abdomen

The abdomen is one of the major regions of the body, being the hollow part of the trunk below the diaphragm.
It is continuous below with the pelvis (the two are often spoken of as the abdomino-pelvic cavity). The abdomen is largely bounded by a muscular (rather than a bony) wall. This means that its shape can vary within the same individual much more than (for example) the thorax, and the abdomen alters with distension of the alimentary canal, with breathing movements and (most spectacularly) with pregnancy.

The major organs inside the abdomen include the stomach, small and large intestine, liver, pancreas, kidneys and spleen.

Flexor muscles of the hip (psoas major and iliacus) have their origins inside the abdomen, as do nerves arising from the lumbar plexus such as the femoral and obturator nerves.

adductor

A muscle which moves one part of the body towards another or towards the midline of the body.

bursa

(pl bursae) A fluid filled sac or cavity lined by synovial membrane and filled with synovial fluid

bursitis

Repetitive movement may inflame and enlarge bursae (bursitis). The best known is "housemaid's knee" (inflamation of the prepatellar bursa). Clergymen who spend long periods on their knees (but in a more upright position) might inflame the infrapatellar bursae.

collateral ligament

Stability is achieved at mobile joints such as those of the limbs by one or more of the following factors
bony fit
the surrounding muscle mass
ligaments which include the joint capsule and its specialised thickenings
Collateral ligaments occur at the sides of joints and they are typical of hinge joints such as the knee and ankle. Here they give stability and prevent excessive or inappropriate movement without impeding the normal movement of the joint.

concave

hollow, rounded inwards
cf convex - rounded, curved outwards

condyle

a rounded protuberance found at the end of some bones forming an articulation with another bone.
eg the femoral condyles form the femoral component of the knee joint articulating with the the tibia.

convex

concave - rounded, curved outward
cf convex - hollow, rounded inwards

deltoid ligament

This is the medial collateral ligament of the ankle joint.
It is triangular in shape (like the greek letter delta). It is attached proximally to the medial malleolus and radiates out to be attached distally to the tuberosity of the navicular, the sustentaculum tali of the calcaneus , the spring ligament and to parts of the talus including its neck.

The deltoid ligament forms (with the spring ligament) a right-angle bracket to support the head of the talus.

dorsiflexion

Dorsiflexion (= extension) of the foot is one of the movements that occurs at the ankle joint, the other being plantar flexion (= flexion). Dorsiflexion is brought about by muscles whose tendons run into the foot anterior to the ankle joint - such as tibialis anterior, extensor digitorum longus and extensor hallucis longus.
Dorsiflexion pushes the talus backwards into the mortice of the ankle joint which therefore becomes progressively locked. Dorsiflexion is, therefore, a more limited movement than plantar flexion which moves the talus forwards and thus frees it.

dynamics

Dynamics is the study of the unbalanced forces and moments acting on a body which result in acceleration or deceleration of the body.

extension is a movement at a limb joint which brings dorsal (posterior) surfaces closer together.
For the lower limb, it is seen at its simplest at the hip joint:
here extension moves the limb backwards.

extension at other lower limb joints is more complex because (during embryological development) the limb undergoes torsion - otherwise you would stand on the backs of your feet rather than the soles! Thus, extension at the knee moves the limb forwards (e.g. as in kicking).
Similarly extension at the ankle is a movement in which the foot points upwards (NB The ankle presents additional complications in that extension is often called dorsiflexion).

femoral artery

This is a continuation of the external iliac artery. It enters the femoral triangle of the front of the thigh by passing behind the inguinal ligament.
Together with the femoral vein it lies anterior to psoas major and is initially contained within the fibrous femoral sheath.

Within the femoral triangle it gives off a number of small branches ( variable, but usually including superficial external pudendal, superficial epigastric and superficial circumflex iliac arteries) as well as the large and important profunda femoris which is the main artery of the thigh.

