Synovial membrane is composed of a form of connective tissue, and secretes a glairy fluid resembling the white of egg, named synovia. It lines joints, which are lubricated by the fluid, and motion is thus facilitated. It also forms sheaths sacro-sciatic ligament for some tendons. Bursae are sacs of synovial membrane interposed between two surfaces which move on each other ; deep-seated bursae are placed between muscle and bone, or tendon and bone ; superficial bursae are between the skin and some firm prominence under it. There are several bursae about the knee joint ; they are also found on the ankle, elbow, and other joints.

Fig. 14.—Ligaments of Pelvis.

1, Ligamentum teres ; 2, capsular ; 3, anterior common ligament ; 4, great

Fig. 15.—Muscles, Front and Side View.

1, Deltoid ; 2, biceps ; 3, triceps ; 4, brachialis anticus ; 5, supinator radii longus ; 6, palmaris longus ; 6', insertion into palmar fascia ; 7, flexor carpi ulnaris ; 8, flexor carpi radialis ; 9, extensor communis digitorum ; 10, extensor carpi radialis longus ; 11, annular ligament ; 12, pectoralis major ; 13, rectus abdominis ; 14, serratus magnus ; 15, gluteus maximus ; 16, tensor fascia femoris ; 17, sartorius ; 18, rectus femoris ; 19, vastus internus ; 20, vastus externus ; 21, adductor longus ; 22, gracilis; 23, biceps; 24, gastrocnemeus ; 25, peroneus tenuis ; 26, extensor digitorum; 27, tendo Achillis; 28, soleus; 29, abductor pollices: 30, tibialis anticus ; 30a, tendon of insertion ; 37, sterno mastoid.

Fig. 16.—Muscles, Back View.

1, Deltoid; 3, triceps; 7, flexor carpi ulnaris ; 10, extensor carpi radialis longus ; 10a, extensor carpi radialis brevis; 15, gluteus maximus ; 15a, gluteus medius; 20, vastus externus; 22, gracilis; 24, gastrocnemeus ; 27, tendo Achillis ; 30, tibialis anticus; 31, trapezius ; 32, infra-spinatus ; 33, latissimus dorsi ; 34, biceps femoris ; 35, semi-tendinosus ; 36, semi-membranosus ; 37, sterno-mastoid.