The main parts or regions of the lower limb are the gluteal region (consisting of the hip at the side and the buttock at the back), the thigh, the knee, the leg, the ankle and the foot. The term leg properly refers to the part between the knee and the foot, although it is commonly used for the whole lower limb.

The hip bone consists of three bones fused together—the ilium ( 3 ), ischium ( 5 ) and pubis ( 4 )—and forms a pelvic girdle. The two hip bones or girdles unite with each other in front at the pubic symphysis ( p. 18 , B33 ), and at the back they join the sacrum at the sacro-iliac joints ( p. 18 , A7 and C6 ), so forming the b ony pelvis.

The femur ( 11 ) is the bone of the thigh; the tibia ( 18 ) and fibula ( 22 ) are the bones of the leg.

The acetabulum ( 6 ) of the hip bone and the head of the femur ( 7 ) form the hip joint ( p. 18 , A12 and 14 , B18 and 20 , C18 and 20 ).

The condyles of the femur ( 12 and 13 ) and tibia ( 15 and 16 ) together with the patella ( 14 ) form the knee joint.

The head of the fibula ( 20 ) forms a small joint with the tibia, the superior tibiofibular joint. The inferior tibiofibular joint, properly called the tibiofibular syndesmosis (a type of fibrous joint), is a fibrous union between the tibia and fibula just above the ankle joint.

The ankle is the lower part of the leg in the region of the ankle joint ( pp. 54 , 56 , 58 and 60 ).

The lower ends of the tibia ( 18 ) and fibula ( 22 ) articulate with the talus of the foot to form the ankle joint ( p. 54 and 56 ).

The body of a long bone is commonly called the shaft.

The adjective ‘peroneal’ (Greek, see p. 43 ) is now replaced by the Latin ‘fibular’ for various vessels and nerves, e.g., common fibular nerve instead of common peroneal nerve. See notes on New Terminology on p. viii .

For details of limb muscles, nerves and arteries, see the Appendix:

Muscles—pp. 116–121 , including Figs. 2–7 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 .

Nerves—pp. 122–123 , including Figs. 8 and 9 .

Arteries—pp. 136 and 137 , including Figs. 27 and 28 .

The curved fold of the buttock ( 37 ) does not correspond to the straight (but oblique) lower border of gluteus maximus ( 23 ).

The tendons of gastrocnemius ( 31 and 32 ) and soleus ( 33 ) join to form the tendo calcaneus ( 36 ), known commonly as the Achilles’ tendon.

The muscles on the back of the thigh with prominent tendons—semimembranosus ( 27 ), semitendinosus ( 28 ) and biceps femoris (long head, 26 )—are known commonly as the hamstrings (see the note on p. 27 ).

At the ankle the great saphenous vein ( 16 ), the longest vein in the body, passes upwards in front of the medial malleolus ( 10 ). At the knee it lies a hand’s breadth behind the medial border of the patella ( 6 ). It ends by draining into the femoral vein ( p. 24 , 12 and 18 ).

The common fibular ( peroneal ) nerve ( 28 ), the only palpable major nerve of the lower limb, can be felt as it passes downward and forward across the neck of the fibula ( 16 ).

The ureters ( 17 , 25 ) conduct urine from the kidneys to the bladder ( 16 ) where it is stored until sensation of volume dictates expulsion via the single tube of the urethra ( 8 ), the extent of its full length seen here laying within the bisected shaft of the penis ( 7 ).

The single prostate gland ( 14 ) and the paired seminal vesicals ( 15 , left) are accessory secretory sex glands, which produce most of the volume of seminal fluid.

The prostate gland ( 14 ), normally the size of a chestnut, lies just below the bladder ( 16 ) and opens into the urethra ( 8 ); the seminal vesicals ( 15 , left) open into the ductus (vas) deferens ( 18 , 19 ), which conduct sperm from the epididymus of each testis to the urethra ( 8 ) on ejaculation.

The rectum ( 1 ) is the terminal part of the large intestine (colon) where faeces collect prior to defecation via the anus ( 4 ), the opening and closing of which is controlled by the muscles that form the external sphincter ( 3 ). The space between the rectum ( 1 ), prostate gland ( 14 ) and seminal vesicals ( 15 , left) is known as the rectovesical pouch ( 34 ).