The femoral artery can be felt (and sometimes seen) as a pulse at the top of the thigh at the mid-inguinal point. The artery is very superficial at this point and therefore may be damaged in traumatic inujury. It can be compressed by hand against psoas and the hip bone to control bleeding from further down the limb.

The femoral artery leaves the femoral triangle to enter the adductor (subsartorial) canal in company with the femoral vein and saphenous nerve. At the lower end of the canal the two vessels pass backwards through a tendinous opening in adductor magnus to enter the popliteal fossa.

In entering the lower limb at the front, but passing progressively posteriorly to lie behind the knee joint, the femoral artery is subjected to the least possible stretching from movements of the hip and knee.

femoral nerve

This is one of the largest branches of the lumbar plexus and arises from the ventral primary rami of L2,3,4. It enters the thigh behind the inguinal ligament and almost immediately splits up into its terminal branches. Its distribution is :
Muscular branches to the quadriceps, sartorius, pectineus and gracilis .
Cutaneous branches to the front of the thigh via

femoral ring

This is the proximal opening into the femoral canal, the expansion space on the medial side of the femoral vein as the vessel enters the thigh enclosed within the femoral sheath.
The femoral ring is bounded anteriorly by the inguinal ligament, medially by the lacunar ligament, posteriorly by the pecten of the pubic bone and the pectineus muscle, and laterally by the femoral vein.

The femoral ring is a weakness of the abdominal wall and hence a potential site of hernia for a viscus and peritoneal sac. If the herniation remains within the canal it is termed an "incomplete" femoral hernia. Any herniation which travels the length of the canal and escapes from its distal end (a "complete" hernia) tends to turn upwards and laterally.

Femoral hernias are commoner in women than men. Women have larger femoral rings and tend to have smaller femoral veins; moreover they have wider pelvic cavities and periods of excess pressure on abdomino-pelvic viscera (e.g. during pregnancy).

femoral sheath

This fibrous sheath is a downward continuation of fascia lining the abdomino-pelvic cavity, viz. transversalis and iliac fascia. It is absent at birth, but forms with the adoption of an upright stance and with limb growth, as these fascias are gradually pulled down into the thigh. It is eventually about an inch long.
The sheath surrounds the femoral artery and vein and is pierced by a) numerous small branches of these vessels which arise in the groin and b) the long saphenous vein.

The femoral sheath does not enclose the femoral nerve which lies lateral to it. However, it does contain the small femoral branch of the genitofemoral nerve.

The clinical importance of the sheath is that it contains extra space within it on the medial side for expansion of the femoral vein (as occurs, for example, in pregnancy where the expanded uterus presses on the blood vessels within the pelvis and slows venous return). This space - the femoral canal - is a weakness of the abdominal wall and hence a potential site of hernia.

The herniating viscus and peritoneal sac enters the canal through its proximal opening the femoral ring Any mobile viscus which travels the length of the canal and escapes from its distal end tends to turn back upwards and laterally.

Femoral hernias are commoner in women than men.

femoral triangle

This is a triangular area at the top and front of the thigh whose boundaries are i) the inguinal ligament, ii) the medial border of sartorius and iii) the medial border of adductor longus.
The floor of the triangle is formed from the muscles adductor longus and pectineus (which are adductors of the hip joint) and iliopsoas (the merged iliacus and psoas muscles, flexors of the hip joint).

