Anatomy of Subtalar and Transverse Tarsal Joints

Study Notes

Subtalar Joint

Two articulations between the talus and calcaneus
Posterior articulation is the major one and is considered a planar synovial joint, but the talus is concave and the calcaneus is convex.
Anterior articulation is between the head and neck of the talus and the anterior facets of the calcaneus, and is considered more with the talonavicular or calcaneonavicular joint.
Sinus tarsi space is between anterior and posterior joint surfaces, doesn't have cartilage.
Cervical or interosseous talocalcaneal ligament is located within the sinus tarsi.
Cervical and interosseous ligaments anchor the talus to the calcaneus.
Plantar calcaneonavicular ligament travels from the sustentaculum tali to the navicular.

Transverse Tarsal Joint

Part of the midfoot, connecting the hindfoot and midfoot
Made up of the talonavicular (spheroidal) and calcaneocuboid (sellar) joints

Ligaments of the Transverse Tarsal Joint

Long Plantar Ligament: long, fibrous, deep to the plantar fascia, extending from the calcaneus to the bases of the lateral three metatarsals.
Plantar Calcaneonavicular Ligament (Spring Ligament): thick, strong ligament connecting the sustentaculum tali to the navicular.
Plantar Calcaneocuboid Ligament: also known as the short plantar ligament, connects the anterior inferior surface of the calcaneus to the cuboid.
Tibialis Posterior Tendon: connects the navicular and metatarsals.

Motions of Pronation and Supination - Open Chain

Pronation: Dorsiflexion, Eversion, Foot Abduction
Supination: Plantar Flexion, Inversion, Forefoot Adduction

Arches of the Foot

Functions: Shock absorption, foot stabilization, prevent compression of neurovascular structures, distribute weight.
Types: Medial Longitudinal, Lateral Longitudinal, Transverse Tarsal

Medial Longitudinal Arch Supports

Tibialis Posterior, Flexor Hallucis Longus, Flexor Digitorum Longus, Tibialis Anterior, Abductor Hallucis, Plantar Calcaneonavicular Ligament

Plantar Foot Muscles

The plantar surface of the foot has 4 layers of muscles.
Knowledge of insertions and origins is not needed, but understanding locations, layers, innervation, and primary actions is essential.

Layer 1 of Plantar Foot Muscles

Abductor Hallucis: pulls the big toe away from midline, innervated by the medial plantar nerve
Abductor Digiti Minimi: pulls the little toe away from midline, innervated by the lateral plantar nerve
Flexor Digitorum Brevis: helps flex the toes, innervated by the medial plantar nerve

Layer 2 of Plantar Foot Muscles

Flexor Digitorum Longus: tendon goes to the toes
Flexor Hallucis Longus: tendon goes to the toes
Quadratus Plantae: attaches from calcaneus to flexor digitorum longus tendon, assists in aligning the pull of the tendon, innervated by the lateral plantar nerve
Lumbricals: help to stabilize the toes, 1st lumbrical is innervated by the medial plantar nerve, the rest are innervated by the lateral plantar nerve

Layer 3 of Plantar Foot Muscles

Adductor Hallucis: pulls the big toe towards the midline (often referred to as the "flip-flop" muscle), innervated by the lateral plantar nerve
Flexor Hallucis Brevis: crosses towards the medial side, innervated by the medial plantar nerve
Flexor Digiti Minimi Brevis: innervated by the lateral plantar nerve

Layer 4 of Plantar Foot Muscles

Dorsal Interossei: abduct the toes, innervated by the lateral plantar nerve
Plantar Interossei: adduct the toes, innervated by the lateral plantar nerve
Mnemonic: 'Pad' (plantar ADduct) and 'Dab' (dorsal ABduct).

Plantar Foot Nerve Supply

The posterior tibial artery splits into the medial and lateral plantar arteries.
Nerves that supply the plantar foot arise from the posterior tibial nerve.
Nerve roots that innervate the plantar foot are S2 and S3.
Medial Plantar Nerve: innervates the medial side of the foot
Lateral Plantar Nerve: innervates the lateral side of the foot
Calcaneal Branches: innervate the heel

Plantar Foot Blood Supply

The posterior tibial artery splits into the medial and lateral plantar arteries.
Tarsal Tunnel Syndrome: compression of the artery and nerve in the foot can cause numbness and tingling in the foot, and reduced blood supply.

Foot Muscles: Interossei

Interossei are located between the metatarsals.
Plantar interossei are located on the plantar side of the foot and help with toe adduction.
Dorsal interossei are located on the dorsal side of the foot and help with toe abduction.
Innervation: All interossei muscles are innervated by the lateral plantar nerve.

General Foot Muscles

Foot muscles play a crucial role in stabilizing the toes, especially during walking.
Focus on recognizing the layers and identifying the muscles within each layer.
Knowing the general action and innervation of each muscle is essential.
Detailed muscle attachments are less important for physical therapists.
Understanding muscle function is critical for diagnosing and treating nerve injuries..

Description

Explore the detailed anatomy of the subtalar and transverse tarsal joints, including their articulations and ligaments. This quiz highlights the structural complexities and functions of these crucial joints in the foot. Test your knowledge on their anatomy and interconnections.