Bones of the lower limb

Bones of the lower limb or ossa membri inferioris just like the upper limb, they are formed by a girdle (cingulum membri) and the skeleton of the free limb (skeleton membri liberi).

The girdle of the lower limb

The plexus of the lower limb is formed by a single bone - the pelvis ( os coxae , which is formed by the union of 3 components connected during development by synchondrosis ) . It is articularly connected to the sacrum, and in the pubic clasp it is connected to the ipsilateral pelvic bone. This creates a closed structure - the pelvis .

Os coxae is made up of 3 bones: hip bone ( os ilium ) , ischial bone ( os ischii ) , pubic bone ( os pubis ) . The cartilaginous boundaries of all 3 bones meet during development in the form of the letter Y in the fossa of the hip joint ( cartilago ypsinoformis ).

Skeleton membri inferioris liberi

Thigh bone ( femur )

The femur is the largest and strongest bone in the human body. It has 4 main parts:

    • Caput femoris - head of the femur, fits into the socket of the acetabulum and is part of the hip joint;
    • Collum femoris - the neck of the femur, connects the head to the body, forms a collodiaphyseal angle with the corpus with an average value of 125°, one of the most common fractures on the lower limb;
    • Corpus femoris - the body of the femur, the longest part of the bone, on the upper side it extends into 2 tufts - trochanter major et minor ;
    • Condyli femoris − on the distal side expands into 2 bumps − epicondylus lateralis et medialis , which are part of the knee joint..

Patella

The patella is considered the sesamoid bone in the insertion tendon of the quadriceps femoris muscle. It has facies articularis, facies anterior and basis and apex patellae . Apex is hidden in leagues. patellae . The patella is palpable along its front surface and along its circumference (through the tendon of  the quadriceps femoris muscle ).

Ossa cruris (leg bones)

This includes the tibia − medially and the fibula − laterally.

Tibia

It is a strong bone, placed medially in front. It is divided into 3 parts:

  • The proximal part - it consists of 2 wide articular bumps - condylus lateralis et medialis , both of which bear at their proximal end articular surfaces ( facies articularis superior ) for contact with the condyles of the femur
  • The body of the tibia ( corpus tibiae ) − strong, triangular
  • The distal part - extends into the inner ankle - malleolus medialis

On the front side, between the condyles, there is a massive roughness - tuberositas tibiae , where the tendon of the quadriceps femoris muscle - lig. patellae .

Calf bone ( fibula )

The fibula is a thin bone, located laterally and posteriorly. It cannot be said that it has a direct load-bearing function, it serves mainly as a place of muscle beginnings (e.g. mm.  fibulares). It again has 3 parts:

  • Caput fibullae − the head of the fibula bone, carries the articular surface for connection with the tibia, just below it is the collum fibullae , the biceps femoris muscle  is attached to the head ;
  • Corpus fibullae − has 4 edges − anterior, posterior, internal and ventromedial;
  • Malleolus lateralis (outer ankle) − extends further distally than the inner ankle, it is connected to the tibia by a syndesmosis complete with an articular cleft.

Leg bones (ossa pedis)

Tarsal bones ( ossa tarsi )  

There are 7 metatarsal bones forming the tarsus pedis :

  • Ankle bone (talus) - articulated with the bones of the lower leg, its parts are trochlea, collum, caput (articular surface for articulation with os naviculare), processus posterior - extends backwards, there is a groove called sulcus tendinis musculi flexoris hallucis longi;
  • The heel bone (calcaneus) - the largest, anteroposteriorly elongated bone of the instep, has 3 articular surfaces on the dorsal side of the bone - facies articularis talaris anterior, media, posterior , sustentaculum tali - a protrusion of the heel bone supporting the talus, the other parts are the tuber calcanei (a conspicuous structure, clamps with the tendon of the triceps muscle − Achilles tendon ) and facies articularis cuboidea ;
  • Navicular bone (os naviculare) - proximally the articular surface for the caput tali, distally 3 triangular surfaces for the ossa cuneiformia, there is a noticeable roughness - tuberositas navicularis, which is palpable in the living;
  • Cuboid bone (os cuboideum) − irregular shape, proximally it has a wavy curved articular surface for connection with the calcaneus, distally articular surfaces for metatarsal axis IV and V and medially articular surface for connection with the external sphenoid bone;
  • Cuneiform bones (ossa cuneiformia) - there are three: os cuneiforme mediale (the largest), intermedium and lateral.

In the assembly of the metatarsal bones, we find 2 proximodistal stripes :

  •   In the assembly of the bones of the metatarsals we find
    • internal − talus − os naviculare − 3 ossa cuneiformia − 3 ossa metatarsalia
    • outer − calcaneus − os cuboideum − 2 ossa metatarsalia

Metatarsal bones ( ossa metatarsi )  

These are 5 metatarsal bones ( os metatarsale ), designated by the Roman IV. Each has 3 parts − basis, corpus, caput . Together they form the metatarsus of the foot (instep). They are similar in structure, development and ossification to the metacarpus of the hand.  



Bones of the toes ( ossa digitorum pedis )  

  The skeleton of the fingers is formed by the phalanges digitorum pedis . Each finger has 3 joints − phalanx proximalis, media et distalis , the exception is the thumb, which has two joints (it does not have a phalanx media). Each article can again be divided into 3 parts - basis, corpus, caput .  



References

  • ČIHÁK, Radomír – GRIM, Miloš. Anatomie. 2., uprav. a dopl edition. Praha : Grada Publishing, 2002. 470 pp. vol. 1. pp. 253-272. ISBN 80-7169-970-5.