The main contents of the femoral triangle include the femoral artery and vein - both of which are initially surrounded by the femoral sheath, a condensation of fascia - and the femoral nerve. The nerve and vessels enter the thigh by passing behind the inguinal ligament.

flexor digitorum longus

As its name suggests, this muscle flexes the toes (with the exception of the big toe) i.e. it makes them point down. It has its origin from the back of the shaft of the tibia and its tendon passes around the lower end of the medial malleolus before entering the sole of the foot and splitting into four tendons. Each tendon inserts into the terminal phalanx of a small toe. It is supplied by the tibial nerve.

foot drop

Foot drop is the inability to raise (dorsiflex/extend) the foot at the ankle joint so that, in walking, the toes drag on the ground.
Foot drop is often the result of damage to the common peroneal nerve (or its terminal branches) which innervates the muscles on the front of the leg and which is vulnerable where it passes superficially around the neck of the fibula.

gastrocnemius

The gastrocnemius is the most superficial of the calf muscles and is the only important one to arise above the knee by a head from each femoral condyle. The heads also blend with the back of the knee joint capsule.
The tendon of gastrocnemius forms part of the tendo calcaneus (Achilles tendon) which inserts into the posterior surface of the calcaneus (the heel bone).

The muscle receives its nerve supply via the tibial nerve.

Gastrocnemius, like other calf muscles, is a) a plantar flexor (= flexor) of the foot, necessary to give power at the "push off" phase of walking and b) an important "anti-gravity" muscle. Gravity passes in front of the ankle joint, but falling forwards is resisted by the calf muscles.

Gastrocnemius is also involved in the "calf pump" mechanism which assists venous return from the lower limb by compressing deep veins.

inferior

This is a general anatomical term of direction or position. It is the equivalent of below or downwards as in:

the femoral artery passes inferiorly (i.e. downwards) from the femoral triangle into the adductor canal
the tibia is inferior to (i.e. below) the femur
terminal branches of the tibial nerve supply skin over the inferior surface of the foot (i.e. its undersurface or sole).
It is the opposite of the term "superior" meaning above or upwards.

However, with structures such as limbs, which can alter their shape and position quite markedly (for example, the upper limb can hang down at the side or be held straight up in the air), it has become useful to use a different pair of words - proximal and distal. Proximal means nearer the trunk of the body and distal means further away from the trunk. Thus distally and distal could more readily be substituted for the terms inferiorly and inferior in sentences 1) and 2).

inferior gluteal nerve

The inferior gluteal nerve (L5, S1 - 2) passes through the greater sciatic foramen of the pelvic girdle and supplies the muscle gluteus maximus, a powerful extensor of the hip joint.

inguinal ligament

This ligament passes between two bony points of the hip bone, the anterior superior iliac spine laterally and the pubic tubercle medially. It has an expanded medial end, the lacunar ligament.
The inguinal ligament is the thickened, recurved free inferior border of the external oblique muscle. It forms the floor of the inguinal canal along which passes the spermatic cord in the male or the round ligament of the uterus in the female.

The femoral artery and vein, femoral nerve and lateral cutaneous nerve of the thigh pass behind the inguinal ligament to enter the femoral triangle of the thigh.

interosseus membrane

This is a tough fibrous membrane which runs between the interosseous borders of the tibia and fibula.

It serves to bind the bones together
to separate the flexor and extensor muscles of the leg (otherwise they would pull against one another and this would be highly inefficient)
to provide extra surface area for the origin of leg muscles.
Blood vessels pass from the back of the leg to the front i) above the top of the interosseous membrane (anterior tibial vessels) and ii) through a perforation in the lower part of the membrane (perforating branches of the peroneal vessels).
The thickest distal part of the membrane is one of the factors that binds the tibia and fibula together where they form the mortice of the ankle joint. This part of the membrane is said to form the interosseous ligament of the tibio-fibular syndesmosis.

intrinsic

In anatomy, this usually means "contained within" and is the opposite of extrinsic. Thus, the toes can be moved by powerful muscles which arise just below the knee and which enter the foot simply as long tendons (extrinsic muscles of the foot such as flexor digitorum longus) or by much smaller muscles which arise within the foot itself (intrinsic muscles of the foot such as flexor digitorum brevis).

