This document describes the radiological anatomy of the thigh and leg through various imaging modalities like plain radiography, CT, and MRI. It details the compartmental anatomy of the thigh and leg muscles, with the thigh composed of anterior, posterior, and medial compartments and the leg composed of anterior, superficial posterior, deep posterior and lateral compartments. Multiple axial images are provided to illustrate the individual muscles and neurovascular structures within each compartment.

1. Radiological anatomy of the thigh and leg.
Dr/ ABD ALLAH NAZEER. MD.

2. RADIOLOGICAL IMAGING:
Plain Radiography.
Computed Tomography (CT).
Magnetic Resonance Imaging(MRI).

4. Lower limb bones.

15. Thigh muscles: cross sectional anatomy.

22. Mid
Leg
Level.

28. Arrows, Red=semitendinosus, Gold=combined hamstring tendons
Yellow=semimembranosus, Green=biceps femoris - long head
Magenta - semimembranosus and biceps femoris - long head
Text. GM=Gluteus Maximus.

29. Arrows, Red=semitendinosus, Gold=combined hamstring tendons
Yellow=semimembranosus, Green=biceps femoris - long head
Magenta - semimembranosus and biceps femoris - long head
Text. GM=Gluteus Maximus. AM=Adductor Magnus

30. Arrows Red=semitendinosus, Yellow=semimembranosus, Green=biceps femoris -
long head Purple=biceps femoris - short head . Text: AM=Adductor Magnus

31. Arrows, Red=semitendinosus, Yellow=semimembranosus
Green=biceps femoris - long head, Purple=biceps femoris - short head

35. Normal MR Imaging.
Anatomy of the Thigh and Leg
The thigh is best described in terms of compartmental anatomy, and
is composed of anterior, posterior, and medial (adductor)
compartments. In terms of spread of pathologic processes, such as
tumor and infection, other delineated compartments include the skin
and subcutaneous fat, bone bounded by periosteum and cortex, and
parosteal space (between the bone and overlying soft tissues).3 The
thigh extends from the superior margin of the subtrochanteric region
through the distal femoral metadiaphysis. Each compartment is
composed of muscles, neurovascular structures, and intermuscular
fascia. Muscles are of intermediate signal intensity to fat on T1W and
T2W FSE sequences.1 Peripheral nerves are round or oval and have a
fascicular appearance, best depicted on T2W sequences. They are
isointense to muscle on T1W sequences with intermixed increased
signal intensity similar to fat. On T2W sequences, they are isointense to
slightly hyperintense relative to muscles.

36. The leg extends from the proximal tibial metaphysis through the distal
metaphysis. The soft tissues are similarly organized in a compartmental
fashion, and are supported by the tibia and fibula. The lower leg is composed
of 4 compartments: anterior, superficial posterior, deep posterior, and lateral.
The interosseous membrane separates the anterior and deep posterior
compartments. The transverse septum separates the superficial and deep
posterior compartments. The anterior compartment contains the tibialis
anterior, extensor digitorum longus, and extensor hallucis longus muscles, and
the anterior neurovascular bundle, including the anterior tibial artery and
vein, and deep peroneal nerve. The tibialis anterior muscle originates from
the lateral surface of the tibia and neighboring interosseous membrane in the
upper leg, and extends distally over the anterior tibia to insert upon the dorsal
aspect of the first metatarsal. The extensor digitorum longus muscle
originates from the anterior surface of the interosseous membrane and fibula,
courses inferiorly along the anterior tibia, and gives rise to tendons that insert
upon the distal phalanges of the second through fifth toes. The peroneus
tertius muscle, when variably present, is closely associated with the extensor
digitorum longus muscle, coursing in the same synovial sheath; however, its
tendon attaches to the dorsal aspect of the base of the fifth metatarsal.

38. Axial T1W images. Compartmental muscle anatomy. (A) Mid thigh.
Compartmental boundaries are delineated by solid black lines. (B) Mid
leg. Compartmental boundaries are delineated by solid black lines.

39. MRI showing cross sectional view of lower leg musculature along with the
position of the 15 electrodes along the circumference of the lower leg.
Muscle activity levels were measured for FDL (flexor digitorum longus),
SOL (soleus), PR (peroneus group) and AC (anterior compartment group.

40. Axial T1W image. Upper thigh. Compartmental muscle anatomy. Add., Adductor; a., artery;
Glut Max., gluteus maximus; m., muscle; n., nerve; Obt. Ext./Int., obturator
externus/internus; Smb, semimembranosus; t., tendon; Tens., tensor; v., vein; V., vastus.

41. Axial T1W image. Upper thigh. Compartmental muscle anatomy. Add., Adductor; a., artery;
BF LH, biceps femoris long head; Interm., intermedius; Long., longus; m., muscle; n., nerve;
Smb, semimembranosus; Smt, semitendinosus; t., tendon; v., vein; V., vastus.

