Anatomy of the Popliteus Muscle (*m. popliteus*)
The popliteus muscle (musculus popliteus) is a relatively small yet functionally significant structure of the lower limb.
Attachment points:
- Origin: The muscle originates from the lateral femoral condyle and blends into the knee joint capsule. When studying this topic, students often choose incorrect options in assessments, such as the lateral tibial condyle, medial femoral condyle, or the fibular head. It is crucial to remember the lateral femoral condyle.
- Insertion: Distally, the muscle fibers course toward the posterior surface of the tibia, attaching just superior to the soleus line (linea m. solei).
Functional significance: The action of the popliteus muscle involves flexing the leg. Additionally, it performs internal rotation of the leg. A major biomechanical task is the tensioning of the knee joint capsule during movement, which prevents it from being impinged between the articular surfaces.
Innervation and blood supply: Nerve impulses reach the muscle via branches of the tibial nerve — n. tibialis (nerve roots L₄–S₁). Oxygen and nutrient delivery to the muscle tissue is supplied by the popliteal artery — a. poplitea.
Dorsal Interosseous Muscles (*mm. interossei dorsales*)
When studying the lower limb musculature, the group of dorsal interosseous muscles (musculi interossei dorsales) consisting of four individual muscles is also examined.
Location and structure: These muscles are located in the interosseous spaces on the dorsal aspect of the foot. Structurally, they are bipennate (in multiple-choice questions, they are sometimes confused with unipennate, bipennate-variant, or digastric muscles, which is incorrect).
Attachment points:
- Origin: Each of the four muscles originates from the opposing surfaces of adjacent metatarsal bones, filling the spaces between them.
- Insertion: Distally, the tendons pass to the bases of the proximal phalanges of digits II–IV of the foot and blend into the dorsal aponeurosis.
Functions and Blood Supply of the Interosseous Muscles
The action of the dorsal interosseous muscles of the foot is strictly specialized and directed toward controlling digit positioning.
Biomechanics: The primary function is the abduction of digits II–IV away from the longitudinal axis of the foot (conventionally represented by the axis of the second digit). Furthermore, they play an important role in stabilizing the metatarsophalangeal joints during walking and weight-bearing.
Innervation and blood supply:
- Innervation: Supplied by the lateral plantar nerve — n. plantaris lateralis (segments S₁–S₂).
- Blood supply: Blood is supplied from the plantar arch (arcus plantaris) and the dorsal metatarsal arteries (aa. metatarseae dorsales). In tests, erroneous options such as dorsal digital, plantar metatarsal, or lateral tarsal arteries should be avoided.