In the upper limb, extrinsic muscles are responsible for powerful, crude grasping ("making a fist" - the power grip) while intrinsic muscles permit delicate finger and thumb grips (the precision grip). Alas, in the foot most of us have lost the latter facility.

kinematics

Kinematics is the mechanical description of the movement of the body. (Ussually in terms of angles and positions)

kinetics

Kinetics is the mechanical description of the action of forces on the body.

knee

This is the hinge joint between the thigh and the leg.
There articulations between the lower end of the femur and the top of the tibia and between the patella and the femur.

lateral cutaneous nerve of thigh

lateral cutaneous nerve of the thigh This nerve arises from the lumbar plexus (L2,3) and passes into the thigh behind the most lateral part of the inguinal ligament. As its name suggests, it supplies skin over the lateral part of the thigh. It can be compressed as it enters the thigh

by repeated movements while the hip is flexed (miners working in low tunnels suffered from this)
again, historically, by the wearing of unnaturally tight clothes e.g. corsets
by strenuous activities demanding much hip flexion such as hillwalking and climbing.

leg

The part of the lower limb from the knee to the foot

ligament

A band of fibrous connective tissue that links bones or cartilage together.
Ligaments are inelastic but flexible. They serve both to strengthen a joint and constrain its range of movement.

linea aspera

A small area at the back of the femur (the rest ofthe surface of the femur serves as an attachment for the quadriceps muscle group) which is used for the attachment of muscle groups such as the adductors.
biceps femoris has a second origin from the linea aspera.

longitudinal

This descriptive term is best understood as "running lengthwise" or "along the length of". Thus, the longitudinal arches of the foot are arranged from heel to toe as opposed to the transverse arch which runs from side to side of the foot.

malleolus

The medial and lateral malleoli are the bony bumps which can be readily felt on either side of the ankle. The medial malleolus is part of the tibia, while the lateral malleolus (which is slightly lower) is part of the fibula.
Each malleolus forms part of the mortice of the ankle joint and each is an attachment for collateral ligaments associated with the ankle.

The long saphenous vein passes just anterior to the medial malleolus, and knowledge of this unusually constant position for a superficial vein can be used to make a "cut down" (e.g. for a drip).

metatarsal

Any of the five bones forming the metatarsus.

moment

The application of a force about a joint or pivot point results in a moment about the joint.
A moment is the product of force (the component of the force acting tangentially to the joint centre) with distance (the distance from the joint centre to the line of action of the force).

Moments are expressed in Newton metres (Nm).

navicular

A bone of the ankle which articulates with the three cuniform bones anteriorly and the talus posteriorly.

peripheral nerve

A nerve lying outside the central nervous system.

peroneal nerve

The common peroneal nerve (L4-S2) is one of the two terminal divisions of the sciatic nerve (the other being the tibial nerve). The site of splitting of the sciatic nerve is quite variable, but is most commonly at mis-thigh.
The common peroneal nerve runs laterally along the medial border of biceps femoris to cross the top of the popliteal fossa and leave at its lateral angle. The common peroneal nerve winds around the neck of the fibula - where it is extremely superficial and hence vulnerable - before splitting up into two branches, the superficial and deep peroneal nerves.

The superficial peroneal nerve supplies the peroneal muscles peroneus longus and brevis which are evertors of the foot.

The deep peroneal nerve continues into the extensor compartment and supplies extensor digitorum longus, extensor hallucis longus and tibialis anterior

peroneus brevis

The tendon of peroneus brevis passes into the foot posterior to the ankle joint hence it is a plantar flexor of the ankle.

peroneus longus

The tendon of peroneus longus passes into the foot posterior to the ankle joint hence it is a plantar flexor of the ankle.

plantar flexion

Plantar flexion (= flexion) of the foot is one of the movements that occurs at the ankle joint, the other being dorsiflexion (= extension). Plantar flexion is brought about by muscles whose tendons run into the foot posterior to the ankle joint - such as tibialis posterior, flexor digitorum longus, peroneus longus and peroneus brevis.
Plantar flexion moves the talus forwards thus freeing it nad resulting in a greater range of movement compared with dorsiflexion which tends to lock the talus into the mortice of the ankle joint.

plantaris

Plantaris is a small calf muscle with a thin, extremely long tendon which forms part of the tendo calcaneus (Achilles tendon) which inserts into the posterior surface of the calcaneus (heel bone).
It arises from the lateral supracondylar line of the femur.

