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GROSS ANATOMY
LOWER LIMB
INSTRUCTOR: DR. BUENSALIDA, DR. DANGOY, DR. DELISO
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OVERVIEW
Primary functions: ● Support the weight of the body ● Produce locomotion Lower limbs are very stable Can bear the weight of body because:
- Two hip bones articulate posteriorly with the trunk at the strong sacroiliac joints
- Anteriorly with each other at symphysis pubis This stability provides the foundation for standing in upright posture, walking and running ● Each lower limb is organized into:
- Gluteal region
- Thigh
- Popliteal fossa
- Leg
- Ankle
- Foot → Thigh and leg are compartmentalized Some of many conditions physician encounters: ● Arthritis, varicose veins, vascular deficiencies, fractures, dislocations, sprains, lacerations, knee effusions, leg pain, ankle injuries, peripheral nerve injuries
OSTEOLOGY
Bones of the lower limb are:
- Os coxae (hip bone)
- Femur
- Patella
- Tibia
- Fibula
- Metatarsal bones
- Tarsal bones
- Phalanges
OS COXAE
“Hip bone” is equivalent of the upper limb clavicle and scapula ● Forms the lower limb girdle that attaches the limb to the vertebral column Three skeletal elements form the os coxae:
- Ilium
- Ischium
- Pubis ● These bones meet one another at the acetabulum via the Y-shaped triradiate cartilage → Articulates with the sacrum at the sacroiliac joints and form the anterolateral walls of the pelvis
→ Also articulates with one another anteriorly at the symphysis pubis Ilium - upper flattened part of the bone, possesses the iliac crest ● Can be felt through the skin along its entire length ● Ends in front at the anterosuperior or iliac spine, behind at the posterosuperior iliac spine Iliac tubercle - lies about 2 in. (5 cm) behind the anterosuperior spine ● Below the anterosuperior iliac spine is a prominence: anteroinferior iliac spine ● A similar prominence, the posteroinferior iliac spine is located below the posterosuperior iliac spine The ilium possesses a large notch: greater sciatic notch , above and behind acetabulum Ischium- L-shaped possessing an upper part ( body ) , and a lower thinner part ( ramus ) Ischial spine - projects from the posterior border of the ischium and intervenes between the greater and lesser sciatic notches Ischial tuberosity - large roughened area that forms the posterior aspect of the lower part of the body of the bone ● The greater and lesser sciatic notches are converted into greater and lesser sciatic foramina by the presence of: sacrospinous and sacrotuberous ligaments Pubis- divided into: ● body, superior ramus, & inferior ramus → bodies of two pubic bones articulate with each other in the midline anteriorly at the symphysis pubis → superior ramus joins the ilium and ischium at the acetabulum, inferior ramus joins the ischial ramus below obturator foramen
Greater and lesser trochanters - large eminences situated at the junction of the neck and the shaft Intertrochanteric line - connects the trochanters anteriorly, where the iliofemoral ligament attaches ● A prominent intertrochanteric crest connects the trochanters posteriorly Shaft - smooth and rounded on its anterior surface but posteriorly has a ridge, the linea aspera (which are attached muscles and intermuscular septa) ● Medial margin: continues below as the medial supracondylar ridge to the adductor tubercle on the medial condyle ● Lateral margin: becomes continuous below with the lateral supracondylar ridge Gluteal tuberosity- is on the posterior surface of the shaft below the greater trochanter Popliteal surface - shaft becomes broader toward its distal end and forms a flat, triangular area on its posterior surface ● The lower end of the femur has lateral and medial condyles , separated posteriorly by the intercondylar notch ● The anterior surfaces of the condyles are joined by an articular surface for the patella → The two condyles take part in the formation of the knee joint ● The medial and lateral epicondyles are above the condyles Adductor tubercle - continuous with the medial epicondyle
PATELLA
“Kneecap”- LARGEST sesamoid bone (i.e., it develops within the tendon of the quadriceps femoris muscle in front of the knee joint). ● triangular, and its apex lies inferiorly Apex - connected to the tuberosity of the tibia by the ligamentum patellae (patellar ligament) ● Posterior surface articulates with the condyles of the femur → Patella is situated in an exposed position in front of the knee joint and is easily palpable through the skin
Prepatellar bursa- important subcutaneous bursa that separates patella from the skin ● The upper, lateral, and medial margins give attachment to the different parts of the quadriceps femoris muscle
TIBIA
Large weight-bearing medial bone of the leg ● Articulates with: the condyles of the femur and the head of the fibula above and with the talus and the distal end of the fibula below ● Has an expanded upper end, a smaller lower end, and a shaft. The lateral and medial condyles (sometimes called lateral and medial tibial plateaus ) are at the upper end. ● Articulates with: the lateral and medial condyles of the femur and the intervening lateral and medial menisci Anterior and posterior intercondylar areas separate the upper articular surfaces of the tibial condyles ● intercondylar eminence lies between these areas
Malleolar fossa - a depression that lies below and behind the articular facet Important muscles and ligaments attached to the fibula: Figs 11.7 and 11. FOOT BONES Bones of the foot are: tarsal bones, metatarsals, and the phalanges ● General groupings are similar to that of the carpals, metacarpals, and phalanges in the wrist and hand
TARSAL BONES
The calcaneum , the talus , the navicular , the cuboid , and the three cuneiform bones ● Only the talus articulates with the tibia and the fibula at the ankle joint ● The tarsal bones, unlike those of the carpus, start to ossify before birth. Centers of ossification for the calcaneum and the talus, and often for the cuboid, are present at birth. ● Ossification takes place in all the tarsal bones by the 5th year. CALCANEUM
- Largest bone of foot
- Forms the prominence of the heel
- Articulates above with the talus and in front with the cuboid
- Has six surfaces
Anterior surface: small and forms the articular facet that articulates with the cuboid bone Posterior surface: forms the prominence of the heel and gives attachment to the tendo calcaneus (Achilles tendon) ● Two articular facets for the talus, separated by a roughened groove: the sulcus calcanei , dominate the superior surface Inferior surface: has an anterior tubercle in the midline and a large medial and a smaller lateral tubercle at the junction of the inferior and posterior surfaces Medial surface: possesses a large, shelflike process
- termed the sustentaculum tali , which assists in the support of the talus Lateral surface: is almost flat. - Its anterior part has a small elevation called the peroneal tubercle , which separates the tendons of the fibularis longus and brevis muscles Important muscles and ligaments attached to the calcaneum: Figs 11.10 and 11. TALUS - Articulates above at the ankle joint with the tibia and fibula, below with the calcaneum, and in front with the navicular bone - Possesses a head, a neck, and a body ● Numerous important ligaments attach to the talus, but NO muscles attach to this bone Head : directed distally and has an oval convex articular surface for articulation with the navicular bone - Articular surface is continued on its inferior surface, where it rests on the sustentaculum tali behind and the calcaneonavicular ligament in front Neck : lies posterior to the head and is slightly narrowed - Its upper surface is roughened and gives attachment to ligaments ● Sulcus tali - deep groove on its lower surface ● Sinus tarsi -tunnel form by the sulcus tali and sulcus calcanei in the articulated foot
