsal or transverse tarsai joint is comprised of two separate joints: the Talocalcaneonavicular and the Calcaneocuboid.
The Talocalcaneonavicular Joint is formed by the articulation between the head of the talus and the posterior facet of the navicular as well as the middle and anterior facets of the talus on the calcaneus. The joint capsule is totally independent from the posterior joint capsule.
The Calcaneocuboid Joint is formed by the articulation between the calcaneus and the cuboid.
LIGAMENTOUS COMPONENTS
There primary ligaments which support the Talocalcaneaonavicular joint are:
- Plantar Calcaneonavicular Ligament (11) also more commonly known as the
"spring ligament".
- Dorsal Talonavicular Ligament (12)
- The medial or calcaneonavicular portion (14) of the Bifurcated Ligament (13).
The primary ligaments which support the Calcaneocuboid joint are:
- Dorsal Calcaneocuboid Ligament (16)
- The lateral or calcaneocuboid portion (15) of the Bifurcated Ligament (13).
- Plantar Calcaneocuboid Ligament, a dense, thick, white structure
consisting of two distinct layers:
Deep layer, (17) running from anterior tubercle of calcaneus to plantar
surface of cuboid posterior to groove for peroneus iongus. Also known as the
short plantar ligament
Superficial layer, (18) arises from calcaneus and inserts into cuboid bone
continuing in anterior direction, forming tunnel for peroneus longus (PL) and
finally inserting into the 5th, 4th, 3rd, and on occasion 2nd metatarsal heads.
Also known as the long plantar ligament.
LOWER EXTREMITY MUSCULATURE
EXTRINSICS
- Anterior Compartment: Anterior Tibialis (inv)
Extensor Digitorum Longus (eve)
Extensor Hallucis Longus
* Extensor Digitorum Brevis
Artery and Nerve:
Deep Peroneal Nerve
Anterior Tibial Artery
- Lateral Comparment:
Peroneus Longus (eve)
Peroneus Brevis (eve)
Nerve:
Superficial Peroneal Nerve
- Superficial Posterior Compartment:
Gastrocnemius
Soleus
Plantaris
Artery and Nerve:
Tibial Nerve
Posterior Tibial Artery
- Deep Posterior Compartment:
Posterior Tibialis
Flexor Digitorus Longus
Flexor Hallucis Longus
Artery and Nerve:
Tibial Nerve
Peroneal Artery
INTRINSICS
FIRST LAYER:
Abductor Hallucis
Flexor Digitorus Brevis
Abductor Digiti Minimi
SECOND LAYER:
Flexor Accessorius (Quadratus Plantae)
Lumbricals
THIRD LAYER:
Flexor Hallucis Brevis
Adductor Hallucis
Flexor Digiti Minimi
FOURTH LAYER:
Dorsal Interossei
Plantar Interossei
Artery and Nerve:
Medial and Lateral Plantar Nerves
Medial and Lateral Plantar Arteries