It is supplied by the tibial nerve.

Realistically, it can have little function in man, being the vestige of a large muscle in lower animals which inserts into the plantar aponeurosis. Its long tendon a) is sometimes used for tendon grafts b) sometimes breaks causing a brief sharp pain in the calf.

poliomyelitis

An infectious virus disease affecting the central nervous system.
The disease may result in both temporary and lasting paralysis.

Immunisation is highly effective.

quadriceps

The quadriceps (= 4 heads) is the muscle of the front of the thigh.
It consists of:
three muscles which arise from the shaft of the femur - vastus medialis, intermedius and lateralis. One muscle - the rectus femoris - which arises from the anterior inferior iliac spine and the adjacent area of the hip bone just above the acetabulum.
These four heads unite in a common tendon which inserts onto the tibial tuberosity. This tendon contains the patella (knee-cap) which is an example of a sesamoid bone - one which keeps a tendon clear of an articulating area.

The quadriceps is supplied by the femoral nerve.

rectus femoris

Rectus femoris is one part of the quadriceps (= 4 heads) muscle on the front of the thigh - the other three parts being the vastus medialis, intermedius and lateralis.
Rectus femoris arises from the anterior inferior iliac spine and the adjacent area of the hip bone just above the acetabulum. It and the other three heads unite in a common tendon which inserts onto the tibial tuberosity. This tendon contains the patella (knee-cap) which is an example of a sesamoid bone - one which keeps a tendon clear of an articulating area.

The quadriceps is supplied by the femoral nerve.

semimembranosus

This is one of the three hamstring muscles (the others being semitendinosus and biceps femoris). It has its origin from the ischial tuberosity and is inserted into the medial surface of the tibia just below the knee.
The hamstrings can flex the knee and (when the knee is flexed) medially rotate the leg. Acting from below, the hamstrings can extend the hip joint. Semimembranosus is supplied by the sciatic nerve.

semitendinosus

This is one of the three hamstring muscles (the others being semimembranosus and biceps femoris). It has its origin from the ischial tuberosity and is inserted into the medial surface of the tibia just below the knee.

The hamstrings can flex the knee and (when the knee is flexed) medially rotate the leg. Acting from below, the hamstrings can extend the hip joint. Semitendinosus is supplied by the sciatic nerve.

sesamoid bone

A sesamoid bone is one which is located inside a tendon.
The largest and best known is the patella (knee-cap) which lies within the tendon of the quadriceps group of muscles. Sesamoid bones help keep tendons clear of the moving parts of a joint and increase the mechanical efficiency of muscle action.

soleus

The soleus muscle is one of the two major superficial calf muscles (the other being gastrocnemius). It arises from the proximal parts of the posterior surfaces of both the fibula and tibia (there is a marked ridge - the soleal line - on the latter).
The tendon of soleus blends with that of gastrocnemius as the Achilles tendon to attach to the posterior surface of the calcaneus .

The soleus is a powerful anti-gravity muscle. Firstly, it powerfully plantar flexes the foot (e.g. as in standing on tip-toe); secondly it resists the tendency to fall forwards at the ankle when standing upright due to the centre of gravity of the body falling on a vertical line some two inches in front of the ankle. Its contractions are also important in assisting venous return from the leg and foot against gravity - "the calf pump".

