AP1 M 4.4 joints and ligaments Flashcards
Joints and Ligaments
Bones are joined at the joints, which are classified as fibrous, cartilaginous, and synovial.
Fibrous joints
Joints and Ligaments
Fibrous joints, such as those between the cranial bones, are immovable.
Cartilaginous joints
Joints and Ligaments
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.
synovial joints
Joints and Ligaments
Most joints are freely movable synovial joints (Figure 4.41), in which bones are separated by a joint cavity
Ligaments
synovial joints
Joints and Ligaments
Ligaments, composed of fibrous connective tissue, bind the bones together. The ligaments hold the bones in place as they form a joint capsule.
joint capsule
synovial joints
Joints and Ligaments
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.
synovial fluid
synovial joints
Joints and Ligaments
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.
hinge joints
synovial joints
Joints and Ligaments
The knee and elbow joints are hinge joints, which largely permit movement in one direction only.
Ball-and-socket
synovial joints
Joints and Ligaments
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.
saddle joint
synovial joints
Joints and Ligaments
Another type of joint is a saddle joint, such as the thumb. This saddle joint allows the thumb to freely cross over the palm.
pivot joint
synovial joints
A pivot joint allows for rotational movement. A pivot joints in the cervical spine (C1 and C2) allow rotation of the vertebrae
Shoulder
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.
sternoclavicular ligament
Shoulder
the sternoclavicular ligament joins the sternum with the clavicle.
coracoclavicular ligament
Shoulder
The coracoclavicular ligament joins the coracoid process of the scapula to the clavicle.
coracoacromial ligament
Shoulder
The coracoacromial ligament joins the coracoid process to the acromion of the scapula.
capsular ligament
Shoulder
The capsular ligament (articular capsule) surrounds the head of the humerus and anchors it to the scapula.
coracohumeral ligament
Shoulder
The coracohumeral ligament connects the head of the humerus to the coracoid process of the scapula.
tendons of the rotator cuff
Shoulder
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.
Hip Joint
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.
ilioinguinal ligament
Hip Joint
The ilioinguinal ligament holds the ASIS of the ilium to the pubic bone.
iliofemoral ligament
Hip Joint
The iliofemoral ligament attaches the femur to the ilium.
Knee Joint
In the knee, as in other freely movable joints, the bone ends are covered by cartilage.
uterosacral ligament
Hip Joint
The uterosacral ligament connects the sacrum to each side of the uterus in females (Figure 4.43)
menisci
Knee Joint
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).
bursae
Knee Joint
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.
Spine
There are many spinal ligaments that attach to the vertebrae, which support the spine (Figure 4.46)
Anterior longitudinal ligament
Spine
connecting the anterior vertebral bodies (also visible in Figure 4.43)
Posterior longitudinal ligament
Spine
connecting the posterior the vertebral bodies
Interspinous ligaments
Spine
connects the spinous process of two adjacent vertebrae
Supraspinous ligament
Spine
connects the posterior portion of the spinous processes
intervertebral discs
Spine
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.
herniated disc
Spine
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.
