AP1 M 4.4 joints and ligaments

Question 1

Joints and Ligaments

Answer 1

Bones are joined at the joints, which are classified as fibrous, cartilaginous, and synovial.

Question 2

Fibrous joints

Joints and Ligaments

Answer 2

Fibrous joints, such as those between the cranial bones, are immovable.

Question 3

Cartilaginous joints

Joints and Ligaments

Answer 3

Cartilaginous joints, such as those between the vertebrae, are slightly movable. The vertebrae are also separated by disks, which increase their flexibility. The pelvic bones are slightly movable because they are anteriorly joined by fibrous cartilage, the pubic symphysis. Due to hormonal changes, this joint becomes more flexible during late pregnancy, allowing the pelvis to expand during childbirth.

Question 4

synovial joints

Joints and Ligaments

Answer 4

Most joints are freely movable synovial joints (Figure 4.41), in which bones are separated by a joint cavity

Question 5

Ligaments

synovial joints

Joints and Ligaments

Answer 5

Ligaments, composed of fibrous connective tissue, bind the bones together. The ligaments hold the bones in place as they form a joint capsule.

Question 6

joint capsule

synovial joints

Joints and Ligaments

Answer 6

The ligaments hold the bones in place as they form a joint capsule. The joint capsule is lined by synovial membrane, which produces synovial fluid, a lubricant for the joint.

Question 7

synovial fluid

synovial joints

Joints and Ligaments

Answer 7

The ligaments hold the bones in place as they form a joint capsule. The joint capsule is lined by synovial membrane, which produces synovial fluid, a lubricant for the joint.

Question 8

hinge joints

synovial joints

Joints and Ligaments

Answer 8

The knee and elbow joints are hinge joints, which largely permit movement in one direction only.

Question 9

Ball-and-socket

synovial joints

Joints and Ligaments

Answer 9

Ball-and-socket joints allow movement in all planes and even a rotational movement. Examples of ball-and-socket joints are the hip (femur into the socket of the pelvis) and the shoulder joint.

Question 10

saddle joint

synovial joints

Joints and Ligaments

Answer 10

Another type of joint is a saddle joint, such as the thumb. This saddle joint allows the thumb to freely cross over the palm.

Question 11

pivot joint

synovial joints

Answer 11

A pivot joint allows for rotational movement. A pivot joints in the cervical spine (C1 and C2) allow rotation of the vertebrae

Question 12

Shoulder

Answer 12

There are many ligaments holding together the ball-and-socket shoulder joint (Figure 4.42). Remember that the clavicle connects to the manubrium of the sternum anteriorly and to the acromion process of the scapula posteriorly (via the acromioclavicular ligament). It is helpful to remember the bone landmarks when naming the ligaments. Often, a ligament is named for the two bone landmarks that it connects.

Question 13

sternoclavicular ligament

Shoulder

Answer 13

the sternoclavicular ligament joins the sternum with the clavicle.

Question 14

coracoclavicular ligament

Shoulder

Answer 14

The coracoclavicular ligament joins the coracoid process of the scapula to the clavicle.

Question 15

coracoacromial ligament

Shoulder

Answer 15

The coracoacromial ligament joins the coracoid process to the acromion of the scapula.

Question 16

capsular ligament

Shoulder

Answer 16

The capsular ligament (articular capsule) surrounds the head of the humerus and anchors it to the scapula.

Question 17

coracohumeral ligament

Shoulder

Answer 17

The coracohumeral ligament connects the head of the humerus to the coracoid process of the scapula.

Question 18

tendons of the rotator cuff

Shoulder

Answer 18

The tendons of the rotator cuff muscles also support the shoulder joint (supraspinatus, infraspinatus, teres minor, subscapularis). The rotator cuff tendons help to limit the movement at the shoulder so that the head of the humerus is stabilized within the joint.

Question 19

Hip Joint

Answer 19

The hip joint is a ball and socket joint, where the head of the femur articulates with the pelvis at the acetabulum (Figure 4.43). There are many ligaments that hold the pelvis together. Posteriorly, the pelvis is held to the sacrum by the iliolumbar ligament, anterior sacroiliac ligament, and posterior sacroiliac ligament.

Question 20

ilioinguinal ligament

Hip Joint

Answer 20

The ilioinguinal ligament holds the ASIS of the ilium to the pubic bone.

Question 21

iliofemoral ligament

Hip Joint

Answer 21

The iliofemoral ligament attaches the femur to the ilium.

Question 22

Knee Joint

Answer 22

In the knee, as in other freely movable joints, the bone ends are covered by cartilage.

Question 22

uterosacral ligament

Hip Joint

Answer 22

The uterosacral ligament connects the sacrum to each side of the uterus in females (Figure 4.43)

Question 23

menisci

Knee Joint

Answer 23

In addition, there are also crescent-shaped pieces of cartilage called menisci, which give added stability for the femur to articulate with the tibia (Figure 4.44). The large patellar ligament is located anteriorly. The medial (tibial) and lateral (fibular) collateral ligaments, also known as the MCL and LCL, stabilize the sides of the knee (Figure 4.44). The interior of the joint contains the anterior cruciate ligament (ACL) and posterior cruciate ligaments (PCL) (Figure 4.45).

Question 24

bursae

Knee Joint

Answer 24

The knee joint also contains thirteen fluid-filled sacs called bursae, which ease friction between tendons, ligaments, and bones. Inflammation of the bursae in a joint is called bursitis.

Question 25

Spine

Answer 25

There are many spinal ligaments that attach to the vertebrae, which support the spine (Figure 4.46)

Question 26

Anterior longitudinal ligament

Spine

Answer 26

connecting the anterior vertebral bodies (also visible in Figure 4.43)

Question 27

Posterior longitudinal ligament

Spine

Answer 27

connecting the posterior the vertebral bodies

Question 28

Interspinous ligaments

Spine

Answer 28

connects the spinous process of two adjacent vertebrae

Question 29

Supraspinous ligament

Spine

Answer 29

connects the posterior portion of the spinous processes

Question 30

intervertebral discs

Spine

Answer 30

There are also intervertebral discs (Figure 4.46) between the vertebrae that act as a kind of padding. They prevent the vertebrae from grinding against one another and absorb shock caused by movements such as running, jumping, and even walking. The presence of the disks allows motion between the vertebrae so that we can bend forward, backward, and from side to side without the vertebrae touching.

Question 31

herniated disc

Spine

Answer 31

Disks tend to become weakened with age and may slip or even rupture. For example, if the posterior longitudinal ligament becomes weakened, the center portion of the disc may bulge into the vertebral foramen, called a herniated disc. Pain results when the damaged disk presses against the spinal cord or spinal nerves. The body may heal itself over time, or the disk can be removed surgically. Surgical procedures can fuse vertebrae together, but this limits the flexibility of the spine permanently. Physical therapy is another option to help strengthen the muscles of the spine. Strengthening exercises help to support the spinal ligaments and restore spinal alignment.