Soleus is supplied by the tibial nerve.

statics

Statics is the study of the forces and moments acting on a body in equilibrium.
In accordance with Newton's first law of motion, a body is in equilibrium when no unbalanced forces act on it.

i.e. at rest or moving at a constant velocity

strap muscle

Muscles have their fibres arranged in a variety of ways which determine (amongst other characteristics) their power. Strap muscles are long compared to their width, and the fibres which make them up are arranged parallel to their line of pull. This means that the full advantage of contraction is available and maximum range of movement is achieved.
Examples of strap muscles in the lower limb include sartorius (the longest muscle in the body) and gracilis .

superficial

This is a term of position or movement meaning near (or nearer) to the surface. It is the opposite of deep.

Thus :-
The long saphenous vein drains superficial (i.e. surface) areas of the limb
adductor longus lies superficial to (i.e. nearer the surface than) adductor brevis.

superior

A term of relationship.
Three pairs of relative terms are used to express the relationship of one structure to another:

anterior - nearer the front surface of the body
posterior - nearer the back surface of the body

superior - nearer the crown of the head
inferior - nearer the soles of the feet

medial - nearer the median plane of the body
lateral - further from the median plabe of the body
NB The body is assumed to be in the anatomical position

superior gluteal nerve

This nerve originates from L4,5 and S1 in the lumbrosacral plexus emerging from the plevis above piriformis.
It innervates gluteus medius, gluteus minimus, and tensor fascia latae.

surface motion

There are three kinds of surface motion at a joint.
rotating
rolling
gliding (or translation)

synovial fluid

Synovial fluid is found in the interior of synovial joints where it aids mobility by lubricating the articulating surfaces.
It is essentially a dialysate of blood from fenestrated capillaries in the synovial membrane which covers all the non-articulating surfaces within the joint:
as this dialysate passes through the synovial membrane to be released into the joint cavity it is supplemented by products of the B-cells within the membrane - notably hyaluronic acid. These products give synovial fluid its THIXOTROPIC property i.e. that its viscosity alters according to the shearing forces applied to it.

Thus, in the resting joint synovial fluid is a clear gel-like substance (synovium = egg white) but as the joint becomes mobile, synovial fluid becomes thin and aqueous.

Inflammation of joints may result in overproduction of synovial fluid (e.g. "water on the knee").

synovial joint

All the major joints of the limbs (e.g. the hip, knee and ankle) are synovial joints.

Synovial joints have the following characteristics
They possess a fibrous sleeve or capsule. Many capsules have specialised thickenings - ligaments - which prevent excessive or inappropriate movement.
They contain synovial fluid which helps to lubricate the articulating surfaces. Synovial fluid is essentially a dialysate of blood with added ingredients such as hyaluronic acid which give the fluid its thixotropic properties i.e. it is gel-like at rest but becomes aqueous during movement as shearing forces are applied to it. The fluid is produced by the synovial membrane lining the capsule and covering every surface inside the joint except for
Articulating surface. These are usually bone ends which are covered in articular (hyaline) cartilage , the remnants of the cartilage models from which limb bones develop. cartilage is much more resilient than bone.
Synovial joints are generally highly mobile. Mobility is inversely related to stability, so that synovial joints are also potentially unstable (capable of dislocation, likely to fold up etc). Stability is conferred on synovial joints by one of three factors a) the bony fit (excellent for the hip and ankle, poor for the knee) b) the strength of the capsule and its specialised thickenings and c) the surrounding muscle mass.

talus

The talus is one of the tarsal bones. It is extremely complex and takes part in several joints. It lies underneath the lower ends of the tibia and fibula and its trochlear (upper) surface articulates with them to form the ankle joint at which dorsiflexion and plantar flexion of the foot occur.

The head of the talus forms an articulation with the posterior surface of the navicular, the anterior part of the calcaneus and the plantar calcaneonavicular ("spring") ligament to form the talocalcaneonavicular joint. Furthermore, there is a joint between the undersurface of the talus and a facet on the upper surface of the calcaneus - the subtalar joint .