42. Axial T1W image. Mid thigh. Compartmental muscle anatomy. Add., Adductor; a., artery; BF
LH, biceps femoris long head; Lat. Intmsclr. Sptm., lateral intermuscular septum; m., muscle;
n., nerve; Smb, semimembranosus; Smt, semitendinosus; t., tendon; v., vein; V., vastus.

43. Axial T1W image. Mid thigh. Compartmental muscle anatomy. Add., Adductor; a., artery;
BF LH, biceps femoris long head; Lat. Intmsclr. Sptm., lateral intermuscular septum; m.,
muscle; n., nerve; Smb., semimembranosus; Smt., semitendinosus; v., vein; V., vastus.

44. Axial T1W image. Lower thigh. Compartmental muscle anatomy. Add., Adductor;
a., artery; BF SH, LH, biceps femoris short head, long head; m., muscle; n., nerve;
Smb, semimembranosus; Smt, semitendinosus; v., vein; V., vastus.

45. Axial T1W image. Lower thigh. Compartmental muscle anatomy. BF SH, LH,
biceps femoris short head, long head; Comm. Peron., common peroneal; F,
femur; Fem., femoris; Interm., intermedius; m., muscle; n., nerve; Smb,
semimembranosus; Smt, semitendinosus; t., tendon; V., vastus.

46. Axial T1W image. Upper leg. Compartmental muscle anatomy. a., artery; Ant. Tib., anterior
tibial; Ext. Dig. Long, extensor digitorum longus; Memb., membrane; M.H./L.H. Gastroc.,
gastrocnemius, medial and lateral heads; m., muscle; Peron. Longus, peroneus longus; Peron.,
peroneal; Post. Tib, posterior tibialis; Tib. Ant., tibialis anterior; Tib. Post., tibialis posterior.

47. Axial T1W image. Upper leg. Compartmental muscle anatomy. a., artery; Ant. Tib.,
anterior tibial; DPN, deep peroneal nerve; Ext. Dig. Long., extensor digitorum longus;
Ext. Hal. Long., extensor hallucis longus; Flex. Dig. Long, flexor digitorum longus;
M.H./L.H. Gastroc., gastrocnemius, medial and lateral heads; m., muscle; n., nerve;
Peron. Longus., Brv., peroneus longus, brevis; Peron., peroneal; Post. Tib, posterior
tibialis; Tib. Ant., tibialis anterior; Tib. Post., tibialis posterior; Tib., tibial.

48. Axial T1W image. Mid leg. Compartmental muscle anatomy. a., artery; Ant. Tib.,
anterior tibial; DPN, deep peroneal nerve; EDL, extensor digitorum longus; EHL,
extensor hallucis longus; FDL, flexor digitorum longus; FHL, flexor hallucis longus;
Gastroc. M.H./L.H., gastrocnemius, medial and lateral heads; m., muscle; n.,
nerve; Peron. L., Br., peroneus longus, brevis; Peron., peroneal; Post. tib., posterior
tibialis; Tib. Ant., tibialis anterior; Tib. Post.,tibialis posterior; Tib., tibial.

49. Axial T1W image. Mid leg. Compartmental muscle anatomy. a., artery; Ant. Tib., anterior
tibial; DPN, deep peroneal nerve; EDL, extensor digitorum longus; EHL, extensor hallucis
longus; FDL, flexor digitorum longus; FHL, flexor hallucis longus; M.H. Gastroc.,
gastrocnemius, medial head; m., muscle; n., nerve; Peron. Lg., Brv., peroneus longus,
brevis; Peron., peroneal; Post Tib, posterior tibialis; SPN, superficial peroneal nerve; Tib.
Ant., tibialis anterior; Tib. Post., tibialis posterior; Tib., tibial.

50. Axial T1W image. Lower leg. Compartmental muscle anatomy. a., artery; Ant Tib.,
anterior tibial; DPN, deep peroneal nerve; EDL, extensor digitorum longus; EHL,
extensor hallucis longus; FDL, flexor digitorum longus; FHL, flexor hallucis longus;
Gastroc., gastrocnemius; m., muscle; n., nerve; Peron. L., Br., peroneus longus, brevis;
Peron., peroneal; Post Tib, posterior tibialis; SPN, superficial peroneal nerve; t.,
tendon; Tib. Ant., tibialis anterior; Tib. Post., tibialis posterior; Tib., tibial.

51. Axial T1W image. Lower leg. Compartmental muscle anatomy. a., artery; Ant Tib.,
anterior tibial; DPN, deep peroneal nerve; EDL, extensor digitorum longus; EHL,
extensor hallucis longus; FDL, flexor digitorum longus; FHL, flexor hallucis longus;
Gastroc., gastrocnemius; m., muscle; n., nerve; Peron. Lg., Br., peroneus longus,
brevis; Peron., peroneal; Post Tib, posterior tibialis; SPN, superficial peroneal
nerve; t., tendon; Tib. Ant., tibialis anterior; Tib. Post., tibialis posterior; Tib., tibial.