Anatomy: Joints, Bursae and Synovial Tendon Sheaths

Question 1

Myotomes

C5, 6, 7, C8/T1

L2

L3/4

L4/5

S1/2

S2,3,4

Answer 1

C5 UE abductors

C6 Forearm flexors

C7 forearm extensor, wrist extensor, finger extensor

C8/T1 Intrinsic hand muscles

L2 Thigh Flexion

L3/4 Leg extension (quads)

L4/5 Foot dorsiflexors and toe extensors (anterior tibial)

S1/2 Foot plantar flexors and toe flexors (posterior tibial)

S2,3,4 Anal contraction

Question 2

Dermatomes:

C5 - C8

T4

T10

L1

L5

S1

S2,3,4

Answer 2

C5 shoulder

C6 thumb

C7 middle finger

C8 Little finger

T4 nipple

T10 umbilicus

L1 groin

L5 medial foot

S1 lateral foot

S2,3,4 Anal area

Question 3

bones joined by this type of joint are separated by connective tissue which permits very limited movements in the joint. There are three subtypes.

Answer 3

Synarthrosis (syndesmosis, synchondrosis, synostosis)

Question 4

the opposed bones are simply joined by intervening fibrous tissue, e.g., the interosseous membrane between the ulna and radius, and the almost immovable joints between skull bones (sutures) that disappears with age and the suture closes.

Answer 4

Syndesmosis

Question 5

two bones are separated from each other by cartilage which permits very limited movement. There are three subtypes.

Answer 5

Synchondrosis

(epiphyseal plate, intervertebral discs, pubic symphysis)

Question 6

two bones are joined together by bone. The joint may have existed during development and grew as a fibrous (suture) or cartilaginous joint, but was replaced by bone upon cessation of growth. e.g. frontal bones, epiphyseal plate (line)

Answer 6

Synostosis

Question 7

found between a tooth and the alveolar bone. The fibrous tissue (periodontal ligament) anchors the tooth to the bone.

Answer 7

Gomphosis

Question 8

Moveable joint =

Answer 8

diarthroses/synovial joint

Question 9

Features of diarthroses (5)

Answer 9

An articular cavity or discontinuity between participating bones - synovial space

b. Synovial fluid for joint lubrication
c. A sleeve-like fibrous capsule
d. A synovial membrane or sac lining the capsule
e. Articular surface (smooth surfaces for articulation) usually composed of hyaline cartilage (articular cartilage) that caps the underlying bones

Question 10

fluid (synovial)-filled sacs that separate certain muscles, tendons, skin, and fascia from bones.

Answer 10

bursa

Question 11

Types of synovial joints (important ones for now)

Answer 11

Hinge, ball and socket

Question 12

Bursa vs synovial tendon sheath

Answer 12

Bursae - closed sacs or cavities of synovial membrane usually separating bone from overlying tendon and/or muscle. Synovial fluid found within the sac or cavity. Bursae reduce friction between structures and frequently communicate with the synovial cavity of an adjacent joint.

Synovial tendon sheaths consist of an inner layer that is attached to the tendon and is called the visceral layer, and an outer layer that is called the parietal layer. Synovial fluid found between the layers of the sheath. The sheath reduces friction and allows free movement of the tendons over bone or joints.