Bones and Ligaments of the Foot PDF

Bones and ligaments of the foot.  LEARNING OUTCOMES At the end of this session, the student should be able to: Identify all the bones of the foot[tarsus] by name and position.[ three rows] Describe features of bones of the tarsus Identify the metatarsals and phalanges. Identify th...

Bones and ligaments of the foot.  LEARNING OUTCOMES At the end of this session, the student should be able to: Identify all the bones of the foot[tarsus] by name and position.[ three rows] Describe features of bones of the tarsus Identify the metatarsals and phalanges. Identify the arches of the foot- names and bones through which each arch passes. Bones of the foot Dry bones- dorsiplantar foot  Tarsal bones. Bone type: short bones Bones of the foot are called TARSAL bones. seven in number. Arranged in three(3) rows- proximal, middle and distal. Proximal row: calcaneum and talus Middle : Navicular Distal: Cuneiforms( lateral, intermediate and medial), and cuboid  Arches of the foot Bones of the foot form arches which are supported by tendons and ligaments as follows: - Medial arch …o/c medial longitudinal arch… extends between the calcaneum, navicular and medial cuneiform & 1st. 2nd & 3rd metatarsals. - Lateral longitudinal arch… extends between calcaneum, cuboid, and 4th. & 5th Metatarsals. - Transverse arch…. o/c metatarsal arch Passes through the bases of the five(5) metatarsals.  Arches…..continued Medial longitudinal arch: This is the higher of the two longitudinal arches, and lies on the inside part of the foot. Lateral longitudinal arch: lies along the outer edge of the foot. Transverse arch: extends across the ball of the foot. Only ½ of an arch is present on each foot. To complete the arch, the 2 feet must be placed together.  Ligaments which maintain the arches Plantar-calcaneo- navicular ligament, o/c spring ligament, which is attached to the sustentaculum tali. Long plantar ligament. Both ligaments strengthen/maintain the longitudinal arches.  Bones of the foot Calcaneum: The largest of the tarsal bones, forms the heel. Articulates with the talus above and the cuboid in front. The sustentaculum tali projects medially and gives attachment to a ligament which helps to form the longitudinal arch of the foot. The posterior part of the bone is called the tuberosity and gives attachment to the Achilles tendon. calcaneum  Talus: Interposed between the lower ends of the tibia and fibula above, and the calcaneus. Has three portions: - head anteriorly and faces forward. - Neck, short and narrow and separates the head from the body. - Body, constitutes the greater portion of the bone. Square in cross-section. Dorsal surface is called the trochlea and is covered by hyaline cartilage. The os trigonum is a process which projects backward from the body. talus  Navicular: Disc-shaped bone found on the medial aspect of the foot, separating the proximal and distal rows of tarsal bones. Its proximal surface is concave and articulates with the head of the talus, while its distal surface is convex and has three articulatory facets for the 3 cuneiform bones. Navicular tuberosity projects downward from the medial aspect of the bone and serves as attachment for the tibialis tendon.  CUBOID: This is the most lateral of the distal row of the tarsus. Flattened and has 6 borders. Articulates proximally with the calcaneum, distally with the 4th & 5th metatarsals,and medially with the lateral cuneiform. An oblique groove for attachment of the peroneus longus muscle starts on the lateral surface of the bone and extends on to the plantar aspect of the bone. Sometimes the peroneus longus may contain a sesamoid bone.  Cuneiforms: These are three small bones lying on the medial side of the distal row of tarsal bones. The medial cuneiform is the largest while the intermediate is the smallest. Proximally, they articulate with the navicular and distally, they articulate with the three medial metatarsals.  Metatarsals Five in number. Bone type- long bone. They all have rounded heads with flattened sides. Bases are proximal and heads are distal. All articulating surfaces are covered by hyaline cartilage. Heads articulate with bases of proximal row of phalanges. 1 st. metatarsal sometimes has two sesamoid bones.  PHALANGES Arranged in three rows ( except for great toe which has 2 rows, two phalanges proximal and distal ). Remaining 4 toes have three phalanges ( proximal, middle and distal) which are relatively small and short.