It is the talocalcaneonavicular and subtalar joints which are especially involved in inversion and eversion movements of the foot.

tarsus

The tarsus consists of the seven bones of the posterior half of the foot. These are the talus, calcaneus , navicular, cuboid and the medial, intermediate and lateral cuneiforms.
The talus lies above the calcaneus and the navicular and is the only one to articulate with the crural bones (the bones of the leg - tibia and fibula) thus forming the ankle joint. The calcaneus or heel-bone lies most posteriorly and the cuneiforms most anteriorly.

The tarsal bones are the homologues of the carpal bones, the small bones of the wrist. However, the tarsal bones are far more massive, as befits their role in supporting the weight of the body. Whilst the tarsal bones are highly irregular, the shape of each is approximately cuboidal i.e. having six surfaces.

tendon

A fibrous cord composed of numerous parallel bundles of collagen fibres that froms the attachment of muscle to bone.
Like ligaments tendons are inelastic but flexible and serve to concentrate the pull of a muscle on a small area of attachment.

tensor fasciae latae

Tensor fasciae latae is a short muscle which arises from the iliac crest and passes downwards to be inserted into the iliotibial tract (in fact the upper part of the tract splits to enclose it).

Its functions are poorly understood; it has been said to
Flex and medially rotate the hip joint
Extend the knee and brace the whole lower limb via the iliotibial tract (which gluteus maximus also inserts into). The tract is seen as their long "tendon".
Most recently it has been considered as another abductor of the hip joint. The fact that its nerve supply (the superior gluteal nerve) is shared with the other abductors gluteus medius and gluteus minimus may be significant.

tibia

The tibia is the shin bone, one of the two crural bones of the leg. (Tibia = a flute, because it can be used as such with the ends cut off and holes drilled into it).

It is much stronger and more massive than the other crural bone, the fibula. Its shaft is approximately triangular in cross section and its anterior border and medial surface can be readily felt just below the skin at the front of the leg; this is why a kick on the shins is especially painful since there is little depth of soft tissue to absorb the injury.

The tibia has expanded upper and lower ends. The upper end forms the tibial plateau consisting of two condyles (with a ridge or intercondylar eminence between them) which articulate with the two condyles of the femur to form the knee joint. The lower end possesses a medial protrusion - the medial malleolus - which can be readily felt at the ankle.

The tibia possesses a anterior tuberosity just below the condyles into which the quadriceps tendon is inserted. Moreover, the shaft of the tibia is the insertion for thigh muscles such as sartorius, gracilis , semimembranosus and semitendinosus, as well as the origin of muscles acting on the foot such as tibialis anterior, tibialis posterior, flexor digitorum longus and soleus and the popliteus muscle which plays a role in knee action.

The tibia not only takes part in the knee and ankle joints, it also has a series of articulations with the fibula by means of the proximal tibiofibular joint (a small synovial joint), the distal tibiofibular joint (a strong fibrous joint or syndesmosis) and the interosseous membrane which runs between the interosseous borders of the tibia and fibula.

tibial collateral ligament

This is a thickening of the capsule of the knee joint on the medial (tibial) side.
It is a broad flat band which arises from the medial epicondyle of the femur. It divides into a deep and superficial part which insert into the medial condyle of the tibia and the upper tibial shaft respectively. Between the two lie the inferior medial genicular vessels and nerve and the hamstring muscle semimembranosus.

Since the knee joint is a hinge joint capable of flexion (backwards) and (extension) forwards movement only, it is appropriate to have collateral ligaments placed at the side where they will lend stability without impeding normal movement.

tibial tuberosity

The raised area on the tibia where the ligamentious patellae (the continuation of the quadriceps tendon) inserts onto the tibia.

tibialis posterior

This muscle is in the posterior compartment of the leg and arises from both the tibia and fibula and the interosseous membrane. Its tendon passes into the foot behind the medial malleolus.
Tibialis posterior is chiefly inserted into the tuberosity of the navicular bone, but it has extensive accessory slips into most other tarsal and metatarsal bones. It is an invertor and a plantar flexor of the foot.

