Osteology (Part 3): Calcaneus Flashcards
Calcaneus
- Largest bone in the foot
- Forms the heel
- Length > width
Calcaneus angulation
- Long axis is directed superiorly and laterally
- Superior angulation is referred to as calcaneal pitch
- ~ 30 - 35⁰ between long axis of talus and calcaneus
Structures of calcaneal superior surface
- Anterior/middle/posterior facet of calcaneus (anterior/middle/posterior talar facet)
- Calcaneal sulcus (sulcus calcanei)
Anterior/middle facet of calcaneus (anterior/middle talar facet)
- Concave facets located on the anterior 1/3 of superior surface
- Articulates with anterior and middle facets of the talus
- Anterior is the smallest facet
- Middle is most medial facet, rest on sustentaculum tali
Posterior facet of calcaneus (posterior talar facet)
- Middle 1/3 of superior surface
- Steep inclination
- Convex
- Articulates with the posterior facet of talus
- Larger than anterior and medial
Calcaneal sulcus (sulcus calcanei)
- Anterior to posterior facet of calcaneus
- Located on the anterior 1/3 of superior surface
- Oriented anterolaterally
- Aligns with sulcus tali to form the sinus tarsi
- Forms inferior aspect
- More wide laterally
Posterior 1/3 of superior surface
- Kager (pre-Achilles) fat pad is located superior
Medial calcaneal surface structures
- Sustentaculum tali
Sustentaculum tali
- Medial projection on calcaneus
- Ligament attachment; pulley for FHL
Lateral calcaneal structures
- Peroneal trochlea (tubercle)
- Retrotrochlear eminence
- Peroneal spine
Peroneal trochlea (tubercle)
- Projection on lateral surface
- Attachment of inferior fibular retinaculum
- Separates tendons of fibularis longus and brevis
- Groove for fibularis longus (below)
- Groove for fibularis brevis (above)
Retrotrochlear eminence
- Posterior to peroneal tubercle
- Peroneus quartus can insert here (if so it is usually prominent)
Peroneal spine
- Superior to retrotrochlear eminence
- Attachment of calcaneofibular ligament
Anterior calcaneal surface structures
- Articular facet for cuboid
- Anterior process of calcaneus
Articular facet for cuboid
- Articulates with cuboid
- Saddle shaped
- Concave superior to inferior
- Convex medial to lateral
Anterior process of calcaneus
- Junction of anterior, superior and lateral surfaces
- Projects over cuboid
- Visible on lateral radiograph
Inferior calcaneal surface structures
- Calcaneal tubercle (anterior calcaneal tuberosity)
- Calcaneal tuberosity (posterior calcaneal tuberosity)
- Trigonum plantare
- Coronoid fossa
Calcaneal tubercle (anterior calcaneal tuberosity)
- Attachment of short plantar ligament (plantar calcaneocuboid)
Calcaneal tuberosity (posterior calcaneal tuberosity)
- Large inferior projection
- Located posteriorly
- Weight-bearing during gait
- Site of muscle attachment
- Medial tubercle or process (larger than lateral)
- Lateral tubercle or process
Medial tubercle or process (posterior calcaneal tuberosity)
- Site of heel spurs
Trigonum plantare
- Area between calcaneal tubercle and calcaneal tuberosity
- Triangular shaped
- Muscle and ligament attachment
Coronoid fossa
- Between calcaneal tubercle and sustentaculum tali
- Part of spring ligament attaches here
- Beak (coronoid process) of cuboid approximates this fossa
Posterior surface of calcaneus
- Superior 1/3 (Trigonum Achilleum)
- Middle 1/3
- Inferior 1/3
Superior 1/3 (Trigonum Achilleum) of posterior surface of calcaneus
- Smooth
- Deep retrocalcaneal bursa located here
Middle 1/3 of posterior surface of calcaneus
- Rough area
- Achilles tendon insertion
Inferior 1/3 of posterior surface of calcaneus
- Covered by fatty heel pad
- Weight-bearing
Sinus tarsi formed by
- Sulcus tali
- Sulcus calcanei
Attachments in the sinus tarsi
- Extensor digitorum/hallucis brevis
- Intermediate and medial roots of frondiform ligament (stem of inferior extensor retinaculum)
- Cervical ligament
- Bifurcate ligament (calcaneonavicular and calcaneocuboid ligaments)
- Interosseous talocalcaneal ligament
Sinus tarsi
- Trumpet shaped
- Lateral part is wide, medial is narrow
- Lateral opening is immediately anterior to lateral malleolus
Tarsal canal (canalis tarsi)
- Medial end of sinus tarsi
Blood supply of calcaneus
- Medial/lateral calcaneal arteries
- Anastomosis between medial/lateral calcaneal branches
- Arteries of tarsal sinus and tarsal canal
- Lateral tarsal artery
- Medial/lateral plantar arteries
Medial calcaneal arteries
- Branches from lateral plantar and posterior tibial arteries
- Supplies posterior, medial and plantar heel
Lateral calcaneal arteries
- Branches from fibular
- Supplies posterior, lateral, plantar aspect of heel
Anastomosis between medial and lateral calcaneal branches
- Supplies superior posterior calcaneus
Arteries of tarsal sinus and tarsal canal
- Supply anterosuperior calcaneus
Lateral tarsal artery
- Supplies anterolateral calcaneus
Medial and lateral planar arteries
- Supply plantar aspect
