Ossos dos Membros Inferiores: Sistema Esquelético 4/5 | Anatomia etc
Overview of Lower Limb Bones
Introduction to the Lesson
- The lesson focuses on a detailed examination of the bones that comprise the lower limbs.
- It is part of a broader playlist discussing the skeletal system, encouraging viewers to explore other related lessons.
Hip Bone Structure
- The hip bone, also known as the ilium, consists of three individual bones: ilium, pubis, and ischium.
- Each hip bone (ilium) is formed by these three components:
- Ilium (the largest bone),
- Pubis (anterior),
- Ischium (posterior).
Thigh and Knee Bones
- The primary bone in the thigh is the femur, which articulates with the ilium at its rounded head. This makes it the longest bone in the body.
- The patella serves as a sesamoid bone located within a tendon associated with quadriceps muscles; it is noted as the largest sesamoid bone in humans.
Leg Bone Composition
- In contrast to the thigh's single femur, the leg comprises two bones: tibia and fibula.
- Tibia:
- Located medially,
- Larger and thicker.
- Fibula:
- Positioned laterally,
- Thinner than tibia; mnemonic: "fibula is fine and outside."
Foot Bone Structure
Overview of Foot Bones
- The foot contains a total of 26 bones divided into three categories:
- Tarsal bones (7),
- Metatarsal bones (5),
- Phalanges (14).
Tarsal Bones Details
- Tarsals include:
- Talus: superior tarsal that articulates with tibia at ankle,
- Calcaneus: largest tarsal forming heel,
- Navicular: flattened anteriorly to talus,
- Three cuneiform bones named medial, intermediate, and lateral based on their position relative to midline.
Metatarsals and Phalanges
- Five metatarsals are identified by their location from big toe (hallux) outward.
(1st metatarsal = hallux; up to 5th for little toe).
- Each toe has phalanges:
Anatomy of the Foot and Lower Limb
Structure of Phalanges
- The foot contains three types of phalanges: proximal, middle, and distal, except for the hallux (big toe), which has only two phalanges: proximal and distal.
Regions of the Foot
- The bones in the foot are categorized into regions:
- Rearfoot: Contains the talus and calcaneus.
- Midfoot: Comprises the navicular, cuneiforms, and cuboid.
- Forefoot: Includes metatarsals and phalanges. Below the head of the first metatarsal are two small sesamoid bones.
Composition of Lower Limb Bones
- The lower limb consists of:
- Pelvic Girdle: Formed by two ilium bones; each ilium is made up of three parts: ilium, pubis, and ischium.
- Thigh: Contains a single bone called the femur.
- Leg: Composed of two bones—tibia (thicker and medial) and fibula (thinner and lateral). The knee also features a large sesamoid bone known as the patella.
Tarsal Bones in Detail
- The tarsal bones include:
- Talus
- Calcaneus
- Navicular
- Three cuneiforms (medial, intermediate, lateral)
- Cuboid
- There are five metatarsals numbered from one to five starting with the hallux. Each toe (except for hallux) has three phalanges. Additionally, there are medial and lateral sesamoid bones beneath the first metatarsal head.
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