It is supplied by the tibial nerve.

tibiofibular ligament

The tibia and fibula are the two bones of the leg (collectively known as the crural bones). They articulate with one another by three devices:

a proximal tibio-fibular joint which is a tiny synovial joint just below the knee involving the head of the fibula and the lateral condyle of the tibia
the interosseous membrane which runs between the shafts of the two bones for virtually their entire length. This provides extra surface area for muscle origins, helps separate the flexor and extensor compartments, yet has spaces which allow blood vessels to pass forwards into the anterior compartment of the leg (e.g. the anterior tibial artery which passes above the membrane and the perforating branch of the peroneal artery which passes through it).
a fibrous joint (syndesmosis) between the lower ends of the two bones. This involves a strong downwards extension of the interosseous membrane plus anterior and posterior tibiofibular ligaments which bind the lateral malleolus of the fibula to the lower end of the tibial shaft.

transverse

Transverse means from side to side and is another term of position of direction.
Thus :- i)
some of the tarsal bones of the foot form a transverse (i.e. side to side) arch. ii)
the superior genicular arteries run transversely (i.e. horizontally) out from the popliteal artery.
The transverse plane or section is also an anatomical term equivalent to a horizontal or cross section. A transverse section of the thigh can be seen in the tutorial on the thigh.

Trendelenberg gait

A Trendelenberg gait or sign is one in which the patient seems to overbalance or slip to one side when that foot is raised off the ground. Naturally, walking becomes an ungainly exercise. Normally this overbalancing does not occur because the smaller gluteal muscles (gluteus medius and minimus) abduct the trunk to shift its centre of mass over the supporting limb when one foot is off the ground.

A positive Trendelenberg sign may be due to many factors including a congenital dislocation of the hip which has gone unnoticed, an ununited fracture of the upper end of the femur (or conditions such as coxa vara in which the neck of the femur develops at the wrong angle to the shaft) or to paralysis of the smaller gluteal muscles e.g. as a result of polio.

trochlea

Trochlea means a "pulley" and several bones have trochlear surfaces which are concave centrally and convex peripherally. In the lower limb, the upper surface of the talus is described as its trochlear surface. This surface is very complex, being concave transversely, convex front to back, wider at the front than at the back, and having side facets which are differently shaped on the medial and lateral sides. In the upper limb there is a trochlear surface on the lower end of the humerus.

Occasionally the word is used to describe a sudden change in direction of tendons (just as a rope would change direction as it went over a pulley). This is true of the tendons which pass behind the lateral malleolus of the ankle, and the term "peroneal trochlea" is sometimes used to describe this.

tubercule

A tubercle or tuberosity (the two terms are interchangeable) is a small projection from a bone. In general they give attachments to ligaments or muscles.
Examples are :-
the pubic tubercle where the inguinal ligament is attached
the tubercles on the undersurface of the calcaneus which give attachment to the plantar aponeurosis and the long and short plantar ligaments.
the adductor tubercle of the femur to which the tendon of adductor magnus is attached.

vastus intermedius

The vasti are three of the four muscles making up the quadriceps, the large muscle on the front of the thigh which is a powerful extensor of the knee joint. The other muscle is rectus femoris.

The vasti arise from the front and sides of the shaft of the femur, completely encircling it except for the small ridge at the back - the linea aspera. The four heads unite in a common tendon which inserts onto the tibial tuberosity. This tendon contains the patella (knee-cap) which is an example of a sesamoid bone - one which keeps a tendon clear of an articulating area.

Vastus medialis and lateralis can be readily seen and felt, but vastus intermedius (which is placed centrally and deep) is overlain by rectus femoris.

Vastus medialis extends more distally that lateralis and its lowest fibres run almost horizontally into the patella, thus ensuring the stability of this bone against lateral displacement.

All four components of the quadriceps are supplied by the femoral nerve.